Diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is defined as the presence of a metabolic acidosis (venous bicarbonate less than 15 mmol/L or pH less than 7.3) and significant ketosis (plasma beta hydroxybutyrate greater than 3 mmol/L or ketonuria greater than 2+ on standard urinalysis sticks) in the presence of a random plasma glucose greater than 11 mmol/L or known diabetes. The latter criterion is important as the entity of normoglycaemic DKA is well recognised and is a diagnostic pitfall for the unwary, especially in pregnancy.

General examination

A thorough general and systemic examination is an essential part of the assessment of the patient with any diabetic emergency. 

Is the patient shocked?

A systolic blood pressure less than 100 mm Hg (less than 90 mm Hg in a previously young fit healthy adult) with tachycardia, cold peripheries and poor urine output is a marker of severity and should prompt urgent fluid resuscitation.

The usual cause of shock in DKA is severe fluid depletion secondary to osmotic diuresis and vomiting leading to intravascular volume depletion.

However, alternative explanations should be considered including septic shock and cardiogenic shock in severe acidosis.

Is the patient conscious?

The obtunded/unconscious patient is a marker of severity and while mental obtundation is usually related to the severity of the metabolic derangement, consideration should still be given to alternative explanations such as CNS infection, intra-cranial catastrophe or toxin ingestion. 

Is the patient febrile?

Infection is a common precipitant of DKA and potential signs of infection should be sought.

Are there any chest signs?

Infection is a common precipitant of DKA and potential signs of infection should be sought.

Abdominal

A thorough abdominal examination is important to seek signs of a 'surgical' abdomen that may be the precipitant for DKA.

Note should also be made of areas of lipohypertrophy at injection sites during abdominal examination.

However, a painful abdomen with some tenderness on palpation (and often a raised amylase as well) is actually a common finding in DKA and will normally resolve as the DKA is treated, only true rigidity and guarding with absolute absence of bowel sounds should prompt surgical referral in the newly presenting DKA.

Ketotic foetor

This is not a consistent sign in DKA as not all people are able to smell ketones.

Urinalysis or blood ketone measurement are more reliable ways of detecting their presence.

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