Hyperosmolar Hyperglycaemia Syndrome

Question 1

In what patients does HHS occur in?

Answer 1

Type two diabetics

Question 2

What is HHS characterised by?

Answer 2

• Hypovolaemia
• Hyperglycaemia >30mmol
• Mild or absent ketonaemia <3mmol/L
• High osmolality >320mOsm/kg

Question 3

What is the pathophysiology of HHS?

Answer 3

• There is a relative lack of insulin coupled with a rise in counter regulatory hormones (cortisol, GH, glucagon)
• Leads to a rise in glucose
• The patient has a certain level of insulin that prevents development of DKA
• The excessive glucose causes osmotic diuresis within the kidneys as SGLT2 channels are saturated, causes loss of electrolytes too
• Causes dehydration for the patient

Question 4

What are precipitants for HHS?

Answer 4

• Most cases represent a new diagnosis of T2DM
• Infection
• High dose steroids
• MI
• Vomiting
• Stroke
• Poor treatment concordance

Question 5

What are the clinical features of HHS?

Answer 5

• Insidious onset, increased renal water loss and dehydration over days->weeks
• Polyuria, polydipsia
• Nausea and vomiting
• Muscle cramps
• Weakness
• Altered mental status, seizures and coma in late stages

Question 6

What are signs of HHS?

Answer 6

• Dehydration (dry mucous membranes, sunken eyes, reduced cap refill, decreased skin turgor)
• Hypotension
• Decreased urine output
• Decreased conscious level
• Coma
• Focal neurological signs
• Features of the precipitating cause

Question 7

What blood investigations would you look for in HHS?

Answer 7

Bloods - 
- Lab glucose >30mmol/L
- Serum osmolarity >320 mOsm
- Ketones (blood <3mmol/L)
- VBG
- U+E
Also...
- CRP and blood cultures to look for source
- troponin to look for source
- amylase to look for source
- CK (renal function)

Question 8

What bedside tests would you order?

Answer 8

• ECG
• Urinalysis +/- MSU
• Urinary pregnancy test

Question 9

What would you order if there is reduced GCS or focal neurology?

Answer 9

CT head

Question 10

What are the principles of management for HHS?

Answer 10

• Aggressive fluid resuscitation

- Normalisation of blood glucose levels and osmolality

Question 11

What is the specific management for HHS?

Answer 11

1. A->E
2. Fluid resuscitation (0.9% saline 1l over 1hr). Monitor and give fluids based on urine output, aim for positive balance of 2-3l by 6hr.
3. Insulin if ketonaemic (>1mmol/L) or ketonuric (2+ or more). Also if blood glucose falls less than 5mmol/L per hr. FRIII at 0.05units/kg/hr. Keep glucose 10-15 in first 24hrs.
4. Electrolyte replacement (monitor Na, K, Phos, Mg every 4hrs). 40mmol K if 3.5-5.5 when urine starts to flow.

Question 12

What monitoring is required for a HHS patient?

Answer 12

Every hour for first 6hrs - 
- Blood glucose 
- U+E
- Plasma osmolality
- Fluid balance and urine output
Reduce to every 4hrs then 12hrs is osmolality falls 3-8mOsm/kg/hr and glucose by 5mmol/L/hr.

Question 13

What are the treatment targets for HHS?

Answer 13

Osmolality - Falls 3-8mOsm/kg/hr

Glucose - Falls 5mmol/L/hr

Question 14

What should the diabetic team do for a HHS patient?

Answer 14

• Should assess them within 24hrs
• Need prophylactic LMWH
• Regularly foot assessment for ulcerations
• Mobilise with catheter early on
• Patient needs daily urinalysis, U+E, CBG

Question 15

What are complications of HHS?

Answer 15

MI - Hypovolaemic, hyperviscious and severe illness

Thombosis - As above. DVT, PE stroke. Prophylactic LMWH to counteract this.

Cerebral oedema - Rapid correction of hyperglycaemia with a resulting drop in plasma osmolarity. Presents as headache, reduced GCS then death.