Postpartum Urinary Tract Infection

Postpartum urinary tract infection is bladder infection (cystitis) in the 6 weeks after birth, with frequency, burning on passing urine and suprapubic pain. It occurs in 2 to 4 percent of women, and more often after catheterisation, caesarean section, epidural, perineal tears and urinary retention. Escherichia coli causes most cases. It matters because untreated cystitis can spread to the kidneys.

• Risk factors: urinary catheter, caesarean section, epidural anaesthesia, instrumental delivery, perineal trauma, urinary retention, diabetes, bacteriuria in pregnancy, HIV.
• Early treatment with a short course cures most cases.
• Dipstick and culture should be done before antibiotics.

Women have burning on passing urine, frequency, urgency, suprapubic pain and cloudy or foul urine, sometimes with blood. Fever and loin pain are absent in simple cystitis.

• Suprapubic tenderness.
• Temperature below 38 degrees Celsius.
• Differential diagnosis: perineal wound pain, urinary retention with overflow, vaginitis, endometritis, pyelonephritis, urethral injury, urinary fistula, sexually transmitted infection.
• Complications: pyelonephritis, recurrent infection, urinary retention, bacteraemia, long term bladder symptoms.

The approach is urine testing before treatment.

• Dipstick for nitrites and leucocyte esterase; midstream urine microscopy and culture.
• Growth of 10^3 colony forming units/mL or more with symptoms, or 10^5 without symptoms, confirms infection.
• Residual urine by bladder ultrasound if symptoms persist or voiding is poor; renal ultrasound for recurrent infection.
• High vaginal swab and chlamydia test if discharge or negative culture.

The principle is a short course of an antibiotic that is safe for breastfeeding, with fluids and treatment of the cause.

• Supportive: oral fluids 2 to 3 litres daily; frequent emptying of the bladder; hygiene of the perineum; remove the catheter when no longer needed; treat constipation.
• Pharmacological: cefalexin 500 mg oral 6-hourly for 5 to 7 days; or nitrofurantoin 100 mg modified release oral 12-hourly for 5 days (avoid if the baby is under 1 month old or either has glucose 6 phosphate dehydrogenase deficiency); or fosfomycin 3 g oral as a single dose; paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours).
• Procedures: none.
• Special groups: diabetic women have a 7 day course and glucose control; recurrent infection (3 or more in a year) uses cefalexin 250 mg oral at night for 6 months after a negative culture.
• Red flags: fever above 38 degrees Celsius, loin pain, vomiting, rigors, blood in the urine with clots, inability to pass urine.
• Follow-up: culture 1 to 2 weeks after treatment if symptoms persist or recur; review at 6 weeks; renal ultrasound for recurrent infection.