Differential Diagnosis for 51-year-old Male with Low WBC

• Single Most Likely Diagnosis
  • Viral infection (e.g., influenza, mononucleosis): A common cause of transient leukopenia, especially in the context of a viral illness.
• Other Likely Diagnoses
  • Medication-induced leukopenia (e.g., chemotherapy, antibiotics): Various medications can suppress bone marrow function, leading to low WBC counts.
  • Vitamin deficiencies (e.g., vitamin B12, folate): Deficiencies in these vitamins can impair bone marrow production, resulting in leukopenia.
  • Chronic diseases (e.g., renal failure, liver disease): Certain chronic conditions can lead to leukopenia due to inflammation, malnutrition, or other mechanisms.
  • Hypersplenism: Enlargement of the spleen can lead to sequestration of white blood cells, resulting in a low peripheral WBC count.
• Do Not Miss Diagnoses
  • Aplastic anemia: A rare but potentially life-threatening condition characterized by bone marrow failure, which can present with leukopenia.
  • Leukemia (e.g., acute lymphoblastic leukemia, chronic lymphocytic leukemia): Although less common, leukemia can cause leukopenia, especially in the early stages.
  • HIV/AIDS: A significant cause of leukopenia, particularly in individuals with advanced disease or those who are untreated.
  • Severe sepsis: In some cases, severe sepsis can lead to leukopenia, which is a poor prognostic sign.
• Rare Diagnoses
  • Congenital disorders (e.g., Kostmann syndrome, Shwachman-Diamond syndrome): Rare genetic conditions that can cause leukopenia due to bone marrow dysfunction.
  • Autoimmune disorders (e.g., systemic lupus erythematosus): Certain autoimmune conditions can lead to leukopenia due to immune system dysregulation.
  • Myelodysplastic syndromes: A group of disorders characterized by bone marrow dysfunction, which can present with leukopenia.
  • Lymphoma: Some types of lymphoma can cause leukopenia, especially if there is bone marrow involvement.