Diagnostic dilemma between Mycoplasma pneumoniae, leptospirosis and severe dengue in a child presenting with shock: a case report

Abstract

Acute febrile illness with shock in children is a common pediatric emergency in tropical countries and often poses a diagnostic challenge. Severe dengue and leptospirosis are important differentials because of their overlapping manifestations, including thrombocytopenia, hepatic dysfunction, shock and multiorgan involvement. Rarely, atypical bacterial infections such as mycoplasma pneumoniae may present with severe extrapulmonary manifestations closely mimicking tropical infections. An 8-year-old boy presented with fever for 7 days, vomiting, facial and pedal edema, abdominal pain, red-coloured urine and altered sensorium. On examination, he had hypovolemic shock, respiratory distress, tender hepatomegaly, splenomegaly and encephalopathy. Laboratory investigations revealed anemia, thrombocytopenia, hyponatremia, transaminitis, conjugated hyperbilirubinemia, hypoalbuminemia, hematuria and proteinuria. Initial dengue IgM was weakly reactive, raising suspicion of severe dengue. Leptospirosis was also considered because of disproportionate hyperbilirubinemia and splenomegaly. The child deteriorated with respiratory failure requiring mechanical ventilation and inotropic support. The tropical fever panel, including dengue PCR, leptospira PCR, malaria and typhoid testing, was negative. Subsequently, Mycoplasma pneumoniae IgM returned positive. Following the treatment with azithromycin along with intensive supportive care, the child improved clinically and was discharged after 10 days. Mycoplasma pneumoniae is classically described as a cause of “walking pneumonia" but rarely can present with severe extrapulmonary manifestations, including shock and multiorgan dysfunction. This case highlights the diagnostic overlap between severe dengue, leptospirosis and mycoplasma pneumoniae infection in tropical settings. Clinicians should maintain a broad differential diagnosis in children presenting with shock and thrombocytopenia, particularly when initial investigations for common tropical infections are inconclusive.