Diseases of the urinary system are not common with EB, but when they do occur, they can be serious and even life-threatening. The urinary system consists of the kidneys, ureters, bladder and urethra.
The kidneys filter the blood and produce urine, and are a key component in maintaining fluid and electrolyte balance. The ureters are tubes that deliver urine from the kidneys to the bladder. The bladder is a reservoir that holds as much as 16 ounces of urine in healthy adults. When full, the urine is voided, leaving the bladder via the urethra, which connects the bladder to the outside of the body.
There are several problems that may arise in the urinary system. With regard to EB, a urine sample frequently reveals the presence of blood. This may be so because of blisters and/or erosions in the bladder or urethra and not because of renal or bladder disease.
With EB, obstructive uropathy is the most common complication, seen most frequently as a urethral stricture or urethral meatal stenosis. A urethral stricture (narrowing) may occur due to blistering and subsequent scarring of the urethra. Urethral meatal stenosis is a narrowing of the external opening of the urethra and also may occur as a result of blistering and scarring. Both have occurred in all subtypes of EB, according to the NEBR, but urethral meatal stenosis was the most common complication and was reported most frequently in patients with severe subtypes of junctional and recessive dystrophic EB (reported in 11.6 percent JEB-Herlitz and 8 percent Hallopeau-Siemens).
Both sexes may experience urethral strictures and meatal stenosis. In males, blisters may be observed over the meatus (the external opening of the urethra) at the end of the penis. If this occurs, the blister must be carefully drained to allow the flow of urine. This condition is less apparent in females but still may occur. If it is a frequent problem, the meatus may narrow considerably or seal (meatal stenosis), preventing the flow of urine altogether. The person may not be able to pass urine, or there may be a reduced flow or a change in the direction of the flow during urination. If the individual is not able to pass any urine, emergency medical attention is required. For males, placing a small piece of Mepitel at the end of the penis after urination and leaving it in place until the next urination may be an effective preventive measure.
Several methods have been used to treat urethral strictures. Each method requires consultation with an EB-informed urologist to determine the best treatment.
- Urethral dilation is achieved by inserting lubricated sheath dilators of increasing sizes, thereby stretching or dilating the urethra. This process may be followed by leaving a silastic foley catherer in place for as long as 10 days, to act as a stent. The results of urethral dilation usually are not permanent, and the procedure may need to be repeated.
- Placement of an indwelling supra-pubic catheter also can be considered in cases of recurrent strictures or restenosis, where frequent dilatations have been required. After the supra-pubic catheter has been surgically placed and the area has healed, it can be capped, then opened intermittently throughout the day for drainage of the bladder. Site care is required, and problems may arise from urine leaking onto the surrounding skin and also from infections at the site.
The supra-pubic catheter is placed through the abdominal wall and into the bladder. A balloon is inflated to keep it from coming out of the bladder. The catheter is capped and then opened periodically to be drained.
- Urinary diversion is another option for treating urethral obstruction. There are several methods of urinary diversion. The surgeries are complex procedures that require long recovery periods. There are no reports in the medical literature of urinary diversions done in the context of EB. Extensive evaluation and collaboration by an EB-informed dermatologist and urologist would be necessary before this treatment could be considered.
It is important to note that catheterization and scoping can result in blistering and erosions of the urethra, which can lead to additional scarring. If either procedure is absolutely necessary, the smallest, most flexible instruments should be used.
Along with obstructive uropathy, gomerulonephritis (acute and chronic), renal amyloidosis and IgA nephropathy have been reported in junctional and recessive dystrophic EB, and all can lead to chronic renal failure (CRF). Renal failure that results from these conditions may develop with a gradual loss of the kidneys’ ability to remove waste, concentrate urine and conserve electrolytes. Early signs of renal failure are fatigue, itching, headache, nausea, vomiting, weight loss and a general feeling of illness. All of these signs are non-specific and may be attributed to other things; therefore, blood and urine tests should be monitored.
The treatment for chronic renal failure is dialysis. Dialysis is a method of filtering the blood to remove impurities when the kidneys are unable to do so. Dialysis usually is not needed until the kidneys have lost 85 percent of their function. Two types of dialysis have been used to treat EB patients:
- Hemodialysis uses a machine to filter the blood. Blood is drawn from the patient’s body, run through a dialysis machine and purified, then returned to the patient’s body.
- Peritoneal dialysis uses the lining of the abdomen, the peritoneal membrane, as a filter. Fluid called dialysate flows into the abdominal cavity through a catheter. This fluid, rich in sugar and minerals, flows into the abdomen. The “good” sugars and minerals are exchanged for the “bad” waste, chemicals and extra fluids. At the appropriate time, the fluid is drained from the abdomen.
Both forms of dialysis take several hours, and there are risks with both types. A physician will decide the best course of treatment if dialysis is necessary.
Circumcision is a common area of concern for families with a son who is diagnosed with EB. If the parents were planning to have the child circumcised, an EB diagnosis should not affect that decision. The data suggests that, within the study population, circumcision was preformed within all subtypes of EB, and none of the study participants reported excessively poor or delayed healing.
Because the risk of kidney injury increases if genitourinary complications are not treated, guidelines are necessary for monitoring and managing these problems.