[Hyperventilation syndrome in a very old woman].

A 92-year-old woman was admitted to our hospital due to hypertension, nausea, pain in the anterior part of the chest, epigastralgia, and tachypnea. During the initial examination of the patient in the emergency ward, she was very excited, howled, and both her hands were numb. Arterial blood gas analysis revealed a marked alkalemia (pH greater than 7.55) and hypocapnia (Pco2 24.1 mmHg). After paper bag re-breathing, the pH and Pco2 were within normal limits. Because there was no lesion in the lungs or the brain that would account for hyperventilation and convulsions, the attack was considered to be a manifestation of hyperventilation syndrome should be carefully considered in the differential diagnosis of disturbance of consciousness even in elderly patients.