Autonomic dysfunction and orthostatic hypotension

The autonomic nervous system normally tightens blood vessels and adjusts heart activity as posture changes. If that response is impaired, blood can pool lower in the body and temporarily reduce blood flow to the brain.

Orthostatic hypotension commonly presents with light-headedness, blurred or dim vision, weakness, mental fogginess or fainting after rising. Symptoms may be more noticeable after prolonged standing, heat exposure, a large meal, dehydration or physical exertion.

Assessment may include blood pressure and pulse measurements while lying and standing, a review of medicines, an examination and tests selected for the clinical picture. Dehydration, blood loss, heart problems and medicine effects can also produce a postural blood pressure fall, so the cause needs evaluation.

Rise in stages: sit on the edge of the bed, move the ankles and stand only when steady. If warning symptoms start, sit or lie down promptly to reduce the chance of falling. Avoid driving, ladders and unprotected heights when episodes are not controlled.

Keep a record of posture, meals, heat, activity, symptoms and medicine timing to help identify triggers. Adequate fluid intake may help some people, but changes to salt, fluids, compression garments or medication should be tailored by a clinician, especially when heart or kidney disease is present.

Seek emergency help if fainting occurs with chest pain, breathlessness, a sustained racing or irregular heartbeat, a severe headache, new speech difficulty, one-sided weakness, or significant injury. These features may point to a problem beyond a simple postural episode.

Book a clinical review for repeated near-fainting, falls, worsening episodes or symptoms that interfere with eating, washing or walking. A new pattern after starting or changing a medicine also deserves prompt review; do not stop prescribed medicine abruptly without instructions.

Ask which possible cause fits your examination, which medicines could worsen the blood pressure drop, and whether home measurements would be useful. Discuss a fall-safety plan and request clear advice about fluids, meals, exercise and any compression garment being considered.