Acute pyelonephritis — MSF Clinical guidelines

What this guideline says

GMJ summary

This MSF clinical guideline provides evidence-based protocols for diagnosing and treating acute pyelonephritis, an infection of the renal parenchyma that is more common in women and potentially severe in pregnant women, neonates and infants. Management is stratified by patient age and risk of complications, with clear criteria for hospital admission including all children, pregnant women, men, patients with urinary tract abnormalities, severe immunodeficiency, complicated pyelonephritis, or signs of severe infection.

The guideline provides detailed, age-specific antibiotic regimens. For neonates under one month, dual therapy with ampicillin plus gentamicin or cefotaxime is recommended for 7–10 days. Children one month and over receive ceftriaxone until clinical improvement (at least 3 days) followed by oral amoxicillin/clavulanic acid to complete 10 days. Adults with uncomplicated pyelonephritis receive a single dose of ceftriaxone or gentamicin plus 7 days of oral ciprofloxacin, or 10–14 days of oral amoxicillin/clavulanic acid or cefixime. Hospitalised adults require IV ampicillin plus gentamicin or ceftriaxone plus gentamicin for at least 3 days, then oral therapy to complete 10–14 days.

The guideline emphasises maintaining proper hydration (1.5 litres daily in adults), avoiding NSAIDs for fever, and reassessing patients with no clinical improvement 24 hours after starting oral therapy. Laboratory diagnosis references the acute cystitis section, and the guideline notes that pyelonephritis pathogens are the same as those causing cystitis.

Key points

For clinicians — doses and thresholds as stated in the guideline

1. Fever >38°C with unilateral flank pain distinguishes pyelonephritis from cystitis in older children and adults; in neonates and infants, unexplained fever may be the only sign.
2. Hospital admission criteria: all children, pregnant women, men, patients with urinary tract abnormalities or severe immunodeficiency, complicated pyelonephritis, sepsis/septic shock, or no clinical improvement after 24 hours of oral therapy.
3. Neonates under one month: ampicillin 50 mg/kg IV every 8–12 hours (age/weight-dependent) plus gentamicin 3–5 mg/kg IV once daily for 5–10 days, or cefotaxime 50 mg/kg IV every 8–12 hours for 7–10 days.
4. Children ≥1 month: ceftriaxone 50 mg/kg IM/IV once daily until improvement (at least 3 days), then amoxicillin/clavulanic acid 25 mg/kg PO twice daily (<40 kg) or adult dosing (≥40 kg) to complete 10 days.
5. Adults with uncomplicated pyelonephritis: ceftriaxone 1 g IM single dose or gentamicin 5 mg/kg IM single dose, plus ciprofloxacin 500 mg PO twice daily for 7 days; alternatives include amoxicillin/clavulanic acid or cefixime 200 mg twice daily or 400 mg once daily for 10–14 days.
6. Hospitalised adults: ampicillin 2 g IV every 6 hours plus gentamicin 5 mg/kg IM once daily for 3 days (preferred to cover enterococci), or ceftriaxone 1 g IV once daily plus gentamicin for 3 days if sepsis, then oral therapy to complete 10–14 days.
7. Maintain hydration with 1.5 litres daily in adults; avoid NSAIDs for fever and pain management.
8. Pyelonephritis with abscess or emphysematous pyelonephritis may require longer antibiotic therapy; adjust according to antibiotic susceptibility testing when available.

Antibiotherapy regimens for children ≥1 month and adults with acute pyelonephritis

Table extracted from the guideline

Source: Médecins Sans Frontières, Acute pyelonephritis — MSF Clinical guidelines. Reproduced in summary form.

From the guideline

Verbatim

“In practice, a urinary tract infection should be suspected in children with unexplained fever or septic syndrome with no obvious focus of infection.”

Editor’s perspective

Why this matters for Georgia and the region

Applicability

Georgia and the South Caucasus

Questions this guideline answers

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