Episodic Visual Disturbances and Hypoglycemic Episodes in a Young Woman

Case at a Glance

A 31-year-old woman presenting with recurrent episodes of visual field defects, neurological symptoms, and hypoglycemic attacks despite normal HbA1c levels, raising suspicion for insulinoma.

Patient's Story

The patient reported experiencing frightening episodes characterized by sudden onset of visual disturbances where she could only perceive half of faces and objects, accompanied by finger tingling, altered mental status, and feelings of dread and hunger. Additionally, she described separate attacks involving sudden onset of diaphoresis, tachycardia, intense epigastric discomfort described as her 'stomach eating itself,' tremors, and weakness that resolved with food intake. These episodes occurred even 4-5 hours after full meals. Associated symptoms included polyuria with sweet-smelling urine, polydipsia, and nausea. The patient expressed concern about potential seizures and felt her symptoms were being inadequately evaluated.

Initial Assessment

Physical examination revealed a 31-year-old female, height 5'2", with normal BMI. Vital signs during episodes showed tachycardia and diaphoresis. Initial laboratory workup demonstrated consistently low-normal HbA1c of 3.6% and fingerstick glucose readings of 3.4 mmol/L during symptomatic episodes, rising only to 3.6 mmol/L after glucose administration.

The Diagnostic Journey

The patient had multiple healthcare encounters over several years. During one acute episode, she was hospitalized with suspected stroke due to neurological symptoms. Point-of-care glucose testing during this admission revealed hypoglycemia (3.4 mmol/L), leading to a diagnosis of hypoglycemic episode. However, with normal HbA1c levels excluding diabetes mellitus, no further investigation was pursued initially. The recurrent nature of symptoms and their relationship to hypoglycemia prompted consideration of other causes of endogenous hyperinsulinism.

Final Diagnosis

Working diagnosis of insulinoma, pending confirmatory testing including supervised fasting study, insulin and C-peptide levels during symptomatic episodes, and imaging studies.

Treatment Plan

Immediate management focused on symptom documentation with home glucose monitoring during episodes. Dietary modifications included frequent small meals to prevent prolonged fasting states. Referral to endocrinology for specialized evaluation including 72-hour supervised fasting test, measurement of insulin, C-peptide, and proinsulin levels during induced hypoglycemia, and imaging studies (CT/MRI pancreas, endoscopic ultrasound) to localize potential pancreatic neuroendocrine tumor.

Outcome and Follow-up

Patient education provided regarding recognition and immediate management of hypoglycemic episodes. Close follow-up scheduled with endocrinology service for comprehensive evaluation. Long-term management plan to be determined based on confirmatory testing results, with surgical consultation likely if insulinoma is confirmed.