Hypoglycemia

Case 1

In the medical intensive care unit, a patient who had sustained a cardiac arrest with return of spontaneous circulation but no recovery of neurological function develops septic shock complicated by end-stage renal disease, shock liver, and now refractory hypoglycemia.

Case 2

An approximately 60 year-old male with diabetes is brought in by ambulance after family called 911 for unresponsiveness. His initial glucose was 35mg/dL, his home medications are unknown.

Symptoms

  • Autonomic: tremor, palpitations, anxiety, diaphoresis
  • Neuroglycopenic: cognitive impairment, psychomotor, seizure, coma

Diagnosis

  • Serum glucose <60mg/dL
  • Generally symptomatic at <55mg/dL though threshold is variable depending on chronicity
  • Whipple Triad:
    • Symptoms suggestive of hypoglycemia
    • Low glucose
    • Resolution of symptoms after administration of glucose

Differential Diagnosis of Hypoglycemia

Differential Diagnosis of Hypoglycemia

Common Anti-hyperglycemic Drugs and Pharmacology

Drug Pharmacology
Onset Peak Duration
Rapid-acting insulin

  • Aspart (Novolog)
  • Lispro (Humalog)
15-30min 1-2h 3-5h
Short-acting insulin

  • Regular
30-60min 2-4h 6-10h
Intermediate-acting insulin

  • NPH
1-3h 4-12h 18-24h
Long-acting insulin

  • Glargine (Lantus)
2-4h None 24h
Sulfonylurea

  • Glimepiride
  • Glipizide (Glucotrol)
  • Glyburide (Glycron, Micronase)
2-6h 12-24h

Evaluation of Hypoglycemia

Patients with known diabetes who are not systemically ill and can identify a clear precipitant, no extensive workup is required. In severely ill patients, consider:

  • BMP
  • LFT
  • EtOH
  • Infectious workup: CXR, UA, urine and blood cultures
  • ECG, troponin
  • Other studies: insulin, C-peptide, pro-insulin, glucagon, growth hormone, cortisol, B-OH, insulin antibodies

Management and Monitoring

Management and Monitoring of Hypoglycemia

Disposition

Admission or observation for oral anti-hyperglycemic agent or intermediate- to long-acting insulin. Consider discharge after 4h uneventful observation if:

  • Hypoglycemia fully and rapidly reversed without continuous infusion of dextrose
  • Tolerated a full meal in ED
  • Clear and innocuous cause identified with recurrence unlikely
  • Adequate patient understanding, home support/monitoring, and ability to detect/prevent recurrence with close primary care follow-up

References:

  1. Self, W. H., & McNaughton, C. D. (2013). Hypoglycemia. In Emergency Medicine (2nd ed., pp. 1379-1390). Elsevier.
  2. Service, FJ. Hypoglycemia in adults: Clinical manifestations, definition, and causes. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Accessed on March 18, 2016.)
  3. Service FJ. Hypoglycemic disorders. N Engl J Med. 1995;332(17):1144–1152. doi:10.1056/NEJM199504273321707.
  4. Krinsley JS, Grover A. Severe hypoglycemia in critically ill patients: risk factors and outcomes. Critical Care Medicine. 2007;35(10):2262–2267. doi:10.1097/01.CCM.0000282073.98414.4B.
  5. Lacherade J-C, Jacqueminet S, Preiser J-C. An overview of hypoglycemia in the critically ill. J Diabetes Sci Technol. 2009;3(6):1242–1249.