(134) Contrast Enhancement of Subdural Effusion in a Pediatric Patient Mimicking a Life-Threatening Bleed

Introduction: Children requiring ventricular assist devices (VADs) are at high risk of both hemorrhage and thrombosis. Acute neurologic change that occurs in a VAD patient warrants urgent evaluation for a new intracranial insult, and imaging guides critical decisions regarding antithrombotic therapy.

Description: A 2-month-old infant with hypoplastic left heart complex who initially underwent Norwood palliation with modified Blalock-Thomas-Taussig shunt developed severe ventricular dysfunction requiring VAD as a bridge to cardiac transplantation. Routine workup noted a stable right extra-axial subdural fluid collection. A week after VAD placement she developed hypoxemia requiring cardiac catheterization which demonstrated patency of the shunt. During cardiac catheterization she had labile blood pressures and drop in her hematocrit. Later that day she had a first-time seizure. Computed tomography of the head (CTH) showed a hyperdense subdural collection in the same location but larger in size compared to the previously imaged effusion, with subtle mass effect. Antithrombotic therapies were held for new subdural hemorrhage. Repeat CTH 16 hours later demonstrated complete resolution of contrast enhancement, inconsistent with subdural hemorrhage. Given her recent contrast for angiography prior to the initial CTH, this was deemed more consistent with enlargement of the existing subdural effusion and subsequent contrast extravasation into this fluid collection. The patient was restarted on antithrombotic therapies without issue, but did require a VAD circuit change for increased clot burden from holding these therapies.

Discussion: Benign extra-axial fluid collections such as subdural effusions and hygromas occasionally occur in infants, and even in the absence of hemorrhage into these spaces, can cause seizures. Adult case reports have shown the ability of systemic contrast to extravasate into benign fluid collections following angiography. However, to our knowledge this has not been reported in the pediatric population. Recognition of this phenomenon in a patient with a pre-existing intracranial extra-axial fluid collection could spare unnecessary holding of antithrombotic therapy in a patient like ours, who depended on these medications for both shunt patency and thromboembolism prevention.