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.

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}

• Cystitis - eg, bacterial cystitis, cistite intersticial; chemical cystitis - eg, cyclophosphamide.

• Uretrite.

• Vaginitis or vulvar vestibulitis.

• Urinary tract infection (UTI).

• Detrusor instability.

• Diabetes mellitus.

• Gravidez.

• Prostate-related - eg, prostatitis, hipertrofia prostática benigna, câncer de próstata.

• Medications - eg, diuretics, doxazosina.

• Radioterapia.

• Esquistossomose.

• Bladder dysfunction - eg, associated with neurological conditions such as esclerose múltipla ou Doença de Parkinson.

• Bladder tumours.

• Urinary tract stones or foreign bodies.

• Other urinary symptoms:
  

  • Disúria.

  • Urgência.

  • Hematúria.

  • Noctúria.

  • Hesitancy.

  • Dribbling.

  • Dor abdominal.

  • Incontinência urinária (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.

Sinais

• May be normal.

• Look for a distended bladder.

• In women vaginal examination may be appropriate.

• In men digital rectal examination should be performed.

Urina

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

Exames de sangue

• FBC, renal function, liver function, glucose, calcium.

• Prostate specific antigen (PSA) in men.

Imagem

• 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.

Outros

A screen for infecções sexualmente transmissíveis (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

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

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

• Urgência

• Frequency

• Noctúria

• 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

Veja também o separado Bexiga Hiperativa artigo.