Diabetic Ketoacidosis l: Introduction

Definition

Diabetic ketoacidosis (DKA) is an acute, life-threatening complication of diabetes mellitus, characterized by a triad of hyperglycemia (blood glucose >250 mg/dL), ketonemia or ketonuria, and metabolic acidosis (arterial pH <7.30 and serum bicarbonate <18 mEq/L). It results from insulin deficiency combined with elevated levels of counterregulatory hormones—glucagon, catecholamines, cortisol, and growth hormone—leading to increased lipolysis, hepatic ketone production, and impaired glucose utilization.

Classification

DKA is clinically classified into mild, moderate, and severe forms based on the degree of acidemia and bicarbonate depletion. In mild DKA, arterial pH ranges from 7.25 to 7.30, and bicarbonate levels range from 15 to 18 mEq/L. Moderate DKA presents with a pH between 7.00 and 7.24, and bicarbonate levels between 10 and <15 mEq/L. Severe DKA is defined by a pH below 7.00 and bicarbonate levels below 10 mEq/L. This severity classification is essential for guiding the intensity of treatment and monitoring, especially in critical care settings.

Clinical Manifestations

The onset of DKA is typically acute, with symptoms developing over approximately 24 hours. Early signs include polyuria, polydipsia, and nocturia, reflecting osmotic diuresis due to hyperglycemia. As dehydration progresses, patients may develop dry mucous membranes, hypotension, and tachycardia.

Gastrointestinal symptoms—such as nausea, vomiting, and abdominal pain—are common and may mimic an acute abdomen. The pain typically resolves with correction of the acidosis.

Respiratory compensation manifests as Kussmaul respirations, characterized by deep and rapid breathing in response to metabolic acidosis. A fruity odor on the breath, caused by acetone, is a classic clinical clue.

In more advanced cases, neurological symptoms such as lethargy, confusion, and coma may occur, particularly when serum osmolality exceeds 330 mOsm/kg. DKA may also present as the initial manifestation of previously undiagnosed type 1 diabetes, especially in pediatric or adolescent patients.