A Dog with Pseudo-Addison Disease Associated with Trichuris vulpis Infection

A female Rottweiler dog was presented with a history of intermittent vomiting and diarrhoea, dysorexia, weakness, and weight loss. Haemocytometry and biochemistry values were within normal ranges except for electrolyte analyses, that demonstrated hyponatremia and hyperkalemia with a decreased sodium/potassium ratio. A diagnosis of hypoadrenocorticism was suspected. Basal and post-ACTH stimulation cortisolemia were within the normal values. Electrocardiography was normal, and thoracic radiography showed no significant modifications. On abdominal ultrasonography, adrenal glands appeared normal, while the bowel was distended, and several thin linear hyperechoic objects floating in the lumen were observed. Two adult female whipworms (Trichuris vulpis) were collected following bowel irrigation. Anthelmintic treatment against the parasite was curative. 1. Introduction Trichuris vulpis, commonly known as whipworm, is characterized by a direct life cycle and by the extremely resistant lemon-shaped eggs that can remain infective in the environment for several years. Usually, T. vulpis infections are asymptomatic, but the presence of high worm burdens in the large intestine may cause the occurrence of haemorrhagic colitis due to the continuous stimulation and damage to the mucosa, where the head of the worm is embedded and moves in search of blood and fluid. Electrolyte imbalance can be associated with helminth infection; however, T. vulpis seems to be the only nematode associated with pseudo-Addison disease, as the present case seems to demonstrate. 2. Case History An 8-year-old, spayed female Rottweiler mixed breed dog was presented to our hospital with several weeks history of intermittent vomiting and diarrhoea (watery faeces with mucus and increased stool frequency) together with dysorexia, weakness, and weight loss. On physical examination, the patient was weak, but alert. Heart rate, respiratory rate, and temperature were within reference ranges. Mucous membranes appeared tacky and pale. The dog was slightly dehydrated, thin (body condition score: 2.5/5, 33？kg), had mild muscle wasting, and generally poor body condition. Haemocytometry and biochemistry showed normal values except for electrolyte analyses that demonstrated 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), with a decreased sodium/potassium (Na？:？K) ratio (23: reference interval 27 to 40), all suggestive of hypoadrenocorticism [1]. A direct fresh smear faecal examination yielded a negative