A 59-year-old male with a past medical history of hypertension and dyslipidaemia presents with sore muscles, jaundice and oliguria.
The following data are taken from venous blood investigations on his admission:
|
Parameter |
Patient Value |
Normal Adult Range |
|
Urea |
25.5 mmol/L* |
3.0 – 8.0 |
|
Creatinine |
523 μmol/L* |
45 – 90 |
|
Sodium |
138 mmol/L |
134 – 145 |
|
Potassium |
6.2 mmol/L* |
3.4 – 5.0 |
|
Chloride |
105 mmol/L |
98 – 108 |
|
Bicarbonate |
16 mmol/L* |
22 – 32 |
|
Calcium (corrected) |
2.07 mmol/L* |
2.20 – 2.55 |
|
Phosphate |
1.6 mmol/L* |
0.8 – 1.5 |
|
Creatine Kinase |
60110 U/L* |
< 200 |
|
Bilirubin |
108 μmol/L* |
< 20 |
|
Alkaline Phosphatase |
221 U/L* |
35 – 135 |
|
Alamine Aminotransferase |
1073 U/L* |
< 40 |
|
g-Glutamyl Transferase |
437 U/L* |
< 60 |
|
Albumin |
29 G/L* |
35 – 50 |
a) What is the diagnosis?
b) Give four likely causes in this patient.
a) Rhabdomyolysis.
b)
This question could just as easily have been slotted into the electrolyte disturbance section or the renal failure section. The patient plainly has rhabdomyolysis. The college were looking for a single-word answer. The decreased bicarbonate indeed suggests that a metabolic acidosis is in play, and it is a high anion gap sort of thing, with probably some combination of uremic, lactic and normal anion gap acidosis (given that the anion gap is (138) - (105 + 16) = 17, or 23.2 when calculated with potassium, and the delta ratio is (17 - 12) / (24 - 16) = 0.62.)
More interestingly, what could have caused it?
The general breakdown of differentials is as follows:
Rhabdomyolysis is discussed at greater length in the discussion of Question 16 from the first paper of 2008.
Allison, Ronald C., and D. Lawrence Bedsole. "The other medical causes of rhabdomyolysis." The American journal of the medical sciences 326.2 (2003): 79-88.