A 26-year-old male found was collapsed in the street. On arrival in the Emergency Department, he was unresponsive and hypotensive with a temperature of 42°C. The following is his arterial blood gas result following intubation:
Parameter |
Patient Value |
Normal Adult Range |
Fi02 |
1.0 |
|
pH |
7.21* |
7.35 - 7.45 |
PC02 |
54 mmHg (7.1 kPa)* |
35 - 45 (4.6 - 6.0) |
P02 |
500 mmHg (65.8 kPa) |
|
Bicarbonate |
21 mmol/L |
21 - 28 (10 - 13) |
Base Excess |
-6 mmol/L* |
-2 - +2 |
Sodium |
143 mmol/L |
135 - 145 |
Potassium |
4.9 mmol/L* |
3.5 - 4.5 |
Chloride |
112 mmol/L* |
95 - 110 |
Calcium ionised |
1.09 mmol/L* |
1.12 - 1.32 |
Glucose |
9.6 mmol/L* |
3.0 - 5.4 |
Lactate |
2.3 mmol/L* |
< 1.3 |
Creatinine |
219 µmol/L* |
60 - 110 |
Haemoqlobin |
139 q/L |
135 - 180 |
a) Describe the acid-base abnormality. (20% marks)
b) Give the likely underlying cause for this clinical picture. (15% marks)
a) Mixed respiratory, high anion gap and normal anion gap metabolic acidosis.
b) Toxidrome – sympathomimetic agent.
a)
Let us dissect these results systematically.
The college only wanted us to comment on the acid-base abnormalities, but other features are also interesting. In summary:
b)
Informed by the above features, the differentials must include:
If he didn't come from the street, malignant hyperthermia would also have to be mentioned.