Hypoglycemia

Background

• Brain depends on glucose as primary source of energy, but is unable to synthesize or store glucose

Clinical Features

• Neuroglycopenic
  • Altered mental status, lethargy, confusion
  • Focal neurologic deficits
  • Unresponsiveness
• Autonomic
  • Anxiety, nervousness, irritability
  • Nausea, vomiting
  • Palpitations
  • Tremor
  • Changes in pupil size
  • Tachycardia or bradycardia
  • Salivation

Differential Diagnosis

• Adrenal insufficiency
• Head trauma
• Hepatic failure
• Insulinoma
• Medication-induced
• Self-induced insulin overdose
• Seizure
• Sepsis
• Stroke
• Sympathomimetic toxicity
• Toxic ingestion

Diagnosis

"Whipple's Triad"

• Symptoms suggestive of hypoglycemia
  • See Clinical Features
• Low glucose
  • Serum glucose <60mg/dL
  • Generally symptomatic at <55mg/dL though threshold is variable depending on chronicity
• Resolution of symptoms after administration of glucose
• Determine etiology of hypoglycemia

Management

• If altered mental status
  • Dextrose 50% 50mL bolus (equals "one amp")
    • Contains 25mg glucose
• If awake
  • Oral glucose
• Glucagon
  • Efficacy dependent on hepatic glycogen stores (less effective in chronic ETOH, cirrhosis, malnourished, neonate, in-born errors, glycogen storage disease, etc.)
  • Onset of action slower than IV dextrose (7-10min)
  • 1mg SC or IM

Hypoglycemia from Sulfonylureas

Activated charcoal

• Administer activated charcoal, preferably within 1 hr of ingestion
• Multiple doses may be beneficial, especially for glipizide

Glucose Treatment

• Initial therapy regardless of known cause

Adults

• 50mL D50W bolus
• Start a D10 1/2NS drip (100mL/hr)

Children

• 1mL/kg of D50W OR
• 2mL/kg D25W OR 5-10mL/kg D10W
• Neonate: 5-10 mL/kg D10W

Octreotide

• Theoretical benefit to reduce risk of recurrent hypoglycemia
• Hyperpolarization of the beta cell results in inhibition of Ca influx and prevents insulin release
• 50-100 mcg subcutaneous in adults with repeat dosing Q6hrs
• 2 mcg/kg (max 150mcg) subcutaneously Q6hrs should be used in children
• Continuous infusion of 50-125 mcg/hr is an alternative in adults
• Administer octreotide for 24 hours, then after discontinuing, monitor for hypoglycemia for another 24 hours

Special Considerations

• Glucagon 5mg IM may be used as temporizing measure, e.g. while obtaining IV access
  • Dependent on glycogen stores which may be depleted in prolonged hypoglycemia
  • Also short duration of action
  • Caution in using glucagon drip
    • Glucagon also has an insulin-releasing effect
    • May subsequently cause initial paradoxical hypoglycemia

Hypoglycemia from Long Acting Insulin

• Similar treatment as for Sulfonylureas except no role for Octreotide
• Treatment should include oral intake as well as maintenance glucose containing drip either D5 or D10

Disposition

• Admit for refractory hypoglycemia, sulfonylurea-induced hypoglycemia or long acting insulins

See Also

• Diabetes Mellitus (Main)
• Hypoglycemia (peds)
• Neonatal hypoglycemia
• Critical care quick reference