Diabetic Ketoacidosis

Key Features

Essentials of Diagnosis

• Hyperglycemia > 250 mg/dL (13.9 mmol/L)

• Acidosis with blood pH < 7.3

• Serum bicarbonate < 15 mEq/L

• Serum positive for ketones

• Elevated lactate (> 2 mmol/L in more than 50% of patients)

General Considerations

• May be the initial manifestation of type 1 diabetes

• Commonly occurs with poor compliance in type 1 diabetics, particularly when episodes are recurrent

• Develops in type 1 diabetics with increased insulin requirements during infection, trauma, myocardial infarction, or surgery

• May develop in type 2 diabetics under severe stress such as sepsis or trauma

• Common serious complication of insulin pump therapy

Demographics

• Incidence is 5 to 8 episodes per 1000 diabetic persons annually

• Incidence in insulin pump therapy is 1 per 80 patient-months of treatment

Clinical Findings

Symptoms and Signs

• May begin with a day or more of polyuria, polydipsia, marked fatigue, nausea and vomiting and, finally, mental stupor that can progress to coma

• Drowsiness is fairly common but frank coma only occurs in about 10% of patients

• Dehydration, possible stupor

• Rapid deep breathing and a "fruity" breath odor of acetone

• Hypotension with tachycardia indicates profound fluid and electrolyte depletion

• Mild hypothermia usually present; elevated or even a normal temperature may suggest infection

• Abdominal pain and tenderness in the absence of abdominal disease; conversely, cholecystitis or pancreatitis may occur with minimal symptoms and signs

Differential Diagnosis

• Lactic acidosis in type 1 diabetics, including the use of metformin

• Alcoholic ketoacidosis

• Hypoglycemia

• Hyperglycemic hyperosmolar state

• Uremia

• Starvation ketoacidosis

• Salicylate poisoning

Diagnosis

Laboratory Tests

• Plasma glucose of 350–900 mg/dL (19.4–50 mmol/L)

• Serum ketones at a dilution of 1:8 or greater or β-hydroxybutyrate more than 4 nmol/L

• Hyperkalemia (serum potassium level of 5–8 mEq/L)

• Mild hyponatremia (serum sodium of approximately 130 mEq/L)

• Hyperphosphatemia (serum phosphate level of 6–7 mg/dL [1.9–2.3 mmol/L])

• Elevated blood urea nitrogen and serum creatinine levels

• Acidosis may be severe (pH ranging from 6.9 to 7.2, and serum bicarbonate ranging from 5 mEq/L to 15 mEq/L)

• PCO₂ is low (15–20 mm Hg) related to hyperventilation

• Fluid depletion is marked, typically about 100 mL/kg

• Acetoacetic acid is measured by nitroprusside reagents [Acetest and Ketostix]; the more prevalent β-hydroxybutyric acid has no ketone group and is therefore not detected by conventional nitroprusside tests

• Nonspecific elevations of serum amylase and lipase occurs in about 16–25% of cases of diabetic ketoacidosis; an imaging study may be necessary if the diagnosis of acute pancreatitis is being seriously considered

• Serum lipase may be useful if the diagnosis of pancreatitis is being seriously considered

• Leukocytosis up to 25,000/mcL (25 × 10⁹/L) with a left ...