Endocrine Abstracts (2017) 49 EP171 | DOI: 10.1530/endoabs.49.EP171

Atypical symptoms of hypoglycemia, hiding a diagnosis of insulinoma: a case report

Agne Petrenaite1,2, Greta Jagucianskaite1,2, Rasa Juskiene2, Rasa Ziukaite2 & Zydrune Visockiene1,2


1Faculty of Medicine, Vilnius University, Vilnius, Lithuania; 2Vilnius University Hospital Santariskiu Klinikos, Vilnius, Lithuania.


Introduction: Insulinoma is a rare pancreatic tumor, typically sporadic, solitary and benign. However, nonspecific symptoms of hypoglycemia, negative laboratory investigations and small size of these tumors can retard the diagnosis, and symptoms may be misattributed to psychiatric, cardiac, neurological disorders.

Case presentation: A 35-year-old male had history of night time seizures with hallucinations, delirium and spasms, lasting from 10 minutes to 1.5 hours for about 2 years. These seizures were always resolving spontaneously. Due to recurrent seizures he was consulted by phychiatrist and diagnosed with depression and conversion disorder and treated with psychotropic medications. As the spasms remained, he was referred to neurologists. During examination early in the morning while performing electroencephalography typical dyscognitive seizures occured. Plasma glucose analysis was performed for the first time and hypoglycemia of 1.4 mmol/l was found. Symptoms disappeared after intravenous glucose infusion.

Management and outcome: The patient was hospitalized due to suspected insulinoma and supervised 72-hour fast test was performed. Plasma glucose was 3.5 mmol/l, plasma insulin - 49.3 pmol/l (43–210 pmol/l) and C-peptide - 780 pmol/l (260–1730 pmol/l) at the baseline. The test was ended after 16 hours with plasma glucose of 1.7 mmol/l, plasma insulin - 29.7 pmol/l, C-peptide - 521 pmol/l. These results confirmed the diagnosis of insulinoma. Abdominal computed tomography scan with contrast demonstrated a well-defined hypervascular lesion involving the head of pancreas measuring 10×15 mm in diameter, typical of neuroendocrine tumor. The patient underwent laparoscopic extirpation of the pancreatic mass. Histopathological evaluation revealed a pancreatic well-differentiated (G1) neuroendocrine tumor – benign insulinoma. The patient gradually discontinued all psychotropic medications following the operation. Currently he is feeling well, without any seizures and normal plasma glucose for about 1.5 years.

Conclusion: We recommend to check plasma glucose for all patients with seizures of unknown origin, although they are not typical to hypoglycemia.

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