[Hypotension from endocrine origin]

Abstract

Hypotension is defined by a low blood pressure either permanently or only in upright posture (orthostatic hypotension). In contrast to hypertension, there is no threshold defining hypotension. The occurrence of symptoms for systolic and diastolic measurements respectively below 90 and 60 mm Hg establishes the diagnosis. Every acute hypotensive event should suggest shock, adrenal failure or an iatrogenic cause. Chronic hypotension from endocrine origin may be linked to adrenal failure from adrenal or central origin, isolated hypoaldosteronism, pseudohypoaldosteronism, pheochromocytoma, neuro-endocrine tumors (carcinoïd syndrome) or diabetic dysautonomia. Hypotension related to hypoaldosteronism associates low blood sodium and above all high blood potassium levels. They are generally classified according to their primary (hyperreninism) or secondary (hyporeninism) adrenal origin. Isolated primary hypoaldosteronisms are rare in adults (intensive care unit, selective injury of the glomerulosa area) and in children (aldosterone synthase deficiency). Isolated secondary hypoaldosteronism is related to mellitus diabetes complicated with dysautonomia, kidney failure, age, iatrogenic factors, and HIV infections. In both cases, they can be associated to glucocorticoid insufficiency from primary adrenal origin (adrenal failure of various origins with hyperreninism, among which congenital 21 hydroxylase deficiency with salt loss) or from central origin (hypopituitarism with hypo-reninism). Pseudohypoaldosteronisms are linked to congenital (type 1 pseudohypoaldosteronism) or acquired states of resistance to aldosterone. Acquired salt losses from enteric (total colectomy with ileostomy) or renal (interstitial nephropathy, Bartter and Gitelman syndromes…) origin might be responsible for hypotension and are associated with hyperreninism-hyperaldosteronism. Hypotension is a rare manifestation of pheochromocytomas, especially during surgical removal when the patient has not been prepared with calcium inhibitors. Every flush with hypotension should suggest a carcinoid crisis, which is very sensitive to subcutaneous somatostatin analog. An accurate etiological diagnosis should allow treat efficiently endocrine hypotension without inducing hypertension in supine posture.