Fatigue
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[edit] Fatigue
Geoffrey A. Modest
Fatigue is a remarkably common problem that affects individuals of all socioeconomic strata, although patients commonly do not identify fatigue as their chief complaint. The algorithm is for patients with chronic fatigue, defined as fatigue of at least 30 days, although some studies define it as 6 months. A large British community survey found that 38% of those surveyed had substantial fatigue, with 18% symptomatic for more than 6 months.[1] Similar numbers have been found in U.S. primary care studies. Fatigue is a major public health problem, similar to other chronic disabilities, interfering with family life and occupation. The pathophysiology of fatigue is not well characterized, although a wide variety of medical and psychologic conditions (see below) are associated with fatigue. One note of caution: although fatigue is associated with many medical diagnoses, it may be erroneous to attribute the fatigue to one of those diagnoses, since there may be a concomitant (perhaps associated) and treatable psychologic cause.
In one study,[2] approximately 25% of 1159 consecutive patients complained of fatigue as a major problem (fatigue that interferes with work or home responsibilities), with fatigue being somewhat more common in women than men (28% vs. 19%). After excluding suspected medical conditions, 80% of the remaining patients (vs. 12% of controls) had underlying depression or anxiety. Laboratory examination in patients without suspected medical causes of fatigue was remarkably unuseful, with only four (4%) having subclinical hypothyroidism (none of whose fatigue improved with thyroxine therapy), four with newly discovered diabetes, and
one with mild anemia. No new illnesses were found on 1-year follow-up in the cohort. Other studies have found similar conclusions.
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History.
There are several components to the history of the chronically fatigued patient. First, it is important to assess the patient for any medical conditions[3] that might cause chronic fatigue. Any chronic organ system dysfunction can be associated with chronic fatigue, including infectious diseases (e.g., tuberculosis, fungal, parasitic, occult bacterial, viral, human immunodeficiency virus [HIV]), endocrinopathy (hyperthyroidism, hypothyroidism, diabetes, Cushing's syndrome, Addison's disease), malignancy, anemia, connective tissue disorder, chronic pulmonary disease (restrictive or obstructive), chronic liver disease, chronic heart disease (congestive heart failure, coronary artery disease), inflammatory bowel disease, and chronic granulomatous diseases (sarcoid). In addition, pregnancy, menopause, and surgery (especially within the previous 3 months) can feature fatigue as a prominent symptom. Second, a detailed sleep history is important to rule out a primary sleep disorder (see Chapter 161 ), obstructive sleep apnea, other causes of disturbed sleep (e.g., asthma, menopausal symptoms, nocturnal limb movements), or psychiatric causes. Third, a detailed assessment of medications and drug use should be sought (see C). Fourth, a screen should be done for depression, anxiety disorder (including posttraumatic stress disorder), domestic violence, and sexual abuse; even in the presence of a medical condition or medication that might cause chronic fatigue, an underlying and treatable psychiatric condition might exist and should still be investigated.
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Physical Examination.
The physical examination should target specific issues uncovered in the history (see A). In addition, it is important to distinguish fatigue from weakness, which may be attributable to neurologic, muscular, or psychiatric disorders (e.g., conversion reaction) (see Chapters 50 , 167 , and 168 ).
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Medications/Drugs.
Chronic fatigue can be associated with the use of several different substances (e.g., alcohol, opiates, cocaine), as well as a variety of medications. See Chapters 51 and 52 for patients identified with substance abuse. Although a large percentage of medications have been associated with fatigue, the major classes clearly associated include β-blockers, centrally acting α-blockers, anticholinergics, antihistamines, antipsychotics, and antidepressants.
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Laboratory Tests.
Although there are very few data to confirm the utility of an extensive laboratory investigation without either abnormalities suggested by history or physical examination, or the use of medications that might cause laboratory test abnormalities, the general workup suggested by several different investigators includes a complete blood count, electrolytes, blood sugar, liver enzymes, renal function, thyroid stimulating hormone, erythrocyte sedimentation rate, and urinalysis.[4]
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Psychologic Etiology.
A psychologic etiology may still account for the chronic fatigue, since patients may be reluctant to discuss depression, anxiety, or physical or sexual abuse, especially on the first encounter. Since psychologic issues are the predominant cause of fatigue, a subsequent reexploration is appropriate.
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Chronic Fatigue Syndrome.
Chronic fatigue syndrome is differentiated from chronic fatigue by a variety of accompanying symptoms as defined by the Centers for Disease Control and Prevention (CDC) (see Chapter 142 ). Of note, in several large studies of chronically fatigued patients, only 1% to 4% met the CDC case definition. A recent community-based study in Kansas,[5] however, found a markedly higher prevalence of chronic fatigue syndrome than expected (303 cases per 100,000 women, instead of the 4 to 9 per 100,000 suggested in prior studies), notably with only 16% previously diagnosed using the strict CDC definition. Fibromyalgia is a condition associated with fatigue, sleep disturbance, and tender “trigger points” (see Chapter 142 ).
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Follow-Up.
In general, there is a low likelihood of uncovering an etiology for the fatigue if none has become apparent so far. In one study[2] if no etiology had been apparent initially, no important new diagnoses were found after 1 year of follow-up, and only 28% of the patients without diagnosis or therapy improved spontaneously in 1 year. Some success has been reported with cognitive behavioral therapy,[6] wherein patients receive 16 weekly sessions geared to helping patients reevaluate their beliefs about their illness, including the role of social and psychologic factors, coupled with a gradual increase in activity.
[edit] REFERENCES
- ↑ T Pawlikowska, T Chalder, SR Hirsch,et al.: Population-based study of fatigue and psychological distress. Br Med J 1994; 308:763 - 766.
- ↑ 2.0 2.1 K Kroenke, DR Wood, AD Mangelsdorff,et al.: Chronic fatigue in primary care: prevalence, patient characteristics, and outcome. JAMA 1988; 260:929 - 934.
- ↑ DM Elnicki, WT Shockcor, JE Brick,et al.: Evaluating the complaint of fatigue in primary care: diagnoses and outcomes. Am J Med 1992; 93:303 - 306.
- ↑ KR Epstein: The chronically fatigued patient. Med Clin North Am 1995; 79:315 - 325.
- ↑ DW Bates, W Schmitt, D Buchwald,et al.: Prevalence of fatigue and chronic fatigue syndrome in primary care. Arch Intern Med 1993; 153:2759 - 2765.
- ↑ M Sharpe, K Hawton, S Simkin,et al.: Cognitive behavior therapy for the chronic fatigue syndrome: a randomised controlled trial. BMJ 1996; 312:22 - 26.
