Interstitial Cystitis (IC)/Painful Bladder Syndrome (PBS)

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

  • Medical Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

Quick GuidePelvic Pain: What's Causing Your Pelvic Pain?

Pelvic Pain: What's Causing Your Pelvic Pain?

What is the cause of interstitial cystitis?

No one knows what causes IC/PBS, but doctors believe that it is a real physical problem and not a result, symptom, or sign of an emotional problem. Because the symptoms of IC/PBS are varied, most researchers believe that it represents a spectrum of disorders rather than one single disease.

One area of research on the cause of IC/PBS has focused on the layer that coats the lining of the bladder called the glycocalyx, made up primarily of substances called mucins and glycosaminoglycans (GAGs). This layer normally protects the bladder wall from any toxic contents in urine. Researchers have found that this protective layer of the bladder is "leaky" in about 70% of IC/PBS patients and have hypothesized that this may allow substances in urine to pass into the bladder wall where they might trigger IC/PBS directly or by making these patients susceptible to other chemicals in the urine, including those from foods or beverages.

Along with altered permeability of the bladder wall, researchers are also examining the possibility that IC/PBS results from decreased levels of protective substances in the bladder wall. Reduced levels of GAGs (discussed previously) or other protective proteins might also be responsible for the damage to the bladder wall seen in IC/PBS.

No matter what the mechanism for disruption of the bladder lining, potassium is one substance that may be involved in damage to the bladder wall. Potassium is present in high concentrations in urine and is normally not toxic to the bladder lining. However, if the tissues lining the inside of the bladder (urothelium) are disrupted or are abnormally leaky, potassium could then penetrate the lining tissue and enter the muscle layers of the bladder where it can cause damage and promote inflammation.

Researchers have isolated a substance known as anti-proliferative factor (APF) that appears to block the normal growth of cells that make up the lining of the bladder. APF has been identified almost exclusively in the urine of people suffering with IC/PBS. Research is under way to clarify the potential role of APF in the development of IC/PBS.

Increased activation of sensory nerves (neurologic hypersensitivity) in the bladder wall is also thought to contribute to the symptoms of IC/PBS. In addition, cells known as mast cells within the bladder wall, which play a role in the body's inflammatory response to injury, release chemicals that are believed to contribute to the symptoms of IC/PBS.

Other theories about the cause of IC/PBS are that it is a form of autoimmune disorder (in which the body's own immune system attacks the body) or that infection with an unidentified organism may be producing the damage to the bladder and the accompanying symptoms.

Medically Reviewed by a Doctor on 6/8/2016

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