Ann IM 1989;111:906

Cause:Gram-negative rods (95%), most commonly E. coli(esp a few uropathic strains—Nejm 1985;313:414), and next most frequently, Proteussp; more rarely, gram-positive cocci (5%), staph, and enterococcus. Possibly ascend from a cystitis, or come from hematogenous seeding

Pathophys:Possible predisposition to infection of renal medulla due to increased osmotic pressures, which cause white cell inhibition, decreased blood flow, and NH₃ inhibition of C\pr4 complement

Increased incidence in patients with urinary retention; females age <18 mo and of childbearing age; patients with gu instrumentation (Nejm 1974;291:215); and with papillary necrosis in sickle cell disease and diabetes

Sx:Fever, flank pain; frequency, urgency, dysuria, and hematuria

Si:CVA punch tenderness

of significant bacteriuria: 1/3 have sx; 80% recurrence over 2 yr with new organism, then stable; later, with marriage and pregnancy may recrudesce (Nejm 1970;282:1443)

Renal failure, chronic pyelo

r/o cystitis, intercourse induced increased bacteriuria (Nejm 1978;298:321), cystitis with congenital vesicoureteric reflux by doing a voiding cystourethrogram if recurrent and/or abnormal ultrasound (Nejm 2003;348:195), acute interstitial nephritis (Ann IM 1980;93:735)

Lab:

Bact:Urine culture 10² col/cc; antibody-coated bacteria may distinguish from cystitis, but unreliable and not available (Ann IM 1989;110:138)

Gram stain of unspun urine show 1 bacterium/oil immersion field

Xray:IVP shows dilated calyces and ureter acutely, r/o peritonitis (Nejm 1972;287:535)

Rx:

Repair of vesicoureteral reflux, but may not alter course (BMJ 1983;287:171)

Antibiotics: ciprofloxacin (Jama 2000;283:1583) × 1 wk, or gentamicin + ampicillin or Tm/S (J Infect Dis 1991;163:325) × 2 wk or until have sensitivities since 30% of E. colinow are resistant to amoxicillin alone