ortostaatiline

Ortostaatiline is an Estonian-derived term used in medicine to describe the physiological and clinical responses to upright posture. In English, the corresponding concept is orthostatic. It covers both normal adjustments the body makes when standing and a group of disorders characterized by abnormal responses to standing, such as orthostatic hypotension and postural orthostatic tachycardia syndrome (POTS). The concept emphasizes the interaction between the cardiovascular and autonomic nervous systems in maintaining adequate cerebral perfusion during postural changes.

Normal physiology involves a redistribution of blood from the central circulation to the legs when a person stands. This reduces venous return to the heart and can lower blood pressure. The autonomic nervous system normally counteracts this with heart rate increase and vasoconstriction to sustain blood pressure and blood flow to the brain. When these compensatory mechanisms are delayed or insufficient, orthostatic symptoms such as dizziness, lightheadedness, fainting, or fatigue can occur. Factors such as dehydration, medications, aging, diabetes, and autonomic neuropathy can contribute to orthostatic dysfunction.

Common conditions associated with ortostaatiline dysfunction include orthostatic hypotension, defined by a drop in systolic blood pressure of at least 20 mmHg or diastolic drop of 10 mmHg within three minutes of standing, and POTS, which features a sustained heart rate increase of 30 beats per minute (or to over 120 bpm) within ten minutes of standing without a significant blood pressure drop. Diagnosis often involves clinical assessment and tests such as a tilt-table test or active standing measurements.

Management focuses on addressing the underlying cause and improving circulatory stability. Nonpharmacological strategies include adequate hydration, increased salt intake when appropriate, compression stockings, slow position changes, and structured exercise programs. Pharmacological options (used selectively) may include agents to raise blood pressure or modify autonomic tone.