A 42-year-old woman presents with anemia (Hb 7.2 g/dL), indirect hyperbilirubinemia, splenomegaly, and spherocytes on peripheral smear. Direct Coombs test is positive (IgG-coated RBCs). Cold agglutinin titer is negative. Which condition most likely underlies this warm autoimmune hemolytic anemia?
- A Mycoplasma pneumoniae infection
- B Chronic lymphocytic leukemia (CLL) ✓
- C Paroxysmal cold hemoglobinuria
- D Infectious mononucleosis (EBV)
Explanation
Warm AIHA (positive direct Coombs for IgG, temperature-optimum 37°C) is secondary to CLL in approximately 5-10% of cases — the most common secondary cause of warm AIHA overall. CLL B cells produce autoantibodies against RBC antigens (particularly Rh antigens). Cold AIHA (positive for C3, IgM) is associated with Mycoplasma pneumoniae and EBV. Paroxysmal cold hemoglobinuria (Donath-Landsteiner antibody, anti-P IgG) follows viral illness in children. The history of a middle-aged woman without recent infection or lymphadenopathy history makes CLL or other lymphoproliferative disease the most important underlying cause to investigate.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.