From pneumonia to pulmonary embolism: refractory Mycoplasma pneumoniae in a 13-year-old girl

Abstract

Macrolide-resistant Mycoplasma pneumoniae pneumonia (MRMP) is increasingly reported in children and may present with extrapulmonary complications, including pulmonary thromboembolism and immune-mediated organ dysfunction. Thromboembolic events related to M. pneumoniae are rare but potentially life-threatening and often associated with transient antiphospholipid antibodies such as anti-beta-2 glycoprotein. A previously healthy 13-year-old girl presented with 7 days of high-grade intermittent fever and productive cough, unresponsive to Oseltamivir and Amoxicillin-Clavulanate. Examination and imaging showed right upper lobe consolidation with minimal pleural effusion. Laboratory evaluation revealed raised ESR and elevated CRP, LDH, ferritin, D-dimer, and procalcitonin, with subsequent maculopapular rash, transaminitis, positive cold agglutinins, following which M. pneumoniae IgM was positive. CTPA confirmed pulmonary thromboembolism, thrombophilia workup showed positive beta-2 glycoprotein antibodies. She was treated with Ceftriaxone and Azithromycin, escalated to Meropenem and Linezolid, and then Doxycycline for suspected MRMP. Persistent fever, high inflammatory markers, and radiological progression warranted Methylprednisolone, resulting in defervescence and clinical improvement. Progressive pleural effusion required thoracentesis, and pulmonary emboli were managed with Enoxaparin. Refractory M. pneumoniae pneumonia in children can be complicated by pulmonary embolism (PE) and transient antiphospholipid antibodies, even without structural heart disease or limb thrombosis. Early suspicion of thrombosis in the presence of elevated D-dimer, prompt CT pulmonary angiography, and combined second-line antibiotics, corticosteroids, and anticoagulants are crucial to optimize outcomes.