What investigations are recommended for chronic fatigue in a young, healthy adult with no comorbidities?

Investigations for Chronic Fatigue in a Young Healthy Adult with No Comorbidities

A comprehensive evaluation for chronic fatigue in a young healthy adult should include screening for treatable contributing factors, focused laboratory testing, and assessment of physical and psychological functioning.

Initial Assessment

• Screen for fatigue severity using a quantitative scale (0-10 where 0=no fatigue, 10=worst fatigue) to determine if fatigue is mild (1-3), moderate (4-6), or severe (7-10) 1
• Perform a focused fatigue history including onset, pattern, duration, changes over time, and factors that worsen or alleviate symptoms 1
• Assess impact on daily functioning and quality of life 1

Laboratory Investigations

• Complete blood count with differential to rule out anemia and assess other cell lines 1
• Comprehensive metabolic panel to evaluate electrolytes, hepatic and renal function 1
• Thyroid function tests (TSH) to rule out hypothyroidism 1
• Erythrocyte sedimentation rate or C-reactive protein to assess for systemic inflammation 1
• Consider testing vitamin D, iron studies, and B12 levels 1

Assessment of Contributing Factors

• Evaluate for sleep disturbances which are present in 30-75% of patients with chronic fatigue 1
• Screen for emotional distress, anxiety, and depression which commonly co-occur with fatigue 1
• Review medication side effect profiles, particularly those causing sedation 1
• Assess nutritional status and recent weight changes 1
• Evaluate activity level and potential deconditioning 1
• Screen for alcohol or substance use that may contribute to fatigue 1

Additional Considerations

• If fatigue is moderate to severe (score ≥4) and persists despite addressing treatable factors, consider referral to appropriate specialists 1
• For persistent unexplained fatigue lasting more than 6 months with significant functional impairment, consider evaluation for chronic fatigue syndrome 2, 3
• Avoid extensive, repeated testing if initial laboratory results are normal, as studies show this affects management in only 5% of patients 4

Management Approach

• Encourage regular physical activity with a structured exercise program, even if moderate (such as walking), as this is a category 1 recommendation for managing fatigue 1
• Address sleep hygiene and treat any identified sleep disorders 1, 3
• Provide education about fatigue patterns and self-monitoring strategies 1
• Consider cognitive behavioral therapy for persistent fatigue 2, 4
• Schedule regular follow-up visits rather than sporadic urgent appointments for effective long-term management 4

Common Pitfalls to Avoid

• Assuming all fatigue is psychological in origin without adequate medical evaluation 3
• Conducting excessive laboratory testing beyond initial screening in the absence of specific clinical indicators 4
• Failing to recognize that fatigue may persist even after treating identifiable contributing factors 1
• Not addressing lifestyle factors such as physical activity, sleep, and stress management 1, 4