Interstitial Cystitis

The cause of interstitial cystitis is poorly understood, however, chronic inflammation and immune system dysregulation may be implicated. One hypothesis for the pathogenesis of interstitial cystitis includes neurologic upregulation of pain sensation, where there is increased activation of bladder sensory neurons during normal bladder filling, resulting in bladder pain. Another proposed mechanism includes altered integrity of the glycosaminoglycan (GAG) layer of the bladder, which functions as a barrier to urinary irritants. Defects in this layer can allow solutes to penetrate the urothelium (i.e., the lining of the urinary tract) and irritate the underlying nerves and muscle tissue. Once damage occurs, bladder mast cells may play a role in propagating ongoing bladder inflammation. Additionally, interstitial cystitis is associated with Hunner lesions, which have the characteristic appearance of small vessels radiating from a central scar. While uncommon, these are specific to interstitial cystitis and may trigger the associated pain.  

While most individuals cannot identify a triggering event for interstitial cystitis, some report the onset of symptoms with a urinary tract infection, post-surgical procedure, and after trauma (e.g., falling onto the tailbone). Certain foods and drinks may worsen interstitial cystitis. Common culprits are caffeine, alcohol, artificial sweeteners, and acidic foods such as tomatoes and oranges. Stress, exercise, sexual intercourse, and prolonged sitting may also play a role. 

The signs and symptoms of interstitial cystitis include a persistent unpleasant sensation in the bladder, which can be described as pain, pressure, or discomfort. Typically, symptoms persist for greater than six weeks, during the day and night. The sensation worsens when the bladder fills and improves with voiding. Thus, an individual with interstitial cystitis may void several times a day to avoid discomfort. The symptoms are usually gradual in onset and worsen over a period of months. The symptoms are typically constant but can vary in severity from day to day. The location of symptoms is often described as suprapubic (i.e., below the umbilicus), however, some individuals may feel pain in their upper abdomen and lower back.  

Other signs and symptoms may include urinary urgency and frequency, nocturia (i.e., frequent urination at night), dysuria (i.e., pain with voiding), perineal pain (i.e., pain of the area between the anus and the genitalia), bladder spasms, pubic pressure, dyspareunia (i.e., pain with intercourse), and depression. Chronic pain, urinary frequency, and fatigue can worsen one’s quality of life and disrupt home and work life. 

Interstitial cystitis can be diagnosed based on patient history, a thorough review of systems, and physical examination. On examination, no identifiable causes for the discomfort may be found, or symptoms persist despite the successful treatment of a urinary tract infection. A clinician will ask about medical history related to the bladder (i.e., history of recurrent urinary tract infections, prior pelvic trauma, surgery, or radiation). On pelvic or rectal examination, an individual with interstitial cystitis will have tenderness or tightness of the pelvic floor muscles. There can also be tenderness of the abdominal wall, hip girdle, bladder base, and the urethra. 

Laboratory testing is not required to make a diagnosis of interstitial cystitis, however, urine testing (e.g., urinalysis and postvoid residual urine volume) may be performed. Urinalysis with microscopy can exclude infection, including sexually transmitted infections (e.g., gonorrhea and chlamydia), and evaluate for hematuria, or blood in the urine. The presence of hematuria can be suggestive of another cause for bladder pain (e.g., malignancy). A high postvoid residual urine may indicate urinary retention due to other bladder diseases (e.g., bladder outlet obstruction or neurologic dysfunction). Additionally, cystoscopy, a procedure where a bladder scope is used to examine the inside of the bladder wall, can be performed to exclude other etiologies, such as malignancy. Hunner lesions may be visualized on cystoscopy, which can help confirm the diagnosis of interstitial cystitis. A biopsy of the bladder wall may be taken if needed, which may show an increased number of mast cells on histologic examination. 

There is currently no curative treatment for interstitial cystitis. The goal of management is to control the symptoms and improve one’s quality of life. At-home treatments and behavioral modification may include using heat or cold packs on the abdominal area overlying the bladder or perineum, and avoiding foods, drinks, or activities that make symptoms worse. Keeping a fluid intake and voiding diary can help guide fluid management; however, it is important to note that individuals should avoid extremes of fluid intake. 

Pelvic physical therapy provided by a physical therapist with specialized training in pelvic soft tissue manual manipulation and rehabilitation can be integrated into the treatment plan for interstitial cystitis. Of note, pelvic floor strengthening exercises (e.g., Kegels) may actually exacerbate pain symptoms. Pharmacologic therapy for mild interstitial cystitis with occasional flares includes nonsteroidal anti-inflammatory drugs (NSAIDs), like ibuprofen. If symptoms are more severe, amitriptyline, a tricyclic antidepressant (TCA), or pentosan polysulfate sodium, a low molecular weight heparin (LMWH), can be prescribed. If the individual has both interstitial cystitis and allergic disorders (e.g., seasonal allergies, asthma), hydroxyzine, an antihistamine, can be used.  

For those with symptoms refractory to medications, a procedure known as bladder hydrodistention may be performed. A cystoscope is used to fill the bladder with water, stretching the bladder wall, in order to disrupt the sensory nerves within the bladder wall and reduce pain. Additionally, intravesical therapies may be used, where a urinary catheter is used to instill medications (e.g., lidocaine, gentamicin, heparin, methylprednisolone, and sodium bicarbonate) directly into the bladder. Lastly, individuals who have Hunner lesions on cystoscopy can be treated with endoscopic resection.