A 28-year-old previously fit male presents with a two-day history of fever, headache and a widespread rash.
Results of investigations are as follows:
Parameter |
Patient Value |
Normal Adult Range |
FiO2 |
0.3 |
|
pH |
6.99* |
7.35 – 7.45 |
PCO2 |
26* mmHg (3.4 kPa)* |
35 |
– 45 (4.6 – 6.0) |
PO2 |
78 mmHg (10.3 kPa) |
||
SpO2 |
96% |
95 |
– 100 |
Base Excess |
-27.5 mmol/L* |
-3.0 – +3.0 |
|
Bicarbonate |
6 mmol/L* |
22 |
– 27 |
Sodium |
126 mmol/L* |
135 – 145 |
|
Potassium |
5.1 mmol/L* |
3.5 – 4.5 |
|
Creatinine |
186 micromol/L* |
60 |
– 110 |
Glucose |
2.4 mmol/L* |
3.6 – 7.7 |
|
Lactate |
16.0 mmol/L* |
0.2 – 2.0 |
Blood cultures show Gram-negative cocci.
a) List the abnormalities shown by the ABG. (10% marks)
b) Give the most likely diagnosis. (5% marks)
c) What complication of this condition may have occurred? (5% marks)
a)
Severe lactic acidosis with inadequate respiratory compensation and acute renal impairment and hypoglycaemia.
b)
Meningococcal septicaemia
c)
Waterhouse Friderichsen syndrome.
Multi-organ failure with liver and renal dysfunction is a reasonable answer and was given some credit.
a) Let us dissect the results systematically:
Thus, in summary:
b)
The trainees were expected to identify the meningococcaemia on the basis of "fever, headache and a widespread rash". This is probably somewhat unfair. The college, in recognition of this fact, acknowledged as correct any answer which explained the lactic acidosis by blaming it on sepsis-induced liver failure.
c)
The patient has features of hypoadrenalism, consistent with Waterhouse-Friedrichsen syndrome. If the trainee managed to connect the dots (gram negative cocci, low sodium, high potassium) they would have only earned a paltry 5% of the total marks for Question 20, which is a poor marks to effort ratio.
Rosenstein, Nancy E., et al. "Meningococcal disease." New England Journal of Medicine 344.18 (2001): 1378-1388.
Mautner, L. S., and W. Prokopec. "Waterhouse-Friderichsen Syndrome."Canadian Medical Association journal 69.2 (1953): 156.
Ferguson, J. Howard, and Orren D. Chapman. "Fulminating meningococcic infections and the so-called Waterhouse-Friderichsen syndrome." The American journal of pathology 24.4 (1948): 763.