Differential Diagnosis for a 2-Month-Old Male Infant
Single Most Likely Diagnosis
- Severe Sepsis: This diagnosis is highly likely due to the presence of persistent fever, cough, poor feeding, and laboratory findings such as low hemoglobin, low WBC count with a left shift (though the percentage of neutrophils is low, the absolute count is relevant in this context), thrombocytopenia, and elevated CRP. The clinical presentation and laboratory results are consistent with a severe infection.
Other Likely Diagnoses
- TORCH Infection: Although less likely than sepsis, TORCH infections (Toxoplasmosis, Other (syphilis, varicella-zoster, parvovirus B19), Rubella, Cytomegalovirus (CMV), and Herpes infections) can present with hepatosplenomegaly and systemic symptoms. However, the specific laboratory findings and the presence of fever and cough might lean more towards a bacterial or viral infection rather than a classic TORCH infection.
- Primary Hemophagocytic Lymphohistiocytosis (HLH): This is a rare condition characterized by excessive immune activation, which can present with fever, hepatosplenomegaly, and cytopenias. While it's less likely given the age and the specific laboratory findings, it should be considered, especially if there's a family history or if the patient doesn't respond to treatment for infection.
Do Not Miss Diagnoses
- Congenital Infections (e.g., Congenital CMV, Toxoplasmosis): These can have severe consequences if not promptly diagnosed and treated. They might present with similar symptoms, including hepatosplenomegaly and systemic illness.
- Bacterial Meningitis or Sepsis due to Encapsulated Organisms: In a young infant, bacterial meningitis or sepsis (e.g., due to Streptococcus pneumoniae, Haemophilus influenzae type b, or Neisseria meningitidis) is a medical emergency. The presence of fever, poor feeding, and drowsiness necessitates a lumbar puncture and appropriate antibiotic coverage.
- Disseminated Tuberculosis: Although less common, TB can present with systemic symptoms, hepatosplenomegaly, and can affect any organ. It's crucial to consider, especially in areas with high TB prevalence or in cases where the patient has been exposed to TB.
Rare Diagnoses
- Leukemia or Other Hematological Malignancies: These can present with hepatosplenomegaly, cytopenias, and systemic symptoms. However, they are rare in infants and would typically have other specific findings on laboratory tests or imaging.
- Storage Diseases or Other Metabolic Disorders: Certain metabolic disorders can present with hepatosplenomegaly and systemic illness. They are rare and would require specific diagnostic tests for confirmation.
- Autoimmune Lymphoproliferative Syndrome (ALPS): A rare condition that can mimic HLH and presents with hepatosplenomegaly, lymphadenopathy, and cytopenias due to autoimmune causes.