# Question 5.2

A 67-year-old patient is admitted with an altered mental state. There is a history of type 2 diabetes on oral agents

 Parameter Patient Value Adult Normal Range pH 7.42 7.35 – 7.45 pO2 60 mmHg (7.9 kPa) pCO2 37 mmHg (4.9 kPa) 35 – 45 (4.7 – 6.0) Standard bicarbonate 24 mmol/L 22 – 29 Base excess 0 mmol/L -3 to +3 Blood haemoglobin 178 g/L* 115 – 155 Haematocrit 0.54* 0.35 – 0.46 Sodium 136 mmol/L 135 – 145 Potassium 3.7 mmol/L 3.5 – 5.2 Ionised Calcium 1.06 mmol/L* 1.15 – 1.30 Chloride 95 mmol/L 95 – 110 Glucose 47 mmol/L* 4.0 – 8.0 Lactate 5.9 mmol/L* 0.5 – 1.3 Urea 22 mmol/L* 3.0 – 8.0 Creatinine 209 µmol/L* 45 – 90

a) List the important biochemical abnormalities, showing your calculations where appropriate. (10% marks)

b) List the diagnosis most consistent with these abnormalities. (5% marks)

c) List three complications of this condition. (15% marks)

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## Discussion

a)

The biochemical abnormalities, important and unimportant, are:

• Hypoxia (assuming this is a gas on 21% FiO2)
• Either polycythaemia or - more likely, looking at the rest of the results - haemoconcentration (a raised haemoglobin, a haematocrit of 0.54)
• Mild hypokalemia
• Hyperglycaemia: BSl 47 mmol/L
• Hypernatremia: the sodium, corrected by a conventional formula, is 148 mmol/L, which is probably what they meant when they said "showing your calculations".

Sodium (corrected) = Sodium (measured) + glucose / 4

= 136 + (47/4)

= 136+ 11.75

= 148, or so

• Lactate is elevated, contributing to the impression that the patient is dehydrated
• The creatinine and urea are raised, in a ration which also supports water loss

b)

This is HHS, an obvious spot diagnosis which was rewarded with the absolute minimum of marks.

c)

To pick three complications would be hard, as this condition has a million possible complications:

• HHS-specific physiological abnormalities
• Hypotension and shock
• Metabolic acidosis
• Coma
• Complications arising from the HHS disease state:
• Cardiac arrest
• Cardiovascular collapse
• Myocardial infarction
• Pulmonary oedema
• Stroke
• Cerebral oedema and brain injury
• Venous thrombosis (DVT, PE)
• Aspiration
• Osmotic demyelination (Hegazi et al, 2013)
• Complications of therapy for HHS:
• Dysnatraemia
• Hyperchloremia from saline administration.
• Phosphate depletion
• Hypokalemia
• Hypoglycaemia
• Cerebral oedema

## References

Hyperglycemic Comas by P. VERNON VAN HEERDEN from Vincent, Jean-Louis, et al. Textbook of Critical Care: Expert Consult Premium. Elsevier Health Sciences, 2011.

Rosenbloom, Arlan L. "Intracerebral crises during treatment of diabetic ketoacidosis." Diabetes care 13.1 (1990): 22-33.

Hegazi, Mohamed Osama, and Anant Mashankar. "Central pontine myelinolysis in the hyperosmolar hyperglycaemic state." Medical Principles and Practice 22.1 (2013): 96-99.

Kitabchi, Abbas E., et al. "Hyperglycemic crises in adult patients with diabetes." Diabetes care 32.7 (2009): 1335-1343.