What is the approach to a fatigue workup?

Approach to Fatigue Workup

A comprehensive fatigue workup should begin with quantifying fatigue severity on a 0-10 scale, followed by a focused evaluation of treatable contributing factors including pain, emotional distress, sleep disturbance, anemia, nutrition, activity level, medication side effects, substance use, and comorbidities. 1

Initial Assessment

• Screen all patients using a numeric rating scale (0-10) or categorization as none, mild, moderate, or severe 1
• Scores of 0-3 (mild) require no further assessment; rescreening at regular intervals is sufficient 1
• Scores of 4-10 (moderate to severe) warrant a more focused evaluation 1
• Note that patients with scores ≥7 typically experience marked decrease in physical functioning 1

Focused History and Physical Examination

For patients with moderate to severe fatigue (score 4-10), conduct:

• Thorough review of systems to identify affected organ systems 1
• In-depth fatigue assessment including:
  • Onset, pattern, duration, and changes over time 1
  • Associated or alleviating factors 1
  • Interference with normal functioning and daily activities 1
  • Patient's self-assessment of potential causes 1

Assessment of Treatable Contributing Factors

Evaluate for common causative elements:

• Pain: Assess and treat effectively as it commonly clusters with fatigue 1
• Emotional distress: Screen for depression and anxiety, which frequently co-occur with fatigue 1
• Sleep disturbance: Evaluate sleep quality, quantity, and hygiene 1
• Anemia: Check complete blood count 1, 2
• Nutrition: Assess dietary intake and nutritional status 1, 3
• Activity level: Evaluate current physical activity patterns 1, 3
• Medication side effects: Review all prescriptions, over-the-counter medications, and supplements 1
• Alcohol/substance use: Screen for misuse that may contribute to fatigue 1
• Comorbidities: Evaluate for conditions like hypothyroidism, cardiac disease, and other medical conditions 1, 2

Laboratory Testing

• Basic laboratory testing should be targeted based on history and physical findings 4, 2
• Note that laboratory studies affect management in only about 5% of patients 3
• If initial results are normal, repeat testing is generally not indicated 3
• Consider:
  • Complete blood count (anemia) 1, 2
  • Thyroid function tests 1, 2
  • Basic metabolic panel 4, 2
  • Additional testing only if warranted by specific symptoms or findings 2

Classification and Management Approach

Fatigue can be classified as:

• Physiologic fatigue: Address with proper sleep hygiene, healthy diet, and balanced energy expenditure 4, 3
• Secondary fatigue: Treat the underlying condition 4, 2
• Chronic fatigue: Consider cognitive behavioral therapy, exercise therapy (when appropriate), and symptom management 4, 3

Special Considerations

• For cancer survivors, consider disease recurrence or treatment effects as potential causes 1
• For patients with suspected myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), assess for postexertional malaise and avoid recommending exercise that may worsen symptoms 4
• Regular follow-up visits are more effective than sporadic urgent appointments for long-term management 3

Common Pitfalls to Avoid

• Focusing exclusively on somatic causes, which can lead to overdiagnosis 2
• Ordering excessive laboratory tests when initial results are normal 2, 3
• Failing to address lifestyle factors and psychosocial stressors 2, 3
• Overlooking medication side effects as potential contributors to fatigue 1
• Not recognizing that fatigue rarely occurs in isolation and often clusters with other symptoms 1