Most children with an upper urinary tract infection (UTI) (acute pyelonephritis) should be urgently referred/admitted for treatment. If they can safely be managed in primary care (i.e. low risk for severe illness, not vomiting, and parents are reliable):

• Treat with an oral antibiotic for 7–10 days.
• The choice of antibiotic should be guided by local information on antibiotic resistance patterns of urinary pathogens.
• If the child has developed the UTI while on prophylactic antibiotic treatment, treat with a different antibiotic.
• Antibiotics that may be suitable include:
• Co-amoxiclav.
• Cefalexin.
• Treat fever or pain with paracetamol.
• Obtain a urine specimen for culture before starting antibiotic treatment.
• Encourage (and monitor) adequate fluid intake.

• For children with suspected upper urinary tract infection (acute pyelonephritis), it is prudent to adopt a low threshold for referral to specialist care. For further information, see Urgent referral or admission.
• For information on contraindications or adverse effects that may influence prescribing, see the sections on co-amoxiclav and cefalexin. If neither drug is suitable, for instance the child has a documented allergy to penicillin, seek specialist advice.
• Avoid ibuprofen and other NSAIDs for the symptomatic treatment of pain or fever, as they can cause renal complications.

These recommendations are based on clinical guidelines on Urinary tract infection in children, published by the National Institute for Health and Clinical Excellence (NICE) [National Collaborating Centre for Women's and Children's Health, 2007].

• NICE recommend that the choice of antibiotic, route of administration and the duration of treatment be made according to the clinical presentation and local sensitivity patterns. The aim is to eradicate the infection, relieve symptoms and minimize the development of renal parenchymal defects.

Antibiotic choice:

• There is little evidence from controlled trials to guide antibiotic selection for children with pyelonephritis. NICE identified four randomized controlled trials (RCTs) that addressed this issue, but all compared intravenous antibiotics and failed to show superiority of one antibiotic compared with another.
• NICE recommend that the choice of antibiotic should be guided by local policies in accordance with the local microbiology laboratory (where resistance patterns have been monitored).
• Co-amoxiclav or a 'first-generation' cephalosporin is recommended by CKS, as there is usually low resistance to these antibiotics. If a cephalosporin is selected, CKS recommends cefalexin, as it is most commonly used, has a convenient dosing schedule, and is relatively inexpensive. However, other cephalosporins, such as cefadroxil, cefaclor, or cefixime, are suitable alternatives.

Antibiotic duration:

• NICE did not identify any RCTs that investigated the optimal duration of antibiotics for children with pyelonephritis. They concluded that in the absence of concrete evidence, common current UK practice should be used, which is treatment for 7–10 days. This is a shorter duration than is commonly used in some countries, but has several theoretical advantages, such as improved compliance, reduced adverse effects, and decreased emergence of antibiotic-resistant organisms, although this has not been observed in practice. CKS recommend a course of 7 days duration for pragmatic reasons.
• The Health Protection Agency recommends for acute pyelonephritis (without specifying the age) a 14-day course of co-amoxiclav (or trimethoprim, if susceptible), or a 7–day course of ciprofloxacin (which is best avoided in growing children; there are also concerns in the UK about increasing bacterial resistance) [HPA, 2006].