Differential Diagnosis for Fever with Thrombocytopenia and Splenomegaly

Single Most Likely Diagnosis

• Viral Infections (e.g., Epstein-Barr Virus - Infectious Mononucleosis): This condition often presents with fever, thrombocytopenia, and splenomegaly due to the viral infection affecting the spleen and bone marrow, leading to these clinical manifestations.

Other Likely Diagnoses

• Malaria: Particularly in endemic areas, malaria can cause fever, thrombocytopenia, and splenomegaly due to the parasite's effect on red blood cells and the spleen's response to infection.
• Bacterial Endocarditis: This condition can lead to fever, thrombocytopenia (due to immune mechanisms or splenic sequestration), and splenomegaly as a result of the infection and subsequent immune response.
• Lymphoma: Certain types of lymphoma can present with systemic symptoms like fever, along with splenomegaly and thrombocytopenia due to bone marrow involvement or splenic sequestration.

Do Not Miss Diagnoses

• Sepsis: Although sepsis might not initially present with all three symptoms, it can lead to thrombocytopenia and splenomegaly in severe cases, especially if there's a focus of infection involving the spleen. Missing sepsis can be fatal.
• Tuberculosis: TB can cause fever, thrombocytopenia, and splenomegaly, particularly in immunocompromised patients or those with disseminated disease. It's crucial not to miss TB due to its treatability and potential for severe outcomes if untreated.
• HIV/AIDS: Early or late stages of HIV infection can present with these symptoms due to opportunistic infections, bone marrow suppression, or lymphoproliferative disorders. Missing HIV/AIDS can lead to delayed treatment and poor outcomes.

Rare Diagnoses

• Langerhans Cell Histiocytosis: A rare disorder that can cause fever, thrombocytopenia, and splenomegaly due to infiltration of the spleen and bone marrow by Langerhans cells.
• Gaucher's Disease: A genetic disorder leading to splenomegaly and can sometimes present with thrombocytopenia due to splenic sequestration. Fever might be less common but can occur in the context of infections or other complications.
• Kala-Azar (Visceral Leishmaniasis): This parasitic infection can cause fever, thrombocytopenia, and splenomegaly, particularly in endemic areas. It's rare in many parts of the world but critical to diagnose due to its treatability and potential severity.