4 Diabetic Ketoacidosis

What DKA is

Diabetic ketoacidosis (DKA) is an acute emergency caused by insufficient insulin. Insufficient insulin leads to ketone production and metabolic acidosis. Suspected DKA requires urgent emergency assessment and treatment by qualified clinicians.

Recognizing DKA

In adults, diagnosis requires all three of the following:

• Diabetes or glucose at least $200\,\text{mg/dL}$ ($11.1\,\text{mmol/L}$).

• Significant ketones, preferably measured as blood β-hydroxybutyrate at least $3.0\,\text{mmol/L}$.

• Acidosis, indicated by $pH < 7.3$ or bicarbonate $< 18\,\text{mmol/L}$.

A glucose concentration below $200\,\text{mg/dL}$ does not rule out DKA. Reduced food intake, pregnancy, and SGLT2-inhibitor use are situations in which it can occur with lower glucose. In someone with diabetes, ketones and acidosis should prompt consideration of euglycemic DKA.

Symptoms and signs that can accompany DKA include vomiting, abdominal pain, dehydration, and deep, rapid breathing. Fruity-smelling breath may also be present. For example, vomiting, abdominal pain, deep rapid breathing, and fruity-smelling breath together with glucose of $385\,\text{mg/dL}$, β-hydroxybutyrate of $5.2\,\text{mmol/L}$, $pH = 7.18$, and bicarbonate of $12\,\text{mmol/L}$ are consistent with DKA. Glucose level alone does not distinguish DKA from other hyperglycemic emergencies.

Initial assessment and priorities

Begin by assessing airway, breathing, circulation, vital signs, mental status, and hydration. Signs such as dry mucous membranes, tachycardia, and confusion are relevant findings in a patient with suspected DKA.

Obtain urgent glucose, electrolytes, ketones, and acid–base studies. These tests help confirm DKA, assess its severity, and guide treatment. Assess for dehydration, altered mental status, and possible triggers, including infection or missed insulin.

The treatment priorities are to restore circulation, correct ketonemia and electrolyte disturbances, and address the precipitating cause. Do not delay assessment until the patient can drink, and do not start insulin without checking potassium.

Fluids and monitoring

Restoring circulating volume is a key early treatment. For a dehydrated adult without known heart or kidney failure, typical early management includes isotonic intravenous fluid resuscitation, individualized to the patient's condition. Fluid type and rate require particular caution in older adults and in people with heart or kidney disease.

Reassess frequently, including vital signs, fluid balance, glucose, and electrolytes. Monitoring glucose alone is not sufficient; close clinical and laboratory monitoring is needed during treatment.

Potassium and insulin

Insulin is used to stop ketone production, but potassium must be checked and managed carefully. Insulin moves potassium into cells and can rapidly worsen hypokalemia, increasing the risk of dangerous arrhythmias and muscle weakness.

For adults, consensus guidance recommends delaying insulin when potassium is below $3.5\,\text{mmol/L}$, replacing potassium according to the treatment protocol, and starting insulin once potassium has been corrected above that level. Follow the local protocol and monitor potassium closely. For example, a potassium concentration of $3.2\,\text{mmol/L}$ calls for withholding insulin initially and correcting potassium, rather than starting insulin immediately.

Continuing treatment as glucose falls

Glucose often improves before ketonemia and acidosis resolve. When glucose falls below about $250\,\text{mg/dL}$, dextrose-containing intravenous fluid is generally added as indicated so insulin can continue safely while ketones are cleared.

Do not stop insulin just because glucose is below $250\,\text{mg/dL}$. Treatment and the decision that DKA has resolved depend on the metabolic abnormalities, not glucose alone.

When bicarbonate may be considered

Bicarbonate is generally not recommended routinely for adult DKA; routine use has not shown clear benefit and may cause harm. Clinicians may consider it in severe acidemia, such as $pH < 7.0$, following specialist and local protocols. Bicarbonate does not replace insulin or fluids and does not remove the need to monitor potassium.

Resolution and transition

Resolution is assessed using ketones and acid–base status rather than glucose alone. Findings supporting resolution are β-hydroxybutyrate below $0.6\,\text{mmol/L}$ and resolved acidosis, indicated by $pH \geq 7.3$ or bicarbonate $\geq 18\,\text{mmol/L}$. Clinical assessment also guides the decision to transition from intravenous insulin.

When changing to subcutaneous insulin, basal insulin is generally administered before stopping the intravenous infusion to reduce rebound hyperglycemia or recurrent ketosis. The recommended overlap is $1$–$2$ hours. A glucose value below $250\,\text{mg/dL}$ by itself, increased urine output, or receipt of a single subcutaneous insulin dose does not establish that DKA has resolved.

• Potassium management

• Dextrose-containing IV fluid

• Transition from IV insulin