Addison’s disease in dogs is usually caused bya malfunction in either the pituitary gland or the adrenal glands. However, rare cases have documented other causes, including barbiturate poisoning and parasite infestation. When these “pseudo-Addison’s
causes are treated, the dog normally returns to full health and will not need to be treated with replacement corticosteroids. Perhaps one of the most unusual cases of pseudo-Addison’s disease was in a dog that contracted a Trichuris Vilpus infection.
What is Trichuris Vulpis?
Trichuris vulpis, or whipworm, is a type of parasite that infests the large intestine of dogs. The head of the worm is embedded in the mucosa (the intestinal lining), where it looks for blood and fluid. Most cases of Trichuris vulpis infections have no symptoms, but a large amount of worms in the intestine may cause hemorrhagic colitis and pesudo-Addison’s disease. Trichuris vulpis appears to be the only parasite documented to cause Addison’s disease in dogs.
Case of Pseudo Addison’s
One veterinarian reported an eight-year-old Rottweiler mix who arrived at the veterinary clinic with symptoms of Addison’s disease: intermittent vomiting, diarrhea, weakness, weight loss and dysorexia (diminished appetite). Blood tests revealed further signs of Addison’s: hyponatremia (sodium 132 mmol/L; reference interval: 140 to 155 mmol/L), hyperkalemia (potassium 5.7 mmol/L; reference interval: 3.8 to 5.2 mmol/L), and a decreased sodium/potassium (Na : K) ratio. However the ACTH test showed negative for Addison’s disease in dogs. Whipworms were discovered only after a bowel irrigation with saline solution found whipworms and whipworm eggs.
Three days after treatment for whipworms, the dog had improved slightly. One month after treatment, the dog fully recovered. Whipworms is a very uncommon cause for Addison’s disease, but when any dog presents with electrolyte imbalances, veterinarians should rule out intestinal parasites as the cause with a fecal examination via centrifugation (a more accurate way of looking for parasites than the usual direct smear test).
Most of us visit the veterinarian once a year for vaccinations. I never gave this annual event a second thought until my border collie, Shakti, developed Addison’s disease. I have since discovered that additives to vaccines (adjuvants) are thought to cause immune disorders in dogs (including Addison’s disease in dogs), so I’ll be foregoing her usual annual shots.
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