Letters August 2004 Issue

Letters: 08/04

Your vet should be a important member of your problem-solving team if your dog displays idiopathic aggression.

I wanted to respond to Pat Miller’s excellent article on idiopathic rage syndrome (“Rage Without Reason,” WDJ July 2004).

While most cases of idiopathic rage syndrome are truly “idiopathic,” some can actually be caused by the early stages of autoimmune thyroiditis. Most veterinarians and even many animal behaviorists may be unaware that this form of thyroiditis can appear as early as puberty or in the first one to two years of life, rather than as the commonly seen mid-life onset of classical clinical signs of hypothyroidism.

In fact, sudden unprovoked rage syndrome of an intermittent nature can be the hallmark of early thyroiditis, and is often undiagnosed because the veterinarian seeing the patient is unaware of the need to screen for thyroid dysfunction or doesn’t perform the requisite complete thyroid anti-body profile.

An association has recently been established between aberrant behavior and thyroid dysfunction in the dog. Typical clinical signs include unprovoked aggression toward other animals and/or people, sudden onset of a seizure disorder in adulthood, disorientations, moodiness, erratic temperament, periods of hyperactivity, hypoattentiveness, depression, fearfulness and phobias, anxiety, submissiveness, passivity, compulsiveness, and irritability. After the episodes, most of the animals appeared to be coming out of a trancelike state, and seemed unaware of their previous behavior.

The typical history starts out with a quiet, well-mannered, and sweet-natured puppy or young adult dog. The animal was outgoing, attended training classes for obedience, working, or dog show events, and came from a reputable breeder whose kennel has had no prior history of producing animals with behavioral problems. At the onset of puberty or thereafter, however, sudden changes in personality are observed. Typical signs can be incessant whining, nervousness, schizoid behavior, fear in the presence of strangers, hyperventilating and undue sweating, disorientation, and failure to be attentive. These changes can progress to sudden unprovoked aggressiveness in unfamiliar situations with other animals, people, and especially with children.

Three recent cases involved young dogs referred for sudden onset rage syndrome shortly after puberty. These dogs (Siberian Husky, Bull terrier, Saint Bernard-cross) were found to have early onset autoimmune thyroiditis, which was rapidly responsive to thyroid supplementation as their behaviors reverted to those of sociable, outgoing family companions.

Collectively, these findings confirm the importance of including a complete thyroid antibody profile as part of the laboratory and clinical work up of any behavioral case.

-W. Jean Dodds, DVM
President, Hemopet
Santa Monica, CA


Regarding Pat Miller’s article about idiopathic aggression: This article was quite timely, as several dog-related e-mail groups have recently circulated the story of a dog who became suddenly and unpredictably aggressive. The cause was attributed to Lyme’s disease.

Although it’s true that Lyme’s disease would be considered a rather rare cause of aggression, it should be on the list of differential diagnoses to consider in the case of a sudden and difficult-to-explain onset of aggression. Also included on this list should be rabies (!), seizures (epilepsy), and hypo-thyroidism. Other metabolic imbalances might also cause unusual signs such as aggression.

My point is that it’s extremely important to rule out medical causes for any behavioral problem prior to consulting a “positive trainer/behavior consultant who can give you a more educated analysis of your dog’s aggression.” I don’t discount the value of a skilled and experienced behavior professional, but no amount of behavioral modification is going to help an animal whose underlying cause is medical. I felt this point wasn’t adequately addressed.

I did, however, appreciate the side box on the evolving vocabulary of aggression. This topic, especially the evolving theories regarding dominance aggression, is something I’d be interested in reading a lot more about!

-J.C. Burcham, DVM
Olathe, KS


Our thanks to Dr. Dodds and Dr. Burcham for their insights; we apologize for omitting the recommendation to have a veterinarian examine any dog who displays unprovoked aggression. This has long been our suggestion when faced with ANY abnormal behavior.

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