Problem 55 A 74-year-old man with confusion and oliguria
A 74-year-old man was brought into the emergency department confused and drowsy. According to his wife he had been unwell for approximately 1 week with a diarrhoeal illness, with nausea and anorexia. The changes to his mental state had appeared over the past 24 hours, and he had become bedridden. There was no history of chest pain.
Immediately prior to this acute illness he had been independent and well, although he had a past history of type II diabetes mellitus and ischaemic heart disease. He had been treated for hypertension for approximately 10 years. His current medications are combination perindopril/indapamide 5/1.25 mg one per day; gliclazide MR 30 mg twice daily; metformin 500 mg twice daily; aspirin 150 mg once daily; and celecoxib 200 mg once daily.
On examination, the man was drowsy but easily roused, and unable to give a clear history. His tongue was very obviously dry. Blood pressure was 100/55 mmHg lying, and he was unable to stand to check for a postural drop. Pulse rate was 90 and regular, although difficult to feel. Temperature was 36.5°C. There was no evidence of right or left heart failure, and his chest was clear to auscultation. Pedal pulses were not palpable, and he had a soft right carotid bruit. ECG is unchanged from previous.
An indwelling catheter was placed in his bladder, and it drained 50 mL of dark urine. Urinalysis showed protein + and blood +. A finger prick blood sugar level was 5.0 mmol/L.
Urgent blood results included the following:
Investigation 55.1 Summary of results
| Sodium | 143 mmol/L | (N: 137–145) |
| Potassium | 7.8 mmol/L | (N: 3.5–4.9) |
| Chloride | 105 mmol/L | (N: 100–109) |
| Bicarbonate | 8 mmol/L | (N: 22–32) |
| Urea | 65 mmol/L | (N: 2.7–8.0) |
| Creatinine | 850 µmol/L | (N: 50–120) |
| Phosphate | 3.5 mmol/L | (N: 0.65–1.45) |
| Calcium | 1.64 mmol/L | (N: 2.10–2.55) |
| Albumin | 30 g/L | (N: 34–48) |
| Haemoglobin | 145 g/L | (N: 135–175) |
Answers
• Severe hyperkalaemia is the most obvious priority, because of the high risk of refractory cardiac arrhythmias and death.
• He is hypotensive with evidence of poor peripheral perfusion, and so resuscitation with intravenous fluids is a high priority.
• There is also the possibility of contributory sepsis, and so intravenous broad-spectrum antibiotics should be considered.
A.3 Severe hyperkalaemia is an emergency requiring rapid and aggressive treatment. While an electrocardiogram is a useful adjunct investigation and will show abnormalities such as peaked T waves and broadening of the QRS complex, at this potassium level it should not be used as a means of deciding whether to treat. Protocols for treatment of hyperkalaemia should be standard items in emergency departments, and consist of a combination of cardioprotective and potassium-lowering manoeuvres using calcium gluconate and dextrose-insulin. An example of such a protocol is shown in Box 55.1.
Box 55.1
Example of a protocol for treatment of hyperkalaemia
