What is the immediate management for a patient with diabetic ketoacidosis (DKA) experiencing low appetite, nausea, vomiting, despite taking long-acting insulin?

Causes of DKA Despite Taking Long-Acting Insulin

The most critical cause of DKA in a patient taking long-acting insulin who presents with nausea, vomiting, and poor oral intake is inadequate or discontinued prandial (mealtime) insulin coverage—basal insulin alone cannot prevent ketoacidosis when the patient stops eating and fails to take bolus insulin. 1

Primary Mechanisms Leading to DKA Despite Basal Insulin

Insufficient Total Insulin Delivery

• Long-acting insulin provides only basal coverage and cannot compensate for the complete absence of prandial insulin, particularly when illness or nausea prevents eating and the patient mistakenly stops all rapid-acting insulin doses 1
• Patients often incorrectly hold all insulin when not eating, creating absolute insulin deficiency despite continued basal insulin, which is a critical error that precipitates DKA 1
• The nausea and vomiting themselves indicate either an evolving DKA (as these are cardinal symptoms) or an intercurrent illness that increases insulin requirements 1

Intercurrent Illness as Precipitant

• Any acute illness (infection, gastroenteritis, pancreatitis) dramatically increases counter-regulatory hormones (glucagon, cortisol, catecholamines) that antagonize insulin action, requiring MORE insulin than usual, not less 2, 3
• The combination of increased insulin resistance from illness plus reduced insulin intake creates the perfect storm for ketoacidosis 4

Medication-Related Causes

• SGLT2 inhibitor use is an increasingly common cause of DKA, including euglycemic DKA (glucose <250 mg/dL), particularly when combined with reduced carbohydrate intake, dehydration, or illness 1
• Risk factors for SGLT2 inhibitor-associated DKA include very-low-carbohydrate diets, prolonged fasting, dehydration, excessive alcohol intake, and presence of autoimmunity 1

Clinical Presentation Confirms DKA Diagnosis

Classic Symptoms Present in This Case

• Nausea, vomiting, and abdominal pain are hallmark symptoms of DKA itself, developing over hours to days 1
• Low appetite and inability to maintain oral intake lead to dehydration, which worsens the metabolic crisis 2
• Patients typically present with polyuria, polydipsia, weight loss, and dehydration in addition to gastrointestinal symptoms 1

Critical Management Pitfall to Address

The "Sick Day" Insulin Error

• The most dangerous misconception is that patients should stop or reduce insulin when not eating—this is categorically wrong and a leading cause of preventable DKA 1
• Individuals treated with intensive insulin therapy should NEVER stop or hold their basal insulin even if not eating, and clinicians must provide explicit instructions on insulin dose adjustments during illness 1
• During illness, insulin requirements typically INCREASE by 20-30%, not decrease, due to stress hormones 3, 4

Additional Contributing Factors to Investigate

Behavioral and Psychosocial Causes

• Intentional insulin omission due to depression, eating disorders, or cost concerns is a common but under-recognized cause of recurrent DKA, particularly in younger patients 1
• Alcohol and substance use are established risk factors for hyperglycemic crises 1

Inadequate Baseline Insulin Regimen

• The patient may have been under-insulinized at baseline, with basal insulin alone insufficient to meet total daily insulin requirements even before the acute illness 5
• High baseline HbA1c levels indicate chronic inadequate glycemic control and increased DKA risk 1

Pregnancy Consideration

• Up to 2% of pregnancies with pregestational diabetes are complicated by DKA, and pregnant individuals may present with euglycemic DKA (glucose <200 mg/dL) 1
• Hyperemesis gravidarum can trigger DKA in pregnant patients with diabetes 1

Immediate Diagnostic Steps

Confirm DKA Diagnosis

• Measure blood glucose, venous pH, serum bicarbonate, anion gap, and blood or urine ketones (β-hydroxybutyrate preferred) to confirm the triad of hyperglycemia, ketosis, and metabolic acidosis 2, 4
• DKA is confirmed when glucose is elevated (or family history of diabetes), ketones are present, and anion gap metabolic acidosis exists 4

Identify Precipitating Cause

• Obtain detailed medication history including SGLT2 inhibitors, recent insulin doses, and any changes in regimen 1
• Evaluate for infection (urinalysis, chest X-ray, blood cultures), myocardial infarction (ECG, troponin), or other acute illness 2, 3
• Check pregnancy status in women of childbearing age 1

Prevention Education for Future Episodes

Sick Day Management Rules

• Patients must understand to CONTINUE basal insulin at full dose even when not eating 1
• Check blood glucose and ketones every 2-4 hours during illness, especially if glucose >200 mg/dL 1
• Maintain hydration with non-caloric fluids and seek immediate medical attention if unable to tolerate oral intake 1
• Discontinue SGLT2 inhibitors immediately during acute illness and 3-4 days before any planned procedure 1, 6