Question

Explain how the different causes of incontinence could be treated by (a) surgery, (b) a drug that blocks specific muscarinic ACH receptors, and (c) a drug that blocks the action of testosterone (by inhibiting its conversion to dihydrotestosterone; see chapter 20 ).

Short answer

Incontinence can be treated through various methods such as surgery, antimuscarinic drugs, and drugs that block the action of testosterone. Surgical treatments, like placing a sling around the urethra or sacral nerve stimulation, can address physical issues contributing to incontinence. Antimuscarinic medications block the action of acetylcholine at muscarinic receptors in the bladder, reducing the frequency and intensity of bladder muscle contractions, which can help with overactive bladder or urge incontinence. Drugs that block the action of testosterone, like 5-alpha reductase inhibitors, can help shrink an enlarged prostate, alleviating symptoms of incontinence due to bladder obstruction or increased pressure on the urethra. A combination of these treatments may be necessary depending on the specific cause of incontinence.

Step-by-step solution

Different causes of incontinence

Incontinence is a condition where an individual cannot control their urine or bowel movements. There are several causes of incontinence, which include stress incontinence, urge incontinence, functional incontinence, overflow incontinence, and mixed incontinence.

(a) Treatment by Surgery

Surgery can help treat incontinence by addressing the physical issues contributing to the condition. For example: 1. Stress incontinence: Surgery might involve the placement of a sling around the urethra to support it and prevent urine leakage during activities that increase abdominal pressure, such as coughing or exercise. 2. Urge incontinence: Sacral nerve stimulation, which involves implanting a device under the skin to stimulate the sacral nerves, may help control bladder contractions and alleviate symptoms of urge incontinence. 3. Overflow incontinence: Surgical procedures to remove obstructions or correct problems with the urinary tract can help treat overflow incontinence caused by issues like an enlarged prostate or bladder stones.

(b) Treatment by Drug Blocking Specific Muscarinic ACH Receptors

Antimuscarinic medications or anticholinergic drugs can help treat incontinence by blocking the action of acetylcholine at the muscarinic receptors in the bladder. This reduces the frequency and intensity of bladder muscle contractions, leading to fewer instances of urine leakage caused by overactive bladder or urge incontinence. Common antimuscarinic drugs include oxybutynin, tolterodine, and solifenacin.

(c) Treatment by Drug Blocking the Action of Testosterone

Drugs that block the action of testosterone, such as 5-alpha reductase inhibitors, can be helpful in treating incontinence in some cases, particularly for men. By inhibiting the conversion of testosterone to dihydrotestosterone (DHT), these drugs can help shrink an enlarged prostate, which may be causing symptoms of incontinence due to bladder obstruction or increased pressure on the urethra. Examples of 5-alpha reductase inhibitors include finasteride and dutasteride. In summary, the different causes of incontinence can be treated by various methods including surgery, antimuscarinic drugs, and drugs that block the action of testosterone. Depending on the specific cause, a combination of these treatments may be necessary to effectively manage incontinence symptoms.

Key concepts

Surgical Treatment for Incontinence

Surgical treatment for urinary incontinence is tailored to address the underlying physical causes of the condition. It aims to correct anatomical issues and support the structures involved in maintaining continence. There are several surgical options available depending on the type of incontinence:

• Stress Incontinence: Surgery often involves procedures such as the placement of a sling or mesh to support the urethra. This helps prevent urine leaks during physical activities that increase abdominal pressure, like coughing or lifting.


• Urge Incontinence: Sacral nerve stimulation is a more advanced surgical option. This technique involves placing a small device under the skin, which sends electrical impulses to the nerves controlling the bladder, potentially reducing the frequency and urgency of urination.


• Overflow Incontinence: Surgical procedures may aim to remove any obstructions in the urinary tract. This could involve surgery to treat an enlarged prostate or to remove bladder stones, helping to alleviate pressure and restore normal urinary flow.

These surgical interventions can significantly improve the quality of life for patients, but they are often considered when other conservative treatments have failed.

Antimuscarinic Drugs

Antimuscarinic drugs, also known as anticholinergic medications, play a crucial role in managing urge incontinence and overactive bladder conditions. These drugs function by blocking muscarinic receptors in the bladder wall. Here's how they work:

• When acetylcholine, a neurotransmitter, interacts with muscarinic receptors, it causes bladder muscles to contract. This can lead to unexpected bladder contractions and urine leakage.


• By blocking these receptors, antimuscarinic drugs reduce the frequency and strength of bladder contractions, allowing for better control over urination.

Common antimuscarinic drugs include:

• Oxybutynin: Often prescribed to decrease muscle spasms of the bladder and urinary tract.
• Tolterodine: Helps relax bladder muscles, reducing symptoms of both urgency and frequency.
• Solifenacin: Specifically designed to target bladder smooth muscle, offering targeted relief from overactive bladder symptoms.

While effective, these medications may have side effects such as dry mouth, constipation, and blurred vision, so they must be used under a healthcare provider's supervision.

5-Alpha Reductase Inhibitors

5-alpha reductase inhibitors are a class of medications primarily used in men to address urinary issues related to an enlarged prostate, medically known as benign prostatic hyperplasia (BPH). These drugs target the testosterone conversion process:

• Mechanism of Action: 5-alpha reductase enzymes convert testosterone into dihydrotestosterone (DHT), a hormone that can enlarge the prostate. By inhibiting this enzyme, the drugs decrease DHT levels, leading to prostate shrinkage over time.


• Impact on Incontinence: For men experiencing overflow incontinence or urinary retention due to an enlarged prostate, these inhibitors can relieve obstruction and improve urine flow by shrinking the prostate.

Examples of commonly used 5-alpha reductase inhibitors include:

• Finasteride: Used for its ability to gradually reduce prostate volume, improving symptoms over several months.
• Dutasteride: Similar to finasteride but may affect more types of 5-alpha reductase enzymes, potentially offering broader effectiveness.

Although beneficial, these medications may take months to show significant results, and users might experience side effects such as reduced libido or erectile dysfunction. Therefore, they should be used in consultation with a healthcare professional.