Clinical features

Symptoms and signs are non specific resulting in delayed diagnosis of the condition (1)

• 60% of patients have consulted two or more doctors before Addison’s is considered as the cause
• according to a study of children with Addison’s disease
  • delay in diagnosis was observed in about one third of cases
  • median time for the correct diagnosis after the onset of first symptom was two years (1)

Symptoms become apparent when over 90% of the adrenal cortex is destroyed (1).

Features common to both primary and secondary hypoadrenalism include:

• lassitude and muscle weakness and pain
• hypotension - often marked in acute hypoadrenalism; usually postural in chronic disease with a fall in blood pressure on standing of 20 mm Hg or more after a few minutes - may cause dizziness and headache; due to ineffective catecholamine action
• gastro-intestinal symptoms - anorexia, weight loss, nausea and vomiting, intermittent abdominal pain salt, craving
• decrease in axillary and pubic hair - common in women
• depression

Pigmentation only occurs in primary hypoadrenalism, due to high ACTH:

• although characteristic, it is absent in about 10% of cases (1)
• the skin assumes a dull, grey-brown colouration
• exposed skin, pressure areas, palmar creases, knuckles, buccal mucosa and recent scars are the commonest sites

Pigmentation may be accompanied by vitiligo, resulting in a patchy appearance.

Other features of hypothalamic-pituitary disease, such as hypothyroidism, are only found in cases of secondary hypoadrenalism.

Uncommonly:

• impotence and amenorrhoea
• hypoglycaemia - reduced opposition to insulin-action
• diarrhoea

Features of associated conditions e.g. vitiligo, hypothyroidism, diabetes, premature ovarian failure, hypoparathyroidism may be present.

Reference:

• (1) Vaidya B, Chakera AJ, Dick C. Addison's disease. BMJ. 2009;339