Polyglandular deficiency syndrome in a boxer dog: Thyroid hormone and glucocorticoid deficiency

Abstract

Primary hypothyroidism and partial primary adrenocortical deficiency (isolated glucocorticoid deficiency) were diagnosed in an 8-year-old spayed female boxer dog, presented because of progressive symmetrical truncal alopecia, lethargy, and intolerance to cold. The diagnosis was based upon the combination of low, non-TSH-responsive concentrations of plasma thyroxine and low urinary excretion of corticoids together with high plasma concentrations of ACTH. Normal suppressibility of ACTH concentrations by a low dose of dexamethasone indicated an intact feedback system. Plasma growth hormone levels were elevated, most probably because somatostatin release was depressed by the glucocorticoid deficiency. The dog improved during oral replacement therapy with thyroxine until death ensued after 9 months as a result of intercurrent disease. Autopsy revealed thyroid atrophy and lymphocytic adrenalitis with complete destruction of the zona fasciculata and zona reticularis of the adrenal cortex. The combination of primary hypothyroidism and primary adrenocortical deficiency in this dog is identical to the entity known as type II polyglandular autoimmunity or Schmidt's syndrome in humans. The adrenocortical insufficiency remained confined to glucocorticoid deficiency during the observation period; on no occasion did electrolyte concentrations in the plasma reach values suggestive of mineralocorticoid deficiency.

Hypothyroidism

“…Combinations of immune-mediated endocrine deficiency disorders such as hypothyroidism and diabetes mellitus, and hypothyroidism and hypoadrenocorticism have been documented in dogs (Hargis et al, 1981;Haines and Penhale, 1985;Bowen et al, 1986;Ford et al, 1993;Kooistra et al, 1995;Greco, 2000;Blois et al, 2011). Combinations of immune-mediated endocrine deficiency disorders such as hypothyroidism and diabetes mellitus, and hypothyroidism and hypoadrenocorticism have been documented in dogs (Hargis et al, 1981;Haines and Penhale, 1985;Bowen et al, 1986;Ford et al, 1993;Kooistra et al, 1995;Greco, 2000;Blois et al, 2011).…”

A review of immunologic diseases of the dog

“…Addison's disease associated with megaesophagus, similar to Allgrove's syndrome of people, has been described in a German shepherd dog (Fritzen et al, 1996). A Boxer dog with both hypothyroidism and Addison's disease has also been reported (Kooistra et al, 1995). Two of four Leonbergers with hypoadrenocorticoism were also found to be hypothyroid (Smallwood and Barsanti, 1995).…”

Autoimmune polyglandular syndrome Type 2: the tip of an iceberg?

“…However, no clear impairment of the corresponding target organs usually occur, so the syndrome remains solely at subclinical level [52]. A spontaneous form of Type 2 APS has also been described in a boxer dog affected by primary hypothyroidism and partial adrenocortical deficiency: the autopsy study has demonstrated thyroid atrophy and lymphocytic adrenalitis with complete destruction of the zona fasciculata and reticularis [53]. Apart from these spontaneous models, there are animal models of experimentally induced autoimmune endocrine diseases obtained after environmental perturbation (e.g.…”