New research that set out to describe the clinical findings, treatment response and outcome in a population of cats diagnosed with hypoadrenocorticism has established that hypercalcaemia was documented more frequently in cats with hypoadrenocorticism than previously documented; a form of hypoadrenocorticism exists without hyponatremia and hyperkalemia; testing for exocrine pancreatic insufficiency may be warranted in cats diagnosed with this condition; and cats with non-neoplastic (not cancer) associated hypoadrenocorticism that survive initial hospitalisation can have a favourable long-term prognosis.
The research, a multi-centre retrospective observational study, was co-ordinated to present the largest case series on cats with the rare condition. It reports on 41 cats with hypoadrenocorticism from 24 referral hospitals across 14 countries. Data for the whole cohort were assessed using descriptive statistics and the differences between cats with and without hyponatremia and hyperkalemia were evaluated.
Within the cohort, 36 cats had hyponatremia, hyperkalemia or both, and five did not. The results found the median age of cats was 5.7 years (range 0.2 to 13.8). Twenty-three (56%) cats were male and 18 (44%) were female. In two (4.9%) cats, hypoadrenocorticism occurred secondary to lymphoma.
Cats with hyponatremia, hyperkalemia or both were less likely to have a history of vomiting but more likely to be hypothermic (have a low body temperature), dehydrated and/or weak on examination than cats without HH. The frequency of hypercalcemia (increased blood calcium level) was 31.7%. Exocrine pancreatic insufficiency (the inability to properly digest food due to a lack or reduction of digestive enzymes made by the pancreas) was diagnosed in 4/7 cases where tested; all four cats had concurrent cobalamin (vitamin B12) deficiency.
Thirty-five (85.4%) cats survived to discharge. Median survival time (MST) for all-cause mortality was 2,035 days (95% CI 294 – 4,380 days); MST for disease-specific mortality was not reached.
Emma Roberts (pictured), senior internal medicine clinician at Bristol Vet Specialists, who led the study, said: “Feline hypoadrenocorticism is sparsely reported in the veterinary literature, with most reports limited to one or two cases. To date there have only been three single case reports of cats with hypoadrenocorticism not associated with hyponatremia, hyperkalemia or both.
“Our world-wide study was warranted to enhance our understanding of this disease in cats. We are pleased that we now have the data both to describe the clinical findings of a large population of cats with this disease and to document their response to treatment and outcome and can share our findings with our colleagues in the veterinary profession.”
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