Case Presentation: A 15-year-old previously healthy female presented with 2 days of fatigue and 1 day of vomiting, watery diarrhea, and dark urine. Labwork revealed a hyponatremic, hypokalemic metabolic acidosis with acute kidney injury. Despite copious electrolyte and fluid resuscitation, her diarrhea persisted, with stool output peaking at 14 liters per day. She exhibited severe kidney injury and worsening oliguria, prompting transfer to the ICU. While laboratory markers for causes of secretory diarrhea were pending, CT imaging of the head, neck, chest, abdomen, and pelvis was performed to look for a primary tumor or metastases and was negative. Contrast was not used due to her severe kidney injury at the time. An abdominal MRI was then performed that showed a 6.5 cm mass off the pancreatic tail. Her serum vasoactive intestinal peptide (VIP) level subsequently returned at 1203 (normal < 78), consistent with a VIPoma and multiple endocrine neoplasia type 1 (MEN1) syndrome given a maternal family history of hyperparathyroidism. She was initiated on octreotide therapy with optimal response and eventually had surgical resection of the mass with close follow-up.
Discussion: This case illustrates the rare presentation of an intrapancreatic vasoactive intestinal peptide secreting tumor known as a VIPoma. In contrast to adults, VIPomas are rare in the pediatric population and often present external to the pancreas, most commonly along the sympathetic ganglia or on the adrenal glands. The classic syndrome caused by this neuroendocrine tumor is characterized by watery diarrhea, hypokalemia, and achlorhydria, known as WDHA syndrome. Generally, they are isolated but can also be found with metastases or in conjunction with MEN1, especially with a strong family history of pituitary or parathyroid abnormalities. The imaging of choice is MRI given its higher sensitivity in locating the primary tumor or metastases compared to CT with surgical resection being the mainstay treatment. A presentation of secretory diarrhea with severe electrolyte derangements refractory to multiple treatments, as seen in this patient, should warrant a high index of suspicion for a hormonal etiology and is rarely explained by viral gastroenteritis, especially in the adolescent population.
Conclusions: Teenagers requiring admission to the hospital for dehydration in the setting of presumed infectious gastroenteritis should prompt consideration of other causes to avoid delay of diagnosis. Less than 11% of children requiring admission for gastroenteritis are over the age of 10. The volume and characteristics of secretory diarrhea are unchanged in the fasting state, thus expanding the differential to hormonal, autoimmune or iatrogenic states if that pattern is observed. Pediatric providers should be aware that VIPomas are rare, with an incidence of 0.05-0.2 cases per million people, but can occur in children and teens exhibiting secretory diarrhea and WDHA syndrome.