Hyperglycemia – Diagnosis
Metabolic / Endocrine
Diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS) are the main hyperglycemic emergencies that should be considered for any patient with significant hyperglycemia.
- DKA more common than HHS with a higher incidence in type 1 diabetes.
- HHS more common in older type 2 diabetics and has a higher mortality rate.
- A high index of suspicion for these conditions is important as ~50% of deaths happen in the first 2-3 days.
- Infection (e.g., UTI, pneumonia).
- Insulin reduction or omission (e.g., noncompliance, pump malfunction).
- New diabetes mellitus diagnosis.
- Acute illness (e.g., MI, stroke, thyrotoxicosis, pancreatitis).
- Atypical antipsychotics.
- Some chemotherapy agents.
- Sglt2 inhibitors.
- Toxins (e.g., alcohol, cocaine).
- May require admission to an ICU or step-down unit.
Not all patients with hyperglycemia have a history of diabetes or are subsequently diagnosed with diabetes. Stress-induced hyperglycemia can occur in acutely ill patients (e.g., sepsis, trauma, burns) and has increased morbidity and mortality.
Common clinical features:
- Hyperglycemia – polyuria, polydipsia, weakness, fatigue, weight loss, signs of volume depletion.
- DKA – acute onset; signs/symptoms of hyperglycemia, diffuse abdominal pain, nausea, vomiting, tachypnea (Kussmaul), acetone/fruity breath, altered LOC.
- HHS – insidious onset; signs/symptoms of hyperglycemia, decreased LOC, signs of severe volume depletion, seizures.
- Look for precipitating factor in both DKA and HHS.
- Volume status.
- Level of consciousness.
- Look for precipitating factor(s).
- Assess for potential complications.
- Serum glucose. Capillary BG is not accurate in severe acidosis and interstitial glucose levels should not be used for diagnosis.
- Consider HbA1c (does not change acute management).
- If DKA or HHS is suspected:
- Serum glucose.
- Anion gap +/- lactate.
- Serum osmolality, Serum and urine ketones, beta-hydroxybutyric acid (if possible).
- Venous Blood gases.
- ECG – assess for acute coronary syndrome.
- Additional tests can be guided by suspicion of precipitating factor(s).
- Arterial pH ≤ 7.3.
- Serum bicarbonate ≤ 15mmol/L.
- Anion gap > 12mmol/L.
- Positive urine/serum ketones.
- Plasma glucose ≥ 14mmol/L.
- It’s important not to interpret these values as hard and fast rules as there are exceptions to each:
- Ketones may be negative if beta-OHB production is favored.
- Bicarbonate may be normal/high if there’s a concomitant severe metabolic alkalosis.
- Normoglycemia is possible with SGLT2 inhibitor use, in pregnancy, if insulin was just given, in T1DM with vomiting, or in cases of starvation, alcohol abuse, or liver failure.
- BG ≥ 34mmol/L.
- Serum osmolality > 320mOsm/kg.
- Minimal/no acidosis (ketones can be present).
- Considerations for interpreting lab values:
- Hyperglycemia causes osmotic shifts of water from the intra- to extra-cellular space causing relative hyponatremia. Correction factor 1.6 mEq/L for every 5.5 mmol/L BS above normal (another source uses 2.4 mEq/L).
- Often total body K+ depleted, but serum K+ is typically normal/high initially due to the shift of K+ to extracellular space.
- Serum PO43-, Ca2+ and Mg2+ may also be high despite total body depletion.
- Some substances (e.g., acetaminophen, ascorbic acid, peritoneal dialysis) can lead to false increases in capillary and home blood glucose monitoring tests.
- Nitroprusside test for ketones does not measure beta-hydroxybutyric acid.
Diagnosis of Diabetes:
Diabetes Canada: an adult with symptomatic hyperglycemia can be diagnosed with diabetes if they have 1 of the following:
- Fasting BG ≥ 7.0mmol/L.
- HgB A1C ≥ 6.5%.
- 2h BG in a 75g OGTT ≥ 11.1mmol/L.
- Random BG ≥ 11.1mmol/L.
- HbA1c can help distinguish stress-induced hyperglycemia from newly diagnosed diabetes.
- Patients with known diabetes can experience stress-related hyperglycemia.
Quality Of Evidence?
We are highly confident that the true effect lies close to that of the estimate of the effect. There is a wide range of studies included in the analyses with no major limitations, there is little variation between studies, and the summary estimate has a narrow confidence interval.
We consider that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. There are only a few studies and some have limitations but not major flaws, there are some variations between studies, or the confidence interval of the summary estimate is wide.
When the true effect may be substantially different from the estimate of the effect. The studies have major flaws, there is important variations between studies, of the confidence interval of the summary estimate is very wide.
Diagnosis of diabetes – Based on consensus – Low.
Diabetes Canada 2018 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada: Hyperglycemic Emergencies in Adults.
Diabetes Canada Clinical Practice Guidelines Expert Committee, Goguen J, Gilbert J. 2018;42(Suppl 1):S109-S114.
–Canadian Journal of Diabetes.
Tintinalli’s Emergency Medicine: A Comprehensive Study Guide.
Goyal N, Schlichting A. Type 1 diabetes mellitus. In: Tintinalli JE, Ma OJ, Yealy DM, Meckler GD, Stapczynski JS, Cline DM, Thomas SH, eds. 9th . 2020. Accessed April 17, 2021.
Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. Diabetic ketoacidosis. In: Tintinalli JE, Ma OJ, Yealy DM, Meckler GD, Stapczynski JS, Cline DM, Thomas SH, eds. 9th ed. 2020. Accessed April 17, 2021.
Diabetes Canada 2018 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada: Definition, classification and diagnosis of diabetes, prediabetes and metabolic syndrome.
Diabetes Canada Clinical Practice Guidelines Expert Committee, Punthakee Z, Goldenberg R, Katz P. . 2018;42(Suppl 1):S10-S15.
—Canadian Journal of Diabetes.
OTHER RELEVANT INFORMATION
Related Information on BC EM Network Website:
The purpose of this document is to provide health care professionals with key facts and recommendations for the diagnosis and treatment of patients in the emergency department. This summary was produced by Emergency Care BC (formerly the BC Emergency Medicine Network) and uses the best available knowledge at the time of publication. However, healthcare professionals should continue to use their own judgment and take into consideration context, resources and other relevant factors. Emergency Care BC is not liable for any damages, claims, liabilities, costs or obligations arising from the use of this document including loss or damages arising from any claims made by a third party. Emergency Care BC also assumes no responsibility or liability for changes made to this document without its consent.
Last Updated May 25, 2021
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