- There is no universally accepted definition of hypoglycaemia (low blood glucose).
- Clinically significant hypoglycemia is confirmed by the presence of ‘Whipple triad’:
- the presence of symptoms consistent with hypoglycemia
- a low serum glucose level
- resolution of the symptoms and signs of hypoglycemia with the administration of glucose
- Clinical hypoglycaemia is defined as a blood glucose low enough to cause symptoms or signs (including brain impairment) or both. For most people this occurs at blood glucose levels less than 2.8- 3.3 mmol/L (50-60 mg/dL).
- Severe hypoglycaemia is defined as an event requiring the assistance of another person to actively administer carbohydrate, glucagon or provide other resuscitative measures.
- Relative hypoglycaemia occurs when a patient with diabetes reports hypoglycaemic symptoms, but the blood glucose remains above 3.8 mmol/L (70 mg/dL). This still requires treatment.
- Conversion of Blood Glucose: 1 mmol/L = 18 mg/dL, 1 mg/dL = 0.056 mmol/L
Known diabetics (most common)
- Hypoglycemic agents (suphonylureas, insulin)
- Decreased glucose delivery (missed meals or overnight fasting)
- Increased glucose utilisation (exercise)
- Reduced endogenous glucose production (alcohol ingestion)
- Increased insulin sensitivity (weight loss, increase in exercise)
- Reduced insulin clearance (renal failure)
No history of diabetes (rare) – mnemonic ‘EXPLAINS H)
- Exogenous drugs (e.g insulin, oral hypoglycemics, ethanol intoxication, quinine, chloroquine, beta-blocker overdose, valproate overdose, salicylate overdose, pentamidine)
- Pituitary insufficiency
- Post-prandial hypoglycemia (e.g. ’late dumping’ after gastric surgery)
- Liver disease (e.g hepatocellular cancer, hepatitis and rare genetic defects)
- Addison’s disease
- Islet cell tumours (e.g. insulinomas)
- Immune hypoglycemia (e.g. anti-insulin receptor antibodies in Hodgkin’s disease or anti-insulin antibodies that release insulin when insulin levels are relatively low)
- Infection (e.g. severe sepsis, malaria)
- Non-pancreatic neoplasms (e.g fibromas, sarcomas, mesotheliomas, and small cell carcinomas that produce IGF-2; extensive metastases that overwhelm the body’s ability to produce glucose)
- Nesidioblastosis or noninsulinoma pancreatogenous hypoglycemia (NIPH) syndrome (islet cell hyperplasia, which can be congenital or acquired, e.g. post-gastric surgery)
- Starvation and malnutrition
- Hypothyroidism (myxoedema coma)
Pseudohypoglycemia (delayed measurement of a sample in the presence of leukocytosis, thrombocytosis or erythrocytosis)
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.