Approach to the Adult Patient with Fatigue

Fatigue is a common, nonspecific symptom that can be caused by a variety of factors, including medical conditions, lifestyle choices, and psychological factors. It is important to evaluate the patient carefully to determine the underlying cause of the fatigue and to develop an appropriate treatment plan.

Definition

The term “fatigue” can be used to describe difficulty or inability to initiate activity (subjective sense of weakness); reduced capacity to maintain activity (easy fatigability); or difficulty with concentration, memory, and emotional stability (mental fatigue). When some patients use the word “fatigue,” careful history reveals that they are referring to sleepiness or an uncontrollable need to sleep. Patients may report one or a combination of these symptoms, and they may occur alone or in conjunction with localized complaints. 
Acute fatigue is defined as lasting one month or less, subacute fatigue as lasting between one and six months, and chronic fatigue as lasting over six months. Patients can have a state of chronic fatigue without meeting criteria for chronic fatigue syndrome (CFS).

Epidemiology

21 to 33 percent of patients seeking attention in primary care settings describe fatigue as an important problem (if not always the chief complaint), resulting in approximately 7 million office visits per year in the United States. Fatigue is reported more commonly in females than males.
The prevalence of fatigue in population-based surveys in Britain and the United States is between 6.0 and 7.5 percent.

History and Physical Examination

The initial evaluation of the patient with fatigue should include a thorough history and physical examination. The history should focus on the following:

• The duration, severity, and pattern of the fatigue
• Any associated symptoms, such as pain, weakness, shortness of breath, or sleep disturbances
• The patient's medical history, including any chronic illnesses or recent infections
• The patient's medication history
• The patient's lifestyle habits, such as smoking, alcohol use, and exercise

The physical examination should focus on the following:

• General appearance and overall health
• Vital signs, including heart rate, blood pressure, respiratory rate, and temperature
• HEENT, neck, chest, abdomen, and extremity examinations

Laboratory Studies

The following laboratory studies may be helpful in evaluating the patient with fatigue:

• Complete blood count (CBC) with differential
• Comprehensive metabolic panel (CMP)
• Thyroid function tests
• Erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP)
• Urinalysis
• Venereal Disease Research Laboratory (VDRL) or rapid plasma reagin (RPR) test for syphilis
• HIV testing

Other Studies

Other studies that may be helpful in evaluating the patient with fatigue include:

• Electrocardiography (EKG)
• Chest x-ray
• Sleep study
• Exercise stress test
• Magnetic resonance imaging (MRI) or computed tomography (CT) scan of the brain or spine

Differential Diagnosis

The differential diagnosis of fatigue is broad and includes a variety of medical, psychological, and lifestyle-related conditions. Some of the more common causes of fatigue include:

• Medical conditions:
  • Anemia
  • Chronic obstructive pulmonary disease (COPD)
  • Heart failure
  • Infection
  • Kidney disease
  • Liver disease
  • Medication side effects
  • Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)
  • Sleep disorders
  • Thyroid disorders
• Psychological conditions:
  • Depression
  • Anxiety
  • Post-traumatic stress disorder (PTSD)
  • Somatoform disorders
• Lifestyle-related factors:
  • Lack of sleep
  • Poor diet
  • Sedentary lifestyle
  • Substance abuse

Treatment

The treatment of fatigue is directed at the underlying cause. For example, anemia may be treated with iron supplements, COPD may be treated with bronchodilators, and heart failure may be treated with diuretics and ACE inhibitors. In some cases, no specific treatment is available, and the goal of treatment is to manage the symptoms. This may include lifestyle changes, such as getting regular exercise, eating a healthy diet, and getting enough sleep. In some cases, medications may be helpful to improve sleep or reduce anxiety.

Prognosis

The prognosis for fatigue varies depending on the underlying cause. In some cases, fatigue is a temporary symptom that resolves with treatment of the underlying condition. In other cases, fatigue may be a chronic condition that requires ongoing management.

Conclusion

Fatigue is a common symptom that can be caused by a variety of factors. It is important to evaluate the patient carefully to determine the underlying cause of the fatigue and to develop an appropriate treatment plan.