A patient who arrived from Sudan two weeks ago presents with fever, night sweats, and pancytopenia. What is the full differential diagnosis?

Differential Diagnosis for Fever, Night Sweats, and Pancytopenia in a Recent Traveler from Sudan

This patient requires immediate exclusion of malaria, followed by systematic evaluation for visceral leishmaniasis, typhoid fever, brucellosis, tuberculosis, and HIV, as these are the most life-threatening and treatable causes in a Sudanese traveler presenting with this triad.

Immediate Life-Threatening Considerations

Malaria (Plasmodium falciparum)

• Most critical diagnosis to exclude first 1, 2
• Sudan is highly endemic for malaria, particularly sub-Saharan Africa where P. falciparum predominates
• Can rapidly progress to severe disease with pancytopenia, altered mental status, and death
• Obtain thick and thin blood smears immediately - repeat every 12-24 hours if initially negative but suspicion remains 2
• Pancytopenia occurs through splenic sequestration and bone marrow suppression
• Critical pitfall: Malaria can present with normal or deranged blood counts in any pattern 1

Visceral Leishmaniasis (Kala-azar)

• Classic presentation matching this patient 1
• Endemic in Horn of Africa including Sudan
• Presents with prolonged fever, night sweats, hepatosplenomegaly, and pancytopenia
• Diagnosis: Leishmaniasis serology and bone marrow examination 1
• Progressive and fatal if untreated
• Look specifically for splenomegaly on physical exam

High-Priority Infectious Causes

Typhoid Fever (Enteric Fever)

• Common in sub-Saharan Africa travelers, especially those visiting friends and relatives 1
• Fever is almost invariable; other symptoms non-specific (headache, constipation/diarrhea, dry cough)
• Blood counts may be normal or deranged in any pattern 1
• Obtain blood cultures immediately - highest yield within first week of symptoms 1
• Bone marrow culture has higher sensitivity than blood culture if initial cultures negative
• Complications (GI bleeding, perforation, encephalopathy) occur in 10-15% if duration >2 weeks 1

Brucellosis

• Endemic in Middle East and sub-Saharan Africa 1
• Presents with fever, night sweats, hepatosplenomegaly, and can cause pancytopenia 3, 4
• Ask specifically about unpasteurized dairy products or livestock contact 1
• Diagnosis: Extended blood cultures and serology 1
• Can mimic other rheumatological conditions and elevate autoimmune markers 4

Tuberculosis (TB)

• Highly endemic in Sudan
• Can present with fever, night sweats, weight loss, and pancytopenia (through bone marrow involvement or miliary disease)
• Obtain chest X-ray, sputum for AFB if respiratory symptoms present
• Consider miliary TB if no focal findings 5

HIV/Acute Retroviral Syndrome

• Can present with fever, night sweats, lymphadenopathy, and cytopenias 1
• Obtain HIV antigen and antibody testing 1
• Pitfall: Many rapid tests do not detect seroconversion illness 1

Additional Important Considerations

Viral Hemorrhagic Fevers (VHF)

• Rare but critical to identify due to infection control implications
• Endemic in sub-Saharan Africa (Ebola, Lassa fever, Crimean-Congo hemorrhagic fever) 1
• Always contact regional infectious disease center if suspected 1
• Look for bleeding manifestations, severe thrombocytopenia

Rickettsial Infections

• Consider if history of tick exposure in game parks 1
• Presents with fever, headache, possible rash or eschar
• Empirical doxycycline if high suspicion 1

Acute Schistosomiasis (Katayama Fever)

• Occurs 4-8 weeks after freshwater exposure 1
• Fever, eosinophilia (though pancytopenia would be atypical)
• Consider if appropriate exposure history

Trypanosomiasis (African Sleeping Sickness)

• Travel to game parks in sub-Saharan Africa 1
• Fever, hepatosplenomegaly
• Diagnosis: Blood film 1

Non-Infectious Causes to Consider

Hematologic Malignancies

• Lymphoma, leukemia, myelofibrosis can present with B-symptoms (fever, night sweats) and pancytopenia 6
• Look for lymphadenopathy, splenomegaly
• Peripheral smear may show abnormal cells

Nutritional Deficiencies

• Vitamin B12 deficiency can present with pancytopenia, fever, and even lymphadenopathy 6
• Though less likely given acute presentation from endemic area
• Check B12, folate levels if other causes excluded

Diagnostic Algorithm

Immediate (within hours):

1. Thick and thin blood smears for malaria (repeat if negative)
2. Complete blood count with differential and peripheral smear review
3. Blood cultures (hold at room temperature for potential Leptospira) 1
4. Basic metabolic panel, liver function tests, lactate dehydrogenase
5. Chest X-ray

Within 24-48 hours: 6. HIV antigen/antibody testing 7. Leishmaniasis serology 8. Brucella serology and extended blood cultures 9. Typhoid serology (though less reliable than culture) 1 10. Hepatitis serologies (HAV IgM, HBsAg, HEV IgM) if jaundice present 1 11. Tuberculosis evaluation (sputum AFB, tuberculin skin test or IGRA)

If initial workup negative: 12. Bone marrow examination (for leishmaniasis, TB, malignancies, culture) 13. Abdominal ultrasound or CT (assess for hepatosplenomegaly, lymphadenopathy, abscess) 14. Rickettsial serologies if appropriate exposure 15. VHF testing if epidemiologically appropriate (contact infectious disease specialist first)

Critical Management Points

• Do not delay malaria treatment if high clinical suspicion - can be fatal within hours 2
• Empirical antibiotics for typhoid (IV ceftriaxone preferred given fluoroquinolone resistance) if unstable and high suspicion 1
• Empirical doxycycline for rickettsial disease if tick exposure and appropriate presentation 1
• Isolate patient if VHF suspected until excluded 1
• Common pitfall: Assuming all fever in endemic travelers is malaria - other causes like typhoid, visceral leishmaniasis, and brucellosis require different treatments and can be equally fatal 1, 7