What is the initial approach to a fatigue workup?

Initial Approach to Fatigue Workup

The initial approach to fatigue workup should include a focused history and physical examination to identify the nine key contributing factors: pain, emotional distress, sleep disturbance, anemia, nutrition, activity level, alcohol/substance abuse, medication side effects, and comorbidities. 1

Assessment Framework

Step 1: Evaluate Fatigue Severity

• Use a 0-10 numeric rating scale:
  • 0: No fatigue
  • 1-3: Mild fatigue (requires education only)
  • 4-6: Moderate fatigue (requires evaluation)
  • 7-10: Severe fatigue (requires prompt evaluation) 1

Step 2: Focused History and Physical Examination

When fatigue is rated as moderate to severe (4-10), conduct:

1. Disease status assessment:

   • Current health conditions
   • Duration and pattern of fatigue
   • Onset and progression
   • Associated or alleviating factors
   • Impact on daily functioning 2, 1

2. Review of systems to determine affected organ systems and guide diagnostic workup 2

3. In-depth fatigue assessment:

   • Pattern (constant, intermittent, post-exertional)
   • Duration and change over time
   • Interference with normal functioning
   • Patient's self-assessment of causes 2

Step 3: Evaluate Key Contributing Factors

1. Pain: Assess location, severity, and impact on daily activities 2, 1

2. Emotional distress: Screen for depression and anxiety, as fatigue is an independent predictor of depression 2, 1

3. Sleep disturbance: Evaluate sleep quality, duration, and hygiene practices 1

   • Sleep disorders affect 30-75% of patients with fatigue 1

4. Anemia: Check for symptoms like pallor, shortness of breath 1

5. Nutrition: Assess dietary habits, weight changes, appetite 1

6. Activity level: Evaluate exercise habits and daily physical activity 1

7. Alcohol/substance abuse: Screen for use patterns and dependency 1

8. Medication side effects: Review current medications with sedating properties 1

9. Comorbidities: Assess for underlying medical conditions 1

Step 4: Initial Laboratory Studies

Include the following basic tests:

• Complete blood count
• Comprehensive metabolic panel
• Thyroid-stimulating hormone
• Urinalysis
• Erythrocyte sedimentation rate
• C-reactive protein
• Iron studies
• Vitamin B12 and folate levels
• Vitamin D level 1

Important caveat: Laboratory studies affect management in only 5% of patients with fatigue, and if initial results are normal, repeat testing is generally not indicated 3

Classification of Fatigue

Categorize fatigue into one of three types to guide management:

1. Physiologic fatigue: Related to lifestyle factors, can be addressed through sleep hygiene, diet, and balancing energy expenditure 4

2. Secondary fatigue: Due to underlying medical conditions; improves with treatment of the primary condition 4

3. Chronic fatigue: May include myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), characterized by postexertional malaise 4

Common Pitfalls to Avoid

• Attributing fatigue solely to one cause without comprehensive evaluation
• Overlooking psychological factors
• Dismissing fatigue as "normal" when it significantly impacts quality of life
• Prescribing exercise without proper assessment of underlying conditions 1
• Excessive focus on somatic causes leading to overdiagnosis 5
• Failing to recognize that previously undiagnosed cancer is a rare cause (only 0.6% of cases) 5
• Missing the fact that depression (18.5%) and excessive psychosocial stress are among the most common causes of persistent fatigue 5

Management Approach

For all types of fatigue:

• Develop a structured plan for regular physical activity (except in ME/CFS where it may worsen symptoms) 3, 4
• Optimize sleep hygiene 1
• Consider cognitive behavioral therapy for persistent fatigue 1, 4
• Schedule regular follow-up visits rather than sporadic urgent appointments 3

By systematically evaluating these factors and classifying the type of fatigue, clinicians can develop an effective management plan that addresses the underlying causes and improves patient outcomes.