The Differential Diagnosis of Weakness and Fatigue

Abstract

ONE of the problems most frequently encountered by the general practitioner and the internist is a complaint variously described as weakness, exhaustion, fatigue, loss of ambition, low vitality or weak spells. Weakness and fatigue, alone or dominating a group of other symptoms, cause thousands of people to suffer disability and a greatly lessened enjoyment of life. What can the physician do to investigate these complaints and how can he determine their cause? To present an answer to this question from our experience at the Lahey Clinic, data have been compiled on 300 consecutive cases in which weakness, fatigue or weak spells were the chief complaint.

Chronic Fatigue in Primary Care

“…In an effort to focus on persistent primary fatigue, ie, fatigue in which the cause was not readily ap¬ parent, we excluded the following pa¬ tients: (1) those who had been fatigued for less than 30 days; (2) those who were under the care of a psychiatrist; and (3) those who had documentation that they had had of any of the following major medical illnesses: renal disease with a serum creatinine concentration greater than 265 pimol/L; anemia with a hematocrit less than 0.30; congestive heart failure; pulmonary disease with a forced expiratory volume in 1 s less than 70% of the predicted value or arterial oxygen saturation less than 0.90; liver disease with a serum bilirubin concen¬ tration greater than 51 (xmol/L, an albu¬ min concentration lower than 30 g/L, or transaminase concentrations more than three times above normal levels; rheu¬ matoid arthritis or another collagen vascular disease; cancer with residual tumor; untreated thyroid disease; and (24) surgery within the past 30 days. Nonfatigued respondents satisfying the same exclusion criteria were recruited as controls and were demographically matched to a subset of fatigued partici¬ pants for statistical comparisons.…”

Toward an understanding of different manifestations of fatigue

“…Diagnostic criteria, with the aim of differentiating fatigue of psychological from fatigue of physiological origin, were studied by Allen [3], who found the day-to-day variability of fatigue, long duration of fatigue, and the association with many other symptoms more often in patients with psychogenic (nervous) fatigue; the latter was also reported by Solberg [4]. Morrison [5] stressed the duration of fatigue as a discriminating criterion.…”

Old wine in new bottles: neurasthenia and ‘ME’

“…What happened between the end of neurasthenia and the arrival of ME? Physicians wrote occasional papers on 'Chronic nervous exhaustion' (Macy & Allen, 1934) or neurocirculatory asthenia (Wheeler et al 1950), but more often patients were simply described by their symptoms, such as ' exhaustion' (Dowden & Johnson, 1929), 'tired, weak and toxic' (Alvarez, 1935) or simply 'weak and fatigued' (Allan, 1944). No attempt was made to describe specific syndromes, and physicians generally resorted to psychological or psychosomatic explanations.…”

“…I shall conclude with a description of the Section on Practice of Medicine held at the 94th Annual Session of the American Medical Association in Chicago on 14 June 1944 (Allan, 1945). Allan began by presenting a series of 300 fatigued patients (Allan, 1944) of whom the majority had minor psychiatric conditions, and emphasized the poor yield of further detailed investigations. Alvarez from the Mayo Clinic spoke next, agreeing with the paucity of clinical signs. '…”