THE ROLE OF DELAYED ORTHOSTATIC HYPOTENSION IN THE PATHOGENESIS OF CHRONIC FATIGUE

Past studies have shown that severe fatigue was the presenting symptom in six of seven patients with delayed orthostatic hypotension and tha t tilt table-induced hypotension was found in 22 of 23 patients with t he chronic fatigue syndrome. We have determined the prevalence of fati gue, volunteered in response to a nonspecific pre-examination question naire used in 431 patients, each subsequently diagnosed as having one of eight neurological or endocrine disorders. The results show that fa tigue is a very common symptom in patients with delayed orthostatic hy potension (n = 21), as well as both primary (n = 30) and secondary (n = 106) hypocortisolism: 70-83% in all groups. In contrast, fatigue was an uncommon complaint in patients with multiple system atrophy (MSA) (n = 30), pituitary disorders without hypocortisolism (n = 106) or idi opathic hirsutism (n = 96): 7-33% in all groups, and was intermediate in prevalence in patients with acute hyperadrenergic orthostatic hypot ension (n = 32): 41%. It is concluded that fatigue commonly results fr om delayed orthostatic hypotension and all forms of hypocortisolism bu t is less common in patients with acute orthostatic hypotension, both idiopathic and due to MSA, which more commonly present with lightheade dness or syncope. (C) 1998 Lippincott-Raven Publishers.