Authors: Miles Medrano, MD; Alberto Barroso, MDSeries Editor: Richard Goodgame, MD


August 17, 2004

Case Presentation

A 46-year-old woman was admitted for evaluation of confusion and syncope.

Two months earlier, she had developed occasional episodes of lightheadedness associated with paresthesias. She had blurred vision and some confusion. These symptoms seemed to improve if she ate or drank something. She subsequently had a few episodes of more severe symptoms, including syncope. Her admission to an outside hospital was prompted by a severe syncopal episode that resulted in her crashing her car into the outside wall of the emergency room. Her blood glucose level was reportedly at 39 mg/dL. She stated that she has no recollection of the event. The patient was subsequently transferred to our institution for further management.

She is obese and previously had a hysterectomy. She is currently taking no medications. Her personal and family history reveal no excessive alcohol or tobacco use, no substance abuse, no travel, and stable family and finances. There was no family history of peptic ulcer disease or other endocrine disorders.

Physical examination showed normal vital signs; height was 65 inches and weight 220 pounds. There were no skin lesions. Besides obesity, there were no abnormalities detected in the physical examination. Results of neurologic examination were completely normal.

Routine laboratory studies revealed the following:

Hemoglobin: 13.4 g/dL
White blood cell count: 11 x 103 cells/mm3
Platelets: 319 x 103/mm3
Mean corpuscular volume: 91 fL
Sodium: 138 mEq/L
Potassium: 3.9 mEq/L
Chloride: 104 mEq/L
HCO2: 31 mEq/L
Glucose: 115 mg/dL
Urea: 9 mg/dL
Creatinine: 0.1mg/dL
Calcium: 9.0 mg/dL
Phosphate: 2.9 mg/dL
Total protein: 6.4 g/dL
Albumin: 3.4 g/dL
Total bilirubin: 0.5 g/dL
Direct bilirubin: 0.3 g/dL
Alkaline phosphatase: 109 U/L
Alanine aminotransferase: 79 U/L
Aspartate aminotransferase: 63 U/L
International normalized ratio: 1.0

Endocrine evaluation revealed an insulin level of 30 mcU/mL (normal range, 5-27) and serum C-peptide of 5.2 nanomol/L (normal range, 1.1-4.6), with normal serum cortisol, 24-hour urinary free cortisol, adrenocorticotropic hormone, thyroid-stimulating hormone, parathyroid hormone, and gastrin levels.