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

Initial Workup for Extensive Fatigue

The initial workup for a patient presenting with extensive fatigue should begin with screening for fatigue severity using a numeric rating scale (0-10) or categorization as none, mild, moderate, or severe, followed by a targeted evaluation based on severity level. 1, 2

Initial Assessment

• Screen all patients using a numeric rating scale (0-10) or categorization as none/mild/moderate/severe 3, 2
• Patients with scores of 0-3 (mild) require no further assessment; rescreening at regular intervals is sufficient 3, 2
• Patients with scores of 4-10 (moderate to severe) warrant a more focused evaluation 3, 2
• Note that scores ≥7 typically correlate with marked decrease in physical functioning 3, 2

Focused History and Physical Examination

• Document onset, pattern, duration, and changes in fatigue over time 2
• Assess for B symptoms (fever, drenching night sweats, unexplained weight loss >10% of body weight over 6 months) 1
• Evaluate for associated symptoms such as pain, cough, dyspnea, or lymphadenopathy 1
• Assess interference with normal functioning and daily activities 2
• Explore patient's self-assessment of potential causes 2

Laboratory Studies for Moderate to Severe Fatigue

• Complete blood count with differential to evaluate for cytopenias, leukocytosis, or abnormal cells 1
• Basic metabolic panel and liver function tests (liver enzymes, alkaline phosphatase, LDH, albumin) 1
• Thyroid-stimulating hormone (TSH) to rule out thyroid dysfunction 1
• Inflammatory markers: erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) 1
• Consider HIV testing and tuberculosis screening (IGRA or TST) in at-risk patients 1
• Consider vitamin D level in patients with risk factors for deficiency 4

Imaging Studies When Indicated

• Chest X-ray as initial screening for pulmonary pathology when respiratory symptoms are present 1
• Consider contrast-enhanced CT scan of neck, chest, and abdomen if lymphadenopathy, organomegaly, or malignancy is suspected 1
• Consider PET/CT scan if lymphoma is suspected based on other findings 1

Assessment of Common Contributing Factors

• Pain assessment, as it commonly clusters with fatigue 2
• Screen for emotional distress, depression, and anxiety 3, 2
• Evaluate sleep disturbance (quality, quantity, and hygiene) 3, 2
• Review medication side effects as potential contributors to fatigue 2, 5
• Screen for alcohol/substance use 2

Important Considerations and Pitfalls

• Medical causes of fatigue are usually evident on initial presentation; excessive testing in the absence of specific findings should be avoided 6, 5
• Previously undiagnosed cancer is a rare cause of fatigue (0.6% of cases) 5
• Depression (18.5%) and excessive psychosocial stress are among the most common causes of persistent fatigue 5
• Sleep disorders and sleep-related breathing disorders are frequent contributors to fatigue 5
• If the diagnosis remains unclear after initial evaluation, watchful waiting with scheduled follow-up is preferred over excessive testing 5
• For cancer survivors, disease recurrence or treatment effects should be considered as potential causes of fatigue 2

Management Approach

• When no clear organic cause is found, provide a positive explanation distinguishing between predisposing, triggering, and perpetuating factors 7
• Promote a consistent pattern of activity, rest, and sleep 7
• Consider moderate-intensity exercise (walking, swimming, cycling) 2-3 times weekly for 30-60 minutes 3
• Address any identified contributing factors (pain, sleep disturbance, emotional distress) 3, 2
• Consider cognitive-behavioral approaches for persistent unexplained fatigue 7
• Avoid prescribing medications specifically for fatigue unless treating an identified underlying cause 3, 7