Diabetic ketoacidosis

What it is

Diabetic ketoacidosis (DKA) is a life-threatening acute complication of diabetes in which severe insulin deficiency triggers dangerous ketone accumulation in the blood, affecting roughly 25–40% of people with newly diagnosed type 1 diabetes at first presentation and causing an estimated 4–9 episodes per 100 patient-years in established type 1 diabetes. Also called DKA, it is the leading cause of death in children and young adults with type 1 diabetes in Canada and worldwide. Without enough insulin, cells cannot absorb glucose for energy, so the body breaks down fat at an accelerated rate, producing acidic by-products called ketones. When ketones accumulate faster than the kidneys and lungs can clear them, blood pH falls below 7.35 — a state called ketoacidosis — and organ function deteriorates rapidly. DKA is a hospital emergency; with prompt treatment, outcomes are generally good.

DKA occurs most often in type 1 diabetes, where insulin production is absent or severely impaired. It can also occur in type 2 diabetes during extreme physiological stress. Diabetes Canada's clinical practice guidelines identify DKA as a priority area for patient education and sick-day management planning across all provinces.

Causes and mechanism

The central trigger is a severe fall in circulating insulin. This simultaneously prevents glucose uptake by cells and removes the brake on fat breakdown (lipolysis). Free fatty acids flood the liver, which converts them to ketone bodies — primarily beta-hydroxybutyrate and acetoacetate. At the same time, counter-regulatory hormones (glucagon, cortisol, adrenaline) surge, driving blood glucose higher and further opposing insulin action. The result is a self-reinforcing cycle of hyperglycaemia, ketonaemia, and acidosis.

Common precipitating triggers include:

1. Missed or insufficient insulin — skipped injections, incorrect dosing, or insulin pump failure; the most preventable cause.
2. New-onset type 1 diabetes — DKA is the first presentation in a significant proportion of newly diagnosed patients, particularly children.
3. Illness or infection — counter-regulatory hormone release during even minor infections can overwhelm usual insulin doses.
4. Surgery or trauma — the physiological stress response sharply increases insulin requirements.
5. SGLT2 inhibitors — medications such as empagliflozin and dapagliflozin can, in rare cases, trigger euglycaemic DKA (near-normal blood glucose), making it harder to recognize.
6. Alcohol — impairs hepatic glucose production and can contribute to ketone buildup.

Symptoms and diagnosis

DKA typically develops within hours in type 1 diabetes when insulin is completely absent, and more gradually over 12–24 hours when some residual insulin remains. Key symptoms:

• Excessive thirst and frequent urination
• Nausea, vomiting, and severe abdominal pain
• Fruity or acetone-like breath odour (from exhaled ketones)
• Deep, rapid, laboured breathing (Kussmaul breathing) — the body's attempt to blow off acid as CO₂
• Extreme fatigue, weakness, and confusion
• Loss of consciousness in severe cases

Warning thresholds for Canadian patients with type 1 diabetes:

• Blood glucose persistently above 14 mmol/L
• Blood ketones above 1.5 mmol/L or large urinary ketones
• Any vomiting alongside elevated glucose or ketones

Hospital diagnosis rests on five findings:

Test	DKA finding
Blood glucose	Typically elevated (may be near-normal in SGLT2-associated DKA)
Blood or urine ketones	Significantly elevated
Arterial/venous pH	Below 7.35 (acidosis)
Serum bicarbonate	Below 18 mmol/L
Electrolytes	Low sodium, potassium, and bicarbonate (total body depletion)

HbA1c is also measured to assess preceding glycaemic control and guide post-discharge management.

Treatment options

DKA requires urgent inpatient treatment built on three simultaneous pillars:

1. Intravenous fluid replacement — large-volume saline corrects dehydration, improves circulation, and begins to dilute circulating ketones. Fluid resuscitation is often the most time-sensitive initial step.

2. Intravenous insulin infusion — a continuous insulin drip halts ketone production and gradually lowers blood glucose. Subcutaneous insulin is not used initially because absorption is unreliable in a dehydrated, acidotic patient.

3. Potassium replacement — DKA depletes total body potassium through urinary losses. At presentation, serum potassium may appear normal or high because acidosis shifts potassium out of cells. Once insulin is given and acidosis corrects, potassium re-enters cells rapidly; without replacement, blood levels can drop to levels that cause fatal cardiac arrhythmias.

Identifying and treating the precipitating cause — infection, missed insulin, pump failure — is essential to prevent recurrence. Continuous monitoring of glucose, ketones, electrolytes, and blood gas continues until resolution criteria are met.

Prevention through education is equally important. Diabetes Canada and most provincial diabetes programs recommend that all people with type 1 diabetes receive written sick-day rules, home ketone testing supplies (blood ketone meters are preferred over urine strips for speed and accuracy), and a clear escalation pathway to emergency care.

When to see a clinician in Canada

Go to the nearest emergency department immediately if you have diabetes and experience any of the following:

• Vomiting that prevents you from keeping fluids or medications down
• Blood ketones above 3 mmol/L or large urinary ketones with elevated blood glucose
• Deep or laboured breathing that feels unusual
• Severe abdominal pain, extreme weakness, or confusion
• Blood glucose that stays above 14 mmol/L despite correction attempts

DKA can be fatal within hours if untreated. Do not wait for symptoms to resolve on their own. Across Canada, 911 or the nearest emergency department is the appropriate first contact — not a telehealth platform or walk-in clinic. Virtual care services (Maple, Tia Health, and others) are not equipped to manage DKA and should not be used as a substitute for emergency care in this situation.

For ongoing diabetes management and sick-day planning between episodes, a family physician, endocrinologist, or certified diabetes educator (CDE) through a provincial diabetes education program can help establish a personalized DKA prevention protocol.

Limitations and open questions

Research is still emerging on several aspects of DKA management. The optimal fluid composition for resuscitation — normal saline versus balanced crystalloids such as Ringer's lactate — remains debated, with some trials suggesting balanced solutions may reduce the risk of hyperchloraemic acidosis but without definitive outcome data. The precise threshold for transitioning from intravenous to subcutaneous insulin is not uniformly agreed upon across guidelines. Euglycaemic DKA associated with SGLT2 inhibitors is increasingly recognized but its true incidence in Canadian clinical practice is not well characterized, and Health Canada has not issued specific monitoring protocols beyond the product monograph warnings. The long-term neurocognitive effects of DKA episodes in children — particularly recurrent episodes — are an active area of investigation, with current evidence suggesting possible but not conclusively proven impacts on brain development. Optimal ketone monitoring targets during sick-day management also lack high-quality randomized trial support and are largely based on expert consensus.