[An aged case of orthostatic hypotension possibly due to parasympathetic neurodysfunction]

94-year-old male patient, with orthostatic hypotension, possibly due to impairment of vasoconstriction and parasympathetic nervous system dysfunction was reported. This patient experienced faintness and lower muscle weakness on standing. The blood pressure was 180/90 mmHg in a supine position, while it significantly decreased to 100/58 mmHg in an upright position. There was no evidence indicating the presence of organic brain diseases, cardiovascular diseases, and endocrine diseases, plasma catecholamine, renin, aldosterone, and vasopressin levels at rest were within normal range. Thus, the cause of orthostatic hypotension of this patient was unknown. His systolic blood pressure decreased by 70 mmHg, and his diastolic blood pressure also decreased by 25 mmHg in response to a 70 degrees head-up tilting test (170/71-100/46 mmHg). Plasma vasopressin level significantly increased in response to this test (0.62-67.2 pg/ml). Plasma catecholamine levels also increased (Adr 0.01-0.10 ng/ml, Ndr 0.05-0.22 ng/ml). Other autonomic nervous system examinations revealed normal responses to mental arithmetic test, hyperventilation test, cold pressure test, and adrenalin test. However, the results of the carotid occlusion test, acetylcholine test, atropine test, phenylephrine test were considered to be abnormal. From these findings, we concluded that the functions of sympathetic nervous system were almost intact, while the parasympathetic functions were impared in this case. The orthostatic hypotension of the patient as effectively treated with fludrocortisone. This report suggests that impairment of vasoconstriction and parasympathetic neurodysfunction might be involved in the development of orthostatic hypotension in the elderly.