The following results were obtained from a 62-year-old female one week following a subarachnoid haemorrhage with increasing confusion:
|
Parameter |
Patient Value |
Adult Normal Range |
|
Sodium |
130 mmol/L* |
135 – 145 |
|
Potassium |
4.0 mmol/L |
3.5 – 5.0 |
|
Chloride |
96 mmol/L |
95 – 105 |
|
Bicarbonate |
26.5 mmol/L* |
22.0 – 26.0 |
|
Glucose |
5.5 mmol/L |
3.5 – 6.0 |
|
Urea |
2.5 mmol/L* |
3.0 – 8.0 |
|
Creatinine |
37 μmol/L* |
45 – 90 |
|
Magnesium |
0.87 mmol/L |
0.75 – 0.95 |
|
Albumin |
33 g/L* |
35 – 50 |
|
Protein |
74 g/L |
60 – 80 |
|
Total bilirubin |
10 μmol/L |
< 26 |
|
Alanine transferase |
26 U/L |
< 35 |
|
Serum Osmolality |
274 mosm/kg* |
285 – 295 |
|
Ionised calcium |
1.19 mmol/L |
1.10 – 1.35 |
|
Calcium corrected |
2.34 mmol/L |
2.12 – 2.62 |
|
Phosphate |
0.97 mmol/L |
0.80 – 1.50 |
a) What are the two most likely causes for this biochemical profile? (10% marks)
b) How would you distinguish between the two biochemically and clinically? (30% marks)
Not available.
What we are seeing here is a patient with recent CNS pathology who has now developed
The two most likely causes of this biochemical profile would surely have to be endocrine, and related to the SAH. Of these the two natural possibilities are:
Hypoadrenalism (due to pituitary dysfunction) is an alternative, and one could also make the argument that any pituitary injury from SAH that is bad enough to cause hypoadrenalism would probably also cause hypothyroidism. However SIADH and CSW are by far more likely. The way to discriminate between these lies in being able to demonstrate that the body fluid volume is decreased.