Dual Challenge: Managing Complicated Diphtheria in a Child With Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is an aggressive childhood malignancy that is associated with increased risk of infections and toxic deaths, particularly in low- and middle-income countries (LMICs). In febrile neutropenia, the predominant pathogens are Gram-negative bacteria, although Gram-positive organisms such as <i>Staphylococcus aureus</i> are also commonly encountered. Diphtheria, caused by <i>Corynebacterium diphtheriae</i>, although controlled by universal immunization programs of the government, is reported sporadically. We report the occurrence of such a fatal infection at the initial presentation of AML. A 10-year-old boy presented with fever, sore throat, gum swelling, poor oral hygiene, and pallor for a three-day duration. He was subsequently diagnosed with acute myeloid leukemia and was started on induction therapy. The baseline echocardiography showed cardiac dysfunction, and hence, he was managed with modified induction with cytarabine and etoposide only and no anthracyclines. As part of the febrile neutropenia protocol, he was started on antibiotics and antifungals. The complaint of sore throat progressed to membranous tonsillitis within a week. This was swabbed and was found to be positive for <i>Corynebacterium diphtheriae</i>. His further course was complicated by septic shock, myocarditis, and prolonged neutropenia. He was managed with induction chemotherapy for AML, broad-spectrum antimicrobials, anti-diphtheritic serum, granulocyte transfusions, antifungals, and cardiac support. Although he achieved remission from AML and recovered from diphtheria-related complications, the left ventricular dysfunction persisted. He remained positive for measurable residual disease for which he received three lines of therapy in view of refractory AML; in view of non-responsive AML, he was palliated and the family opted to discontinue therapy. To the best of our knowledge, this is the first reported case of pediatric AML, associated with complicated <i>Corynebacterium diphtheriae</i> infection. A review of literature reports the rarity and diagnostic and treatment options in this scenario. It also underscores the need for vigilance regarding vaccine-preventable diseases in pediatric oncology. We also discuss the need for prophylaxis of close contacts. The complicated and abridged induction may have contributed to the persistence of disease and eventual poor outcome in this child. The case underscores the dual challenge of managing AML and treating diphtheria infection, further complicated by myocarditis with left ventricular dysfunction and prolonged neutropenia. Prompt anti-diphtheritic serum helped in defervescence and reversal of symptoms.