Autoimmune Polyendocrinopathy Syndrome Flashcards
Autoimmune Polyendocrinopathy Syndrome
Autoimmune polyendocrinopathy syndrome
Addison’s disease (autoimmune hypoadrenalism) is associated with other endocrine deficiencies in approximately 10% of patients. There are two distinct types of autoimmune polyendocrinopathy syndrome (APS), with type 2 (sometimes referred to as Schmidt’s syndrome) being much more common.
APS type 2 has a polygenic inheritance and is linked to HLA DR3/DR4. Patients have Addison’s disease plus either:
type 1 diabetes mellitus
autoimmune thyroid disease
APS type 1 is occasionally referred to as Multiple Endocrine Deficiency Autoimmune Candidiasis (MEDAC). It is a very rare autosomal recessive disorder caused by mutation of AIRE1 gene on chromosome 21
Features of APS type 1 (2 out of 3 needed)
chronic mucocutaneous candidiasis (typically first feature as young child)
Addison’s disease
primary hypoparathyroidism
Vitiligo can occur in both types
Type 1 Polyglandular Autoimmune Syndrome - Example Question
A 19 year-old man is referred by his GP to the outpatient department after having several episodes of collapse at college. He reports that during these episodes he feels tired and ‘blacks out’. Afterwards, he feels shaky and weak. There is no tongue biting or incontinence during these episodes and the patient reports that he often feels dizzy after standing up too quickly from a chair. The only other symptoms he reports is a sore throat that has persisted for a few weeks and lethargy.
On examination of the patient’s mouth and throat, there are some white plaques located at the back of the tongue and throat. His sitting blood pressure is 130/80 mmHg and his standing blood pressure is 95/70 mmHg. He is otherwise well.
Blood tests are performed and reveal:
Hb 13.9 g/dL Platelets 200 * 109/l WBC 6.2 * 109/l Na+ 132 mmol/l K+ 5.1 mmol/l Urea 4.7 mmol/l Creatinine 81 µmol/l Calcium 1.9 mmol/l Random glucose 3.9 mmol/l
What is the most likely diagnosis?
Type II polyglandular autoimmune syndrome Thymoma > Type 1 polyglandular autoimmune syndrome Type III polyglandular autoimmune syndrome HIV
The most likely diagnosis is type 1 polyglandular autoimmune syndrome. This autosomal recessive syndrome is a subtype of autoimmune polyendocrine syndrome, whereby a number of endocrine glands dysfunction. The patient’s oral candidiasis is caused by a mild immune deficiency and hyposplenism. Furthermore, the patient has hypocalcaemia, caused by autoimmune dysfunction of the parathyroid gland and hypoglycaemia with hypotension, caused by autoimmune dysfunction of the adrenal gland.
