Clinical feature: 

Definition: Hypotension is dizziness and fatigue caused by low blood pressure, usually below 100mmHg.

Pathogenesis: Low blood pressure is predominantly caused by fluid and sodium losses. Other causes may be cardiac failure and diminished tension of blood vessels. Congenital forms of hypotension are due to disturbances in the endocrine system and renal handling of water and solutes.

Clinical description: Dizziness and fatigue are frequent complains of low blood pressure, but they also occur in many cases with still normal blood pressure. More typical symptoms of sodium and water depletion are thirst and hunger for salt.

Diagnostics: 

Diagnosis: Blood pressure measurements under normal condition and physical stress give an impression whether or not blood pressure regulation is disturbed.

Strategy: If blood pressure is reduced into pathologic range and cardiac and vascular reasons excluded, renal excretion of water and solutes should be measured.