Acute Uncomplicated Cystitis

Acute uncomplicated cystitis is bacterial infection of the bladder in a non-pregnant, premenopausal woman with no structural or functional urinary tract abnormality, no catheter, no recent instrumentation, no immunosuppression and no diabetes with poor control (the term "uncomplicated" is used here for otherwise healthy women).

• One of the commonest infections: about 50 to 60 percent of women have at least one episode in their lifetime.
• Organisms: Escherichia coli (75 to 90 percent), Staphylococcus saprophyticus (5 to 15 percent, in young sexually active women), Klebsiella pneumoniae, Proteus mirabilis, Enterococcus faecalis.
• Risk factors: sexual intercourse, new sexual partner, spermicide and diaphragm use, previous urinary tract infection, postmenopausal state, diabetes, short urethra, delayed voiding.
• Natural history: about 25 to 45 percent of mild episodes resolve without antibiotics within 1 week; antibiotics shorten symptoms by about 1 to 2 days and reduce the risk of progression to pyelonephritis (about 1 to 2 percent).
• Resistance: E. coli resistance to trimethoprim approaches 25 to 30 percent in some areas, to co-amoxiclav about 20 percent, to ciprofloxacin 10 to 20 percent, and to nitrofurantoin and fosfomycin generally below 5 percent. Use local resistance data.

• Dysuria, frequency, urgency, suprapubic pain or tenderness, nocturia, sometimes visible haematuria, cloudy or offensive urine.
• Absence of vaginal discharge or irritation raises the probability of cystitis to above 90 percent (when dysuria and frequency are both present).
• Fever above 37.8 C, rigors, loin pain, vomiting, malaise suggest upper tract involvement.
• Exclude: vaginal candidiasis, vaginitis, sexually transmitted infections (chlamydia, gonorrhoea, herpes), urethritis, interstitial cystitis, urinary stones, atrophic vaginitis.
• Red flags: pregnancy, fever or loin pain, male sex, recurrent infections, symptoms for over 7 days, failure to respond after 48 hours of antibiotics, haematuria persisting after treatment, recent instrumentation, immunosuppression, known renal tract abnormality.

• Women under 65 with typical symptoms and no vaginal discharge: treat on clinical grounds; dipstick may support (nitrite positive and leucocyte esterase positive: positive predictive value above 90 percent; both negative: infection very unlikely, about 20 percent chance; consider alternative diagnoses).
• Urine culture and sensitivity before treatment in: pregnancy, suspected pyelonephritis, males, age over 65 (with symptoms), recurrent or treatment failure, recent antibiotics (within 3 months), recent hospital admission, abnormal renal tract, diabetes, persistent haematuria, immunosuppression, catheterisation.
• Midstream urine culture: threshold 10^3 CFU/mL or more of a uropathogen in symptomatic women is significant.
• Pregnancy test if sexually active and not known to be pregnant.
• Consider sexually transmitted infection screening (nucleic acid amplification for chlamydia and gonorrhoea) if new partner or discharge.

• Analgesia: paracetamol 1 g orally every 6 hours (maximum 4 g per day); ibuprofen 400 mg orally three times daily with food for up to 3 days if no contraindication. Increase fluids; there is no evidence that alkalinising agents are effective.
• Delayed or watchful waiting option for mild symptoms: ibuprofen 400 mg three times daily for 3 to 5 days, with review at 48 hours and antibiotics if worsening.
• First line antibiotics (choose by local resistance):
  • Nitrofurantoin 100 mg modified release orally twice daily for 3 days (or 50 mg immediate release four times daily for 3 days), take with food. Contraindicated if estimated glomerular filtration rate (eGFR) under 45 mL/min (may be used with caution 30 to 44 mL/min for short course if resistance prevents alternatives), glucose-6-phosphate dehydrogenase (G6PD) deficiency, near term pregnancy (38 weeks and beyond). Rare pulmonary and hepatic reactions with long term use.
  • Pivmecillinam 400 mg orally as a first dose, then 200 mg three times daily for a total of 3 days (400 mg three times daily for 3 days is an alternative regimen where licensed). Avoid in carnitine deficiency, porphyria.
  • Fosfomycin trometamol 3 g single dose sachet orally (dissolved in water, on an empty stomach, at bedtime after emptying the bladder). Lower efficacy in some studies; repeat dose in 3 days for complicated settings.
  • Trimethoprim 200 mg orally twice daily for 3 days (only if local resistance is below 20 percent, or sensitivities known; avoid in first trimester of pregnancy, folate deficiency, severe renal impairment, concurrent methotrexate).
• Second line: cefalexin 500 mg orally twice daily (or 250 to 500 mg four times daily) for 3 to 5 days; co-amoxiclav 500/125 mg orally three times daily for 3 to 5 days; ciprofloxacin 250 mg orally twice daily for 3 days (reserve fluoroquinolones for when alternatives are unsuitable because of tendon rupture, QT prolongation, aortic aneurysm, neuropsychiatric effects, and aortic dissection risk).
• Review at 48 hours if no improvement: send urine for culture, check adherence and resistance.
• Pregnancy: always culture, treat for 7 days (cefalexin 500 mg twice daily for 7 days, or nitrofurantoin 100 mg modified release twice daily for 7 days except at term, or amoxicillin 500 mg three times daily if sensitive); repeat culture after treatment.
• Pyelonephritis: ciprofloxacin 500 mg orally twice daily for 7 days, or co-amoxiclav 500/125 mg orally three times daily for 7 to 10 days if sensitive, or cefalexin 500 mg orally two to three times daily for 7 to 10 days; admit if vomiting, sepsis, pregnancy, or unable to take oral treatment.
• Test of cure is unnecessary in asymptomatic women except in pregnancy.
• Advice: complete the course; hydration; post-coital voiding; avoid spermicides and diaphragms; return if symptoms persist.