What is interstitial cystitis?

What is Interstitial Cystitis?

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic bladder condition defined by an unpleasant sensation (pain, pressure, or discomfort) perceived to be related to the urinary bladder, associated with lower urinary tract symptoms lasting more than six weeks, in the absence of infection or other identifiable causes. 1, 2

Core Clinical Features

Pain Characteristics (The Hallmark Symptom)

• Bladder/pelvic pain, pressure, or discomfort is the defining feature that distinguishes IC/BPS from other urinary conditions 1, 2
• Pain is typically felt in the suprapubic region but commonly extends throughout the pelvis—including the urethra, vulva, vagina, rectum—and to extragenital locations such as the lower abdomen and back 1
• Many patients use the word "pressure" rather than "pain" and may actually deny having pain, making it critical to use broad descriptors when evaluating symptoms 1, 2
• Pain characteristically worsens with bladder filling and improves with urination 1, 2
• Symptoms are often exacerbated by specific foods or drinks 1, 2

Associated Urinary Symptoms

• Urinary frequency is nearly universal (92% of patients) but is not specific to IC/BPS and can occur in many bladder disorders 1, 2
• Urinary urgency affects 84% of patients but differs qualitatively from overactive bladder 1, 2
• IC/BPS patients experience a more constant urge to void and void to avoid or relieve pain, whereas overactive bladder patients void to prevent incontinence 1, 2
• Nocturia (nighttime urination) is common 1, 3

Diagnostic Criteria

Minimum Duration and Exclusions

• Symptoms must be present for at least six weeks with documented negative urine cultures 1, 2
• The diagnosis requires exclusion of urinary tract infection and other identifiable causes such as bladder cancer, bladder stones, or intravesical foreign bodies 1

Clinical Evaluation

• Diagnosis requires careful history documenting the number of voids per day, sensation of constant urge to void, and the location, character, and severity of pain, pressure, or discomfort 1
• Document dyspareunia (painful intercourse), dysuria, ejaculatory pain in men, and relationship of pain to menstruation in women 1
• Perform a brief neurological exam to rule out occult neurologic problems and evaluate for incomplete bladder emptying 1
• Baseline symptoms should be documented using validated tools such as the Interstitial Cystitis Symptom Index (ICSI), Genitourinary Pain Index (GUPI), or visual analog scale (VAS) 1, 4

Role of Cystoscopy

• There are no agreed-upon cystoscopic findings diagnostic for IC/BPS except for the presence of Hunner lesions 1
• Cystoscopy should be performed in patients for whom Hunner lesions are suspected, as this is the only reliable way to diagnose their presence 1, 2
• Cystoscopy is also indicated when clinical mimics such as bladder cancer, bladder stones, or intravesical foreign bodies are suspected 1
• Routine cystoscopy is not required for every IC/BPS patient 1

Urodynamics

• There are no agreed-upon urodynamic criteria diagnostic for IC/BPS, and urodynamics are not recommended for routine clinical use 1, 2
• Urodynamic evaluation may be useful when suspecting outlet obstruction, poor detrusor contractility, or other conditions explaining refractoriness to therapy 1

Special Considerations in Men

• Historically considered rare in men (female-to-male ratio of 10:1), but male IC/BPS may be more common than previously recognized 1
• The diagnosis of IC/BPS should be strongly considered in men with pain, pressure, or discomfort perceived to be related to the bladder and associated with urinary frequency, nocturia, or urgent desire to void 1, 2
• The clinical characteristics of IC/BPS overlap significantly with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), which is characterized by pain in the perineum, suprapubic region, testicles, or tip of the penis, often exacerbated by urination or ejaculation 1, 2
• Some men meet criteria for both conditions, and treatment can include therapies for both IC/BPS and CP/CPPS 1, 2

Pathophysiology (Current Understanding)

• The etiology is likely multifactorial and may involve urothelial dysfunction, chronic inflammation, neurogenic upregulation, mast cell activation, and central sensitization 3, 5
• Possible mechanisms include bladder wall defects, autoimmune disorder, viral/bacterial infection, toxin exposure, pelvic floor dysfunction, and inflammatory response 6
• IC/BPS is a heterogeneous clinical syndrome with subgroups or phenotypes, including Hunner's IC (HIC) and non-Hunner's IC (NHIC), each with distinct clinical presentations 1, 3

Common Diagnostic Pitfalls

• Misdiagnosis and delayed diagnosis are common due to the wide spectrum of symptoms and overlap with conditions such as overactive bladder, recurrent urinary tract infection, endometriosis, chronic pelvic pain, and vulvodynia 1, 5
• Do not use research or clinical trial definitions (such as NIDDK criteria) in clinical practice, as these are not appropriate outside of research settings and can lead to misdiagnosis or treatment delays 1, 2
• Avoid treating with antibiotics when no infection is present, as this leads to antibiotic resistance and disruption of protective flora 2
• The condition affects over 700,000 people in the US, with more than 90% being women, though it is often overlooked and misdiagnosed 7