Introduction::Hyperinsulinemic Hypoglycemia (HH) is a rare condition characterized
by inappropriately elevated insulin levels in the presence of low glucose levels. A proper
diagnostic framework is fundamental to avoid patients undergoing unnecessary diagnostic and
therapeutic invasive procedures.
Objective::The study aimed to assess the clinical presentation, diagnostic work-up, and treatment
of a single-center cohort of patients affected by HH.
Methods::We conducted a retrospective analysis of data collected from January 2000-2023
Results::Our study included 104 patients: 81 (58% F) affected by insulinoma, 11 (91% F) by
autoimmune hypoglycemia, 7 (71% M) by post-gastric surgery hypoglycemia, and 5 (80% F) by
factitious hypoglycemia. HH was more frequent in females (63 F vs. 41 M, p-value 0.039). The
median age at diagnosis was lower in insulinoma than in the autoimmune group (52.7 vs. 63.7 y,
p < 0.001). During the hypoglycemic event, insulin and C-peptide levels were significantly
higher in autoimmune hypoglycemia than in insulinoma (insulin 324.6 vs. 36.4 μU/ml, p-value
0.033; C-peptide 14.25 vs. 3.99 ng/ml, p-value 0.003). Specifically, C-peptide levels < 9.6 ng/ml
and insulin levels < 75 μU/ml exhibited 97.3% vs. 93.4% sensitivity and 80% vs. 90% specificity
for insulinoma diagnosis, respectively. Regarding insulinoma, the sensitivity of localizing imaging
was 88% for Endoscopic Ultrasound (EUS), 86% for Magnetic Resonance Imaging (MRI),
82% for Computed Tomography (CT) scan, 52% for nuclear imaging, and 100% for angiography
with the Doppman test. Among insulinoma patients, 79% received surgical treatment
while 4% radiofrequency ablation. Symptomatic remission occurred in 100% of cases.
Conclusion::We have confirmed insulinoma as the primary cause of HH. The autoimmune form
should be suspected when insulin and C-peptide levels are markedly elevated.