Wednesday, July 23, 2008

Chronic Fatigue Syndrome

Chronic fatigue is relatively common, but criteria-based chronic fatigue syndrome (CFS) is rare. Fatigue is defined as severe mental and physical exhaustion that differs from somnolence or lack of motivation and is not attributable to exertion or diagnosable disease. Chronic fatigue is defined as persistent or relapsing fatigue lasting 6 or more consecutive months. CFS is characterized by severe disabling fatigue lasting more than 6 months and symptoms that feature impairments in concentration and short-term memory, sleep disturbances, and musculoskeletal pain. About 24% of patients complain of fatigue.

Management of the fatigued patient

Regular exercise will improve functional capacity, mood, and sleep. Regular sleep habits should be advised. In those complaining of depressive symptoms or sleep disturbance, an antidepressant or sleep hypnotic is indicated. A sedating antidepressant, such as <<>>amitriptyline (Elavil) 25 mg qhs, may be helpful for complaints of insomnia or restlessness. If the primary complaints are hypersomnia and psychomotor retardation, a selective serotonin reuptake inhibitor is indicated.

For physical symptoms such as headaches, myalgias, or arthralgias, nonsteroidal anti-inflammatory agents may be helpful. Therapies for which no effectiveness has been demonstrated in CFS include vitamins, acyclovir, gamma globulin, folic acid, cyanocobalamin, and magnesium.

Laboratory evaluation of chronic fatigue

Specific physical findings such as nonexudative pharyngitis, lymphadenopathy, skin rashes, muscle tenderness and orthostatic hypotension are often seen in chronic fatigue syndrome patients. The Romberg test and tandem gait test may be abnormal in up to 20% of chronic fatigue syndrome patients.

For all patients

  • Complete blood cell count with differential
  • Erythrocyte sedimentation rate
  • Urinalysis

Other tests based on findings

  • Thyroid stimulating hormone
  • Blood Chemistry levels:
  • Alanine aminotransferase
  • Aspartate aminotransferase
  • Blood urea nitrogen
  • Electrolytes
  • Glucose
  • Heterophil antibody test (Monospot)
  • Serologic studies for Lyme or HIV antibody titers

Chronic Fatigue Syndrome Clinical evaluation

Evaluation of chronic fatigue should exclude diseases associated with fatigue. The time of onset of symptoms and the nature of the fatigue should be determined. Chronic fatigue syndrome is characterized by fatigue that is typically present throughout the day (even upon awakening), worsens with exercise, and is not improved with rest.

Fever, chills, night sweats, weight loss or anorexia may be seen in chronic fatigue syndrome; however, infectious disease or malignancy should also be considered. Confusion and cognitive difficulties are reported by nearly all chronic fatigue syndrome patients.

Headaches, myalgias, arthralgias, and painful adenopathy are common complaints in chronic fatigue syndrome, although the presence of arthritis may also suggest connective tissue diseases. Anhedonia is suggestive of depression.

Recent travel, insect bites, tick exposure, skin rashes, and use of prescription and over-the-counter drugs should be sought.

Common causes of Chronic Fatigue Syndrome

The differential diagnosis of fatigue includes many infections, malignancies, endocrinopathies, and connective tissue disease. The psychiatric illnesses include depression, anxiety, bipolar disease, and somatoform and psychotic disorders. Depression is one of the most common underlying diagnoses when fatigue is a primary complaint.

  • Depression
  • Environment (lifestyle)
  • Anxiety, anemia, asthma
  • Diabetes
  • Infections
  • Thyroid, tumors
  • Rheumatologic
  • Endocarditis, cardiovascular
  • Drugs

Anxiety. Both depression and anxiety tend to be accompanied by sleep disturbance symptoms. Anemia characteristically will cause a more generalized physical fatigue without sleep disturbances. Asthma and other lung diseases are common causes of fatigue.

Diabetes should be considered in the obese patient with fatigue. Hypothyroidism and hyperthyroidism are easily treatable causes of fatigue. Tumors and other malignancies may cause tiredness. Many infections cause fatigue, including viruses, tuberculosis, Lyme disease, and HIV infection.

Rheumatologic disorders, including rheumatoid arthritis, systemic lupus erythematosus and fibromyalgia, are common causes of fatigue.

Endocarditis is a very rare cause of fatigue associated with valvular and other cardiovascular diseases.

Drugs that may cause fatigue including analgesics, psychotropics, antihypertensives, and antihistamines. Over-the-counter medications and substance abuse (caffeine, alcohol, and illicit drugs) may cause fatigue.