Cortisol Blood Test

HIGH Cortisol: Cushing Syndrome

Persistently elevated cortisol is called Cushing syndrome. Causes: long-term steroid medication (most common), a pituitary tumour producing excess ACTH (Cushing disease), an adrenal tumour producing excess cortisol, or an ectopic ACTH-producing tumour (lung, pancreas). Symptoms: central obesity (round face and belly with thin limbs), purple stretch marks (striae), easy bruising, high blood pressure, high blood sugar, muscle weakness, depression, and in women, irregular periods and hirsutism. Diagnosis involves 24-hour urine cortisol, late-night salivary cortisol and a 1mg dexamethasone suppression test.

LOW Cortisol: Adrenal Insufficiency

Low cortisol is called adrenal insufficiency. Primary adrenal insufficiency (Addison disease) means the adrenal glands are damaged: causes include autoimmune destruction (most common in developed countries), tuberculosis, HIV/AIDS, cancer and bilateral adrenal haemorrhage. Secondary adrenal insufficiency means the pituitary is not producing enough ACTH, most commonly caused by sudden withdrawal of long-term steroid therapy. Symptoms: profound fatigue, weight loss, low blood pressure, salt craving, nausea, darkening of the skin (primary only). An adrenal crisis (acute severe cortisol deficiency) is a medical emergency.