A 40-year-old patient with Acute Myeloid Leukaemia who received induction chemotherapy 1 week ago, was admitted to ICU from the ward with fever, chills, and repeated episodes of hypotension. Urine dipstick showed the following result:
|
Urine dipstick result |
|
|
Leukocytes |
Negative |
|
Nitrite |
Positive |
|
Protein |
+ |
|
Glucose |
+++ |
a) Explain the urine dipstick result. (15% marks)
b) Briefly outline the salient management principles. (10% marks)
Aim: To allow the candidate to demonstrate expertise in data interpretation.
Key sources include: Common clinical practice with urinalysis, and paired urine and serum samples. CanMEDS Medical Expert.
Discussion:
Candidates are encouraged to read the question carefully and refer to the glossary to ensure their answers address the question. Candidates who explained the abnormalities instead of just listing them gave the better answers and were marked accordingly. For example, the explanation for the absence of leukocytes is related to the neutropenia common in the immunosuppressed patient. The presence of nitrites points to the presence of bacteria.
a)
In order for there to be leukocytes in the urine, there need to be leukocytes in the patient. This sample was taken from somebody at the nadir of their WCC, one week following induction chemotherapy. They are both rather likely to have an infection, and rather likely to have abnormal immune responses. Among neutropenic children with UTI, Klaassen et al (2011) found only 4% had leukocytes in the urine, as compared to 68% of non-neutropenic controls. Nitrites will still be present even if the patient is neutropenic, as they are a product of bacterial metabolism (specifically nitrate reductase activity, which is mostly a feature of gram-negative bacteria). So, in summary, this patient has a UTI, probably because of their hyperglycaemia, which makes their urine an excellent culture medium.
b) "briefly outline management principles" of a febrile rigoring neutropenic patient, who's clearly developing shock from urosepsis, in 90 seconds (for 15% mark) would have to be an exercise in extreme verbal economy, the mastery of which does not come naturally to this notoriously verbose author. Nonetheless:
Klaassen, I. L. M., et al. "Pyuria is absent during urinary tract infections in neutropenic patients." Pediatric Blood & Cancer 56.5 (2011): 868-870.
Simerville, Jeff A., William C. Maxted, and John J. Pahira. "Urinalysis: a comprehensive review." American family physician 71.6 (2005): 1153-1162.