Pyelonephritis

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Contents 1 More Specific Terms 2 Introduction 3 Etiology 4 Epidemiology 5 Pathology 6 Clinical-manifestations 7 Laboratory 8 Diagnostic-procedures 9 Radiology 10 Differential-diagnosis 11 Management 12 More General Terms 13 Additional Terms 14 References

More Specific Terms

• chronic pyelonephritis (xanthogranulomatous pyelonephritis)

Introduction

• Inflammation/ infection of the upper urinary tract. In adults, chronic pyelonephritis usually does not develop in the absence of a major underlying functional or structural anomaly.

Etiology

• etiologic agents

• Escherichia coli (most common etiologic agent)
• Proteus
• Klebsiella
• Staphylococcus saprophyticus
• Enterococcus

• risk factors

• urinary obstruction
• indwelling urinary catheters
• neurogenic bladder

Epidemiology

• short length & positioning of urethra makes females more susceptible to UTIs & pyelonephritis than men

Pathology

• colonic bacteria ascend through the urinary tract & invade the renal parenchyma
• virulence factors make some strains of bacteria more prone than others to cause pyelonephritis

Clinical-manifestations

• fever/ chills
• nausea/vomiting
• back or flank pain ( costovertebral angle tenderness)
• symptoms of cystitis:

• dysuria, urinary frequency, urinary urgency
• 1/3 of patients with pyelonephritis have symptoms of cystitis only

• tachypnea
• tachycardia
• altered mental status (elderly)

Laboratory

• urinalysis: clean-catch or in & out catheterization

• spun urine specimen with > 5 WBC/ high-power field
• gram stain: bacteria
• RBC (non-specific)
• WBC: pyruria
• WBC casts suggests pyelonephritis

• urine culture

• culture & antibiotic sensitivities on all suspected case of pyelonephritis
• > 10E6 colonies/ mL indicates significant infection

• blood culture

• indicated if patient appears ill-enough for hospitalization
• more likely to be positive in elderly individuals

Diagnostic-procedures

• cystoscopy: if indicated after ultrasound

Radiology

• renal ultrasound

• persistence or worsening of symptoms after 48-72 hours of IV antibiotic therapy
• recurrent glomerulonephritis in women
• single episode of pyelonephritis in men
• may show blunting of cortical- medullary junction

• CT or MRI preferable to intravenous pyelogram if ultrasound not adequate [3]

Differential-diagnosis

• pelvic inflammatory disease ( PID)
• acute appendicitis
• acute cholecystitis
• nephrolithiasis
• diverticulitis
• pneumonia
• intestinal obstruction

Management

• factors favoring hospitalization

• elderly patient
• underlying medical condition

• diabetes
• pregnancy

• male gender (likely underlying anatomic anomaly)
• known genitourinary tract abnormality
• uncontrolled nausea/vomiting
• signs/symptoms of sepsis

• hypotension
• altered mental status
• 15-30% of patients with pyelonephritis may become septic

• obstructing urinary calculi with pyelonephritis is a surgical emergency
• emergency department observation

• hydration with IV fluids for 8-12 hours
• administration of antiemetics
• administration of 1-2 doses of parenteral antibiotics
• reassessment for hospital admission

• outpatient oral treatment for young, otherwise healthy females, reliable & tolerating oral intake
• pharmacologic agents

• empiric oral antibiotic coverage

• fluoroquinolone

• ciprofloxacin ( Cipro) 250 mg every 12 hours
• norfloxacin ( Noroxin) 400 mg every 12 hours

• amoxicillin clavulanate ( Augmentin) 250-500 mg every 8 hours
• Bactrim DS BID (not recommended [3])
• do not used 1st generation cephalosporin [3]

• empiric intravenous antibiotic coverage

• fluoroquinolone
• 3rd generation cephalosporin

• ceftriaxone ( Rocephin) 1-2 g QD

• beta lactam/beta-lactamase inhibitor
• aminoglycoside
• monobactam
• carbapenam
• linezolid or Synercid + 3rd generation cephlosporin or beta lactam/beta-lactamase inhibitor

• antibiotic coverage for patients admitted from long-term care facilities should include coverage for vancomycin-resistant enterococci & fluoroquinoline-resistant gram-negative bacteria

• ampicillin 1 g every 6 hours & gentamicin 1.5 mg/kg every 8 hours

• suspected Enterococcus ( Gm+ cocci on Gm stain)
• not recommended [3]

• trimethoprim-sulfamethoxazole (Bactrim, Septra) 160/800 mg every 12 hours

• not recommended [3]

• duration of therapy:

• 10-14 days (14 days in the elderly)
• 7 days if ciprofloxacin is used
• 42 days for recurrent pyelonephritis (failure of 14 days of therapy)

• patient education

• patients should improve after 2-3 days of therapy
• patients should complete full course of antibiotics
• voiding ofter sexual intercourse can decrease frequency of UTIs in some women
• adequate hydration is important

More General Terms

• urologic disease
• nephritis
• renal tubular disease

Additional Terms

• urinary tract infection (UTI)

References

1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 542-43
2. The Sanford Guide to Antimicrobial Therapy, 29th ed., Gilbert, DN et al (editors), Antimicrobial Therapy, Inc., Hyde Park VT, 1999
3. Medical Knowledge Self Assessment Program (MKSAP) 14, 15, American College of Physicians, Philadelphia 2006, 2009
4. Pyelonephritis (Kidney Infection) in Adults [1]
5. National Guideline Clearinghouse ACR Appropriateness Criteria acute pyelonephritis. (American College of Radiology) ngc-guideline: [2]
   - International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: a 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. ngc-guideline: [3]

pyelonephritis