Monday, February 1, 2010

Renal I

This is kidney week! The cases will get progressively harder.

The CT scan shown above is from a 20 year old otherwise healthy woman presenting with flank pain, nausea, and vomiting. She does not have any urinary frequency, urgency, or pain. Her temperature is 38.1, and she has costovertebral angle tenderness. Pregnancy test is negative. A urinalysis is nitrite negative but shows WBCs and WBC casts in the urine.

Challenge: What's the diagnosis?

Image is shown under Fair Use.

6 comments:

Suheil said...

TB Pyelonephritis??

tree said...

Pyelo!

Craig Chen said...

yep pyelo
-
Renal I

The CT scan shows a markedly enlarged right kidney with a wedge shaped area of low attenuation. This is acute pyelonephritis, an infection that has spread from the lower urinary tract to the upper urinary tract. Symptoms of cystitis may or may not be present. Fever and pyruia are strongly correlated, but nitrite testing may be negative, especially if the organism is enterococcus or staphylococcus. E. coli is the most common organism. Hospitalization may be appropriate in severe illness, high fever, intractable pain, marked debility, pregnancy, inability to have PO intake, and poor compliance.

Sources: UpToDate; LearningRadiology.

Suheil said...

umm.. i have a doubt.. why 38.1 fever? i was expecting higher temperatures for Regular Pyelo.. Thats why i said TB pyelo.. :(

Craig Chen said...

Good point! You're right that mycobacterial infections often have lower fevers than bacterial infections, but I wasn't trying to distinguish between the two in this case. For the temperature, I was using this reference:

Fever in the clinical diagnosis of acute pyelonephritis.
Pinson AG; Philbrick JT; Lindbeck GH; Schorling JB
Am J Emerg Med 1997 Mar;15(2):148-51.

Acute pyelonephritis is a clinical syndrome that can be confused with other conditions. To investigate this problem, a retrospective cohort study was conducted using two mutually exclusive sets of clinical criteria for acute pyelonephritis in women 15 years of age or older who presented to the emergency department of a university hospital. All patients had pyuria, and one group had documented fever (temperature of>or = 37.8 degrees C) while the other group had a temperature of<37.8 degrees C but had other evidence of possible upper tract infection. The study cohort was comprised of 103 febrile and 201 afebrile patients. Afebrile hospitalized patients were ultimately found to have another diagnosis more often than were the febrile hospitalized patients (35% v 7%; P = .02), and the afebrile nonhospitalized patients were more likely to have another diagnosis than were the febrile nonhospitalized patients (13% v 0%; P = .004). Other diagnoses included cholecystitis, pelvic inflammatory disease, and diverticulitis. The positive predictive value of the definition of pyelonephritis in the febrile group was 0.98, and it was 0.84 for the afebrile group. Physicians examining patients with clinical evidence of acute pyelonephritis but without objective fever should be alert for alternative diagnoses.

Division of General Medicine, Medical College of Virginia, Richmond 23298, USA.
PMID 9115515

So I was only indicating the temperature was higher than 37.8 as in this study - there may be other studies that look at higher temperatures to see if you can discriminate etiology, but I'm not sure.

Suheil said...

hmmm... k cool thanx a ton.. again.. ur doing a brilliant job keeping us sharp.. keep up the good work chief!