Pediatrics · MU Sofia

27. Acute and chronic pyelonephritis. Anomalies of renal system.

Covers acute pyelonephritis, including the usual causative germs, who is at risk, the clinical picture in infants and older children, and how urine samples, dipstick and culture are used for diagnosis. It then sets out treatment and imaging after a urinary tract infection, followed by vesicoureteric reflux, its grading, and chronic pyelonephritis with kidney scarring. The final section is a table of congenital anomalies of the kidneys and urinary tract, with key facts for each, and a short note on oral health.

Inside: 4 sections · 2 tables · 16 flashcards · 5 min

Topic 27 of 30 in the MU Sofia syllabus for Pediatrics (Medicine, Year 5). The free AceMed note covers it in 4 sections, about 481 words (5 min of reading), with 16 flashcards.

In this note

  1. Introduction
  2. Acute pyelonephritis
  3. Vesicoureteric reflux and chronic pyelonephritis
  4. Anomalies of the kidneys and urinary tract (CAKUT)

Introduction

Urinary tract infection (UTI) is one of the commonest bacterial infections of childhood: about 1 in 10 girls and 1 in 30 boys have one before puberty. An infection of the kidney (pyelonephritis) in a young child can scar it, especially when urine flows back from the bladder (vesicoureteric reflux). Many children with repeated infections have an anomaly of the kidneys or urinary tract.

Acute pyelonephritis

  • Germs: E. coli (80–90%), Klebsiella, Proteus (boys, stones), Enterococcus, Pseudomonas (abnormal tracts, catheters).
  • Who: in the first months boys more (especially uncircumcised), later girls. Risks: reflux, obstruction, constipation, poor bladder habits, neurogenic bladder.

Clinical picture

Lower UTI (cystitis): dysuria, frequency, urgency, wetting, suprapubic pain, little or no fever.

Diagnosis

  • A clean urine sample before antibiotics: clean-catch, or catheter or suprapubic aspiration in infants (bag samples are only useful when negative).
  • Dipstick: nitrite (specific) and leucocyte esterase (sensitive); nitrite is often negative in infants who empty the bladder often.
  • Culture confirms: a single organism over about 10⁵ CFU/mL in a clean-catch sample (lower counts count from a catheter, any growth from suprapubic aspiration), with pyuria.
  • Blood count, CRP, creatinine, blood culture in ill infants.

Treatment

  • Under 3 months: IV antibiotics (e.g. cefotaxime or ampicillin with gentamicin), as for sepsis.
  • Older children with pyelonephritis: oral antibiotic if they can take it (co-amoxiclav, cefixime, cefuroxime; guided by local resistance) for 7–10 days; IV if very ill or vomiting.
  • Cystitis: oral trimethoprim, nitrofurantoin or cephalexin for 3 days.
  • Prevent recurrence: good fluid intake, regular voiding, treat constipation, good hygiene; prophylactic antibiotics only for selected children (high-grade reflux, frequent recurrences).

Imaging after a UTI

  • Ultrasound of kidneys and bladder for infants and young children after a first febrile UTI, or any child with an atypical or recurrent UTI.
  • Voiding cystourethrogram (VCUG/MCUG) if ultrasound is abnormal or febrile UTIs recur: shows reflux and urethral valves.
  • DMSA scan 4–6 months later for scarring after atypical or recurrent infection.

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