Successful treatment of atypical hypoadrenocorticism in a cat presenting with hypoglycaemic seizures

A 4-year-old male castrated Ragdoll cat presented for generalised seizures. The cat displayed hyporexia, lethargy and hiding behaviour 24-48 h before presentation. The cat had a chronic history of daily vomiting and tachypnoea for 12 months. Severe hypoglycaemia was noted at 1.8 mmol/l (reference interval 4.11-8.84) on initial presentation. The hypoglycaemia persisted despite multiple glucose boluses, resulting in the cat being treated with a glucose and glucagon continuous rate infusion. The cat underwent extensive diagnostic evaluation during hospitalisation, consisting of serial venous blood gas assessment, haematology and biochemistry analysis, urinalysis, serum insulin assay, resting cortisol, adrenocorticotropic hormone (ACTH) stimulation test, abdominal and thoracic imaging, and airway culture. A resting cortisol level of <14 nmol/l was obtained on day 2 of hospitalisation with a follow-up ACTH-stimulation test reporting a baseline cortisol of <28 nmol/l and a 1 h post-ACTH cortisol of 7 nmol/l, supporting a diagnosis of hypoadrenocorticism. The cat was successfully treated with glucocorticoid therapy and discharged home 8 days after initial presentation.

There are limited cases of feline hypoadrenocorticism present in the literature, most of which describe cats with both glucocorticoid and mineralocorticoid deficiency. Only two previous case reports of feline atypical hypoadrenocorticism exist. Only one of these case reports describes hypoglycaemia with signs of neuroglycopaenia on initial presentation. To the author's knowledge, this is the first successfully treated case of atypical hypoadrenocorticism presenting with hypoglycaemic seizures in a cat, demonstrating successful long-term management.