FATIGUE & CHRONIC FATIGUE SYNDROME

ESSENTIAL INQUIRIES

Weight loss.
Fever.
Sleep-disordered breathing.
Medications.
Substance use.

General Consideration

Fatigue, as an isolated symptom, accounts for 1–3% of visits to generalists. The symptom of fatigue is often poorly described and less well defined by patients than symptoms associated with specific dysfunction of organ systems. Fatigue or lassitude and the closely related complaints of weakness, tiredness, and lethargy are often attributed to overexertion, poor physical conditioning, sleep disturbance, obesity, undernutrition, and emotional problems. A history of the patient’s daily living and working habits may obviate the need for extensive and unproductive diagnostic studies.

Chronic fatigue syndrome may be due to retrovirus infection or an immune dysregulation mechanism, or both. Recent studies, however, have failed to show any differences in levels of xenotropic murine leukemia-virusrelated virus in US patients with and without chronic  fatigue syndrome. The diagnosis of chronic fatigue syndrome remains hotly debated because of the lack of a gold standard. Persons with chronic fatigue syndrome meeting specific criteria (such as those from the CDC) report a greater frequency of childhood trauma and psychopathology and demonstrate higher levels of emotional instability and self-reported stress than persons who do not have chronic fatigue. Neuropsychological, neuroendocrine, and brain imaging studies reveal neurobiologic abnormalities in most patients, but none with a consistent pattern. Sleep disorders have been reported in 40–80% of patients with hronic fatigue syndrome, but their treatment has provided only modest benefit, suggesting that it is an effect rather than a cause of the fatigue. Veterans of the Gulf War show a tenfold greater incidence of chronic fatigue syndrome compared with nondeployed military personnel.

Clinical Findings

A. Fatigue

Clinically relevant fatigue is composed of three major components: generalized weakness (difficulty in initiating activities); easy fatigability (difficulty in completing activities); and mental fatigue (difficulty with concentration and memory). Important diseases that can cause fatigue include hyperthyroidism and hypothyroidism, CHF, infections (endocarditis, hepatitis), COPD, sleep apnea, anemia, autoimmune disorders, irritable bowel syndrome, and cancer. Alcoholism, side effects from such drugs as sedatives, and b-blockers may be the cause. Psychological conditions, such as insomnia, depression, anxiety, panic attacks, dysthmia, and somatization disorder, may cause fatigue. Common outpatient infectious causes include mononucleosis and sinusitis. These conditions are usually associated with other characteristic signs, but patients may emphasize fatigue and not reveal their other symptoms unless directly asked. The lifetime prevalence of significant fatigue (present for at least 2 weeks) is about 25%. Fatigue of unknown cause or related to psychiatric illness exceeds that due to physical illness, injury, medications, drugs, or alcohol.

B. Chronic Fatigue Syndrome

A working case definition of chronic fatigue syndrome indicates that it is not a homogeneous abnormality, and here is no single pathogenic mechanism (Figure 2–2). No physical finding or laboratory test can be used to confirm the diagnosis of this disorder. 

The evaluation of chronic fatigue syndrome includes a history and physical examination as well as complete blood count, erythrocyte sedimentation rate, serum chemistries blood urea nitrogen (BUN), electrolytes, glucose, creatinine, and calcium; liver and thyroid function tests antinuclear antibody, urinalysis, and tuberculin skin test; and screening questionnaires for psychiatric disorders. Other tests to be performed as clinically indicated are serum cortisol, rheumatoid factor, immunoglobulin levels, Lyme serology in endemic areas, and tests for HIV antibody. More extensive testing is usually unhelpful, including antibody to Epstein-Barr virus. There may be an abnormally high rate of postural hypotension. MRI scans may show brain abnormalities on T2-weighted images—chiefly small, punctate, subcortical white matter hyperintensities, predominantly in the frontal lobes; however, brain MRI is not recommended in the routine evaluation of chronic fatigue syndrome.

Treatment

A. Fatigue

Management of fatigue involves identification and treatment of conditions that contribute to fatigue, such as cancer, pain, depression, disordered sleep, weight loss, and anemia. Resistance training and aerobic exercise lessens fatigue and improves performance for a number of chronic conditions associated with a high prevalence of fatigue, including CHF, COPD, arthritis, and cancer. Continuous positive airway pressure is an effective treatment for obstructive sleep apnea. Psychostimulants such as methylphenidate have shown inconsistent results in randomized trials of treatment of cancer-related fatigue.

B. Chronic Fatigue Syndrome

A variety of agents and modalities have been tried for the treatment of chronic fatigue syndrome. Acyclovir, intravenous immunoglobulin, nystatin, and low-dose hydrocortisone/ fludrocortisone do not improve symptoms except in patients with postural hypotension, some of whom report response to increases in dietary sodium as well as fludrocortisone, 0.1 mg orally daily. There is a greater prevalence of past and current psychiatric diagnoses in patients with this syndrome. Affective disorders are especially common. Patients with chronic fatigue syndrome have benefited from a comprehensive multidisciplinary intervention, including optimal medical management, treating any ongoing affective or anxiety disorder pharmacologically, and implementing a comprehensive cognitive-behavioral treatment program. Cognitive-behavioral therapy, a form of nonpharmacologic treatment emphasizing self-help and aiming to change perceptions and behaviors that may perpetuate
symptoms and disability, is helpful. Although few patients are cured, the treatment effect is substantial. Response to cognitive-behavioral therapy is not predictable on the basis of severity or duration of chronic fatigue syndrome, although patients with low interest in psychotherapy rarely benefit. Graded exercise has also been shown to improve functional work capacity and physical function. At present, cognitive-behavioral therapy and graded exercise are the treatments of choice for patients with chronic fatigue syndrome. A 2011 randomized trial (PACE trial) has confirmed the independent benefits of cognitive behavioral therapy and graded exercise, and found no benefit of adaptive pacing therapy.

In addition, the clinician’s sympathetic listening and explanatory responses can help overcome the patient’s frustrations and debilitation by this still mysterious illness. All patients should be encouraged to engage in normal activities to the extent possible and should be reassured that full recovery is eventually possible in most cases.

When to Refer

• Infections not responsive to standard treatment.
• Difficult to control hyperthyroidism or hypothyroidism.
• Severe psychological disease.
• Malignancy.

When to Admit

• Failure to thrive.
• Fatigue severe enough to impair activities of daily living.