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Pediatric Emergency Medicine

When Insulin Works Too Well: Part 1: Hypoglycemia in Type 1 Diabetics

Hypoglycemia is one of the most common side effects of insulin treatment of diabetes.  Current management of type 1 diabetes includes a regimen of strict glycemic control with intensive insulin therapy.  This tight control of blood glucose levels is key in reducing the risk of microvascular complications and improving daily quality of life.  However, the risk of hypoglycemia increases with this treatment model.

Even with the development of new insulin analogs and pump delivery methods, the average T1D patient will experience about two mild (self-treated) episodes of symptomatic hypoglycemia per week, a figure that has not changed in the last 20 years. (1)  Frier estimates to annual prevalence of severe hypoglycemia (requiring external help) to be 30% for T1D patients, and even higher in those with risk factors such as strict glycemic control, impaired awareness of hypoglycemic symptoms, and increasing duration of diabetes. (2)

Hypoglycemia in diabetes can be defined as the occurrence of a wide variety of symptoms in association with a plasma glucose concentration of:

  •  50 mg/dL or less in men
  •  45 mg/dL or less in women
  •  40 mg/dL or less in infants and children

Hypoglycemic Symptoms: (3)

Autonomic  Neuroglycopenic  General Malaise
Shaking
Palpitations
Sweating
Hunger
Pallor
Anxiety
 
Confusion
Drowsiness
Odd behavior   
Difficulty speaking
Incoordination
Dizziness
Vision disturbances
Headache
Nausea

Treatment  and Management of Hypoglycemia: (4)

Pre-Hospital Care:

EMS response consists of performing a serum glucose/Accucheck prior to administering dextrose 50% (D50) in the field.  When uncertain, administration will help determine if hypoglycemia is present.  If the patient is awake, or awakens following administration of D50, further treatment or transport to the ED for evaluation may be declined.  Patients should be encouraged to comply with EMS protocol to transport to ED, as advised.

Emergency Department Care:

Initial care in the ED includes standard practices:

  • ABC (Airway, Breathing, Circulation)
  • Intravenous access
  • Oxygen
  • Monitoring
  • Blood glucose/Accucheck

Administration of glucose as part of the initial assessment of a patient with an altered/confused mental status may correct hypoglycemia. Withholding glucose while waiting for laboratory results may be detrimental in hypoglycemia; the brain requires glucose as its primary energy source.

Once the diagnosis of hypoglycemia is made, practitioners can proceed to determine the cause.  In a diabetic patient, the episode may be the result of medication changes, dietary changes, new metabolic changes, recent infections, or occult infection.

Admission Criteria:

According to Smeeks et al., admission criteria for patients with acute hypoglycemia include the following:

  • No obvious cause
  • No previous episodes
  • Oral hypoglycemic agent
  • Long-acting insulin
  • Persistent neurologic deficits
  • Children:  inadequate data to predict the extent or time course of the hypoglycemic episode
  • For overdose, accidental ingestion, or “therapeutic misadventures” with oral hypoglycemics, little correlation exists between the amount of the oral hypoglycemic agent ingested and the length/depth of coma. 

One hypoglycemic complication with important implications for Emergency Department staff is the development of impaired awareness of hypoglycemia (IAH) in diabetics who lose the ability to perceive their autonomic symptoms.  Diabetic patients with IAH have a sixfold higher incidence of severe hypoglycemia than those with normal awareness, affecting 25% of type 1 diabetes patients. (5) Frier finds that with long duration of type 1 diabetes, there is a cerebral adaptation to hypoglycemia, resulting in a lowering of the glycemic threshold for autonomic activation. As the set point for triggering awareness drops, daily activities, such as driving or physical exercise, may be impacted.  These patients may present to the ED with extreme hypoglycemia, requiring immediate acute care. (6)

  1. McCrimmon RJ, Sherwin, RS.  Hypoglycemia in Type 1 Diabetes.  Diabetes 2010; 59:2333-2339.
  2. Frier BM.  How hypoglycemia can affect the life of a person with diabetes.  Diabetes Metab Res Rev 2008:24:87-92.
  3. McAulay V, Dreary IJ, Frier BM.  Symptoms of hypoglycaemia in people with diabetes.  Diabetes Medicine 2001:18;690-705.
  4. Smeeks FC, Hemphill RR, Talavera F, Bessen HA, Schraga ED.  Emergent management of acute symptoms of hypoglycemia. Medscape Reference, June 20, 2011.
  5. Leese GP, Wang J, Broomhall J, Kelly P, Marsden A, Morrison W, Frier B, Morris AD.  Frequency of severe hypoglycemia requiring emergency treatment in type 1 and type 2 diabetes: a population-based study of health service resource.  Diabetes Care 2003:26;1176-1180.
  6. Frier BM. Morbidity of hypoglycemia in type1 diabetes. Diabetes Res ClinPrac 2004:65S;S47-52.
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