UTI, upper (acute pyelonephritis)

Pyelonephritis (Upper UTI) consists of fever, loin pain and urinary symptoms (WITH positive urinalysis)

Modify empirical treatment within 48 hours or when culture and sensitivity is available, whichever is sooner:

For patients with penicillin allergy label consider penicillin allergy assessment and delabelling

Preferred

If associated with suspected sepsis - see UTI with sepsis/ severe sepsis (Urosepsis)

If patient needs IV treatment e.g. recurrent vomiting - see UTI with sepsis/ severe sepsis (Urosepsis)

If patient can have Oral medication or for ambulatory management - see Ambulatory care: Urinary tract infection

For patients with high frailty score (i.e high risk of C.diff) - see UTI and functional decline

For pregnant patients - see UTI, upper or acute pyelonephritis (pregnant )

Pyleonephritis in the setting of renal transplantation - see Pyelonephritis/ upper UTI (Transplanted kidney)

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NICE NG111 Pyelonephritis (acute): antimicrobial prescribing October 2018. Available: Overview | Pyelonephritis (acute): antimicrobial prescribing | Guidance | NICE

Last reviewed: 24 Mar 2026

Next review date: 23 Mar 2029

Author(s): AMST.

Approved By: MMTC