Hyperosmolar Hyperglycaemic State

Question 1

What characterises HHS?

Answer 1

Hyperglycaemia (glucose ≥30 mmol/L
Hyperosmolality (effective serum osmolality usually ≥320 mmol/kg
Volume depletion in the absence of significant ketoacidosis (pH ≥7.3 + bicarbonate ≥15 mmol/L

Question 2

In which patients does HHS usually present?

Answer 2

Elderly with T2DM

Question 3

Describe the pathophysiology of HHS

Answer 3

Hyperglycaemia leads to
Increased serum osmolality leads to
Osmotic diuresis leads to
Severe volume depletion

Question 4

Lit 3 precipitating factors for HHS

Answer 4

Intercurrent illness
Dementia
Sedative drugs

Question 5

How does HHS differ to DKA?

Answer 5

DKA presents within hours of onset, HHS comes on over many days, consequently, the dehydration + metabolic disturbances may be more extreme

Question 6

List 3 symptoms arise as consequences of volume loss in HHS

Answer 6

Clinical signs of dehydration
Polyuria
Polydipsia

Question 7

Name 2 systemic complications of HHS

Answer 7

Lethargy
N+V

Question 8

Name 2 neurological S/S of HHS

Answer 8

Altered levels of consciousness
Focal neurological deficits

Question 9

What haematological consequence may arise due to HHS?

Answer 9

Hyperviscosity
May result in MI, Stroke + Peripheral Arterial Thrombosis

Question 10

List 5 features typically seen in HHS

Answer 10

Hypovolaemia
Marked hyperglycaemia >30 mmol/L
High serum osmolarity >320 mosmol/kg
No significant hyperketonaemia <3 mmol/L
No significant acidosis

Question 11

What equation can be used to calculate serum osmolarity?

Answer 11

2 x (Na + glucose + urea)

Question 12

What may cause acidosis in HHS?

Answer 12

Renal impairment secondary to dehydration
Lactic acidosis due to sepsis

Question 13

What investigation distinguishes HHS from DKA?

Answer 13

Blood ketones
HHS: Low
DKA: High

Question 14

What investigations should be performed in HHS?

Answer 14

Blood glucose
Blood ketones
VBG
U+Es + Creatinine
Serum osmolarity
FBC
ECG

Question 15

What are the estimated fluid losses in HHS?

Answer 15

100 - 220 ml/kg

Question 16

Describe management of HHS

Answer 16

Fluid replacement
+/- Insulin (in certain circumstances)
VTE prophylaxis

Question 17

Describe fluid replacement in HHS

Answer 17

1. IV 0.9% NaCl 1L over 1h
2. IV 0.9% NaCl 0.5-1L/h

Question 18

Why should caution be taken in the elderly with fluid replacement for HHS?

Answer 18

Too rapid rehydration may precipitate heart failure
Insufficient may fail to reverse AKI

Question 19

How much potassium should be given alongside the IV fluids?

Answer 19

K+ >5.5: None
K+ 3.5-5.5: 40 mmol/L
K+ <3.5: Senior review

Question 20

When is insulin indicated in management of HHS

Answer 20

If there is HHS + ketonaemia (3ß-hydroxybutyrate >1- ≤3 mmol/L or urine ketones < 2+) + not acidotic (pH >7.3 + bicarbonate >15 mmol/L)
Use 0.05 units/kg/h
OR
If significant ketonaemia (3ß-hydroxybutyrate >3 mmol/L) or ketonuria (≥ 2+) with a pH <7.3 + bicarbonate <15 mmol/L (i.e. mixed DKA + HHS)
Use DKA guidelines at 0.1 units/kg/h

Question 21

How is hypoglycaemia avoided in management of HHS?

Answer 21

Aim to keep BG 10-15mmol/L in first 24h
If falls <14: start 5% dextrose at 125ml/h

Question 22

What should the target fluid balance be in management of HHS?

Answer 22

At 6h: +ve fluid balance of 2-3L
At 12h: +ve fluid balance of 3-6L

Question 23

What complication may arise due to HHS?

Answer 23

Vascular complications due to hyperviscosity e.g. MI, Stroke