Differential Diagnosis

Occasional Diagnoses

  • Interstitial Cystitis
  • Bladder Stone or Tumour
  • After Abdomino-Pelvic Surgery and Radiotherapy
  • Fistula: Vesicovaginal/Uterine, Ureterovaginal (Surgery and Malignancy)
  • Polyuria (any Cause, e.g. Diabetes, Diuretics – Particularly If Compounded by Immobility in the Elderly)
  • Bladder Stone
  • Bladder Tumour

Rare Diagnoses

  • After Pelvic Fracture (Direct Sphincter Damage with or without Neurological Damage)
  • Congenital Abnormalities: Short Urethra, Wide Urethra, Epispadias, Ectopic Ureter
  • Sensory Neuropathy (e.g. Diabetes and Syphilis)
  • Multiple Sclerosis, Syringomyelia
  • Paraplegia, Cauda Equina Syndrome
  • Psychogenic
  • Ketamine-Associated Ulcerative Cystitis

Ready Reckoner

Key distinguishing features of the most common diagnoses

Stress IncontinenceInfective CystitisOveractive Bladder SyndromeOutflow ObstructionProstatectomy
Stress PatternYesNoNoPossiblePossible
Urge PatternNoYesYesNoYes
Overflow PatternNoNoNoYesNo
Palpable BladderNoNoNoYesNo

Possible Investigations

Likely:Urinalysis, MSU

Possible:PSA, U&E, ultrasound, urodynamic studies, uroflowmetry.

Small Print:Fasting sugar or HbA1c blood sugar, syphilis serology, cystoscopy, neurological investigations.

  • Urinalysis: To test for infection and diabetes.
  • MSU: To confirm infection and guide antibiotic treatment.
  • Fasting sugar or HbA1c and syphilis serology: If diabetes or syphilis a possible cause of neuropathy.
  • PSA: Consider this if LUTS or prostatic enlargement on examination
  • U&E: To assess renal function in chronic outflow obstruction.
  • Ultrasound: May suggest outflow obstruction or chronic infection.
  • Specialist investigations may include: Urodynamic studies (helpful to distinguish between urge and stress incontinence), uroflowmetry (prostatic enlargement), cystoscopy (may reveal cause of outflow obstruction, stone or tumour) and neurological investigations (e.g. imaging of spinal cord).

Top Tips

  • Incontinence has many causes, but can often be broadly categorised into one of three groups – stress incontinence (e.g. with coughing), urge incontinence (‘when I’ve got to go, I’ve got to go’) and continuous, like water over the edge of a dam (e.g. through a vesicovaginal fistula, or in overflow from a chronically distended bladder).
  • The aetiology may be multifactorial, particularly in the elderly. Mobility, vision, distance to the toilet and ongoing medication may all be relevant.
  • Overactive bladder syndrome and stress incontinence can be difficult to distinguish. The latter rarely causes nocturnal incontinence, while it may be a feature of overactive bladder syndrome. If in doubt, refer for urodynamic studies.
  • Adopt a sympathetic approach. Incontinence can have a devastating impact on self-esteem and seriously affect a patient’s social and sexual functioning

Red Flags

  • Incontinence with saddle anaesthesia and leg weakness suggests a cauda equina lesion. This is a neurological emergency – refer urgently.
  • Continuous incontinence suggests significant pathology, such as a fistula, chronic outflow obstruction or a neurological problem.
  • Never empty the huge bladder of chronic retention in one go. This can cause bleeding and renal complications. Admit for catheterisation and controlled release.
  • Adult-onset nocturnal enuresis suggests chronic retention.
  • Remember the possibility of chronic ketamine abuse in young people.
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