P2.212: Emergency Department Point-of-Care Ultrasound (POCUS) Utilization in the Diagnosis of an Intrabdominal Pseudocyst for a Pediatric Patient with a Ventriculoperitoneal Shunt

Introduction: The utilization of point-of-care ultrasound (POCUS) in the pediatric emergency department is becoming more common as the need for speedy, reliable diagnostic tools increases and technology accessibility improves. POCUS is particularly valuable in the evaluation of ventriculoperitoneal (VP) shunt patients presenting with nonspecific GI complaints or respiratory distress. In this patient, the use of POCUS was critical to establishing the cause of his distress and drastically changed the treatment plan.

Case Description: A 16-year-old male patient with a complex past medical history, including grade IV IVH with hydrocephalus and ventriculoperitoneal shunt, presented to the emergency department with one-day history of respiratory distress and emesis. He had had increased work of breathing and persistent desaturations to the 70% range on pulse oximetry despite the use of his home CPAP machine. On exam, he had some mild abdominal distension and decreased air movement in the bilateral lower lung fields. A CT head and XR shunt series were both normal. A chest x-ray was relatively unremarkable and a KUB demonstrated some retraction of his G-J tube. After suctioning and supplemental oxygen, his saturations improved and he was admitted for concern for an aspiration event. A bedside POCUS was initially performed to evaluate cardiac function. On evaluation of his IVC, a fluid collection was noted near his liver. The exam was transitioned to a FAST which demonstrated a massive, walled-off fluid collection in the RUQ with the VP shunt tip present in the pocket but no free fluid present in the LUQ or suprapubic regions. A CT abdomen demonstrated a 12.8x9.5x18.5 cm multiloculated pericapsular fluid collection with significant ascending mass effect and associated bilateral ground-glass opacities consistent with aspiration pneumonia. The patient was admitted to the PICU where he improved after drainage of 985 ml of fluid from the pseudocyst.

Discussion: Prior to the POCUS exam, the working diagnosis was aspiration pneumonia secondary to emesis. However, the discovery of the massive intrabdominal pseudocyst and subsequent CT abdomen demonstrated that the pseudocyst was applying a significant upward mass effect and a major contributor to his symptoms. Once the pseudocyst was drained, he made a rapid recovery with improvement in his baseline respiratory needs. There are several articles in the literature review that support evaluation for pseudocyst with these symptoms.

Conclusion: POCUS is a valuable tool in the emergency department and helped provide a clear diagnosis in this patient. The finding of the pseudocyst and subsequent CT scan demonstrated that mass effect was largely contributing to his respiratory distress. VP shunt patients who present with non-specific GI symptoms or respiratory distress should be evaluated for intrabdominal pseudocyst formation as part of their differential diagnosis.