Hyperosmolar hyperglycaemic state (E&M)

Question 1

Define HHS.

Answer 1

Characterised by profound hyperglycaemia (>30mmol/L), hyperosmolarity (>320mOsm/kg) and volume depletion (dehydration) in the absence of significant ketoacidosis (pH>7.3 and bicarbonate>15mmol/L)

Question 2

What is HHS also known as?

Answer 2

Non-ketotic hyperglycaemic hyperosmolar syndrome (NKHS)

Question 3

How is ketogenesis avoided in HHS?

Answer 3

Small amounts of insulin still being secreted by pancreas

Question 4

Which groups does HHS commonly affect? (2)

Answer 4

• older people with T2DM
• may be initial presentation of T2DM

Question 5

What are the clinical features of HHS? (10)

Answer 5

• acute cognitive impairment (recorded via GCS, due to hyponatraemia)
• polyuria
• polydipsia
• weight loss
• nausea and vomiting
• weakness
• dry mucous membranes + poor skin turgor (dehydration)
• abdominal pain
• focal neurological signs + seizures
• more insidious onset (over days)

Question 6

What might you see on examination of HHS?

Answer 6

Dehydration - dry mucous membranes, reduced skin turgor

Question 7

When can coma occur in HHS?

Answer 7

Coma is rare and, if seen, is usually associated with a serum osmolarity >340mOsm/kg

Question 8

What are some risk factors for HHS? (5)

Answer 8

• infection (pneumonia, UTI, diabetic foot infection)
• surgery
• inadequate insulin therapy / non-adherence to diabetes medications
• corticosteroids or antipsychotics
• acute illness (MI, stroke, sepsis)

Question 9

What do we measure in bloods for HHS and what would we see? (3)

Answer 9

• blood glucose - markedly raised (>30mmol/L)
• blood ketones - negative/low (<3mmol/L - distinguish HHS vs DKA)
• VBG - none/mild acidosis (pH>7.3, bicarbonate>15mmol/L); lactic acidosis

Question 10

What would serum osmolarity be like in HHS?

Answer 10

Significantly raised (>320mmol/L) due to hypovolaemia - key parameter to monitor

Question 11

What would urinalysis show in HHS? (5)

Answer 11

• renal impairment
• hypo/hyperkalaemia
• hypo/hypernatraemia
• hypophosphataemia
• hypomagnesaemia

Question 12

What would FBC show in HHS?

Answer 12

Leukocytosis

Question 13

What would ECG show in HHS? (2)

Answer 13

• abnormal T or Q waves or ST-segment changes in MI
• evidence of hypokalaemia (U waves) or hyperkalaemia (tall ‘peaked’ T waves)

Question 14

What overall triad is seen in HHS?

Answer 14

Severe hyperglycaemia (>30) + hypotension + hyperosmolarity (>320)

Question 15

What are some differential diagnoses for HHS? (8)

Answer 15

• DKA
• lactic acidosis
• alcoholic ketoacidosis
• ingestion of toxic substances
• paracetamol OD
• salicylate OD
• seizures
• stroke

Question 16

What is the order of management in HHS?

Answer 16

1. correct hypotension + electrolyte abnormalities
2. correct hyperglycaemia - not done first as IV insulin can result in cerebral oedema due to quick shift in glucose

Question 17

How do we manage hypotension and dehydration in HHS?

Answer 17

• fluid resuscitation with IV fluids - isotonic saline (1L 0.9% NaCl over 1h)
• if SBP<90 give 500mL bolus saline - if no response give second bolus
• if SBP>90/response to first bolus - start 0.9% NaCl
• 500mL normal saline over 15-30min until SBP>100
• use 0.45% saline if serum Na+>170

Question 18

What do we give for HHS if pH<6.9?

Answer 18

Give sodium bicarbonate

Question 19

What can excess infusion of NaCl cause? (2)

Answer 19

• hyperchloraemic acidosis (hence Hartmann’s solution may be preferred when large volumes of fluid are needed)
• excessive infusion of any IV fluid can cause pulmonary oedema and potentially cardiac failure

Question 20

How do we correct electrolyte disturbance in HHS?

Answer 20

• add potassium (KCl) to saline solution infusion
• serum potassium often high on admission despite total body potassium being low
• potassium replacement needed as insulin drives K+ into cells
• if rate of K+ infusion>20mmol/hr, cardiac monitoring may be required

Question 21

How do we correct hyperglycaemia in HHS?

Answer 21

• corrected only if BGC stops falling while giving fluids
• IV insulin (0.05 units/kg/hr)
• if mixed DKA+HHS 0.1 units/kg/hr
• if BGC falls <15mmol/L, infusion of 5% dextrose started
• if capillary ketones<0.3, pH>7.3 or HCO3>18, use SC insulin instead - but there must be an overlap between IV and SC insulin for 1-2h

Question 22

What prophylaxis do we need for HHS and why?

Answer 22

VTE prophylaxis as patients at high risk due to dehydration

Question 23

What are some complications of HHS? (10)

Answer 23

• insulin-related hypoglycaemia
• treatment-related hypokalaemia
• stroke
• MI
• PE
• DIC
• coma
• mesenteric vessel thrombosis
• cerebral oedema
• central pontine myelinolysis

Question 24

Describe the prognosis of HHS.

Answer 24

Mortality ranges from 5-15% mostly as a consequence of older patient population that is affected by HHS + their comorbidities