Pyelonephritis 🔥

• Acute pyelonephritis / upper UTI: bacterial infection of the kidney and upper urinary tract.
• Consider when there is flank pain radiating to the iliac fossa and suprapubic area.
• Sudden onset systemic disturbance with fever, rigors, and vomiting is typical.
• Examination may show tenderness and guarding over the kidney, with nausea and/or vomiting.
• Lower UTI symptoms (dysuria, frequency, urgency) may coexist but are not required for the diagnosis.
• Usual pathogens are Enterobacterales (commonly E. coli).

• Significantly dehydrated or unable to take oral fluids and medicines.
• Child or young person under 16 years with acute pyelonephritis.
• Aged 16 years and over with acute pyelonephritis and severe systemic infection (use HSE sepsis pathway).
• Pregnancy.
• Higher risk of complications: known or suspected structural or functional genitourinary abnormality, diabetes, or immunosuppression.
• No clinical response within 24 hours of starting antibiotics: consider hospital referral (per HSE).
• Inpatients: escalate for IV antibiotics, imaging, or urology if obstructed, septic, or not improving.

• Send MSU for culture and sensitivity in all cases before starting antibiotics (per HSE Expert Advisory Group).
• Tailor empirical antibiotic choice using previous culture results where available.
• Vitals, NEWS/MEWS, and sepsis screen if systemically unwell.
• Examine for loin tenderness, abdominal guarding, bladder fullness, and genital findings if relevant.
• Pregnancy test in people of childbearing potential.
• Bloods if unwell or admitted: FBC, U&E, CRP; lactate if sepsis suspected. Blood cultures if febrile/septic.
• Consider renal tract imaging (e.g. ultrasound) if obstruction, stones, abscess, or atypical course suspected; follow local protocol.

• Oral regimens below are from HSE Acute Pyelonephritis / Upper UTI v2.1.
• Nitrofurantoin is NOT a suitable antibiotic choice in pyelonephritis (inadequate tissue levels).
• If no response within 24 hours, consider referral to hospital.
• Review culture results and switch to a narrower agent when susceptibility is known.
• Severe infection, vomiting, or inability to take oral therapy: use local inpatient / IV antibiotic protocol and sepsis pathway.

• Male patients: consider referral to secondary care for further investigation after a single episode of pyelonephritis without an obvious cause (per HSE).
• Female patients with recurrent pyelonephritis: consider referral to secondary care for further investigation.
• Address predisposing factors: stones, obstruction, incomplete emptying, catheter use, diabetes control.
• Document antibiotic start time, MSU sent, allergies, pregnancy status, and safety-net advice on discharge.

• Advise adequate oral fluids to avoid dehydration if able to drink.
• Paracetamol for pain and fever; avoid NSAIDs unless a clinician advises otherwise (kidney risk).
• Seek urgent review if unable to keep fluids down, worsening fever/rigors, confusion, or no improvement within 24 hours.
• Complete the full antibiotic course even if feeling better.
• Switch IV to oral when improving: see antibiotic IV-to-PO topic for inpatients.

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