Mineralocorticoids

Primary adrenal insufficiency results from destruction or dysfunction of the adrenal cortex. Because the cortex produces both cortisol and aldosterone, patients develop deficiencies of both hormones. Without aldosterone, the kidneys lose their ability to conserve sodium effectively. Large amounts of sodium are excreted into the urine. Water follows sodium, resulting in progressive loss of intravascular volume. As circulating volume falls, patients develop: - Orthostatic hypotension - Persistent hypotension - Tachycardia - Reduced tissue perfusion - Fatigue - Weakness - Dizziness - Syncope - Acute kidney injury if severe At the same time, potassium excretion decreases. Serum potassium gradually rises, producing hyperkalemia. Hyperkalemia may initially cause fatigue and generalized weakness but can eventually produce conduction abnormalities, ventricular dysrhythmias, and cardiac arrest. Hydrogen ion excretion is also impaired, predisposing patients to metabolic acidosis. When cortisol deficiency occurs simultaneously, patients also develop impaired glucose regulation, decreased vascular responsiveness to catecholamines, and reduced ability to respond to physiologic stress. This combination explains why untreated adrenal insufficiency may rapidly progress to adrenal crisis during acute illness. --- For REx-PN (Canada), items rarely announce the topic...