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Pyelonephritis

Definitions

  • Acute PN – acute, non-spec infectious (MC bacterial), uni or bilateral tubulointerstitial disease (GLN is bilateral)
    • CF – flank pain, tenderness, fever, chills, bacteriuria
  • Chronic PN – disease of renal pelvis, calyces and underlying parenchyma (tubulointerstitial sys). Caused by long term bact inf. Periods of exacerbation and remission. Can progress to CRF
  • Bacteriuria – significant >100,000 CFU/ml (E.Kass)
    • Asymp BU – SBU in absence of symptoms of disease
    • Pyuria – >5 PMNLs per high power field
  • UTI
    • Uncomplicated – without physical and anatomical abnormalities of UT
      • Absence of urological surgery/instrumentation
      • Community acquired
    • Complication – in pts with anatomical abnormalities, obstruction, instrumentation, catheterisation , males

Epidemiology

  • Women – MC, childbearing age
  • Men – >60 years; prostatic obstruction, ureteric calculi

Etiology

  • Bacterial (G- more common)
    • E.coli (OKH), Proteus, Enterobacter, Pseudomonas, Klebsiella
    • Staph, H.influenza, Bacteroides, Clostridium
  • Mycoplasma
  • C.albicans

Pathogenesis

  • Ways of penetration
    • Ascending (from outside to in) – urethra, bladder, ureter, kidney
    • Hematogenic
    • Lymphogenic
  • Predisposing + defence factors
    • Local host defence
      • Length of male urethra – 16-20cm
      • Prostatic antibacterial factor
      • Normal vaginal flora
      • Cervicovaginal Ab production
      • Voiding mechanism
      • Bladder surface GAGs – IgA defends
    • Local predisposing factors
      • Refluxes, disturbances of renal vascular system
      • Prostatic adenoma
      • Renal + bladder calculi – IMP
      • Pregnancy – leads to abnormal urine flow due to
        • Enlarged uterus compresses ureters
        • Progesterone causes atony of ureters
      • Urethral strictures
      • PKD
    • Microorganism virulence factors
      • Pili attachment
      • K mechanisms – E.coli
      • Urease production – Proteus (ammonia alkalises urine >> inhibits phagocytosis)
      • Coagulase production – Staph
      • Hemolysin prod
      • Motility

Pathophysiology

  • Disturbance of urine drainage – atony, stasis
  • Disturbance of concentrating ability of kidneys – dysfunctional transport of Na, water, urea
  • Disturbance of acid-base regulation
  • Tubular proteinuria – <1.5g/l (always mild)
  • Disturbance of BP regulation
    • Retention of NaCl
    • Production of renin and PGs

*Normal USG – 1.010-1.040

Clinical features

  • APN
    • General – fever, headache, weakness, tachycardia, tachypnea
    • Local CF – lumbar + abdominal pain, dysuria, frequency
    • Lab – pyruia, bacteriuria, mild PU, low USG*, high RBC sedimentation rate
    • Triad – pain, fever, leukocyturia w/ SBU
    • NOTE – no HTN in APN
  • CPN
    • History – weakness, headache, dysuria, nocturia, fever, weightloss, lumbar heaviness. UTI in childhood; DM; prostatic adenoma
    • Physical – fever, palpable pain, anemia, HTN
    • Lab – leukocyturia, BU, PU (in remission there is no LU or BU). Low USG
    • US – decreased size, structural change

Classification

  • APN
    • Course – acute, subacute, asymptomatic
    • Morphology of inflam – non-purulent or suppurative
  • CPN
    • Regarding PG – primary or secondary
    • Regarding location – UL or BL
    • Leading symptom – hypertonic, anemic, hematuric
    • Tubular atrophy – thyroidisation

Diagnosis

  • History
  • Physical exam – positive succussio renalis / costo-vertebral angle tenderness
  • Lab exam – urinalysis, peripheral blood, BUN, RBC sedimentation
  • Renal function exam
    • Probes of Zimnitsky (see box)
    • Clearance – FF (GFR/RPF)
  • Radioisotope – ING, scintigraphy
  • US + Venous pyelography
  • CT – when suspicious of neoplasm
  • VCUG – check vesicoureteral reflux VUR
  • Renal biopsy – NEVER used to diagnose

Complications

  • Sepsis, abscess, papillary necrosis (DM/immunocompromised)

Zimnitsky probes

  • Collect separate portions of urine every 3 hours and measure the volume and USG
  • Add all the volumes together and estimate daily diuresis
  • If the highest USG in at least 1 sample is >1.018 then it means that the concentrating ability of kidney isn’t affected

Treatment

  • Regimen + diet – increase water (2L/day), no alcohol
  • Scheme (total course for 30 days)
    • AB course (may be empirical) for 10 d
      • If after course urine culture is (+), begin course with a different AB
    • Sulphonamide course for 10d
    • Quinolone course for 10-15d
  • Drugs
    • Antibiotics
  • Dose – 2mg/kg
  • Amps – 40mg/ml
      • Aminoglycosides – gentamicin(see box) + tobra
        • Not allowed – strepto + kana
      • Beta lactams – cephalosporins, hemisynthetic pens
        • NA – pen + methicillin
      • Clarithromycin
      • Fosfomycin – safe for pregnancy [3g/1 dose]
    • Sulphonamides – biseptol (SMX/TMP : 400mg/80mg tabs, 2 tabs bid)
    • Chemotherapeutics – ciprofloxacin, levofloxacin, pefloxacin
      • Ciprofloxacin – 250mg tab bid/ 500mg tab qd
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