The following blood tests are from an otherwise well 53-year-old patient, admitted to a general medical ward five days previously for intravenous antibiotic therapy for lower limb cellulitis. Admission blood tests were all normal. Over the last 24 hours the patient has become progressively oliguric but remains otherwise stable with normal vital signs.
The results of the full blood count and urea and electrolytes are as follows:
|
Parameter |
Patient Value |
Normal Adult Range |
|
Haemoglobin |
132 g/L |
130-175 |
|
White Cell Count |
9.8 x 109/L |
4.0-11.0 |
|
Platelets |
321 x 109/L |
150-450 |
|
Neutrophils |
10.4 x 109/L* |
1.8-7.5 |
|
Lymphocytes |
2.06 x 109/L |
1.50-4.00 |
|
Monocytes |
0.3 x 109/L |
0.2-0.8 |
|
Eosinophils |
4.3 x 109/L* |
0.0-0.4 |
|
Haematocrit |
0.35* |
0.40-0.52 |
|
Mean Cell Volume |
92 fL |
82-98 |
|
Mean Cell Haemoglobin |
29.9 pg/cell |
27.0-34.0 |
|
Mean Cell Haemoglobin Concentration |
326 g/L |
310-360 |
|
Parameter |
Patient Value |
Normal Adult Range |
|
Sodium |
140 mmol/L |
135-145 |
|
Potassium |
3.8 mmol/L |
3.2-4.5 |
|
Chloride |
106 mmol/L |
100-110 |
|
Bicarbonate |
22 mmol/L |
22-27 |
|
Urea |
28.0 mmol/L* |
3.0-8.0 |
|
Creatinine |
310 µmol/L* |
45-90 |
|
Total Calcium |
2.17 mmol/L |
2.15-2.60 |
|
Phosphate |
1.6 mmol/L* |
0.7-1.4 |
|
Albumin |
31 g/L* |
33-47 |
|
Total Bilirubin |
20 mmol/L |
4-20 |
|
Conjugated Bilirubin |
4 mmol/L |
1-4 |
|
g-Glutamyl transferase |
22 U/L |
0-50 |
|
Alkaline phosphatase |
60 U/L |
40-110 |
|
Lactate dehydrogenase |
213 U/L |
110-250 |
|
Aspartate transaminase |
34 U/L |
< 40 |
|
Alanine aminotransferase |
25 U/L |
< 40 |
23.3.1 List the most likely cause of the oliguria. (2 marks)
Syllabus topic/section:
2.1.14 Environmental Injuries and Toxicology in ICU – L1.
2.1.21 Applied Pharmacology in Intensive Care.
Aim:
To explore the understanding of data interpretation, toxidromes and management of dysnatraemias.
Discussion:
Overall, this question scored highly but the answers were not as well structured as the other data question 19. Some candidates missed parts of the question, which was really the only way to 'fail' this repeat data interpretation. The management of hyponatraemia was frequently muddled by candidates with many stressing that the correction must be slow but then giving both a fluid restriction and iv hypertonic saline or normal saline. These candidates appeared to have remembered parts of the management but not fully applied it correctly.
Apart from subtle changes in grammar and a gender reassignment, this SAQ is an exact copy of Question 13.3 from the second paper of 2016, and so is the discussion section below:
The eosinophils. They are high.
Everything else is normal.
It could be nothing else. The cellulitis, presumably it got flucloxacillin - and then the cillin caused an interstitial nephritis, as they tend to do.
The college model answer from that year was even shorter:
Allergic / Acute Interstitial nephritis secondary to antibiotic use.
Perazella, Mark A., and Glen S. Markowitz. "Drug-induced acute interstitial nephritis." Nature Reviews Nephrology 6.8 (2010): 461-470.