Recently I lost a dear friend and hunting partner to something called IMHA (Immune-mediated Hemolytic Anemia). He was just eighteen months old and an expert hunter way beyond his years. Let's just call him Rover.
Despite having spent a few years in dogs as a breeder, handler, performance and conformation judge, I really didn't know what IMHA was; at least I'd never heard it called that. After ten days of around-the-clock treatment, transfusions and about $6,000, we lost the battle.
I must preface this article with some disclaimers. I am not a veterinarian and don't want to be. They have a tough job. Neither is any of the information presented here my own. It was all gleaned, under pressure, from available published data and research papers. The article is intended to give you enough information to make intelligent decisions at the outset of the problem. It is neither scholarly nor authoritative.
IMHA is defined as the accelerated destruction or removal of red blood cells due to the formation of anti-red cell antibodies. The reported range of affected dogs is from one to 13 years of age and predominates in females. Some of the breeds that are predisposed to IMHA are Old English Sheepdogs, Cocker Spaniels, Poodles, Collies, Irish Setters, Scottish Terriers and -- more recently -- several Norfolk Terriers.
The early symptoms of IMHA include general weakness and lethargy, loss of appetite, vomiting, diarrhea, shortness of breath and rapid breathing and heartbeat. By the time paleness of the gums and tongue is noted, the dog is in trouble. These, of course, are also the symptoms of a number of other diseases making it difficult for your, or for that matter the average veterinarian, to identify the problem without sophisticated laboratory tests.
While isolated families of dogs have been proven susceptible to IMHA, no genetic basis for the disease has been scientifically established. Likewise, no research exists that proves an exact cause. Frequently, more common diseases such as Leptospirosis, Heartworm, and several viruses are suggested causes. With equal frequency, IMHA is attributed to reaction to certain drugs such as sulfa drugs, cephalosporins, heparin and methamazole. In the majority of cases, such as Rover's, none of these was a factor.
The only relevant event in Rover's case was his annual vaccination for Rabies, Distemper, Hepatitis, Leptospirosis, Parvo and Lyme. That occurred in mid-January along with his mother, a five-year-old Norfolk bitch, and a six-month-old Dachshund puppy. All received the same serums. Only Rover contracted IMHA. There is no scientific evidence to confirm that IMHA is caused by or related to vaccinations. In a significant number of cases, the onset of IMHA follows vaccinations by several weeks, just coincidentally the same amount of time it may take for the immunization process to become effective.
IMHA is not an allergic, or other reaction to serums used in vaccinations. It is, in essence, the turning of the organs of the dog's immune system, the spleen and/or liver, against its own red blood cells. Kind of like immunization gone wrong. It is not sudden, although the symptoms usually appear and develop over a 48-hour period. By then IMHA is well underway.
Once diagnosed with IMHA, the survival rate of dogs is almost universally 50% with no way of predicting which will make it and which won't. The treatment consists of rebuilding the red blood cell supply through transfusions and the almost random trial of a selection of drugs and steroids that sometimes have worked. Half the time, nothing works.
With treatment, most dogs recover with few, if any, residual after effects. If we'd won the battle, I would have had my hunting companion, show dog and pet for many more years.
Here it is then, IMHA for Dummies:
More accurate and detailed information on IMHA is available on many web sites and probably from your veterinarian.
By Richard Reynolds
ANTIC, September, 2004
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