Migration of VP Shunt Causing Pulmonary Infarction

Posted By Connor Crowley
Migration of VP Shunt Causing Pulmonary Infarction

CASE: A three-year-old male presented with a one-week history of fussiness, lack of appetite, intermittent nausea and vomiting, and a one-day history of fever. Five weeks prior, he had a VP shunt placed for persistent hydrocephalus following resection of a cerebellar astrocytoma. To evaluate for shunt malfunction, shunt series radiographs were acquired. These demonstrated an abnormal location of the shunt tubing, which coursed over the heart with the catheter tip seen projecting over the right middle lobe (Fig. 1). A lateral chest radiograph confirmed the intracardiac course of the shunt tube (Fig. 2). Transthoracic echocardiography was subsequently performed, confirming multiple loops of the shunt tube in the right atrium and right ventricle and extending through the right ventricular outflow tract into the main pulmonary arteries. Next, a standard noncontrast chest CT was performed, which also demonstrated the coiled shunt catheter tubing within the right atrium, right ventricle, pulmonary artery and branch pulmonary arteries finally extending into a segmental branch of the middle lobe pulmonary artery. There was an associated wedge-shaped area of consolidation in the adjacent middle lobe consistent with infarction (Fig. 3). Because a thrombus along the course of the catheter in the cardiac chambers or pulmonary artery could not be excluded prior to operative intervention, an ECG-gated cardiac CT was then performed, which eliminated pulsation artifact and confirmed absence of thrombus (Fig. 4). Three-dimensional post processing was performed by the interpreting radiologist. The acquired images revealed entry of the VP shunt catheter into the venous system at the junction of the right subclavian and internal jugular veins (Fig. 5) with subsequent course through the superior vena cava, right atrium, right ventricle and main pulmonary artery and bilateral branch pulmonary arteries. Multiple coils along the course of the catheter were seen (Fig. 6) especially within the main pulmonary artery and bilateral branch pulmonary arteries. The tip of the catheter was identified extending into a segmental branch of the right middle lobe pulmonary artery causing occlusion and infarction in the lateral segment. No associated thrombus was identified along the course of the malpositioned shunt tube. Enlargement of the right atrium was noted with reflux of contrast into the inferior vena cava and hepatic veins, which could have been due to tricuspid regurgitation. Based on the information provided by the ECG-gated cardiac CT findings, the cardiothoracic surgery team felt that a simple retrieval by retraction of the shunt catheter via a neck incision might be difficult, with potential for injury to the tricuspid and pulmonary valves. Therefore, a more extensive surgical intervention was employed. Following removal of the shunt tube, a repeat TEE showed unchanged trivial tricuspid regurgitation with trivial pulmonary valve insufficiency. Right

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