Diabetes

Hyperglycaemic hyperosmolar state

Hyperglycaemic hyperosmolar state (HHS) is a medical emergency that is different from DKA and so treatment requires a different approach

It is characterised by:

1- Hypovolaemia.
2- Severe hyperglycaemia (> 30 mmol/L (600 mg/dL))
3- Hyperosmolality (serum osmolality > 320 mOsmol/kg),
4- No significant ketonaemia (< 3 mmol/L)
5- No acidosis (pH > 7.3 (H+ < 50 nmol/L), bicarbonate > 15 mmol/L).





Although typically occurring in older patients, HHS is increasingly seen in younger adults.
Common precipitating factors include
1- Infection.
2- Myocardial infarction.
3- Cerebrovascular events.
4- Drug therapy (e.g. glucocorticoids).

Poor prognostic signs include:

1- Hypothermia.
2- Hypotension (systolic blood pressure < 90 mmHg).
3- Tachy­ or bradycardia.
4- Severe hypernatraemia (sodium > 160 mmol/L).
5- Serum osmolality > 360 mOsmol/kg.
6- The presence of other serious comorbidities.

MANAGEMENT

The aims are to normalize osmolality, replace fluid and electrolyte losses, and normalize blood glucose, at the same time as preventing complications such as arterial or venous thrombosis, cerebral edema and central pontine demyelinosis.





If osmolality cannot be measured frequently, osmolarity can be calculated as follows and used as a surrogate (based on plasma values in mmol/L):
Plasma osmolality = 2[Na]+[glucose]+[urea]
The normal value is 280–296 mOsmol/kg and consciousness is impaired when it is high (> 340 mOsmol/kg), as commonly occurs in HHS.

Emergency management of HHS

Time 0–60 mins

Commence IV 0.9% sodium chloride 1 L over 1 hr
• Commence insulin infusion (0.05 U/kg/hr) • Perform initial investigations
• Perform clinical assessment to assess degree of dehydration, mental status and any source of potential sepsis

Assess foot risk score

• Establish monitoring regimen – generally hourly glucose and calculated osmolality (2Na+ + glucose + urea) for first 6 hrs. then 2-hourly if responding
• Insert urinary catheter to monitor hourly urine output and calculate fluid balance
• Commence LMWH in a prophylactic dose • Consider antibiotic therapy if sepsis suspected

Time 60 mins to 6 hrs

Continue with 0.9% sodium chloride infusion 0.5–1.0 L/hr, depending on clinical assessment and response

Maintain potassium in the reference range (3.6–5.0 mmol/L), as with DKA

Avoid hypoglycaemia – aim to keep blood glucose at 10–15 mmol/L (180–270 mg/dL) in the first 24 hrs. If blood glucose falls below 14 mmol/L (252 mg/dL), commence 5% or 10% glucose infusion in addition to 0.9% saline

Time 6–12 hrs

• Continue IV fluid replacement to target 3–6 L.
• Continue treatment of underlying precipitant
• Avoid hypoglycaemia

Time 12–24 hrs

Assess for complications of treatment
• Continue IV fluid replacement
• Continue IV insulin with or without 5% or 10% glucose to maintain blood glucose at 10–15 mmol/L (180–270 mg/dL)
• Continue treatment of underlying precipitant
• Avoid hypoglycaemia

Time 24 hrs to day 3

Continue IV fluids until eating and drinking.
• Convert to appropriate SC insulin regimen
• Assess for signs of fluid overload
• Encourage early mobilization
• Carry out daily foot checks
• Continue LMWH until discharge