Urinary Frequency

Urinary frequency is voiding more than eight times in 24 hours (normal 4 to 8) or more often than the person finds acceptable; daytime frequency is voiding more than 7 times while awake. It is a symptom, not a diagnosis.

• Mechanisms:
  • Polyuria (24 hour urine volume more than 2.8 L or 40 mL/kg): diabetes mellitus, diabetes insipidus, primary polydipsia, hypercalcaemia, hypokalaemia, diuretics, SGLT2 inhibitors, lithium, caffeine, alcohol, excess fluids, resolving renal failure, post-obstructive diuresis.
  • Normal volumes with reduced bladder capacity or increased sensation: overactive bladder, urinary tract infection, bladder pain syndrome, bladder stones, tumour, carcinoma in situ, radiation cystitis, outlet obstruction (men), neurogenic bladder, pelvic organ prolapse, pregnancy, uterine fibroids, pelvic mass, atrophic urogenital changes in menopause, anxiety, habit.
  • Incomplete emptying: retention with overflow, large residual volume.
• Common causes in clinic: overactive bladder (about 15 to 17 percent of adults), urinary tract infection, benign prostatic enlargement, diabetes, and high fluid intake.

• Frequent voiding of small or large volumes. Ask about timing (day versus night), volumes, thirst, dysuria, urgency, urge incontinence, stress incontinence, haematuria, pain, stream, hesitancy, incomplete emptying, drugs (diuretics, lithium, SGLT2 inhibitors, anticholinergics, calcium channel blockers), caffeine and alcohol, fluid intake (including tea, coffee, fizzy drinks), weight loss, pelvic radiation, bowel habit, sexual function, gynaecological history.
• Red flags: visible haematuria, persistent microscopic haematuria, weight loss, pelvic or bone pain, neurological features (saddle numbness, back pain, leg weakness), retention, recurrent infections, smoking history (bladder cancer risk), pelvic mass, chronic loin pain, constitutional symptoms.
• Examination: abdomen and palpable bladder, pelvic and vaginal examination (prolapse, atrophy, mass), digital rectal examination (prostate), neurological screening (perineal sensation, tone), signs of diabetes, thyroid, dehydration.

• Bladder diary (3 days): time and volume of voids, fluid intake, urgency episodes, incontinence episodes.
• Urinalysis: glucose, ketones, protein, blood, leucocytes, nitrites; midstream culture if dipstick positive or symptoms of infection.
• Bloods: urea, creatinine, eGFR, electrolytes, glucose or HbA1c, calcium, full blood count; PSA after counselling in men.
• Pregnancy test in women of childbearing age.
• Post-void residual (bladder scan) if suspected retention; renal tract ultrasound if haematuria, residual, recurrent infection, pain, or renal impairment.
• Flexible cystoscopy: persistent haematuria, risk factors for malignancy, persistent irritative symptoms with sterile urine, suspected bladder pain syndrome or stones.
• Urodynamics: when diagnosis is unclear or before surgery.
• Water deprivation test if suspected diabetes insipidus.

• Treat the cause: diabetes, hypercalcaemia, infection, retention, drugs.
• Conservative measures for overactive bladder:
  • Fluid intake 1.5 to 2 litres daily, spread through the day.
  • Reduce caffeine (below 200 mg per day), alcohol and carbonated drinks.
  • Weight loss (a 5 to 10 percent loss reduces incontinence episodes in obese women), stop smoking, treat constipation.
  • Bladder training: 6 weeks minimum; start with the shortest interval comfortable (for example 1 hour), lengthen by 15 to 30 minutes each week to a target interval of 3 to 4 hours; use urge suppression techniques (pelvic floor squeeze, relaxation, distraction).
  • Pelvic floor muscle training (supervised) for women with urge or mixed symptoms.
  • Timed voiding for those with cognitive impairment.
• Drug therapy for overactive bladder after at least 4 to 6 weeks of conservative measures:
  • Mirabegron 50 mg orally once daily (25 mg once daily if eGFR 15 to 29 or moderate hepatic impairment; contraindicated with severe uncontrolled hypertension of 180/110 mmHg or higher; monitor blood pressure; interacts with digoxin and flecainide), or vibegron 75 mg daily.
  • Solifenacin 5 mg orally once daily, increase to 10 mg after 4 weeks (maximum 5 mg in severe renal or moderate hepatic impairment or with strong CYP3A4 inhibitors); oxybutynin immediate release 2.5 to 5 mg two to three times daily (maximum 5 mg four times daily) or modified release 5 to 10 mg once daily (maximum 30 mg); tolterodine 2 mg twice daily (1 mg twice daily in renal or hepatic impairment); fesoterodine 4 mg once daily increased to 8 mg; trospium 20 mg twice daily (once daily in elderly or renal impairment).
  • Anticholinergic cautions: narrow angle glaucoma, urinary retention, severe constipation, myasthenia gravis, dementia and elderly (cognitive decline); oxybutynin has the highest central effects; consider avoiding in those over 75 or on other anticholinergics. Assess after 4 weeks and, if effective, review every 6 to 12 months. Anticholinergic and beta-3 combination is used in refractory cases.
  • Postmenopausal women: vaginal oestrogen (estradiol 10 microgram vaginal tablet nightly for 2 weeks, then twice weekly) improves frequency and urgency from atrophy.
• Urinary tract infection: choose the antibiotic by culture result (for example nitrofurantoin 100 mg modified release twice daily for 3 days).
• Benign prostatic enlargement: tamsulosin 400 micrograms orally daily, with finasteride 5 mg daily for prostate volume above 30 to 40 mL.
• Refractory overactive bladder: refer for intradetrusor onabotulinumtoxinA 100 units by cystoscopy (risk of retention and urinary infection; teach intermittent self-catheterisation if retention), sacral or tibial neuromodulation.
• Bladder pain syndrome: refer to urology; amitriptyline 10 to 25 mg at night, bladder instillation; avoid unnecessary antibiotics.
• Follow up at 4 to 8 weeks to review diary, response and adverse effects.