Tuesday, December 13, 2011

How Does Diabetes Affect the Bladder?

Diabetes is a staggering health burden. There are approximately 26 million Americans with diabetes, and about 79 million who are “prediabetic”. Bladder dysfunction in those with diabetes has been reported in 80% of diabetic individuals. By comparison, neuropathy occurs in about 60% of diabetics, and kidney dysfunction in 50% of diabetics. The effect of diabetes on the bladder can be wide ranging: from underactive bladder (with retained urine that can lead to UTIs), to Overactive Bladder, to urinary incontinence.

Damage from diabetes can occur on various levels: nerve dysfunction, muscle dysfunction, and urothelial (lining of the bladder) dysfunction.

Nerve dysfunction- this is a type of neuropathy, where sensation is lost, meaning, the urge to void is not perceived until the bladder is overfilled, or the nerves that control bladder contraction are weakened leading to less urine expulsion and more retained. This leads to chronic stretch and loss of elasticity. Bladder capacity can increase slowly, like a sinking boat, “taking on water”, till the bladder loses its ability potentially to contract. Mini-strokes or major strokes, brought on by diabetes can exacerbate bladder dysfunction, as the stroke may affect also perception of a full bladder till too late when incontinence may occur, or with sever stroke, bladder retention occurs outright.

Muscle dysfunction- This may be related to neuropathy as described above. Direct damage from diabetes to bladder muscle does not occur, unlike direct nerve damage to axons leading to neuropathy, by impaired nerve signals lead to muscle weakness, poor contraction, poor emptying, chronic stretch, loss of elasticity, thinning of the muscles. The urethra, or bladder opening, can be directed affected, by impaired relaxation/opening when voiding should occur, leading to elevated urinary residual levels. Impaired contraction combined with impaired sensation and perception can lead to urgency, frequency, retained urine, UTIs and incontinence.

Urothelial dysfunction- The inner bladder lining in contact directly with urine is not simply a barrier, but also acts a signaling way station as well between deeper surfaces. Rat models show that in diabetes, the urothelium thickens, releasing certain chemicals that can contribute to overactive bladder symptoms. This bladder overactivity has been reported in 48% of diabetics, and is the most common finding on urodynamics testing, followed by poor muscle contraction in 30%, and poor compliance in 15%.

Diabetics are already more susceptible to developing infections, and elevated bladder urine residuals simply increases this risk. Interestingly, certain types of E coli bacteria adhere more readily to the urothelium of diabetic patients.

So, what is diabetic patient to do? Tight sugar control minimizes the deleterious effects on blood vessels and all organs including the bladder. Timed bathroom trips and “double urinating”, can help empty a bladder that is weak. Fluid management helps prevent over production of urine that may stress the bladder. Consistent hygiene around the genitals helps to reduce the chance of infection. Medications are available that help reduce the tone of the urethra to help bladder emptying, and self catheterization can be used to empty bladders without any function. In addition, Interstim sacral neuomodulation can be attempted in bladders with poor contractile function as well.