What is the recommended workup for a new immigrant presenting with severe fatigue, considering their country of origin, travel history, and potential exposures to infectious diseases?

Workup for Severe Fatigue in New Immigrants

For new immigrants presenting with severe fatigue, begin with fatigue severity quantification using a 0-10 numeric scale, then pursue a focused evaluation targeting infectious diseases endemic to their country of origin (particularly malaria, tuberculosis, and intestinal parasites), alongside standard metabolic and hematologic screening, rather than extensive unfocused testing. 1, 2

Initial Severity Assessment

• Quantify fatigue severity using a 0-10 numeric rating scale over the past 7 days, or categorize as none/mild/moderate/severe 1, 3
• Scores of 4-10 (moderate to severe) warrant immediate focused evaluation 1, 3
• Scores ≥7 typically indicate marked functional impairment requiring urgent workup 1, 3

Focused History Specific to Immigrants

Travel and Exposure History

• Document country of origin and regions visited, as 51% of febrile travelers have visited Africa and 29% Asia, where tropical diseases are endemic 4
• Assess duration of travel and time since arrival, as median presentation is 7 days post-return but can extend to 360 days 4
• Evaluate for pre-travel medical advice and malaria prophylaxis adequacy, as 72.8% have inadequate prophylaxis 4

Associated Symptoms Assessment

• Screen for B symptoms: fever, drenching night sweats, unexplained weight loss >10% over 6 months 2
• Evaluate for pain, pulmonary complaints, and unintentional weight loss, which warrant extensive workup 4
• Assess for diarrheal illness, as acute diarrheal disease accounts for 13.6% of non-tropical infections in travelers 4
• Document lymphadenopathy, hepatosplenomegaly, and skin manifestations 2

Contributing Factors

• Complete medication review including over-the-counter supplements 4, 3
• Screen for emotional distress, depression, and anxiety 3
• Evaluate sleep quality, quantity, and hygiene 3
• Assess alcohol and substance use 3

Laboratory Workup

Essential Initial Screening

• Complete blood count with differential to evaluate for cytopenias, leukocytosis, eosinophilia, or abnormal cells 1, 2
• Comprehensive metabolic panel including liver enzymes, alkaline phosphatase, lactate dehydrogenase, and albumin 1, 2
• Thyroid-stimulating hormone (TSH) to rule out hypothyroidism 1, 2
• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) for inflammation 1, 2

Immigrant-Specific Infectious Disease Screening

Critical for new immigrants given disease prevalence:

• Malaria testing (thick and thin blood smears, rapid diagnostic test) as malaria accounts for 22.2% of all febrile illness and 67.7% of tropical diseases in travelers 4
• Tuberculosis screening with interferon-gamma release assay (IGRA) or tuberculin skin test (TST), followed by chest radiograph if positive 2
• Intestinal parasite screening with stool ova and parasites (3 specimens), as helminthic infections affect 67% of refugees pre-treatment 5
• Strongyloides antibody testing, particularly for those from endemic areas, given risk of hyperinfection syndrome 5
• HIV testing given higher prevalence in certain immigrant populations 2
• Hepatitis B surface antigen and antibody as 10% of refugees may be infected 5

Additional Testing Based on Exposure

• Schistosomiasis serology if freshwater exposure in endemic areas (0.5% prevalence) 4
• Dengue fever serology if from Asia or Latin America (5.2% prevalence in travelers) 4
• Enteric fever blood cultures if prolonged fever (2.3% prevalence) 4
• Rickettsial serology if appropriate exposure history (1.7% prevalence) 4

Imaging Studies

• Chest X-ray as initial screening for pulmonary pathology, tuberculosis, and to evaluate for active TB if screening positive 2
• Contrast-enhanced CT chest/abdomen/pelvis only if red flags present: persistent fever, weight loss, lymphadenopathy, or abnormal laboratory findings 1, 2
• PET/CT reserved for suspected lymphoma or when malignancy is a concern 2

Physical Examination Focus

• Lymph node assessment for regional or diffuse lymphadenopathy 1, 2
• Hepatosplenomegaly evaluation as splenomegaly occurs in malaria, visceral leishmaniasis, and myeloproliferative disorders 2
• Skin examination for rashes, lesions, or signs of parasitic infection 4

Common Pitfalls to Avoid

• Do not overlook malaria even with reported prophylaxis, as it accounts for 70% of tropical disease diagnoses and inadequate prophylaxis is common 4
• Do not delay tuberculosis screening in high-risk populations, as active TB can present with isolated fatigue 2, 6
• Do not miss Strongyloides in refugees from Southeast Asia, as untreated infection can cause chronic fatigue and life-threatening hyperinfection if immunosuppressed 5
• Do not attribute fatigue solely to adjustment stress without ruling out treatable infectious and metabolic causes first 6
• Do not forget anemia screening, as moderate-to-severe anemia (hemoglobin <10 g/dL) affects 14% of refugees and is readily treatable 5

Treatment Considerations

• Initiate structured physical activity with stretching and aerobic exercise 2-3 times weekly for 30-60 minutes regardless of cause, as this benefits all patients 1
• Treat identified infections promptly: helminthic infections decrease from 67% to 12% with appropriate treatment 5
• Address anemia aggressively, as treatment can halve the prevalence of moderate-to-severe anemia 5
• Avoid psychostimulants and dietary supplements as they lack efficacy for fatigue management 1