10. Hypoglycemia

Definition

  • Glucose level sufficiently low to trigger autonomic counter-regulation, often < 70 mg/dL.
  • May meet Whipple’s triad: glucose <50mg/dl, concurrent symptoms, resolution of symptoms with treatment of the low glucose.

Etiologies

  • Patients with diabetes: excessive insulin, excessive oral agent(s), insufficient carbohydrate intake while on insulin or oral agents, renal failure, impaired counter-regulation.
  • Patients without diabetes: alcohol, liver failure, renal failure, adrenal insufficiency, hypopituitarism, exogenous insulin, insulin secretagogues (e.g. sulfonylureas), “reactive” (post-GI surgery), insulinoma, discontinuation of TPN.

Evaluation

  • Symptoms/signs: hunger, diaphoresis, palpitations, tremor, headache, vision changes, confusion, coma.
  • Laboratory testing:
  • Creatinine/eGFR (in renal failure insulin stays around longer).
  • Transaminase levels, bilirubin (total and direct), alkaline phosphatase, INR, albumin (in liver failure poor gluconeogenesis/glycogenolysis).
  • If concern for surreptitious sulfonylurea use, send sulfonylurea level (confirm that the screen detects glimepiride and meglitinides). 
  • If concern for insulin-secreting tumor, send glucose, insulin level, C-peptide while hypoglycemic.
  • If concern for surreptitious insulin use, send C-peptide (found only in endogenous insulin, not exogenous).
  • Full work up for insulinoma involves a supervised fast protocol. Consult Endocrine for guidance.

Management

  • Asymptomatic/non-altered patients with low risk for persistent hypoglycemia can be treated with glucose tabs or juice.
  • D5 or D10 drip for patients with insulin overdose or others at risk for persistent hypoglycemia who cannot take PO. Check glucose level q1h and adjust rate accordingly.
  • Give one amp of D50 to any patient with compromised mental status and hypoglycemia.   

Key Points

  • Whipple’s triad: glucose <50mg/dl, concurrent symptoms, resolution of symptoms with treatment of the low glucose.
  • C-peptide differentiates between endogenous and exogenous insulin.

 

Cryer, PE et al. Evaluation and management of adult hypoglycemic disorders. J Clin Endocrinol Metab 2009; 94:709

Service, FJ. Hypoglycemic disorders. N Engl J Med 1995; 332:1144.