Hypotension

Hypotension, or low blood pressure, is commonly defined as a systolic reading below 90 mmHg or a diastolic reading below 60 mmHg. Some people live with lower pressures without symptoms, while others experience symptoms related to insufficient blood flow to organs. Hypotension can be a normal finding in healthy individuals, or it may indicate an underlying condition or medication effect.

Symptoms, when present, include lightheadedness, dizziness, fainting (syncope), blurred vision, fatigue, nausea, and confusion. A common related condition is orthostatic hypotension, where blood pressure falls after standing and is often accompanied by a rapid heart rate or symptoms of poor cerebral perfusion.

Causes are diverse and include dehydration and excessive blood loss, sepsis or severe infection, endocrine problems such as adrenal insufficiency or hypothyroidism, heart disorders (eg, arrhythmias, heart failure), pregnancy, malnutrition, and the effects of medications (diuretics, vasodilators, nitrates, certain antidepressants and antipsychotics). Autonomic dysfunction can contribute to chronic hypotension.

Diagnosis combines blood pressure measurement in different positions with history and exam. Tests may include blood tests, kidney and thyroid function, ECG, and, when indicated, imaging to identify causes. Treatment targets the underlying reason and may involve fluid management, electrolyte correction, compression garments for orthostatic hypotension, lifestyle modifications, and, in selected cases, medications to raise blood pressure. Prognosis varies with cause.