Interstitial cystitis ( IC )

Interstitial cystitis (IC) is a clinical syndrome characterised urinary frequency, urgency, and pelvic pain of unknown aetiology (1,2,3,4). Unfortunately IC does not have a universally agreed diagnostic criteria (5), nor a definitive marker - therefore the diagnosis of IC is one of exclusion.

Aetiology:

• the aetiology of IC is unknown although it is believed that it may be the result of an autoimmune process

Epidemiology:

• in the USA (1) there is a prevalence of 60-70 cases per 100,000 women. This contrasts with a prevalence in Europe of 18 cases per 100,000 women and only 3-4 cases per 100,000 women in Japan. The differences in prevalences are likely to reflect differences in diagnostic criteria used
• in the USA - incidence is 2.6 cases per 100,000 women per year
• female:male ratio 9:1
• the median age at presentation is 40 years

Diagnosis:

• IC is a diagnosis of exclusion - also there is no universally accepted clinical criteria for the diagnosis of IC
  
  
• cystoscopy is often described as the most important diagnostic tool (apart from a detailed history and examination) for assessing a patient who may have IC. Usually cystoscopy is performed under general anaesthesia - this allows examination for coexisting urethral and bladder pathology (e.g. transitional cell carcinoma) and features of IC such as Hunner lesions (6) and glomerulations (petechiae). Bladder capacity is also measured
  • Hunner Lesion IC - bladder capacity is decreased (<400 ml); ulcers, or scars may be see; seen in about 5- 20% of patients with IC (6)
  • non Hunner Lesion disease - bladder capacity is generally greater than 400 ml - mucosal cracking, ulcers or scars are generally absent; seen in about 80-95% of patients with IC (6)
    
    
• potassium sensitivity test - it has been noted that some patients with IC have an increased urothelial permeability to certain intravesical components. Intravesical potassium chloride (KCl) sensitivity test has been used to detect urothelial leakage in patients with IC (2)

Management:

• requires specialist advice
• no single agent has proven universally effective in the management of IC
• Treatment options for people with bladder pain syndrome and either glomerulations or Hunner's lesions include (7):
  • oral treatments (such as amitriptyline, gabapentin, pregabalin, paracetamol, nonsteroidal anti-inflammatory drugs, hydroxyzine, cimetidine and ranitidine)
    
    
  • bladder instillations (a plastic tube inserted into the bladder to administer liquid medication)
    
    
  • NICE have recommended Pentosan polysulfate sodium as an option for treating bladder pain syndrome with glomerulations or Hunner's lesions in adults with urinary urgency and frequency, and moderate to severe pain, only if various criteria are met including (7):
    • condition has not responded to an adequate trial of standard oral treatments
    • it is not offered in combination with bladder instillations
    • any previous treatment with bladder instillations was not stopped because of lack of response
    • it is used in secondary care

Notes:

• glycosaminoglycan replacement therapy (achieved by the intravesical instillation of pentosan polysulphate or hyaluronidase) has showed benefit in some patients (4)
  
  
• an improvement in pelvic pain and urinary frequency has been reported in 60% of women with interstitial cystitis following intravesical instillation of the bacille Calmette-Guerin (4)
  
  
• Hunner lesion (HL) interstitial cystitis (6)
  • key difference between HL IC and N-HL IC/BPS is the presence of HLs on cystoscopy
    • typical appearance of HLs are circumscribed, reddened mucosal areas with small vessels radiating towards a central scar (The nomenclature has changed from Hunner 'ulcer' to 'lesion' since it is not a true ulcer)
  • HL IC is relatively rare, with prevalence ranging from 5% to 20%
    • patients with HL IC tend to be older, have a more severe form of the disease with lower bladder capacity and greater urinary frequency, and have histologic changes that implicate an inflammatory process
    • HLs are more commonly found in male patients with IC/BPS

Reference:

1. J Urol. 1999 Feb;161(2):549-52.
2. Urol Int. 2003;71(1):61-5.
3. Urol Clin North Am. 2002 Aug;29(3):649-60.
4. Kroon N, Reginald P. Medical management of chronic pelvic pain. Curr. Obs. & Gynae. 2005; 15 (5): 285-290.
5. Malde S et al. Guideline of guidelines: bladder pain syndrome.BJU Int. 2018 Nov;122(5):729-743
6. Han E et al. Current best practice management of interstitial cystitis/bladder pain syndrome. Ther Adv Urol 2018, Vol. 10(7) 197- 211
7. NICE (November 2019). Pentosan polysulfate sodium for treating bladder pain syndrome