II. Definitions

  1. Pyelonephritis
    1. Upper Urinary Tract Infection involving Kidney

III. Epidemiology

  1. Accounts for 200,000 hospitalizations annually in U.S
  2. Highest Incidence in otherwise healthy women ages 15 to 29 years

IV. Causes

  1. Ascending infection via Bladder and ureter (most cases)
  2. Hematogenous spread
    1. Prostatitis or Benign Prostatic Hyperplasia
    2. Serious comorbid chronic illness
    3. Immunocompromised patients
    4. Hematogenous spread of staph. or fungal infection

V. Etiologies

  1. Normal host
    1. Escherichia coli (80%)
    2. KlebsiellaPneumoniae (3-6%)
    3. Staphylococcus saprophyticus (<3%)
    4. Other Gram Negative Bacteria (e.g. Proteus, Enterobacter)
    5. Enterococcus
  2. Elderly
    1. Escherichia coli (60%)
    2. Proteus
    3. Klebsiella
    4. Serratia
    5. Pseudomonas
  3. Urinary Catheter associated infection
    1. Bacteriuria in 50% at 5 days, and 100% at 30 days
    2. Mixed Bacterial Infection
  4. Diabetes Mellitus
    1. Klebsiella
    2. Enterobacter
    3. Clostridium
    4. Candida
  5. Immunosuppression
    1. Aerobic, Gram Negative Rods (non-enteric)
    2. Candida

VI. Risk Factors: Pyelonephritis in women

  1. Frequent sexual intercourse in prior month (3 times weekly)
  2. New sexual partner in the last year
  3. Recent Spermicide use
  4. Family History of Urinary Tract Infections (esp in patient's mother)
  5. Prior Urinary Tract Infections in the last year
  6. Diabetes Mellitus
  7. Stress Incontinence in the last 30 days

VII. Risk Factors: Antibiotic Resistance

  1. Frequent medical care
  2. Recent antibiotic use (esp. Fluoroquinolones, Cephalosporins)
  3. Advanced age
  4. Recurrent Urinary Tract Infections
  5. Diabetes Mellitus

VIII. Risk Factors: Complicated Pyelonephritis (with higher risk of complications such as abscess, Antibiotic Resistance)

  1. Age under 1 or over 60 years
  2. Abnormality (Polycystic Kidney, Vesicoureteral reflux)
  3. Obstruction (Nephrolithiasis, BPH, tumor)
  4. Immunocompromised (Diabetes, HIV, Corticosteroids)
  5. Indwelling Urinary Catheter
  6. Pregnancy

IX. Symptoms

  1. Fever
  2. Chills and malaise
  3. Flank Pain
  4. Nausea and Vomiting
  5. Acute Cystitis symptoms
    1. Dysuria
    2. Urinary Frequency
    3. Urinary urgency

X. Signs

  1. Fever
  2. Tachycardia
  3. Hypotension
  4. Costovertebral Angle Tenderness
  5. Abdominal tenderness (esp. suprapubic tenderness)

XI. Diagnosis

  1. Fever over 100.4 F
    1. May be absent early in course
    2. Not uniformly present in elderly (only in 80%)
    3. Not uniformly present in catheter-associated UTI
  2. Flank Pain
  3. Urinalysis with bacteriuria and pyuria

XII. Labs

  1. Urinalysis
    1. Leukocyte esterase or nitrite positive
    2. Microscopic Hematuria may be present (contrast with Gross Hematuria in Acute Cystitis)
    3. Microscopic examination may show WBC Casts
    4. Consider urine Gram Stain where available
      1. Gram Positive Cocci suggests Enterococcus or Staphylococcus saprophyticus
  2. Urine Culture (positive in 90% of Pyelonephritis)
    1. Manditory in all suspected cases of Pyelonephritis
    2. Diagnosis requires at least 10,000 CFU/mm3
    3. Consider lower threshold in men and in pregnancy
  3. Blood Culture indications (positive in up to 30% cases, obtain in severe infection or hospitalized patients)
    1. Immunocompromised patient
    2. Unclear diagnosis
    3. Hematogenous source suspected
  4. Other labs
    1. Urine Pregnancy Test
    2. Serum Creatinine
    3. Complete Blood Count
    4. Other testing as indicated by differential diagnosis in unclear cases

XIII. Imaging

  1. Modalities
    1. CT Abdomen with contrast (preferred in non-pregnant patients)
    2. Renal Ultrasound (pregnant patients)
    3. Renal MRI (specific indications as directed by local Consultation)
  2. Indications
    1. Not routinely indicated in uncomplicated Pyelonephritis
    2. Reserve for recurrent or refractory infections, critcial illness, new Renal Failure, suspected ureteral stone

XV. Disposition: Hospitalization indications

  1. Inability to stay hydrated and take medications orally
  2. Comorbidity
    1. Diabetes Mellitus
    2. Underlying urologic or renal disorder
    3. Severe liver disease
    4. Severe heart disease
  3. Noncompliance
  4. Uncertain diagnosis
  5. Male gender
  6. Toxic appearance
  7. Severe illness with high fever (>103 F)
  8. Severe flank or Abdominal Pain
  9. Debilitated condition
  10. Pregnancy (some cases may be treated outpatient)

XVI. Management: Pregnancy

XVII. Management: Oral agents for acute uncomplicated non-pregnant cases

  1. Treatment course
    1. Uncomplicated Pyelonephritis: 7 days
    2. Complicated Pyelonephritis: 14 days
      1. Indicated in Urinary Tract Obstruction, male gender, immunosuppression
  2. Consider a single initial dose of IV antibiotics if Emesis (see below)
    1. Example: Ceftriaxone 1 g IV in Emergency Department
  3. Preferred agents: Fluoroquinolones (if community E. coli resistance rate <10%)
    1. Ciprofloxacin 500 mg orally twice daily for 7 days
    2. Ciprofloxacin XR 1000 mg daily for 7 days
    3. Levofloxacin 750 mg orally daily for 7 days
  4. Alternative agents (higher resistance rates, accompany with initial dose of a broad spectrum IV antibiotic)
    1. Amoxicillin-Clavulanate (Augmentin) twice daily for 14 days
    2. Trimethoprim-Sulfamethoxazole (Bactrim) twice daily 14 days
    3. Cefixime 400 mg orally daily

XVIII. Management: IV agents in non-pregnant patients

  1. Duration of treatment
    1. Convert from IV to oral in first 48-72 hours
  2. Preferred Agents: LOW risk for Bacterial resistance
    1. Ciprofloxacin 400 mg IV twice daily
    2. Levofloxacin (Levaquin) 750 mg IV daily
    3. Ceftriaxone (Rocephin) 1000 mg IV q24 hours
  3. Preferred Agents: HIGH risk for Bacterial resistance
    1. Ertapenem 1 g IV every 24 hours
    2. Meropenem 1 g IV every 8 hours
    3. Piperacillin-Tazobactam (Zosyn) 3.375 g IV every 6 hours
    4. Cefepime 2 g IV every 12 hours
  4. Alternative regimens
    1. Gentamicin 5 mg/kg IV every 24 hours

XIX. Complications

  1. Perinephric Abscess
    1. May also occur secondary to Staphylococcus aureus bacteremia
  2. Emphysematous Pyelonephritis
    1. Occurs in older women with Diabetes Mellitus
    2. Infection produces intraparenchymal gas
    3. Associated with papillary necrosis and Renal Failure
  3. Urinary Tract Infection due to obstruction
    1. Associated with Nephrolithiasis, BPH, or tumor
    2. May result in renal abscess and severe infection
  4. Malacoplakia (rare)

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Related Studies

Ontology: Pyelonephritis (C0034186)

Definition (NCI_CTCAE) A disorder characterized by an infectious process involving the kidney.
Definition (NCI) An acute or chronic inflammatory process affecting the kidney. It is caused by bacteria and in most cases it is the result of a urinary tract infection. Signs and symptoms include fever, chills, flank pain, painful and frequent urination, cloudy or bloody urine, and confusion.
Definition (CSP) inflammation of the kidney and its pelvis due to infection.
Definition (MSH) Inflammation of the KIDNEY involving the renal parenchyma (the NEPHRONS); KIDNEY PELVIS; and KIDNEY CALICES. It is characterized by ABDOMINAL PAIN; FEVER; NAUSEA; VOMITING; and occasionally DIARRHEA.
Concepts Disease or Syndrome (T047)
MSH D011704
ICD9 590.80
ICD10 N10-N16 , N16, N12
SnomedCT 197779009, 197784003, 45816000
English Pyelonephritides, PYELONEPHRITIS, Pyelonephritis unspecified, Pyelonephritis, unspecified, Unspecified pyelonephritis NOS, pyelonephritis (diagnosis), pyelonephritis, Pyelonephritis NOS, Kidney Infection, Pyelonephritis, Pyelonephritis [Disease/Finding], bacterial infection of the kidney, Pyelonephritis unspecified (disorder), Unspecified pyelonephritis NOS (disorder), Kidney infection, Pyelonephritis (disorder), Pyelonephritis, NOS
French PYELONEPHRITE, Pyélonéphrite, non précisée, Pyélonéphrite SAI, Pyélonéphrite
Portuguese PIELONEFRITE, Pielonefrite NE, Pielonefrite
Spanish PIELONEFRITIS, Pielonefritis NEOM, Pielonefritis no especificada, pielonefritis no especificada, SAI, pielonefritis no especificada, pielonefritis no especificada, SAI (trastorno), pielonefritis no especificada (trastorno), pielonefritis (trastorno), pielonefritis, Pielonefritis
German PYELONEPHRITIS, Pyelonephritis, unspezifisch, Pyelonephritis NNB, Pyelonephritis
Dutch pyelonefritis NAO, pyelonefritis, niet-gespecificeerd, pyelonefritis, Nefritis, pyelo-, Pyelonefritis
Italian Pielonefrite NAS, Pielonefrite, non specificata, Pielonefrite
Japanese 腎盂腎炎、詳細不明, 腎盂腎炎NOS, ジンウジンエンNOS, ジンウジンエン, ジンウジンエンショウサイフメイ, 急性壊死性腎盂腎炎, 腎盂腎炎-急性壊死性, 壊死性腎盂腎炎, 腎盂腎炎
Swedish Pyelonefrit
Czech pyelonefritida, Pyelonefritida, Pyelonefritida blíže neurčená, Pyelonefritida NOS
Finnish Pyelonefriitti
Polish Zapalenie nerek odmiedniczkowe, Pielonefryt, Zakażenie górnego odcinka układu moczowego
Hungarian pyelonephritis k.m.n., pyelonephritis, Pyelonephritis, nem meghatározott
Norwegian Pyelonefritt

Ontology: Acute pyelonephritis (C0520575)

Concepts Disease or Syndrome (T047)
ICD9 590.1
ICD10 N10
SnomedCT 197771007, 155862004, 266620001, 36689008, 22352007
English Acute pyelonephritis NOS, PYELONEPHRITIS ACUTE, Acute pyelonephritis, Pyelonephritis acute NOS, acute pyelonephritis, Acute pyelonephritis NOS (disorder), Pyelonephritis acute, Acute PN - pyelonephritis, APN - Acute pyelonephritis, Acute pyelonephritis (disorder), acute; pyelonephritis, pyelonephritis; acute, Pyelonephritis;acute
Italian Pielonefrite acuta, Pielonefrite acuta NAS
Dutch acute pyelonefritis, pyelonefritis acuut NAO, acuut; pyelonefritis, pyelonefritis; acuut, pyelonefritis acuut
French Pyélonéphrite aiguë SAI, Pyélonéphrite aiguë
German Pyelonephritis akut NNB, akute Pyelonephritis
Portuguese Pielonefrite aguda NE, Pielonefrite aguda
Spanish Pielonefritis aguda NEOM, pielonefritis aguda, SAI, pielonefritis aguda, SAI (trastorno), pielonefritis aguda (trastorno), pielonefritis aguda, Pielonefritis aguda
Japanese 急性腎盂腎炎NOS, 急性腎盂腎炎, キュウセイジンウジンエン, キュウセイジンウジンエンNOS
Czech Akutní pyelonefritida NOS, Akutní pyelonefritida
Hungarian Acut pyelonephritis, Acut pyelonephritis k.m.n., acut pyelonephritis