Chapter 50: Urosepsis/Pyelonephritis

DEFINITIONS

URINARY TRACT INFECTION (UTI)

• An infection of the kidney, ureter, bladder, or urethra.

PYELONEPHRITIS

• Inflammatory process of the kidney or upper urinary tract = UTI + systemic symptoms

UROSEPSIS

• UTI/pyelonephritis + systemic inflammatory response syndrome (SIRS) criteria

ETIOLOGY

COMMON ORGANISMS

• Ascending genitourinary (GU) infections: E. coli, gram-negative bacteria (Klebsiella, Proteus, Enterobacter, Pseudomonas), gram-positive bacteria (enterococci, staphylococci, group B Streptococcus)

• Catheter-associated UTI (CAUTI): fungi

PREDISPOSING RISK FACTORS

• Congenital anomalies: hydronephrosis, posterior urethral valves, vesicoureteral reflux

• Neurologic abnormalities: neurogenic bladder, quadriplegia

• Dysfunctional elimination: constipation, voiding dysfunction

• Indwelling catheters

• Sexual activity

CLINICAL MANIFESTATIONS

NEONATES/INFANTS

• Fever of unknown origin

• Jaundice

• Irritability

• Poor feeding or failure to thrive (FTT)

OLDER CHILDREN

• Fever

• UTI symptoms: urinary frequency, urgency, dysuria, enuresis

• Pain: flank, back, abdominal, costovertebral angle (CVA), suprapubic

SYSTEMIC SYMPTOMS IN ANY AGE

• Fever, chills, rigors

• Nausea/vomiting, diarrhea

• Shock

DIAGNOSIS

LABORATORY EVALUATION

• Urinalysis (UA): pyuria + bacteriuria +/− hematuria

  • Routine “test of cure” not necessary

  • Repeat within 48 to 72 hours if clinical response is poor

• Positive urine Gram stain and culture

  • Any bacteria from suprapubic tap

  • >50k CFU/mL from catheterization specimen

  • >100k CFU/mL from “clean catch” (exclude polymicrobial growth)

• Blood culture: to identify concomitant bacteremia

IMAGING

• Recommended for the following patients:

  • Children <5 years with febrile UTI

  • Females <3 years with first UTI

  • Males of any age with first UTI

  • Children with recurrent UTI

  • Children who do not respond promptly to antimicrobial therapy

• Renal-bladder ultrasound:

  • Identifies gross anatomy abnormalities

  • Obtain in patients with poor clinical response within 48 hours of antimicrobial therapy

• Voiding cystourethrogram (VCUG):

  • Identifies vesicourethral reflux (VUR)

  • Perform immediately after therapy

• Technetium 99m-dimercaptosuccinic acid (^99mTc-DMSA) scan:

  • Identifies acute pyelonephritis (of limited value) and renal scars (if performed >5 months after infection)

TREATMENT

See Surviving Sepsis Guidelines to reverse shock

ANTIMICROBIAL THERAPY

• Empiric IV antibiotics:

  • Second- (cefuroxime) or third-generation (cefotaxime, ceftriaxone) cephalosporin

  • Ampicillin-sulbactam

  • Gentamicin

• Switch to enteral antimicrobial: afebrile and able to tolerate enteral medications

• Narrow antimicrobial therapy: based on culture results

• Duration: 10 to 14 days

COMPLICATIONS

RENAL OR PERINEPHRIC ABSCESS

• Suspect when fever is persistent despite appropriate antimicrobial therapy

• Treatments: drainage + antimicrobial therapy

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