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Hypoglycaemia

Table of Contents

Overview #

Definition: Blood Glucose Level (BGL) <4 mmol/L in a patient receiving hypoglycaemia-inducing medications (i.e. insulin, sulphonylureas, or meglitinides)

Prioritisation: hypoglycaemia should be treated as a high priority presentation due to the risk of deterioration 

Key points:

  • Manage hypoglycaemia based on the conscious state of the patient and their ability to tolerate oral intake
  • After hypoglycaemia has been corrected, ensure a cause/precipitant is identified and corrected as appropriate

Triage #

Hypoglycaemia can be classified as:

  • Severe (an unconscious patient unable to tolerate oral intake) -> emergency requiring immediate attention
  • Non-severe (a conscious patient able to tolerate oral intake) -> attend within 30 minutes (1)

Causes #

Causes/precipitants in patients with diabetes:

  • Reduced oral intake or fasting
  • Medications (e.g. insulin, sulfonylureas)
  • Physical activity
  • Alcohol intake 
  • Infection (1)

Hypoglycaemia is uncommon in patients without diabetes. Causes can include fasting, endogenous hyperinsulinaemia or inadvertent/malicious use of oral hypoglycaemics/insulin (2).

Clinical features #

Symptoms can be divided into sympathominergic (autonomic) and neuroglycopaenic symptoms: 

  • Neurogenic (autonomic) symptoms: hunger, sweating, tremor, palpitations, anxiety, paraesthesia 
  • Neuroglycopaenic symptoms: dizziness, weakness, drowsiness, delirium, confusion, seizure and coma  (1, 4)

Note: Hypoglycaemia can be asymptomatic, especially in patients who have had diabetes for a long period of time. Patients with hypoglycaemic unawareness are at a higher risk of serious complications and should be closely monitored. (1)

Diagnosis #

BGL <4 mmol/L 

Investigations #

Initial investigations

InvestigationSignificance
Fingerprick BGLHypoglycaemia = BGL <4 mmol/L
VBGHypoglycaemia = BGL <4 mmol/L

Further investigations

Further investigation of hypoglycaemic episodes should be guided by clinical suspicion. Consider the following in conjunction with a discussion with endocrinology:

  • Plasma glucose
  • Plasma insulin
  • Proinsulin
  • C-peptide
  • Insulin antibodies
  • Sulfonylurea screen (3)

Note that the first four of the above tests must typically be performed during a period of hypoglycaemia before the glucose has returned to normal to be valuable.

Management – Severe (unconscious or unable to tolerate oral intake) #

Step 1 

  • Activate code blue/MET call
  • DRSABCD

Step 2

If no IV access

Glucagon 1 mg IM/subcut (1, 5)

If IV access

50% Dextrose 25 – 50 mL IV by slow injectionFlush with 20 mL of saline. Extravasation can cause necrosis (1, 5)

Step 3

Further management/monitoring:

  • Recheck BGL in 10-15 minutes and repeat Step 2 if still hypoglycaemic
  • If hypoglycaemia persists and the patient remains unconscious or in an altered conscious state commence an intravenous dextrose infusion
  • Once patient is conscious, give a long-acting carbohydrate
  • Consider the need for an ongoing maintenance dextrose infusion
  • Check BGL every 1-2 hours for the first 4 hours (1, 5)

Step 4

  • Review cause/precipitant (including medication review)
  • Discussion with endocrinology 

Management – Non-severe (conscious and able to tolerate oral intake) #

Step 1 

15 g quick acting oral glucose  Examples: glucose gel, jelly beans (5-7), non-diet soft drink, fruit juice (1, 5)This will most often be nurse-initiated

Step 2

Monitor for symptoms of hypoglycaemia. 

Recheck BGL in 10-15 minutes and repeat Step 1 if still hypoglycaemic.

Step 3

When BGL normalises (≥4 mmol/L)

Long acting carbohydrateExamples: sandwich, fruit (1, 5)

Step 4

If patient responds well and BGL normalises, check BGL every 1-2 hours for first 4 hours and then resume usual testing regime 

If more than 3 doses of oral glucose are required, escalate to senior (1, 5)

Step 5

  • Review cause/precipitant (including medication review)
  • Discuss with senior staff
  • Discuss with endocrinology if required 

References #

  1. eTG complete [Internet]. Melbourne (Vic): Therapeutic Guidelines Ltd; 2019. Hypoglycaemia in patients with diabetes [updated 2019 Jan; cited 2021 Aug 28]. Available from: https://tgldcdp.tg.org.au.acs.hcn.com.au/viewTopic?topicfile=hypoglycaemia-in-patients-with-diabetes&guidelineName=Diabetes&topicNavigation=navigateTopic 
  2. Vella A. Hypoglycemia in adults without diabetes mellitus: Clinical manifestations, diagnosis, and causes. In: Hirsch IB, Mulder JE, editors.; UpToDate. [Internet]. UpToDate Inc; 2017. [updated 2021 Feb 09, cited 2021 Aug 28]. Available from: https://www.uptodate.com/contents/hypoglycemia-in-adults-without-diabetes-mellitus-clinical-manifestations-diagnosis-and-causes?search=hypoglycemia&source=search_result&selectedTitle=5~150&usage_type=default&display_rank=4
  3. Ng CL. Hypoglycaemia in nondiabetic patients. AFP. 2018, June;39(6):399-404.
  4. Cryer PE. Hypoglycemia in adults with diabetes mellitus. In: Hirsch IB, Mulder JE, editors.; UpToDate. [Internet]. UpToDate Inc; 2017. [updated 2021 Apr 19, cited 2021 Aug 28]. Available from: https://www.uptodate.com/contents/hypoglycemia-in-adults-with-diabetes-mellitus?search=hypoglycemia&source=search_result&selectedTitle=3~150&usage_type=default&display_rank=3
  5. Hypoglycaemia Diagnosis and Management (Adult). Monash Health Policy and Procedure.  [updated 2019 Sep 18, cited 2021 Aug 28].

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