Pyelitis

Pyelitis is infection and inflammation of the renal pelvis and calyces, which in most cases accompanies the renal parenchymal infection of acute pyelonephritis.

• It is the term used for pelvicalyceal infection, especially in pregnancy (physiological ureteric dilatation, right-sided predominance) and in children with reflux.
• Organisms: Escherichia coli, Klebsiella, Proteus (urease splitting, stones), Enterococcus, Pseudomonas.
• Risk factors: pregnancy, urinary tract anomaly, reflux, stones, catheters, diabetes, neurogenic bladder, urinary schistosomiasis.

Fever, flank pain, dysuria, frequency, urgency, rigors, nausea and vomiting, tenderness over the loin.

• In infants: fever, irritability, poor feeding, vomiting, jaundice, foul-smelling urine.
• In pregnancy: right flank pain, fever, uterine irritability and preterm contractions.
• Differential diagnosis: cystitis, renal stone, appendicitis, pelvic inflammatory disease, pneumonia, cholecystitis, perinephric abscess, malaria, typhoid.
• Complications: renal abscess, pyonephrosis, sepsis, acute kidney injury, preterm labour and low birth weight in pregnancy, renal scarring in children, chronic pyelonephritis and hypertension.

Midstream or catheter urine for microscopy and culture; blood cultures if febrile.

• Full blood count, creatinine, electrolytes, C-reactive protein.
• Ultrasound for hydronephrosis, stones and abscess; contrast CT in complicated or non-responding disease; in pregnancy ultrasound only.
• In children: renal ultrasound after the first febrile infection; dimercaptosuccinic acid scan at 4 to 6 months for scarring; voiding cystourethrogram if recurrent or abnormal ultrasound.

Supportive: fluids 2 to 3 L daily, paracetamol 1 g every 6 hours (children 15 mg/kg), rest, antiemetics (ondansetron 4 mg).

Pharmacological

• Mild to moderate, non-pregnant adults: ciprofloxacin 500 mg twice daily for 7 days, cefixime 400 mg daily for 10 days, or amoxicillin-clavulanate 625 mg three times daily for 10 to 14 days.
• Severe: ceftriaxone 1 to 2 g IV daily, or gentamicin 5 mg/kg IV daily; step down after 24 to 48 hours afebrile to complete 10 to 14 days.
• Pregnancy: admit; ceftriaxone 1 g IV daily until afebrile for 48 hours, then cefalexin 500 mg four times daily to complete 10 to 14 days, then suppression with nitrofurantoin 100 mg at night until delivery or cefalexin 250 mg at night; monitor fetal wellbeing.
• Children: ceftriaxone 50 to 75 mg/kg IV daily for 2 to 4 days then oral cefixime 8 mg/kg daily or amoxicillin-clavulanate 25 mg/kg/day (amoxicillin component) in two doses, for 7 to 10 days; prophylaxis (trimethoprim 2 mg/kg at night or nitrofurantoin 1 to 2 mg/kg at night) only for high grade reflux or recurrent infections.
• Resistant organisms: meropenem 1 g IV every 8 hours (children 20 mg/kg every 8 hours).

Procedures: ureteric stent or percutaneous nephrostomy for infected obstruction; drainage of abscess; correction of reflux or obstruction (ureteric reimplantation, pyeloplasty) in children.

Special groups: pregnancy (high risk of sepsis and preterm labour), diabetes, immunosuppressed patients (longer courses), elderly.

Red flags: sepsis, obstruction, persistent fever beyond 72 hours, pregnancy with contractions, infants under 3 months.

Follow-up: repeat culture at 1 to 2 weeks in pregnancy and monthly thereafter; ultrasound after treatment; hydration and timed voiding.