Hyperosmolar hyperglycaemic state

HHS (formerly known as HONK or hyperosmolar non ketotic coma) is the typical hyperglycaemic emergency of type 2 diabetes. It is characterised by hyperglycaemia and significant hyper osmolality (serum osmolality, calculated as 2xNa+glucose, of greater than 320 mOsmol/kg) in the absence of significant ketosis.

General examination

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

Is the patient shocked?

A systolic blood pressure less than 100 mm Hg 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 HHS is severe fluid depletion secondary to osmotic diuresis leading to intravascular volume depletion.

However, alternative explanations should be considered including septic, hypovolaemic shock secondary to heamorrhage and cardiogenic shock.

Is the patient conscious?

The obtunded/unconscious patient is a marker of severity. While mental obtundation is usually related to the severity of dehydration, 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 HHS and potential signs of infection should be sought.

Are there any chest signs?

Infection is a common precipitant of HHS 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 HHS.

Ischaemic small bowel due to the hypercoagulable state associated with extreme dehydration is an occasional trap for the unwary physician.

Neurological

A thorough neurological examination is essential as CVA can be both a precipitant and a consequence of HHS.

Peripheries

HHS is often seen in those who have had T2DM for some time and who have already acquired complications, thus the presence of neuropathy, ulcers and ischaemia should be sought.

Pedal gangrene can be both a precipitant and a consequence of HHS.

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