Diagnosing The Cause Of Seizures

Placing any animal on seizure medication without first trying to find the cause is a mistake

By Sam Vaughn, DVM, Dip., ABVP ?Avian Practice

I have a blue-and-gold female macaw that is 8 years old. She has had seizures for 8 months, and they are increasing in frequency and length. She is on a good diet (seed mixture, fruits and vegetables) and a vitamin supplement twice weekly. We also feed monkey biscuits twice weekly. We currently have her on phenobarbital and valium, which have helped some but not much. Can you shed any light on this case that might help?

Well, I must say this is a challenging case and your question gives no hint of diagnostics done by your veterinarian. Thus, I will go through the diagnostic protocol that I would use to approach this case. The cause of seizures are many, we basically rule out everything we can before we declare a bird epileptic and decide on lifetime anti-seizure medication.

The Importance Of A Profile
The physical examination, complete blood count and serum biochemistry profile with bile acids are integral to any diagnosis. Physical examination is the most important tool for veterinarians. The simple act of touching, feeling and palpating can reveal a tumor, enlarged liver, bruises or broken bones. Oftentimes in severe calcium deficiency (like that which occurs with seed diets), bones break just from the stress of bearing weight. While this is most common in the cockatiel, it can also occur in the macaw. A complete blood count can give clues to infectious processes that may be responsible for seizure activity. Fungal infections of the spinal canal have been relatively well-documented in psittacines. Blastomycosis, aspergillosis and cryptococcosis have all three been diagnosed in our hospital as contributors to meningoencephalitis. Serum chemistries can reveal calcium deficiency, liver malfunction (which can produce a hepatoencephalopathy), kidney disease (which can poison a bird by uric acid increase), and liver disease can be differentiated from muscle damage by the addition of bile acids to the profile.

This old standard diagnostic tool is still as great as it ever was. You might find tumors that could not be palpated, an enlarged liver, kidneys that are too dense (indicating uric acid deposition), metabolic fractures and low bone density (both indicative of severe calcium deficiency). You might find an old fracture of the spine that has just now produced enough bony growths to cause impingement on the spinal cord. Radiographs might visualize a granuloma in an air sac that can be biopsied and find a severe fungal infection.

This is a favorite of mine. Recently, I endoscoped a blue-and-gold macaw that had a normal white blood cell count and negative X-rays. What I found were two tiny white granulomas in the abdominal air sacs. We biopsied these for culture and grew the fungus Cryptococcus sp. Endoscopy can show a granuloma at the tracheal syrinx that was missed by radiology or a cardiac pericardium that is white in color, indicating uric acid deposition, helping confirm kidney malfunction. Endoscopy can also reveal an enlarged spleen and biopsy it and find evidence of Chlamydia infection, which has rarely been associated with seizures in birds.

Fungal Titers
Fungal titers are blood tests that look for antibodies in your bird’s blood to specific fungal diseases. Aspergillus is the most common and is easily tested for by several laboratories.

Placing any animal on seizure medication without first trying to find the cause is a mistake. Many times this is done, and the animal dies of a condition that was not diagnosed by taking the above steps to rule out nutritional, metabolic and infectious causes of seizure disorders. In animalsthat are, indeed, epileptic ?and birds are susceptible to this disorder ?appropriate medication and ongoing blood chemistries and therapeutic drug levels can produce great results with a normal life span.

Thank you for an excellent question with a very involved set of circumstances. I am sure that with proper diagnostics, your bird will live to a healthy old age.

If you have a question for Dr. Vaughn, send him an e-mail care of BIRD BREEDER at birdbreeder@fancypubs.com. We regret that columnists are not able to respond to letters individually.

Sam Vaughn, DVM, Dip., ABVP ?Avian Practice is an avian specialist based in Louisville, Kentucky. Certified in Avian Practice by the American Board of Veterinary Practitioners, Dr. Vaughn owns Avian Medical Services Inc. (an avicultural service and consultation practice) and is a partner in Veterinary Associates Stonefield, a full-service avian/exotic and small animal practice. Dr. Vaughn holds degrees in biology, chemistry and a Doctorate of Veterinary Medicine from Auburn University. Feel free to visit his web site at http://www.vetcity.com. Telephone consultations by appointment are available by calling (502) 245-7863.

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Birds · Lifestyle