What is the initial workup for a patient presenting with fatigue?

Initial Workup for Fatigue

The initial workup for fatigue should begin with screening all patients using a numeric rating scale (0-10) or categorization as none, mild, moderate, or severe, with scores of 4-10 (moderate to severe) warranting a more focused evaluation. 1

Initial Assessment

• Screen all patients for fatigue severity using a 0-10 numeric rating scale (0 = no fatigue; 10 = worst fatigue imaginable) or categorize as none, mild, moderate, or severe 2
• Patients with scores of 0-3 (mild) require no further assessment; rescreening at regular intervals is sufficient 2
• Patients with scores of 4-10 (moderate to severe) require a more focused history, physical examination, and laboratory testing 1
• Patients with scores ≥7 typically experience a marked decrease in physical functioning 2

Focused History and Physical Examination

• Conduct a thorough review of systems to identify affected organ systems 1
• Assess fatigue characteristics: onset, pattern, duration, changes over time, and associated or alleviating factors 2
• Evaluate interference with normal functioning and daily activities 1
• Document presence of concerning symptoms such as unintentional weight loss, night sweats, or fever 3
• Review all current medications, including over-the-counter drugs and supplements 2
• Assess for common contributing factors that can be treated immediately:
  • Pain 1
  • Emotional distress (depression, anxiety) 1
  • Sleep disturbances 1
  • Alcohol/substance use 1

Laboratory Studies for Initial Evaluation

• Complete blood count with differential to evaluate for anemia, infection, or malignancy 3
• Basic metabolic panel to assess electrolyte abnormalities and kidney function 3
• Thyroid-stimulating hormone (TSH) to rule out thyroid disorders 3
• Liver function tests to evaluate hepatic causes 3
• Erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP) to screen for inflammatory conditions 3
• Consider HIV testing and tuberculosis screening in at-risk populations 3

Imaging and Additional Testing

• Chest X-ray as initial screening for cardiopulmonary pathology in patients with respiratory symptoms or concerning history 3
• Further testing should be guided by findings from history, physical examination, and initial laboratory results rather than performed routinely 4
• Advanced imaging (CT, MRI, PET) should be reserved for patients with specific indications based on clinical findings 3

Important Considerations

• Medical causes of fatigue are usually evident on initial presentation through history, physical examination, and basic laboratory tests 5
• Sleep disorders, depression, and excessive psychosocial stress are the most common causes of persistent fatigue 4
• Previously undiagnosed cancer is a rare cause of fatigue (0.6% of cases) 4
• If initial evaluation is unremarkable, avoid excessive testing which can lead to overdiagnosis 4
• For patients with chronic fatigue without clear etiology, scheduled regular follow-up visits are more effective than sporadic urgent appointments 6

Management Approach Based on Initial Findings

• For physiologic fatigue: address sleep hygiene, nutrition, and energy balance 7
• For secondary fatigue: treat the underlying condition 7
• For all types of fatigue: recommend a structured plan for regular physical activity including stretching and aerobic exercise 6
• Consider cognitive behavioral therapy for patients with chronic fatigue 6
• Be alert for signs of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), particularly postexertional malaise, which requires a different management approach 7