Resolution of cor pulmonale after medical management in a patient with cblC-type methylmalonic aciduria and homocystinuria: a case report

Abstract

We describe a 3-year-old Hispanic male with cblC-type methylmalonic aciduria and homocystinuria who presented to the emergency department with progressive tachypnea, vomiting, and edema secondary to pulmonary embolism and cor pulmonale. With aggressive medical management, there was complete resolution of right heart failure and pulmonary hypertension after 3 months. Pulmonary embolism is rare in the pediatric population. Children with cblC-type methylmalonic aciduria and homocystinuria may be at increased risk for thrombus formation and pulmonary embolism due to chronic hyperhomocystinemia, a risk factor for thrombus formation in the adult population. Aspirin therapy may be indicated in children with inborn errors of metabolism that predispose to hyperhomocystinemia.

Figure 1.

Schematic illustrating how the molecular defect in cblC results in the accumulation of methylmalonic acid and homocysteine.

Figure 2.

Parasternal short axis 2D echocardiographic images. (A) At the time of admission there was severe right ventricular (RV) dilation and evidence of RV hypertension with marked interventricular septal (IVS) flattening in systole. (B) At 2.5 month follow-up, the RV size is normal and there is resolution of RV hypertension with no IVS flattening in systole.

Figure 3.

Spectral Doppler interrogation of severe tricuspid regurgitation showing a maximal instantaneous gradient of 48 mmHg. The right ventricular systolic pressure is estimated at 48 mmHg plus the right atrial pressure (more than one-half systemic pressure with systolic BP of 100 mmHg) using the modified Bernoulli equation.

Figure 4.

Spectral Doppler interrogation of the pulmonary regurgitant jet showing the pulmonary artery diastolic pressure to be elevated at 35 mmHg above the right ventricular end diastolic pressure.