Cold Agglutinin Syndrome

This case involves a 3-year-old girl who presented with dark urine and jaundice one week after an upper respiratory infection. Physical exam showed conjunctival pallor, scleral icterus, and pharyngeal erythema with exudates. Laboratory findings confirmed anemia with hemolysis. Peripheral-blood smear showed erythrocyte agglutination, reticulocytes, spherocytes, and striking rosettes of neutrophils coated with agglutinated red cells. Rare phagocytosis of erythrocytes by neutrophils and macrophages was documented. A direct antiglobulin test (DAT) was positive for C3d and weakly positive for IgG. Cold agglutinin titer was 1:1024. Viral testing ruled out Mycoplasma pneumoniae, Epstein–Barr virus, and other common respiratory pathogens. Diagnosis: Cold Agglutinin Syndrome (CAS) as autoimmune hemolytic anemia triggered by viral upper respiratory infection. The patient received supportive care (blood transfusions and cold avoidance). At 3-week follow-up, anemia had resolved, and the child was clinically well.

This case involves a 3-year-old girl who presented with dark urine and jaundice one week after an upper respiratory infection. Physical exam showed conjunctival pallor, scleral icterus, and pharyngeal erythema with exudates. Laboratory findings confirmed anemia with hemolysis. Peripheral-blood smear showed erythrocyte agglutination, reticulocytes, spherocytes, and striking rosettes of neutrophils coated with agglutinated red cells. Rare phagocytosis of erythrocytes by neutrophils and macrophages was documented. A direct antiglobulin test (DAT) was positive for C3d and weakly positive for IgG. Cold agglutinin titer was 1:1024. Viral testing ruled out Mycoplasma pneumoniae, Epstein–Barr virus, and other common respiratory pathogens. Diagnosis: Cold Agglutinin Syndrome (CAS) as autoimmune hemolytic anemia triggered by viral upper respiratory infection. The patient received supportive care (blood transfusions and cold avoidance). At 3-week follow-up, anemia had resolved, and the child was clinically well.