Case report: Insulinoma masquerades as epilepsy - quantitative EEG analysis

Area of Science:

• Neuroscience
• Endocrinology
• Gastroenterology

Background:

• Insulinomas are rare tumors causing hyperinsulinism and hypoglycemia.
• Hypoglycemia can manifest as central nervous system (CNS) symptoms, including seizures, potentially leading to misdiagnosis.
• Epileptic seizures are a common misdiagnosis for hypoglycemia-induced neurological events.

Observation:

• A 46-year-old male presented with recurrent, prolonged, seizure-like episodes, primarily nocturnal.
• Quantitative electroencephalogram (EEG) analysis during two episodes revealed significant EEG power spectrum changes preceding motor activity.
• Hypoglycemia-related EEG alterations were observed across all frequencies except delta, with pronounced changes in the left temporal region.

Findings:

• EEG changes preceded clear motor activity by tens of minutes.
• Increased EEG power spectra in all frequencies except delta correlated with profound motor activity.
• Complete resolution of seizure-like episodes post-insulinoma removal confirmed the causal relationship.

Implications:

• This case underscores the importance of considering hypoglycemia in patients with unexplained seizure-like episodes.
• Quantitative EEG analysis offers insights into the electrophysiological correlates of hypoglycemia-induced neurological events.
• Early diagnosis and treatment of insulinomas are crucial to prevent severe neurological manifestations and misdiagnosis.