How common is epilepsy?

Epilepsy is one of the most common neurologic diseases in dogs, but no one knows for sure just how common it is. Some studies estimate up to 4% of all dogs are affected. In some breeds, the incidence may be higher and some  may have up to 14% epileptics.

  Beowulf Mastiffs is dedicated to testing and doing our part for cutting edge research.

  I am part of a group working to educate pet owners on the seizure disorder and how they can help in the research currently underway by the University of Missouri.    I am proud to be a conduit for people submitting blood samples in the hopes that through the data gathered one day they will find the DNA marker. This will be the beginning for a percentage of the disorder to be irradicated through testing and careful breeding. 

This page is dedicated to information on Seizure Disorder and where and how to send in blood to help the DNA research.    I ask that eveyone send in blood so that we are part  of the cure.....................................

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SENDING INFORMATION AND SAMPLES

for DNA Research at the University of Missouri

First, THANK YOU for participating in this important research project! The samples you provide will allow

researchers to continue discovering the genes controlling traits in your breed, and dogs in general. As the canine

genome is mapped, breeders will have an unprecedented opportunity to identify and avoid producing disease,

and concentrate on positive advances in their breeding programs.

It is of utmost importance that the information you provide with the samples is as complete and accurate as

possible. The presence of disease, unusual, or “undesirable” characteristics should be revealed to the

researchers wherever it has been identified. Information on specific, individual dogs will not be revealed - results

of the research will identify what markers have been found, but not the names of those who submitted the

samples where a characteristic was located, nor which individual dogs show affected or carrier status for any

given condition. Information provided will be kept strictly confidential. As the research produces results,

participants may request information on the genetic status of their dog(s).

Complete families are critical to locating specific genes and markers. Wherever possible, submit samples

from all siblings, both parents, and all available grandparents.

Begin by gathering the pedigree, litter information, and litter list(s) for each family you plan to submit. You

will need a correctly formatted (sire on top, dam on the bottom), typed or computer-generated pedigree (3- to 5-

generation) of the litter where an affected appeared. If the sample is for a DNA bank, send a pedigree of the

individual dog. The pedigree will connect each sample you submit to the family it comes from, so make copies

for each individual dog who will be sampled. The breeder of the litter, or other person familiar with the litter

should make a “Litter Packet” for each litter - this consists of the Litter Information sheet, Litter List, and the

Pedigree. For the Litter ID code use the kennel name or breeder name, plus the date of birth of the litter, so if

Pat Doe had a litter born May 15, 1992, the code would be “Doe 05-15-92". Dr. Johnson’s staff has a different

system of coding in the lab to anonymously identify samples, but the Litter ID code is a way to tie your

information together and place individuals in the families where they belong as samples are submitted. This ID

code should be on each form sent in. Keep a copy of the packet for your own records, and send a copy to Dr.

Johnson. This family information may be sent with the blood samples, or separately.

Next, begin collecting and submitting samples for DNA extraction. See the Sample Handling sheet for

procedures. The Individual Dog submission form should accompany each sample, along with the marked

Pedigree copy that will tie in with the family information sent. Make copies of the Sample Handling and Individual

Dog forms as needed for all samples to be submitted. If several dogs’ samples are being sent together, number

the forms and samples to be certain there is no confusion (Sample #1, #2, etc). On a spare copy of the pedigree

you may want to mark (for yourself) who is alive and sampled, not sampled, and those no longer living, to keep

track of who you need to get samples from. As stated before, entire families will give the best chance at finding

specific genes - do your best to include all living family members.

Send samples and information to Dr. Johnson’s lab at this address;

Dr. Gary Johnson - (breed of dog) DNA Research

320 Connaway Hall

University of Missouri

Columbia, MO 65211

If you need clarification, or have any questions about any of these procedures, please contact Liz Hansen by

phone (573-884-3712), email (HansenL@missouri.edu), or regular mail (321 Connaway Hall, University of

Missouri, Columbia, MO 65211). Liz is Dr. Johnson’s Coordinator of Veterinary Information, and can help with

any questions you may have.

Once again, thank you for participating in this important research - you are contributing to the betterment of

future generations.
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CANINE DNA RESEARCH Breed _________________________

Individual Dog Information Litter ID code:___________________

Blood – Tissue – other _______________________

Registered Name _________________________________ Call name _________________

AKC# ________________ Birth Date _____________ Male / Female - - Intact / Neutered

Sample Submission Date: ____________________ Color __________________________

Sample submitted for which research project? _____________________________________________

Owner: name ___________________________ Alternate _______________________

address _________________________ Contact ________________________

__________________________ ________________________

phone (day) ______________________ ________________________

phone (eve) ______________________ ________________________

fax __________________________ ________________________

e-mail ___________________________ ________________________

Does this dog exhibit any of the following conditions? (Please attach history for any Yes answer)

Y - N Allergies Y - N Digestive difficulties

Y - N Arthritis Y - N Heart Problems

Y - N Autoimmune Disorders Y - N Hernia (where? ____________________ )

Y - N Bite or Tooth Abnormalities Y - N Reproductive Problems

Y - N Cancer / Tumors Y - N Seizures

Y - N Cataracts / Vision Problems Y - N Skin / Coat Problems

Y - N Deafness / Hearing Impaired Y - N Skeletal Abnormalities (Hip Dysplasia, etc.)

other (please list): Y - N Temperament Problems (shy, aggressive, etc.)

Testing done on this dog:

OFA/PennHip Y - N age at test: __________ result:________ #__________

CERF Y - N age last tested:_______ result:________ #__________

Thyroid Y - N age last tested:_______ result:________

other (please list):

Other Comments / Questions / Concerns?

Please circle your response to the following;

- I am / am not willing to provide additional blood samples if needed for research.

- I will / will not consider donation of a tissue sample (spleen, kidney, or liver) upon the death of this dog, and will

discuss this decision with my veterinarian so that a notation is placed in my file.

I submit this sample and pedigree for the purpose of DNA research; I understand that the identity of dogs and

owners participating in the research will not be revealed; and I have supplied complete and accurate information,

to the best of my knowledge.

Signed: ______________________________________ date __________________

____________________________________________________________________________________________________

SAMPLE HANDLING

For Canine DNA Research at the University of Missouri

Blood Sample - The ideal sample for DNA extraction is 5-10cc’s of whole blood, in

purple-topped (EDTA) tubes. For very small dogs or puppies, 3ccs should be sufficient. The

blood sample needs only to be put in the tubes and rocked gently a few times to distribute the

anticoagulant - do not spin, extract serum, or anything further. Refrigerate if the sample is being

held for any time before shipping.

Frozen Semen - If there is frozen semen stored from sires or affected dogs, DNA can be

extracted from it. Please send 2 straws. They do not need to be shipped frozen, but do pack

them in a crush-proof container.

Tissue Sample - Tissue removed as a result of surgery, or an organ sample upon death

of the dog will provide a large amount of DNA for research. Please discuss this with your vet

ahead of time if you intend to do this. (If the dog is to be euthanized, have a blood sample pulled

first, if possible, and send both samples.) First choice is spleen, second choice kidney, and third

choice is liver (a piece about the size of your thumb is all that is needed - not the entire organ).

One tissue sample is sufficient. Have the organ removed as soon as possible following death,

place into a labeled freezer bag, put that into a second bag, freeze, and ship.

Label sample with the following;

call name - owner’s last name

(If samples from several dogs are sent together, number samples and forms)

An Individual Dog Information form should be completed, and a pedigree copy must

be included with the sample to tie it in with the correct family. If the dog is not affected but is a

relative of an affected, please indicate the relationship.

Shipping - Ideally the sample should be shipped immediately (with a tissue sample

make certain it is completely frozen first). If samples are held for a day or over a weekend, blood

must be refrigerated, and tissue samples must be kept frozen. Ship via overnight delivery (US

Mail, UPS, or FedEx). Do not send on a Friday - there will not be anyone to accept the delivery

on a weekend, and the sample could be unusable by Monday. Pack in a small insulated

container (most vets have these for shipping samples to labs), with one or more cool packs - it is

important that blood samples be kept cool but not frozen, and tissue samples be kept as frozen

as possible.

The delivery address is;

Dr. Gary Johnson - (Breed of Dog) DNA Research

320 Connaway Hall

University of Missouri

Columbia, MO 65211

If you need clarification, or have any questions about any of these procedures, please contact

Liz Hansen by phone (573-884-3712), email (HansenL@missouri.edu), or regular mail (321

Connaway Hall, University of Missouri, Columbia, MO 65211). Liz is Dr. Johnson’s Project &

Information Coordinator, and can help with any questions you may have.

Thank you for your cooperation and participation!

________________________________________________________________________

All information is as written with no editing on the part of Beowulf Mastiffs. 

 by Marion Mitchell

Seizures are the result of muscle responses to an abnormal nerve-signal burst from the brain. They are a symptom of an underlying neurological dysfunction. Toxic substances, metabolic or electrolyte abnormalities and/or imbalances cause an uncoordinated firing of neurons in the cerebrum of the brain, creating seizures from mild "petit mal " to severe "grand mal".

There are four basic stages to a seizure:

·         The Prodome: may precede the seizure by hours or days. It is characterized by changes in mood or behavior.

·         The Aura: signals the start of a seizure. Nervousness, whining, trembling, salivation, affection, wandering, restlessness, hiding and apprehension are all signals.

·         The Ictus, the actual seizure:. A period of intense physical activity usually lasting 45 seconds to 3 minutes. The dog may lose consciousness and fall to the ground. There may be teeth gnashing, frantic thrashing of limbs, excessive drooling, vocalizing, paddling of feet, uncontrollable urination and defecation.

·         The Post Ictus/Ictal: after the seizure, the dog may pace endlessly, appear blind and deaf and eat or drink excessively.

The Cause: anything that disrupts normal brain circuitry:

·         Idiopathic Epilepsy: meaning no known cause and possibly inherited. This is also referred to as Primary Epilepsy. Check history of pedigree and make sure your veterinarian has looked for possible underlying factors.

·         Seizures caused by underlying factors are referred to as Secondary Epilepsy. The following tests are advised before a diagnosis of idiopathic/inherited epilepsy is made.

·         Glucose tolerance test, to check for hypoglycemia.

·         Thyroid panel, 6 tests, to check for low thyroid function/hypothyroidism.

·         EEG, to see if there are findings suggestive of a lesion (an abnormal EEG is standard with epilepsy, but a vet or a physician will also be able to tell if there is a lesion.

·         Cerebrospinal fluid analysis, to look for encephalitis, distemper and other infection.

·         Blood test to check for lead poisoning;

·         CT scan or MRI, again to look for a brain lesion

Types of Seizures:

·         Mild: (Petit Mal) this can be a simple as momentarily staring into space, or upward eye movement.

·         Moderate: (Grand Mal) the dog falls down, loses consciousness and extends its limbs rigidly. Paddling of limbs, salivation followed by possible loss of control of bladder and bowels and vocalization (blood curdling scream) may follow. This may occur for 1-3 minutes and is most often followed by a period of restlessness, pacing, bumping into objects and loss of balance. (Post Ictal period) The dog is conscious but may appear deaf, blind and disoriented. Great care must be taken to prevent the dog from injuring itself at this time. The use of Bachs Flower Essence Rescue Remedy (found in any Health Food Store) has been found to be extremely useful when given at this time. Simply put a 4 drops of the Essence into the dog's mouth after the seizure has finished. In most dogs the post ictal time will be cut considerably.

·         Status Epilepticus: Status can occur as one continuous seizure lasting 10 minutes or more, or a series of multiple seizures in a short time with no period of normal consciousness, this may be life threatening.

·         Cluster Seizures: Multiple seizures within a 24-hour period time, may also be life threatening. It is often difficult to distinguish between the two types and veterinarian assistance is imperative. Rectal Valium is extremely useful in breaking cluster seizures.

Medications

·         Phenobarbital

·         Potassium Bromide

·         Phenobarbital & Potassium Bromide

·         Primidone (Mysoline)

·         Valium (Diazepam)

·         Dilantin

·         Gabapentin

Most dogs can be controlled by using Phenobarbital and/or Phenobarbital and Potassium Bromide. Potassium Bromide is used alone if the dog's liver has become damaged by Phenobarbital. IMPORTANT: Dogs on Phenobarbital need to have their liver enzymes tested every few months using the following tests ALT (SGPT), AST (SGOT), GGT ALKALINE PHOSPHATASE. Both drugs are available by prescription in pill capsule or liquid form. Primidone, once commonly used, metabolizes to Phenobarbital in the liver. With prolonged treatment it can also cause liver damage. Valium, injectable, or rectal and oral is a good choice to halt a cluster seizure or interrupt status epilepticus. Dilantin, is currently not recommended for use. Gabapentin is a newer drug being used for humans. It does offer exciting possibilities for dogs as it is only partially metabolized by the liver. At present it is very costly to use around $250.00 a month, however with the few dogs that have used it, the results have been very positive.

Low Thyroid Function - Hypothyroidism & Seizures
Seizures are one of the symptoms of hypothyroidism along with chronic skin disease, hair loss, weight gain, lethargy and slow metabolism, behavioral changes (aggression, hyperactivity, poor concentration, passivity, phobias, anxiety.) A recent study of 634 dogs showed that 77% of the dogs who were hypothyroid also had seizures. Dr William Thomas, a board certified neurologist, had this to say about thyroid testing:

"Thyroid testing should be considered in any dog with recurrent seizures. Such testing is relatively inexpensive and carries little risk to the patient. Any dog that is diagnosed with hypothyroidism by appropriate testing should be treated with thyroid replacement therapy. This applies to all dogs, whether or not they suffer seizures. If the seizures improve with thyroid therapy, then great! If not, the patient should still be treated because hypothyroidism can cause many other health problems. Appropriate use of thyroid medication is one of the safest and effective treatments available in veterinary medicine. " WB Thomas DVM, Dipl.ACVIM (Neurology) University of Tennessee, Knoxville, TN

It is a good idea to have a full thyroid panel of 6 different tests to determine if your dog is hypothyroid. The tests you want to have done are T3, T4, free T3, free T4, T3 and T4 Autoantibodies. Two or three thyroid tests (e.g.T4, free T4 or TSH), are not conclusive for hypothyroidism. You need all 6 tests listed. Proper thyroid medication may reduce or eliminate seizures.

Diet:
Diet plays an important role in the management of Canine Epilepsy. It is very important to feed a kibble that is preservative free. Preservatives such as Ethoxyquin and BHT, BHA should be avoided as they can cause seizures. Many "Supermarket " foods are loaded with chemical dyes and preservatives, buy a high quality kibble made from "human grade" ingredients or better yet cook for your dog or feed a raw ( BARF) diet. Many recipes can be found in Dr Pitcairn's Complete Guide to Natural Health for Dogs and Cats. Two helpful books on a raw diet are Dr Ian Billinghurst's "The BARF Diet" & Susan Johnson's "Switching to Raw". There is also a good article on the web site called " The Role of a Healthy Diet in the Management of Canine Epilepsy" PLEASE NOTE: If your dog is taking Potassium Bromide be very careful when you switch dog foods. Try to make sure the chloride content is the same as the previous food. Change over very slowly, whether it is the same chloride content or different, so that the absorption rate of the KBr remains constant.

There is some growing evidence that dogs suffering from seizure disorders have responded in some cases with a complete irradication of the seizures by consuming a totally raw diet.   In others it has reduced the incident and allowed owners to reduce the amount of medication needed to control the occurances.

There has been success with giving dogs with seizures one 325mg appx asprin daily.  Ascription is an asprin that is coated with Maalox and is easy on the stomach.

Also Taurine is a wondeful supplement

2-   500 mg tablets of Taurine  2X a day
It has been used with some dogs to replace Potasium Bromide
the dogs taking Taurine instead of the Potasium Bromide are typically

Brighter eyes, less grogginess
More energy
Happier



Vitamins and Supplements:

 

 

In this day and age, it would be rare to see vitamin deficiency in our dogs. Individuals feeding a good quality commercial dog food to a healthy animal probably do not need to add vitamins to their dog's diet. However, many owners of epileptic dogs have discovered that vitamins may help. The following are vitamins often used and what role they play in our dogs health:

Vitamin B Complex - Important to the nerve tissue and cell functions throughout the body. The body does not store B vitamins and they are required daily. Excess is excreted by the kidneys so B vitamins are relatively nontoxic.

Vitamin C - (also known as Ascorbic Acid) - Assists in detoxification and is an antioxidant.

Vitamin E - Functions in the body as an antioxidant and is required for maintenance of cell membrane structure

Zinc (taken in part from a post to epil-k9 by Maureen Setter with approval)

Zinc deficiency might cause seizures in a dog. Dr. Dodman, from Tufts University, in his book entitled "The Dog Who Loved Too Much" discusses a compulsive/obsessive dog in chapter 6 that fits the previous statement. In 1990 an article by M. Fukahori and M. Itoh entitled "Effects of dietary zinc status on seizure susceptibility and hippocampal zinc content in the El (epilepsy) mouse" further noted that zinc deficiency caused convulsive seizures in the mouse. Zinc has also been recommended for people with epilepsy.

 

SUSAN WYNN, DVM says: "Dogs evolved from Canis lupis - the wolf. Wolves eat caribou or the like, but if they are forced, they will eat smaller game (rarely). They have been observed to graze on grass, eat berries, etc, but only when they need to. This is our lesson in canine nutrition - they are omnivores who do well with fresh meat, the vegetation they get in a caribou stomach (which is mostly green, unless the beast is eating from baited fields), and a smattering of other stuff if they are hungry.

Food companies have, in the main, revolutionized pet nutrition by eliminating major nutritional deficiencies and providing optimal nutrition for the average pet. Our concern, however, is not for the average pet. It is for the sick pet. If epileptic animals have a disease with even a small nutritional component, wouldn't we want to deal with it? Is your epileptic animal showing other signs of allergies? If s/he is chewing feet, scratching ears, having anal gland problems, vomiting bile seasonally, etc., etc., one may want to consider dietary changes, including hypoallergenic diets, if appropriate.

I think that the main benefit of feeding real food meat, - (raw or cooked, raw or steamed veggies, cooked grains) - is to provide stuff that is killed in the kibble extrusion process. If you or I were to eat a diet of Wheaties, yogurt, VegAll, and Spam day after day for 20 years, would this be enough? I don't know, but it makes me uncomfortable. I think our pets need a more varied diet and a fresher one than we can give them with commercial kibble. So I do recommend supplementing pet food with lean meat and vegetables."

Environment:
It is important to keep your epileptic dog as free from chemical pollutants as possible. Think about the environment your dog is living in. Do you use chemical sprays on your lawn? Dogs will sometimes seize only when the lawn is sprayed for weeds. How about the cleaner you use for the floor? Some dogs have been known to seize after the floor has been washed with a pine scented cleaner. Flea and tick medications can also cause seizures. It is recommended that epi dogs be given Interceptor as a monthly heartworm preventative and Frontline used for fleas. Avoid products with Ivermectin it has been known to cause seizures in some breeds. There are many things that can lower a dog's seizure threshold. Keep a diary of your dog's seizures. Note down anything you have done or that the dog could have come in contact with that day which could have contributed to seizure. It is also a known phenomenon that some dogs may seizure around the full moon.

Vaccinations :
Vaccinations can lower a dog's seizure threshold and trigger a seizure. If you feel that this is the case for your dog, ask the vet to split the shots, give them separately at weekly or two weekly intervals and ask for the Rabies shot to be given 2 weeks after that. Ask your vet if he/she knows about the new 3-year protocol now being used by many vets and veterinary schools.

Marion is a co-owner of Epil-K9 and Director of the Dalmatian Club of America's Study Group on Seizure Disorders
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What Anesthetics Should be Used or Avoided

There are several anesthetic protocols that are safe for dogs with epilepsy. In general, phenothiazine tranquilizers (such as acepromazine) and ketamine should be avoided.

Many veterinarians have certain protocols that they are comfortable and familiar with. For example, we often use isoflurane (an inhalant anesthetic), propofol (an injectable anesthetic) and/or thiopental (a barbiturate anesthetic) in dogs with epilepsy. The choice often seems to depend on which anesthesiologist is on duty. Although clients should certainly feel free to ask about the particular anesthetic protocol that the veterinarian is going to use, I would be careful about "insisting" on a specific protocol. The least safe anesthetic is the one the veterinarian is not familiar with.

Finally, the most important aspect of anesthesia is not the particular drug(s) used but rather adequate monitoring during and after the procedure.

Spaying/Neutering and Epilepsy

There is a fair amount of experimental data on the effect of sex steroid hormones on brain cell excitability and seizures. Estrogen, one of the female sex hormones, is consistently found to increase susceptibility to seizures. In contrast, androgens (male sex hormones) have little effect.

While there may be other reasons to neuter or not neuter a male dog with epilepsy, the hormonal changes will probably have little effect on the seizures.

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Safely Cooling a 'Hot' Dog

Prolonged seizure activity can indeed cause dangerous elevations in body temperature (hyperthermia). In dogs, body temperatures greater than 107 F can be dangerous and requires prompt veterinary attention. Treatment may include cooling, intravenous fluids, oxygen, and close monitoring. Obviously dogs in this situation should be evaluated by a veterinarian to treat hyperthermia as well as to stop the seizures.

Cooling the body surface with ice or ice water is not usually recommended as this can cause constriction of blood vessels in the skin, which impedes cooling. Also, it may induce shivering, which tends to increase body temperature. A more effective technique is to wet the body surface with cool, not cold, water (eg. tap water) and use a fan. Any active cooling procedure such as this requires close monitoring of body temperature to avoid excessive cooling.

Actively cooling a dog is not a risk-free procedure and should be done only on the direct advice of a veterinarian.

What are the Signs of Liver Failure?

Signs of liver failure are often vague, and can include lethargy, weight loss, increased urination, vomiting, and diarrhea. More specific signs include icterus (yellow gums and eyes), distended belly (due to fluid), and neurological signs.

Since many of these signs may not be apparent until late in the course of liver failure, periodic laboratory monitoring of liver function is often helpful in detecting liver failure while it is still potentially reversible. Serum bile acids are probably the best laboratory test to screen for liver failure. Liver enzymes (e.g. ALT, alkaline phosphatase) are often elevated in dogs taking phenobarbital are not necessarily indicative or predictive for significant liver disease.

Defining Status

There are several definitions of status epilepticus that have been used, so I hope the following can help clear up any confusion.

The literal definition of status epilepticus is a state of continuous seizures (its Latin). From a practical standpoint this is a useless definition.

In 1981, the International League Against Epilepsy defined status epilepticus as a seizure that "persists for a sufficient length of time or is repeated frequently enough that recovery between attacks does not occur".

The lack of a specific duration of the seizures made this definition difficult to use. So, in 1993, the Epilepsy Foundation of America's Working Group on Status epilepticus defined status as more than 30 minutes of (1) continuous seizure activity or (2) two or more sequential seizures without full recovery of consciousness between seizures. The 30 minute duration was chosen because animal researchrevealed that deleterious effects in the brain began to occur soon after this time.

But, clinicians recognized the need to institute treatment well before 30 minutes. ("How long has this patient been seizing? Only 20 minutes? Well, I'm going to get a cup of coffee and be back in 10 minutes.") So, with this consideration and the recognition that isolated seizures rarely last more than 2-3 minutes, several authors have recently recommended the following practical definition:

Status epilepticus -- Either a continuous seizure lasting at least 5 minutes or two or more discrete seizures between which there is incomplete recovery of consciousness.

In my opinion, this is a practical, useful definition and the one I use. Realize that there are as many types of status epilepticus as there are types of seizures, including generalized tonic-clonic (the most common and most dangerous) and a variety of focal seizures.

Multiple seizures within a short period of time with full recovery of consciousness between the seizures does not meet the strict definition of status epilepticus. This situation (called cluster, serial, or acute repetitive seizures) nevertheless represents a serious condition that may evolve into status and should be treated vigorously.

Anti-epileptic Drug Dosing

The dosing interval (time between doses) is chosen to minimize the fluctuation in blood levels (and brain levels) that occur between doses. The greater the fluctuation the more likely the dog is to have side effects at the maximum (peak) level or seizures at the minimum (trough) level.

How much the blood levels vary depends on two things: (1) how quickly the drug ieliminated--the slower the better, and (2) the dosing interval--the more frequent the doses the better. However, increasing the number of doses per day has the disadvantage of decreasing compliance. In my experience, most clients will comply with twice daily medication. Some can not or will not give medication three times a day and many can not give medication four times a day, at least on a long term basis. So, the goal is to strike a balance between fluctuations in blood levels and the problems with frequent dosing.

The ideal dose interval varies for each drug. For example, bromide is eliminated *very* slowly (half-life of about 3 weeks). So even with a dosing interval of 24 hours, the blood level will fluctuate very little. The only reason to give bromide more frequently than every 24 hours is in those dogs that have nausea or vomiting with each dose. This can often be prevented with smaller, more frequent doses.

Phenobarbital is different. The half-life when starting therapy is usually about 50 hours, so a dosing interval of 12 hours is usually sufficient. But, with long-term therapy, the half-life can decrease to 24 hours, or less. In these cases, a dosing interval of 8 hours is sometimes better.

By measuring a peak and tough blood level, you can estimate the half-life. This is sometimes helpful when deciding whether to decrease the dose interval. This is usually done for those dogs that consistently tend to seizure a short time before the next dose is due.

What are adverse reactions to AEDs

The terms "toxic" and "poisoned" may mean different things to different people, so it may help to discuss some general points:

Any treatment carries the risk of undesirable effects or adverse reactions. There are two general types of adverse reactions that can occur with anti-seizure drugs.

1. Dose-dependent side effects are the most common. These are often exaggerated, but otherwise normal, pharmacologic effects of the drug and are more likely with higher blood levels. Examples of dose-dependent side effects are sedation, drowsiness, and weakness with phenobarbital or bromide. Dose-dependent side effects are generally predictable and can often be managed by lowering the dose. In the case of bromide, these side effects are completely reversible.

2. Another type of adverse drug reaction is called an idiosyncratic reaction. These reactions are unpredictable and not dependent on dose or blood level. An idiosyncratic reaction is due to a peculiar, often genetically determined, response of an individual patient to a certain drug. Idiosyncratic reactions to anti-seizure drugs are rare in dogs. Examples include bone marrow suppression and skin rashes. A severe idiosyncratic reaction usually means the offending drug must be discontinued.

Memory, Seizures & AEDs

Impairment of short-term memory and attention is a substantial problem in people, especially children, receiving antiseizure drugs, including phenobarbital. Although these effects are dose related, impairment has been recognized at therapeutic blood concentrations.

Epilepsy itself can also impair cognitive function in people. Early age of onset, frequency of seizures, and episodes of status epilepticus (prolonged seizures) are all risk factors for mental deterioration.

Of course there are problems extrapolating theses findings to animals (to my knowledge, there is no comparable studies in epileptic dogs), but it would not be unreasonable to assume similar effects in dogs.

A good review is: Trimble MR. Anticonvulsant drugs and cognitive function: a review of the literature. Epilepsia 1987;28 Suppl 3:S37-45.

Types of Therapy: Proven & Unproven

Putting aside arbitrary classifications such as allopathic vs. holistic vs. natural, etc., there are really only three types of therapy.

(1) Proven therapy--that is, treatment in which the relative safety and efficacy have been shown in controlled clinical trials published in scientific journals. (The term "relative" is important as no treatment is 100% safe and 100% effective).

(2) Unproven therapy. Efficacy and safety have not been shown in controlled clinical trials.

(3) Unproven therapy which is offered as proven therapy. In less kind circles, this is called fraud.

Why insist on controlled clinical trials? Because anecdotal evidence is notoriously unreliable in assessing medical therapy. My 50 year old next door neighbor has smoked 2 packs of cigarettes a day since he was 15 years old. He feels fine. Based on this anecdote, do we conclude that smoking is safe? Of course not, because there is overwhelming scientific evidence to the contrary. However, with conditions that are less understood (e.g. epilepsy) we are more tempted to accept anecdotal evidence as valid. In my opinion, proven therapy, if available, is the initial treatment of choice. If proven therapy is not available (which is OFTEN the case in veterinary medicine) or does not work for the individual patient (also more common then we would like, especially with epilepsy) then I see nothing wrong with trying unproven therapy--as long as everyone is well informed. What I am very much against, is anyone offering an unproven therapy and claiming it is effective, when in reality nobody knows.

Lead Poisoning and Seizures

Poisoning with many substances can cause a sudden onset of seizures. In most cases, the seizures stop when the patient recovers from the poisoning. Thus, poisoning is not usually a major diagnostic consideration in dogs with chronic, recurrent seizures. However, lead
poisoning (plumbism) is an exception because many dogs with this disorder are being exposed to lead on a continual basis, resulting in long term signs. In some geographic regions, lead poisoning is an important diagnostic consideration in any dog with seizures.

Although any age dog can be affected, young dogs are predisposed. In most cases of lead poisoning in dogs, the owners are not aware the dog was being exposed to lead. The most common source is tiny particles or dust from degenerating paint. In the US, the amount of lead in household paint was reduced in 1950 and further reduced in 1978, but many older homes still contain lead-based paint. Other sources include linoleum, plumbing solder, caulking, drapery weights, fishing sinkers, golf balls, and many others.

Common signs include vomiting, poor appetite, diarrhea, lethargy, and abnormal behavior such as hysteria. Seizures are seen in about 40% of affected dogs and may be the only sign. Definitive diagnosis is based measuring the amount of lead in tissue, usually blood (blood lead level).

Several drugs are used to treat lead poisoning, including calcium disodium edetate (CaEDTA), penicillamine, and Succimer (DMSA). These drugs act as lead chelators, forming water-soluble chelates with lead, which increases the excretion of lead in the urine. Several course of treatment may be necessary, depending on results of blood lead levels.

Surgery may be necessary to remove any swallowed lead objects. It is also important to identify and remove the source of lead exposure. This is especially important because people, especially children, may be exposed to the same sources as the affected dog.

Although severe cases can be fatal, treatment is usually successful.

Morgan RV, et al. Clinical and laboratory findings in small companion animals with lead poisoning: 347 cases (1977-1986). Journal of the American Veterinary Medical Association 199:93-97,1991.

Morgan RV , et al. Demographic data and treatment of small companion animals with lead poisoning: 347 cases (1977-1986). Journal of the American Veterinary Medical Association 199:998-102,1991.

Flashing lights & Seizures

Stimulus-sensitive seizures refers to seizures that are elicited by specific stimuli or events. These are also called reflex seizures. In people with stimulus-sensitive seizures, the most common triggering stimulus is light, especially the flickering light of television or video display screens. These stimuli do not cause seizures in all people, or even all people with epilepsy, only in a subgroup of epileptic patients.

In dogs, stimulus-sensitive seizures triggered by certain events, such as engine noise (lawn mower or motorcycle), car rides, and veterinary offices, have been recognized. It is important to realize that in this type of epilepsy the time from the stimulus to the seizure is short (seconds), the stimulus is specific, and seizures do not usually occur in the absence of the stimulus.

 

Tick-borne disease

There are several tick-borne diseases that can cause encephalitis (inflammation of the brain) or meningitis (inflammation of the membrane that covers the brain and spinal cord) in dogs. This may cause seizures or other neurological problems. Examples of these diseases include ehrlichiosis, Rocky Mountain spotted fever, and babesiosis.

These diseases usually cause systemic illness (fever, lethargy, etc.) in addition to seizures, so they are not usually confused with idiopathic epilepsy. However, ehrlichiosis can occasionally cause seizures with no other problems.

Heartworm treatment & Heartworm preventive

Treatment of heartworm infection entails medication to kill the adult worms in the heart and lung vessels followed 3 to 6 weeks later by medication to kill the immature heartworms (microfilaria) circulating in the blood.

There are two drugs used to treat the adult worms:
1. Thiacetarsamide has been used for over 25 years. It is given intravenously, twice a day, for 2 days. Vomiting, lethargy, and decreased appetite occur in about 15% of patients. About 5% develop liver or kidney disease, which usually necessitates stopping treatment. Effectiveness of treatment varies between dogs. Immature worms, especially females, are more resistant to treatment.

2. Melarsamine has been approved within the last few years and has been shown in clinical trials to be more effective and much safer than thiacetarsamide. It is given intramuscularly once a day for 2 days. Although this drug is much less toxic to the patient, anytime you kill adult worms, there is a risk of blood clots as the worms die.

3. Ivermectin (at much higher dose than used in monthly prevention) is the most effective drug for treating the baby worms (microfilaria). Vomiting and lethargy occur in about 5% of cases, but is more common in dogs with high numbers of microfilaria. This is not a direct effect of the drug, but rather a reaction to the death of the microfilaria. In severe cases, this reaction progresses to shock, which is potentially fatal if not treated appropriately.

We are fortunate that there are several safe and effective options available for heartworm prevention. Until there are controlled studies evaluating these various preventatives in dogs with epilepsy, we will continue to hear conflicting advice as to which is the best drug to use in our dogs. However, considering the risk associated in treating heartworm infection in any dog, I think it is safe to say that ALL dogs in heartworm endemic areas should be on some type of heartworm preventative program. Heartworms are one of the diseases where the adage "an ounce of prevention is worth a pound of cure" is quite appropriate, ehrlichiosis can occasionally cause seizures with no other problems.

Seizures and distemper

Infection with canine distemper virus often causes encephalitis--inflammation of the brain. (I have 3 patients in the hospital with this right now). Affected dogs can suffer seizures and
other neurological dysfunction. Neurological abnormalities can occur during or after the systemic illness, which is manifested as vomiting, diarrhea, coughing, etc. In other cases, particularly adult dogs, signs of systemic illness are mild or absent, and the neurological problems are the only manifestation of infection.

Treatment consists of supportive care, anti-seizure drugs to control seizures, and sometimes corticosteroids to decrease brain inflammation. Unfortunately, there is no specific anti-viral treatment. Some dogs are able to eventually recover from the infection.

Thomas WB et al. A retrospective evaluation of 38 cases of canine distemper encephalomyelitis. Jour Amer Anim Hosp 29:23-28,1993.

Tipold A. et al. Neurological manifestations of canine distemper virus infection. Jour Small Animal Practice 33:466-470,1992.

Seizures, Narcolepsy & REM

Narcolepsy is a disorder characterized by cataplexy, excessive sleepiness, and an abnormality in the phase of sleep called rapid eye movement (REM) sleep. In dogs, the most obvious sign is recurring cataleptic attacks. During a cataplectic attack, the dog suddenly collapses with paralysis of all muscles except for muscles that move the eyes and muscles responsible for breathing. The attacks are often provoked by excitement, such as feeding or play. They usually last only a few seconds, although severe episodes can last for several minutes. During a cataplectic attack, the dog is usually conscious but unable to move. During a cataplectic attack the dog may enter REM sleep. Calling to the dog or touching the dog may terminate an attack.

The association with excitement, lack of unconsciousness, lack of violent muscle movements, and rapid recovery are features of narcolepsy that help in the differentiation from epileptic seizures. Narcolepsy is a sleep disorder, not a seizure disorder. There is strong evidence that it is inherited in Doberman pinschers, Labrador retrievers, and Miniature Poodles. It occurs in other breeds of dogs as well. Narcolepsy can often be treated successfully with certain drugs, including methylphenidate and protriptyline. Anti-seizure drugs are not effective.

REM Behavior Disorder

Some dogs have abnormally excessive, even violent movements during sleep. They may lift their head and propel themselves across the floor with running movements. They may attack inanimate objects. In contrast to a seizure, dogs can be aroused during these episodes and awake with no confusion or incoordination. This syndrome may be similar to a sleep disorder in people called REM behavior disorder. The drug clonazepam is often successful in affected dogs and people.

Thyroid & Phenobarbital

Question: "I'm a little confused about this. Should those dogs on PB who test normal on TSH and depressed in baseline thyroxine be supplemented with the synthetic hormone? Or is he saying that they SHOULDN'T be supplemented unless they have an abnormal TSH test and have true hypothyroidism?".

Yes, the whole situation is confusing. Briefly, in people and rats, phenobarbital can cause a decrease in total T4. These patients (and rats) are NOT hypothyroid and do not need to be treated. We think the same thing happens in dogs, although nobody has actually done such a study.

Measurement of only a total T4 level is insufficient in the diagnosis of hypothyroidism in a dog taking phenobarbital. (In fact, it is insufficient in many other conditions as well). A normal T4 rules out hypothyroidism but a low value must be further evaluated by another test. Many people think that the next test to do is to measure TSH levels. In "real" hypothyroidism, TSH is usually increased, while the effects of phenobarbital result in normal or slightly low TSH levels (we think).

Realize a TSH level is not the same as a TSH-response test, where the thyroid hormones are measured before and after giving the dog TSH. TSH-response tests are not often done anymore because TSH has become difficult to obtain.

These comments are necessarily an oversimplification. Interpretation of such results can be quite complicated in individual patients, and can only be done in the context of all of the other clinical information.
______________________________________________________________________

Why Does My Dog Have Seizures
A dog may seizure for any number of reasons. Just because a dog has a seizure does not mean that the dog has epilepsy. Just because I have a running nose does not mean that I have a cold. I could have a reaction to someone's perfume, I could have a sinus infection, I could have allergies, I could have ... . There are many tests to determine what exactly I have that is causing my running nose. However, there is no test in the medical industry for the existence of epilepsy (primary, inherited or idiopathic). To determine whether a dog has epilepsy or something else, a veterinarian or neurologist arrives at their diagnosis by a process of elimination. They determine what is not and then, hopefully, come to a logical conclusion as to what it is. The following is a list of conditions which can cause seizures in dogs. Each condition is discussed in the following sections:

 

·         1. Brain tumor, Head injury

·         2. Lyme Disease and Rocky Mountain Spotted Fever

·         3. Distemper

·         4. Environment - toxins

·         5. Epilepsy

·         6. hyper' and 'hypo' Conditions
Hypoglycemia
Hypocalcemia
Hypoxia or Hypoxemia
Hepatic Encephalopathy or Liver Disease
Renal (kidney) disease
Hyperkalemia
Hyperlipoproteinemia
Gastrointestinal disease ("garbage" poisoning)
Tick Bites
Toxoplamosis (Toxo)

·         7. Lissencephay

 

The above list is not all-encompassing, but close, these items are the major causes for seizures in dogs. 

 

1. Brain Tumor, Head Injury.

A brain tumor is an abnormal growth in the brain. There are two types of tumors: primary and metastases. Primary tumors grow from tissues in the brain and their cause is unknown. Metastases are spread via the bloodstream from tumors in other places in the body. A tumor may be malignant. A tumor in the brain may also put pressure on the brain as it grows. Pressure on the brain tissue in the area of the tumor may cause:

·         loss of vision

·         motor coordination

·         seizures

Malcolm B. Willis and other noted authors state that a brain tumor is an "intracranial" cause of seizures. A tumor will probably occur in an older dog and "may leave the dog with a weak or paralyzed limb . . .". According to the Dog Owner's Home Veterinary Handbook, brain tumors occur in older dogs over 5 years of age. Outside of surgery, the MRI (magnetic resonance imaging) or CAT (computed axial topography) are the two most useful diagnostic tests to show brain tumors. Of all canine tumors reported, the brain tumor only accounts for 3.0% of these, a very small percentage. Over time, the tumor would grow and seizures would continue to occur and the anticonvulsant medications would not control the seizures caused by a tumor.

 

An injury to the skull, possibilly hard enough to crack the skull, would require a significant impact to cause an intracranial disturbance. If such an event did occur, then, if seizures were to occur, they will not be observed immediately. The dog would not have seizures until weeks, or even months, after the event. If such an impact did occur, then the MRI would show an "abrasion" on the skull. The anticonvulsant drugs would not be effective against a skull injury. The anticonvulsant drugs are designed to stabilize the neurons within the brain cells. Phenobarbital and Primidone are designed to prevent the seizure from starting. Phenytoin is designed to stop the seizure from spreading. With a head injury, the neurons in the brain cells are already stable. The head injury itself is causing the seizure because of what Dr. deLahunta calls the "cerebral scar" which could be putting pressure on the brain and thus csausing the seizures.

 

If you are going to have an MRI preformed on your pet, also have a spinal tap - CSF analysis performed while the pet is under a general anesthetic. The results from the CSF should be normal. In the words of Dr. deLahunta "Cerebrospinal fluid (CSF) is a clear, colorless fluid that surrounds and permeates the entire central nervous system (CNS) and therefore protects, supports, and nourishes it." The CSF analysis is the best test to determine if any central nervous system inflammatory disease (i.e., distemper) is present. There is an accepted standard or count for the WBC and protein levels of the fluid. Any increase in the levels of these values is cause for concern. The presence of any inflammatory disease would be indicated by an increased protein level in the fluid. Similarly, the presence of any bacterial or fungal disease would be shown by an increased white blood count. The table below, derived from Dr. deLahunta's book Veterinary Neuroanatomy and Clinical Neurology shows the relationship between normal CSF readings and those associated with a disease.

 

 

The text book Handbook of Veterinary Neurology, by Oliver and Lorenz, discusses the neurologic exam. The first chapter is devoted to the discussion of the neurologic examination. In lay person's terms, the neurologic exam evaluates how the nerves of the limbs are "talking" or communicating to the central nervous system and the brain and how the brain is responding. The examination is divided into 6 parts:

·         observation

·         palpitation

·         postural reactions

·         spinal reflexes

·         cranial nerve

·         sensation

In the observation portion, the examiner notes the posture and movement of the dog. This can be done while the dog is allowed to roam and sniff around the doctor's office. In the palpitation portion, the examiner notes the muscle tone and size. They also check for any abnormalities in the skin and skeletal system. In the postural reaction portion, the examiner evaluates the responses that maintain the dog's posture. In the spinal reflex portion of the examination, the examiner evaluates the integrity of the sensory and motor components of the reflex arc. An example of the reflex arc in humans, is the reaction of tapping the tendon below the knee cap. The impact of the small mallet causes the lower leg to jerk. The reflex arc is the path that the nerve signal takes from impact at the knee to the brain, and then the brain sends the signal to the lower leg to somewhat kick. In the cranial nerve portion of the examination, the examiner notes the position of the head, notes the symmetry of the eyes and the pupils, notes the reactions of the nose when touched, evaluates the mucous membranes of the mouth and tonsils, the symmetry of the tongue, etc. Finally, in the sensation portion of the examination, the examiner evaluates the dog's response to pain based on the stimulus of the other tests.

 

 2. Lyme Disease and Rocky Mountain Spotted Fever.

Both of these diseases are caused by a tick, a member of a super-family (Ixodoidea) of wingless bloodsucking arachnids, including many species that transmit diseases. The bite of the Ixodes genus tick causes Lyme Disease. This little critter is also knows as the deer tick, black-legged tick, or the seed tick. The tick attaches itself to the dog and begins to feed. The spirochetes (a spiral shaped bacteria that cause the disease) in the stomach of the tick move to the salivary glands of the tick and then into the host dog. If the tick is discovered within the first 24 hours after attachment, the chance of infection is very small. Appel and Jacobson, in their article CVT Update: Canine Lyme Disease, estimate that about 5% of the dogs in the geographical areas of the U.S. where Lyme Disease is endemic and are exposed to Lyme Disease, become affected, i.e., they develop the clinical signs of the disease. In other words, dogs have a small chance of acquiring Lyme Disease. A type of tetracycline antibiotic is used to kill the Lyme infection. "The proportion of dogs in endemic areas that develop clinical disease is relatively small." The canine citizenry responds fairly well to administered antibiotics.

Arthritis is the main sign of a dog affected with Lyme Disease. In humans the signs are chronic arthritis and "severe central nervous system involvement" according to Appel and Jacobson. The "Veterinary News" section of the April 1994 AKC Gazette, discuses the Western Blotting test for Lyme Disease. It is used to "conform or refute a positive (antibody) titer and it can also differentiate between a titer caused by a vaccine and a titer caused by natural exposure to the disease". In severe cases of Lyme Disease, seizures may be evident and they are much more likely to be evident in a human than a dog.

The July 28, 1997 issue of TIME Magazine, contains an informative article on Lyme's disease. It shows a map of the 48 states and indicates the number of reported cases of Lyme's disease in each state. A Center for Disease Control report in 1998 indicated that the upper midwest and east have the highest incidence of Lyme disease. The March 2000 issue of Your Dog (Vol VI, Number 3) published by the Tuffs University School of Veterinary Medicine has an excellent article on Lyme Disease.

  

3. Environment - Toxins.

The environment can be many things to a dog - the back yard, the kennel, the basement, etc. Wherever a dog can go, curiosity follows it andclamity is real close behind. In your back yard you may have Russian Olive trees, CottenlessCottonwoods, pine trees, spreading junipers, apple trees and apples in the fall, plenty of grass, mushrooms when it is damp, many birds, garter snakes, etc.

In their Handbook of Veterinary Neurology on page 360, Table 16-21, Oliver and Lorenz have a list of toxins, their use around the house, the management of the toxin if ingested, and the prognosis for the affected dog. Of the 10 toxins that can cause seizures, the prognosis falls into 3 groups:

·         good if treated early

·         fair with treatment or treated early

·         poor

The table below shows a list of toxins that were compiled from data from Oliver and Lorenz, Handbook of Veterinary Neurology and Carlson and Giffin, Dog Owner's Home Veterinary Handbook

 

 

 

4. Epilepsy.

There are many things that can cause a seizure in a person or a dog. Epilepsy is a subset of one of the many things that cause seizures. Just because a dog has a seizure does not mean that the dog has epilepsy. Seizures come in two "flavors" or types, primary and secondary. Some external influence or some outside stimulus causes secondary seizures. With secondary seizures, the source is known. Primary epilepsy, also known by the names of idiopathic or genetic or inherited or true epilepsy, has no known source. A genetic factor may be highly suspected when seizures occur in dogs 1 to 3 years of age.

Before going into any detail about epilepsy, it is best to define the act of epilepsy itself, the seizure. By way of the thesaurus that comes with this word processor, the word "seizure" has the following synonyms: fit, convulsion, attack, epileptic fit, paroxysm, etc. A seizure begins unexpectedly and ends suddenly and does occur again. Epilepsy is referred to as being idiopathic when the seizures it causes have no known origin and the seizures do recur. Idiopathic, from the Greek language, is a combination of "idio" meaning "one's own or personal" and "pathy" meaning "disease". So idiopathic really means "one's own disease". One veterinarian that we talked to stated that idiopathic is really a fancy term for saying "we do not know".

As the uncontrolled discharge of neurons in the brain spreads, a partial seizure can become a generalized seizure. A generalized or grand mal is the most common form of a seizure. It is interesting to note that 'mal', meaning bad or wrong or ill, is generally used as a prefix, for example "maladroit" (bungling). The seizure itself is broken into 3 stages, the pre ictal, ictal and post ictal. Ictal is from the Latin 'ictus' meaning attack.

In a text book seizure, the dog will lose consciousness, will paddle or go through running movements, will chomp at the air and will salivate. In a seizure caused by strychnine poisoning for example, stiffening of the legs is observed but there is no leg movement or paddling.

In his exemplary text Veterinary Neuroanatomy and Clinical Neurology, Dr. Alexander de Lahunta of Cornell University, mentions that all dogs have a seizure threshold. A seizure occurs when this threshold is exceeded. Dogs with a low seizure threshold are divided into 2 groups - stimulus and non-stimulus. In the stimulus group, seizures may be caused by some external influence such as hormones, (e.g., estrogen which can lower the threshold to seizures in parts of the brain), fatigue or injury, and hyperventilation.

In the non-stimulus group, the seizures occur spontaneously, or as stated earlier, they have a sudden beginning. According to Dr. de Lahunta, the non-stimulus seizure is typical of many idiopathic epileptics.

The table below is similar to the one that appears on page 329 - Table 18-1 - in Dr. de Lahunta's text Veterinary Neuroanatomy and Clinical Neurology. The table lists the 3 categories that cause seizures and the agents under each category. Please note, that there are no agents listed under idiopathic epilepsy - they just happen.

 

 

 

Dr. de Lahunta also discusses the "interictal" period in his text. The interictal period is the time frame between seizures or clusters of seizures. The interictal symptoms are listed here:

 

·         paresis - the diminished ability to move muscles or body parts voluntarily.

·         infarct - localized tissue death.

·         lesions - any disease induced abnormality of tissue or tissue function. A lesion could be an abscess, ulcer, or tumor.

·         neoplasia - formation of a tumor or tumors. Assuming a brain tumor, the MRI showed none and any tumor growth would show
progressive deterioration of all activity.

These symptoms are usually the result of one of the extracranial agents that are discussed in detail below. Dr. de Lahunta states in his text that "Dogs with idiopathic epilepsy do not have interictal signs." We will now briefly describe the agents mentioned in each category in the table above.

 

 
 

5. 'hyper' and 'hypo' Conditions.

 

5.1 Hypoglycemia.
A dog with hypoglycemia (low blood sugar) usually has seizures prior to feeding when their blood sugar or glucose levels are at a low level. The signs of hypoglycemia depend on 1) level of the blood glucose and 2) the rate the glucose level drops. Some of the causes of hypoglycemia are:

·         a pancreatic tumor that produces an insulin like substance

·         liver disease

·         cortisone deficiency

·         diabetic dogs that obtain an insulin overdose

Seizures are occasionally observed in hunting dogs during periods of excessive activity.

 

5.2 Hypocalcemia.

This is an endocrine disorder (affects electrolyte, calcium, magnesium, and phosphorous) that is characterized by low levels of calcium. Typically the acceptable range of calcium levels from the blood serum chemistry is in the range of 8.5 to 11.0 (mg/dl). Loss of appetite in a dog will cause the calcium levels to decrease which in turn may cause seizures. Some dogs may develop muscle weakness early in the disease. Another symptom of hypocalcemia is cataracts.

 

5.3 Hypoxia or Hypoxemia.

Hypoxia (Hypoxemia) is a condition of low blood oxygen levels that results in reduction in the capability of the red blood cells to carry oxygen. It may be the result of a disease of the lungs that prevents an adequate supply of oxygen getting to the brain thus causing seizures.

 

5.4 Hepatic Encephalopathy or Liver Disease.
Excess ammonia in the blood from liver disease may be a cause of seizures. Measurements of blood ammonia provides a truly reliable test to identify a dog with liver disease. According to the UC Davis School of Veterinary Medicine Book of Dogs, "It is the only test that can determine whether clinical signs of central nervous system dysfunction can be attributed to liver disease (hepatic encephalopathy)". Of all the signs of liver disease, anorexia (reduced food intake) is the first to appear and it too is a sign of hepatic encephalopathy. Portasystemic Shunts also known as Portacaval Shunt(s) fall into this category. This is the abnormal communication between the portal vein (coming from the gastrointestinal tract) and the vein which carries blood back to the heart (known as the posterior vena cava). During fetal life, the communication is normally there but shortly after birth it may close off. When the communications fail to close properly, the vessels serve as shunts so that portal blood flow does not pass through the liver for processing or detoxification before being delivered to the rest of the body. Small breeds such as Yorkshire Terriers, Maltese and Miniature Schnauzers are commonly affected by this. The signs will usually appear before 1 year of age. Some of the signs are: depression, seizures, ataxia (incoordination), vomiting, polydipsia (excessive thirst) and retarded growth. Blood chemistry panel results are usually normal. The best way to diagnose this is by performing an ammonia tolerance test. Diagnosis can be confirmed by an X-ray. The condition can be alleviated with dietary management or partial surgical closure of the shunt. (UC Davis School of
Veterinary Medicine Book of Dogs provided the information for the above descripition.)

 

5.5 Renal (kidney)disease.

Kidney disease and kidney failure are two different conditions. The kidney fails when it is unable to perform its function of cleansing the blood of impurities. A kidney disease may hamper the kidneys from performing but it is still able to remove impurities from the blood. Uremia is a condition when there are high levels of urea nitrogen in the blood, other nitrogenous waste products in the blood, and the body pH falls below 7.0. The bodies buffering mechanisms that are under the control of the kidneys regulate the acidity in the blood and the body itself. High acidic levels of the body or acidosis may be the cause of seizures. The seizures are the result of the buildup of toxins (high nitrogen levels) in the blood. Uremia occurs at the terminal stages of kidney failure. It may also cause the body temperature to lower and may increase the respiratory rate. On page 270 of the UC Davis School of Veterinary Medicine Book of Dogs, the authors state "Failure to initiate therapy in a timely manner will result in irreversible damage to kidney tissue and ultimately death". Part of a complete blood work-up is the chemistry analysis. Included in that are the blood urea nitrogen (BUN) and creatinine, the two most common tests used to evaluate kidney performance. The normal BUN range for an adult dog is 10 to 25 (MG/DL) with the average being 17.5. The range for the creatinine is 1.0 to 2.2 (MG/DL) with the average being 1.6.

 5.6 Hyperkalemia

Hyperkalemia is the condition of a high concentration of potassium in the blood. Another term for this condition is Addison's disease. The heart rate of a dog suffering from hyperkalemia may be slower than normal. The condition may show itself as a generalized weakness in the dog and the condition becomes worse with exercise.

 

5.7 Hyperlipoproteinemia.

Dr. de Lahunta's text Veterinary Neuroanatomy and Clinical Neurology has a small paragraph on this disorder but we were unable to find this disorder as it is spelled or described in any of the other veterinary texts we own. He states that "defective lipid metabolism" causes this disorder. Lipids are classified as simple and complex. Simple lipids do not contain fatty acids. Complex lipids are essentially fatty acids and include glycerides, glycolipids, phospholipids, and waxes (ear wax). Lipids can combine with proteins to form lipoproteins. Apparently this disorder does not properly break down the fatty acids in the blood and the affected dog may have seizures. Dr. de Lahunta states that the Miniature Schnauzer is the most commonly affected dog. A high concentration of lipids (triglycerides) in the blood is known as hyperlipemia. Other clinical signs of hyperlipemia include dullness, poor appetite, and rapid loss of body condition.

 

5.8 Gastrointestinal disease ("garbage" poisoning).

Decaying and rotten garbage may be a breeding ground for staphylococcal and or botulism toxins. These may cause central nervous system stimulation, i.e., seizures.

 

5.9 Tick Bites.

We have discussed tick bites and two of their diseases - Rocky Mountain Spotted Fever and Lyme Disease earlier.

 

5.10 Toxoplamosis (Toxo)

The information that we obtained on Toxo comes by way of the internet. Toxo is a disease caused by a germ (protozan parasite - Toxoplasma gondii) and the most likely places of contact are cat feces, raw meet and uncooked vegetables. Approximately half of the people in the U.S. have the Toxo parasite, but the disease is dormant. This parasite is similar to giardia in that once a dog has giardia, it is dormant and may flare up at any time to affect the dog. Toxo has many symptoms and included in these are muscle spasms and seizures (neurologic difficulties). The symptoms worsen and the patient may go into a coma if the disease is not treated properly. The 2 most common drugs used in the treatment of Toxo are the combination of sulfadiazine and pyrimethamine. Depending on the dog's reaction to these drugs, other drugs may be substituted - clindamycin, dapsone, or doxycycline. In the winter of 1994 and 1995, Victoria B.C. experienced the world's largest outbreak of Toxo ever reported.