Diabetic Ketoacidosis Clinical Presentation and Pathophysiology

Clinical Presentation

The American Diabetes Association recommends recognizing diabetic ketoacidosis (DKA) by classic signs, including hyperglycemia, metabolic acidosis, Kussmaul respirations, sweet-smelling breath, and altered mental status 1, 2, 3, 4
Patients with DKA often present with recent polyuria and weight loss, which are critical factors in the diagnosis 1, 2

DKA results from insulin deficiency and increased counterregulatory hormones, leading to increased hepatic and renal glucose production, impaired peripheral glucose utilization, lipolysis, and ketogenesis 1, 2, 3
The metabolic acidosis in DKA triggers compensatory hyperventilation, resulting in decreased PaCO₂ 1, 2
The American College of Clinical Endocrinologists notes that DKA is characterized by an increased anion gap metabolic acidosis, with anion gap calculated as [Na⁺] - ([HCO₃⁻] + [Cl⁻]) 1, 2

Hyperglycemia increases plasma osmolarity, and effective serum osmolality can be calculated as 2[measured Na (mEq/l)] + glucose (mg/dl)/18 1, 3
Despite respiratory compensation, the metabolic acidosis in DKA predominates, resulting in a expected pH between 7.00-7.24 1, 2
The Endocrine Society recommends avoiding common pitfalls, such as confusing sweet breath odor with alcohol intoxication and mistaking Kussmaul respirations for primary respiratory alkalosis 1, 2