A Case of Canine Polyglandular Deficiency Syndrome with Diabetes Mellitus and Hypoadrenocorticism

Generalized megaesophagus associated with Schmidt-like syndrome in a dog

A 2-year-old intact male Asian Shepherd dog was referred with a history of chronic regurgitation along with normal appetite and diagnosis of megaesophagus on plain radiography. Clinical examination revealed normothermia, normocardia, normopnea, low body condition score and poor hair coat. The most important laboratory findings include anemia, azotemia, hyperlipidemia, increased thyroid stimulating hormone, decreased thyroxine and hypocortisolemia, as well as a marked increase in acetylcholine receptor antibody concentration. Based on the results, in addition to primary hypothyroidism and primary hypoadrenocorticism, myasthenia gravis was also diagnosed as an underlying cause of megaesophagus. Following nursing care and preferred treatment of each disease, the megaesophagus was resolved in the next visit. This clinical report describes for the first time, to the authors' knowledge, a dog with a rare type of autoimmune polyglandular syndrome (APS) known in human medicine as a Schmidt's syndrome. We want to emphasize the importance of clinicians' awareness regarding the possibility of APS to identify different diseases caused by it in order to achieve successful treatment.

[Polyendocrine syndromes in dogs]

The autoimmune polyendocrine syndrome (APS) refers to a combination of autoimmune endocrine disorders. It is rarely described in dogs. The most common combinations are hypoadrenocorticism and hypothyroidism, followed by diabetes mellitus, and less often hypoparathyroidism and orchitis. The diagnosis of the APS is based on the diagnosis of each endocrinopathy, as is the therapy, which involves the substitution of deficient hormones. If a patient was previously stable under treatment and is showing further signs (e.g. polyuria, polydipsia, or weight loss), the development of additional endocrinopathies like hypoadrenocorticism or diabetes mellitus should be considered. The diagnosis of the initially diagnosed endocrinopathy should also be critically questioned. This article summarizes some cases of our own animal hospital and selected cases published in the available literature.

Histopathological evaluation of the adrenal glands in a cat with primary hypoadrenocorticism and multiple endocrine disease

Case summary

A 6-year-old male neutered domestic longhair cat was referred for investigation of weight loss, hyporexia, vomiting and diarrhoea. The cat was diagnosed with primary hypoadrenocorticism, exocrine pancreatic insufficiency, cobalamin deficiency and a chronic enteropathy, and started on therapeutic treatment. Diabetes mellitus developed 4.5 months later, and the cat was started on insulin therapy. The cat was euthanased 10 months following the diagnosis of hypoadrenocorticism due to the development of status epilepticus, which was not associated with glucose or electrolyte abnormalities. Histopathological assessment of the adrenal glands at post-mortem examination documented lymphoplasmacytic adrenalitis, with the lymphocytic population being predominant. Immunohistochemical staining classified the lymphocytic infiltrate as T-cell rich, supportive of the cat's hypoadrenocorticism being due to autoimmune disease.

Relevance and novel information

This case documents the novel use of immunohistochemical staining in combination with histopathology to further assess the adrenal glands in non-neoplastic-associated primary hypoadrenocorticism in a cat. This identified similar pathological changes to those previously described in dogs with autoimmune primary hypoadrenocorticism. Additionally, this is the first report of a cat with multiple endocrine disease that included primary hypoadrenocorticism and highlights that monitoring for the development of additional endocrine disease should be advised in these cases.