Toxocara Myopericarditis and Cardiac Magnetic Resonance Imag
A 9-year-old generally healthy girl with a history of a small muscular ventricular septal defect presented to the emergency room with chest pain and dyspnea. She had recovered from a recent upper respiratory infection and had also sustained minor trauma to the anterior chest wall in a fall a week prior. At presentation, she appeared well with temperature, 98.6 degrees Fahrenheit; heart rate, 104 beats per minute; respiratory rate, 28 breaths per minute; blood pressure, 113/66mmHg; pulsus paradoxus, 8mmHg; and normal pulse oximetry with minimal pulse amplitude variation on plethysmography. Her physical exam was notable only for mild tenderness over the sternum, with normal findings on cardiac auscultation. Chest radiography revealed a mildly enlarged cardiomediastinal silhouette and a focal opacity over the right middle lung possibly representing infection or pulmonary contusion. An electrocardiogram (ECG) was normal. Echocardiography demonstrated a moderate-sized circumferential pericardial effusion, right atrial collapse, normal inflow and outflow variability across valves, normal biventricular systolic function, and no ventricular septal defect. Laboratory findings were notable for a leukocyte count of 12,000 cells/µl with an elevated absolute eosinophil count of 1,570 cells/µl, elevated C-reactive protein of 1.94mg/dL, elevated erythrocyte sedimentation rate of 45mm/hr, and elevated cardiac troponin T of 0.25ng/mL. CMR showed an elevated myocardial global T2 value (70 ms), an elevated native myocardial global T1 value (1150ms), increased left ventricular wall thickness, and a moderate-sized pericardial effusion. There was no myocardial late gadolinium enhancement.

Chest computed tomography revealed multiple pulmonary nodules with adjacent ground-glass opacities, consistent with vasculitis or infection. In the absence of systemic symptoms, an infectious workup was broadened, and a full rheumatologic evaluation and steroid initiation was postponed until the results of the infectious diseases workup were finalized. Microbiologic testing included negative PCRs for influenza, respiratory syncytial virus, parainfluenza virus, rhinovirus, and adenovirus. Bartonella henselae titers and a T-SPOT tuberculosis test were also negative. Mycoplasma pneumonia IgM and IgG were elevated, but nasopharyngeal Mycoplasma PCR was negative. Toxocara serology was sent and was pending at discharge on hospital day 3.

At a two-week follow-up visit, the patient remained asymptomatic on ibuprofen and colchicine. Diffuse T-wave inversion appeared on serial ECGs, consistent with pericarditis. Her absolute eosinophil count continued to rise to 2,450 cells/µl. Twelve days into her illness, the Toxocara antibody resulted positive. An abdominal ultrasound examination was normal, without signs of liver involvement. A repeat echocardiogram showed a very small residual pericardial effusion. Ibuprofen and colchicine were discontinued, and treatment was initiated with a five-day course of oral albendazole (6mg/kg/dose twice daily) and prednisolone (0.5mg/kg/dose twice daily). At late follow-up there was a normal eosinophil count, and on echocardiogram, there was normal ventricular function and no pericardial effusion.