Case Presentation: A 40-year-old female with a history of morbid obesity status post Roux-en-Y gastric bypass in 2009 presented to hospital with blood glucose level of 33. She reported hypoglycemic episodes every day since 2007 with prior labs demonstrating elevated insulin and low c-peptide levels. The differential diagnoses included exogenous administration of insulin, given she is a health care worker who lived with a family member using insulin, and post gastric bypass hypoglycemia, although patient reports her symptoms starting prior to gastric bypass surgery.During her hospital stay, the patient had undergone extensive evaluation for hypoglycemic episodes. Labs showed elevated insulin and low, but unsuppressed c-peptide, negative insulin antibody, and negative sulfonylurea screen, ruling out exogenous insulin administration. CT pancreas and MRI abdomen did not demonstrate any pancreatic lesions. However, selective arterial calcium stimulation test showed a diffuse increased insulin production with no localization. A subsequent MRI pancreas showed an indeterminate abnormality in the pancreatic tail with inconclusive findings in Dotatate scan. In addition to numerous labs and imaging, diagnostic workup was further challenged by tensions between patient and medical team due to team’s initial concern for factitious hypoglycemia, causing emotional distress to patient.During the hospitalization, normoglycemia was maintained with D-10 drip, and patient was started on Ocreotide with transition to Lanreotide and acarbose. She was not a surgical candidate for subtotal pancreatectomy, given diffused pattern of insulin production. After multidisciplinary collaboration and extensive workup, patient was discharged with a most likely diagnosis of non-insulinoma pancreatogenous hypoglycemia (NIPH) with a component of Dumping Syndrome. The patient was advised to follow outpatient with Endocrinology.

Discussion: Here we report a complex case of unexplained hypoglycemia of 15 years, possibly related to NIPH, which is extremely rare. Most NIPH were reported to occur after gastric bypass surgery secondary to pancreatic beta-cell hypertrophy with islet hyperplasia (Mathavan 2010). This case is notable in that the hypoglycemia occurred prior to surgery. As NIPH requires extensive diagnostic workup, inpatient setting is likely an ideal place for evaluation of unexplained hypoglycemia. In our case, patient stayed two weeks inpatient for a complete workup. Although NIPH is rare, clinicians should consider NIPH as a diagnosis in patients with unexplained hypoglycemia. The low prevalence of NIPH might be contributed by underdiagnosis and underreporting. There is need for more research to increase clinicians’ awareness to reduce further underdiagnosis and delay in diagnosis associated with NIPH.

Conclusions: This report describes a much more complex case of NIPH complicated by not only a rare disease but also Dumping Syndrome. This case highlights the need to consider NIPH as a diagnosis in patients with unexplained and persistent hypoglycemia.