#EMconf: Obstructive Pyelonephritis

 Obstructive pyelonephritis is a urologic emergency that requires emergent decompression, broad spectrum antibiotics and monitoring for urosepsis

 The management of this patient includes resuscitation of sepsis as well as management of acute renal failure
        -Due to complete urinary obstruction, frequent reassessment of her respiratory status necessary during fluid resuscitation
        -Acute renal failure will cause a number of complications; including uremia, platelet dysfunction and severe electrolyte disorders (hyperkalemia) that may result in an arrhythmia
        -This patient required dialysis for emergent treatment of severe electrolyte abnormalities and uremia preceding her emergent stone removal, followed by admission to the ICU

 Stone removal can be completed via ureteral stent placement by urology or percutaneous nephrostomy (PCNT) by interventional radiology
        -Final decision should be made in conjunction with these specialists, as well as anesthesia if the patient is going to require sedation for the procedure
        -There are currently only two small trials comparing percutaneous nephrostomy to stent placement, which show no clear advantage of one approach
        -Consider stent: IR not available, failed PCNT, uncorrected coagulopathy, minimal hydro, challenging anatomy for PCNT
        -Consider PCNT: Urology not available, failed stent attempt, difficult urologic access anatomically, concern for impacted stone, unable to tolerate general anesthesia 

Additional pearls on obstructive pyelonephritis:
        -Negative urinalysis does not rule out obstructive pyelonephritis, as the urine above the stone may be infected and the urine distal to the stone may be sterile
        -During acute unilateral renal obstruction, most patients have no rise in serum creatinine because the unobstructed, normal kidney can function as high as 185% of its normal capacity
        -Mortality rates are 9% in those treated with decompression and 19% in those without decompression
        -The risk of urosepsis is increased after decompression, however there is no clear evidence describing increased risk based on method of decompression (percutaneous nephrostomy vs ureteral stent)

 

References:
-Marian, T., Miller, NL. Treatment of the Infected Stone. Urologic Clinics of NA. Elsevier Inc; 2015 Nov 1;42(4):459–72
-Manjunath AS, Hofer M. Urologic Emergencies. Medical Clinics of NA. Elsevier Inc; 2018 Mar 1;102(2):373–85 
-Ramsey S, Robertson A, Ablett MJ, Meddings RN, Hollins GW, Little B. Evidence-based drainage of infected hydronephrosis secondary to ureteric calculi. J Endourol. 2010 Feb;24(2):185–9
-Tintinalli et al.  Tintinalli’s Emergency Medicine: A Comprehensive Study Guide.  8th Ed.  New York:  McGraw hill Education, 2016. Print