P2A296: Acute Subarachnoid Hemorrhage in a Pediatric Patient with Klippel-trenaunay-weber Syndrome

Introduction: Klippel-Trenaunay-Weber Syndrome (KTWS) is a very rare, congenital malformation syndrome involving lymphatic and blood vessels. The classic triad includes capillary malformation, venous malformation, and limb overgrowth. We present a case of a 14-year-old female with a history of KTWS who presented with a sudden, severe headache with altered mental status and found to have a subarachnoid hemorrhage (SAH). KTWS is considered a vascular anomaly with a potential for morbidity and mortality in the case of central nervous system (CNS) involvement, making it crucial for clinicians to have a high index of suspicion if presented in a pediatric patient with acute neurologic symptoms.

Case Description: A 14-year-old female with history of KTWS presents to the emergency department via EMS for severe sudden onset occipital headache prior to becoming unresponsive. CT brain without contrast was obtained, revealing diffuse SAH in the basal cisterns as well as 3rd and 4th intraventricular hemorrhage. In the pediatric intensive care unit, an external ventricular drain (EVD) was placed to monitor intracranial pressure and facilitate therapeutic drainage. Transcranial doppler was used to detect and monitor cerebral vasospasm and the patient was treated for ongoing vasospasm with Nimodipine and Milrinone. Angiography ruled out aneurysm and arteriovenous malformation. Throughout her hospitalization, she endorsed moderate to severe headaches. After undergoing several EVD clamp trials, the patient’s intracranial pressure normalized, EVD was removed, and she was discharged with no residual neurologic sequelae.

Discussion: One of the primary concerns of KTWS is increased risk of bleeding due to intracranial capillary and venous malformation. There are limited cases linking KTWS and SAH, all of which are associated with positive findings on cerebral angiography. Arteriovenous malformation and cavernous angioma of brain and spinal cord, intracranial aneurysms, and anomalies of the circle of Willis are the CNS manifestations reported in KTWS. However, neither intracranial vascular malformation nor aneurysm was demonstrated in this case. Therefore, we hypothesize perimesencephalic nonaneurysmal SAH (PMSAH) as a possible diagnosis. PMSAH is defined as hemorrhage in the cisterns surrounding the brainstem and negative cerebral angiogram. Imaging in our patient showed bleeding in the subarachnoid and basal cisterns, specifically in the suprasellar and interpeduncular cisterns. This finding is in line with the radiographic pattern of PMSAH, with hemorrhage centered anterior to the midbrain or pons with possible extension into the suprasellar cistern.

Conclusion: KTWS rarely presents with CNS involvement. Our patient presented with acute SAH with negative angiography. One should consider PMSAH, a rare subtype of SAH, in the evaluation of KTWS patients with acute neurologic symptoms.