Introduction
Interstitial cystitis (IC) is a chronic inflammatory disorder of the bladder with typical cystoscopic and/or histological features in the absence of infection or other pathology. It is one of the causes of painful bladder syndrome (PBS) and in the past the two terminologies were used interchangeably.
However, the International Continence Society prefers the term PBS defined as ‘suprapubic pain related to bladder filling, accompanied by other symptoms such as increased daytime and night-time frequency in the absence of proven urinary tract infection or other pathology’1.
The term PBS, therefore, includes cases with painful urinary symptoms that may not meet the strictest definition of interstitial cystitis, for example, radiation cystitis, cyclophosphamide cystitis and it encompasses a broader range of causes that need to be excluded e.g. carcinoma in situ and endometriosis. Interstitial cystitis should be used when describing cases that meet all of the IC criteria established by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) (Table 1) and should be a diagnosis of exclusion2.
Skene and Hunner were pioneers in the discovery of interstitial cystitis. The name interstitial cystitis was given to the disease in the late 19th century by A.J Skene. In 1914, Guy Hunner described this inflammatory bladder lesion as ulcers in the bladder wall hence the name ‘Hunner’s ulcers’. However, only 5-10% of interstitial cystitis patients have these ulcers, leading to many decades of under-diagnosis.
It’s only in recent years, that IC has been classified into two types – classical or ulcerative and non-ulcerative3. IC is difficult to manage, can be debilitating with considerable morbidity and a poor quality-of-life in affected women. The aim of this review is to summarise the presentation, investigation and management of women with interstitial cystitis.
Epidemiology
Reported prevalence rates for this condition vary widely because of the lack of a uniform, definition, lack of readily available diagnostic markers and overlapping conditions. In addition, the true prevalence of IC is hard to determine as most patients remains undiagnosed although it is thought to occur in up to 7.5% of the general female population and in 38-85% of women who present with chronic pelvic pain4. Women between the ages of 40 and 60 years are most commonly affected. The condition occurs far more frequently in Caucasians with a 9:1 female predominance5. A recent survey from Finland indicated the prevalence of clinically confirmed probable interstitial cystitis in women was 230 per 100,000 and that of possible/probable interstitial cystitis 530 per 100,0006.
Aetiology
The pathophysiology of interstitial cystitis remains elusive and many theories have been proposed with varying degrees of evidence. Some of the proposed theories are as follows.
Bladder wall dysfunction and GAG layer deficiency
The current body of evidence supports the idea that interstitial cystitis is associated with an intrinsic pathology of the bladder urothelial cells. Keay and Warren7 have identified a low-molecular-weight peptide termed anti-proliferative factor (APF) in the urine of interstitial cystitis patients that inhibits the proliferation of normal bladder epithelial cells in vitro. The chronically damaged epithelium is prone to colonisation with various micro-organisms, and the resulting exposure to these micro-organisms, other urinary antigens, and / or damaged epithelial cells prompts the low-level inflammatory response commonly seen in this disorder. In addition, dysfunctional lower urinary tract epithelium is said to be characterised by damage to the glycosaminoglycans (GAG) layer8. This can lead to increased permeability to potassium, which then permeates the bladder musculature, triggering imperative urgency and bladder contractions.
Mast cell activation is considered to be a result of GAG layer deficiency: this provokes a neurogenic inflammation with overexpression of neurotransmitters. An increased number of mast cells have been associated with interstitial cystitis, but the published reports are inconclusive.
Autoimmune system disorders
Disorders of the immune system are suspected as being causative because of the association with certain HLA groups, allergies and autoimmune processes9.
Visceral hypersensitivity theory
Interstitial cystitis has been descr