Urinary Frequency

What causes urinary frequency?

The basic causes of urinary frequency can be divided into three groups:

• Polyuria when too much urine is being produced.
• Instability of the detrusor mechanism.
• Inability of the bladder to stretch.

However, urinary frequency strictly speaking occurs when there is an increased need to urinate more often without a concomitant increase in the volume of urine.

How common is urinary frequency?

The true prevalence of urinary symptoms is difficult to study as embarrassment may contribute to under-reporting, but studies suggest it increases with age, as causative risk factors become more likely- eg, benign prostatic hypertrophy in men and genito-urinary syndrome of the menopause in women.

In a 2015 UK-based postal survey 7% of the women had symptoms of overactive bladder and 20% had mixed urinary incontinence.^[1] A 2018 study of adults aged over 40 years in South Korea showed nocturia (36%) and frequency (30%) were the most often reported symptoms.^[2] In the elderly it is very common in both sexes.^{[3, 4]}

Aetiology

• Cystitis - eg, bacterial cystitis, interstitial cystitis; chemical cystitis - eg, cyclophosphamide.
• Urethritis.
• Vaginitis or vulvar vestibulitis.
• Urinary tract infection (UTI).
• Detrusor instability.
• Diabetes mellitus.
• Pregnancy.
• Prostate-related - eg, prostatitis, benign prostatic hypertrophy, prostate cancer.
• Medications - eg, diuretics, doxazosin.
• Radiotherapy.
• Schistosomiasis.
• Bladder dysfunction - eg, associated with neurological conditions such as multiple sclerosis or Parkinson's disease.
• Bladder tumours.
• Urinary tract stones or foreign bodies.

Urinary frequency - associated symptoms

• Other urinary symptoms:
  • Dysuria.
  • Urgency.
  • Haematuria.
  • Nocturia.
  • Hesitancy.
  • Dribbling.
  • Abdominal pain.
  • Urinary incontinence (may suggest detrusor instability or may relate to inability to get to the toilet on time; also common in pregnancy).
• Also question about systemic symptoms - eg, weight loss, fever, etc.

Signs

• May be normal.
• Look for a distended bladder.
• In women vaginal examination may be appropriate.
• In men digital rectal examination should be performed.

Investigations

Urine

• Midstream urine for dipstick, microscopy, culture and sensitivities and pregnancy testing as appropriate.

Blood tests

• FBC, renal function, liver function, glucose, calcium.
• Prostate specific antigen (PSA) in men.

Imaging

• This will depend on the clinical suspicion.
• Bladder, renal and ureteric ultrasound.
• CT scan or intravenous urography (IVU) looking for ureteric stones.
• Bladder flow studies and cytometry.
• Cystoscopy.

Other

A screen for sexually transmitted infections (STIs) may be appropriate:

• Urinary tract symptoms may also be associated with STIs.
• A 2018 study of 1,052 women presenting to an emergency department with UTI-type symptoms with possible STI, found sterile pyuria in 74% with negative urine cultures.^[5]

Urinary frequency treatment

This depends on the underlying cause and may range from medications such as a course of antibiotics to surgery.

Overactive bladder

This is a clinical syndrome with one or more of the following:

• Urgency
• Frequency
• Nocturia
• Incontinence

Patients have an immediate need to empty the bladder, which comes on suddenly. European guidelines recommend keeping a symptom diary for 3-7 days.^[3] This both assesses the scale of the presenting problem and acts as a marker for response to treatment.

Current management options include bladder training, anticholinergic drugs, intravesical botulinum toxin injections, intermittent self-catheterisation and sacral or posterior tibial nerve stimulation. Current research is focusing on novel therapeutic agents and some modifications of existing drugs.^[6]

See also the separate Overactive Bladder article.