Genitourinary and Renal Disorders II: BPH, ED, and Renal Failure

Benign Prostatic Hyperplasia (BPH)

• The prostate is a walnut-sized gland that is a critical component of the male reproductive system.

• It is anatomically positioned in front of the rectum and directly below the urinary bladder.

• The primary roles of the prostate gland include:

  • Providing prostatic fluid into the urethra during the movement of sperm.

  • Forming approximately $30\%$ of semen.

  • Energizing the sperm and neutralizing the acidity of the vaginal canal to facilitate reproduction.

• As men age, it is common for the prostate gland to enlarge, a condition known as benign prostatic hyperplasia (BPH).

BPH Pathophysiology and Progression

• Prostate growth occurs in two distinct main periods during a man's life:

  • The first period occurs early in puberty when the prostate doubles in size.

  • The second period begins around age $25$ and continues for most of the man's life.

• BPH often results from this second growth period years later.

• Symptom manifestation timing:

  • BPH rarely causes noticeable symptoms before the age of $40$.

  • Approximately $50\%$ of men in their $60s$ exhibit symptoms of BPH.

  • As many as $90\%$ of men in their $70s$ and $80s$ experience symptoms related to the condition.

• Mechanical Effects of Enlargement:

  • The enlarging prostate presses against the urethra and the bladder.

  • This pressure causes the bladder to contract even when it contains very little urine, leading to frequent urination.

  • Over time, the bladder weakens and loses the ability to empty urine completely.

  • The combination of strain on the bladder and failure to empty completely can lead to urinary tract infections (UTIs), bladder damage, kidney damage, and incontinence.

Etiology and Theories of BPH Development

• The exact cause of BPH is not well understood, and risk factors remain unclear. Three primary theories explain its development:

  • Theory 1 (Hormonal Balance): Men produce both testosterone and small amounts of estrogen. As men age, testosterone levels decrease, leading to a higher proportion of estrogen. This higher amount of estrogen may promote prostate cell growth.

  • Theory 2 (Dihydrotestosterone Accumulation): Older men continue to produce and accumulate dihydrotestosterone (DHT) in the prostate. High levels of DHT encourage the growth of cells. Evidence for this includes the observation that men who do not produce DHT do not develop BPH.

  • Theory 3 (Cellular Reawakening): Some prostate cells may follow instructions from early embryonic development and "reawaken" later in life. These reawakened cells deliver signals to other cells in the gland, instructing them to grow or making them more sensitive to growth-influencing hormones.

Symptoms and Diagnosis of BPH

• Common symptoms include:

  • Frequent urination.

  • Interrupted or weak urinary stream.

  • Leaking or dribbling of urine.

• Diagnostic Procedures:

  • Rectal Examination: This is typically the first test performed. A clinician inserts a gloved finger into the rectum to feel the prostate to determine its size and condition.

  • Urine Flow Study: The patient urinates into a specialized device that measures the velocity of urine flow. A reduced flow suggests the presence of BPH.

  • Cystoscopy: The penis is numbed, and a small tube is inserted through the urethra. This tube, equipped with a lens and light system, allows the clinician to determine the size of the gland and identify the specific location and degree of the obstruction.

Treatment Options for BPH

• Medication:

  • $5$-Alpha Reductase Inhibitors: Finasteride (Proscar) and Dutasteride (Avodart) inhibit the production of DHT. These drugs can prevent the progression of prostate growth or even shrink the prostate.

  • Alpha Blockers: Terazosin (Hytrin) and Doxazosin (Cardura) relax the smooth muscles of the prostate and the bladder neck. These medications improve urine flow and reduce bladder outlet obstruction.

• Minimally Invasive Therapy:

  • This involves using microwaves and ultrasound waves to heat and destroy excess prostate tissue.

• Surgery:

  • Considered the best long-term solution for BPH.

  • Only the enlarged tissue pressing against the urethra is removed.

  • The goal is to relieve the obstruction and address incomplete bladder emptying.

  • Recovery from surgery can take between a couple of months to $1$ year.

  • Potential post-surgical complications include problems urinating, incontinence, blood in the urine, and reduced sexual activity.

Erectile Dysfunction (ED)

• Erectile Dysfunction is defined as the inability to get or keep an erection firm enough for sexual intercourse. It is considered a symptom rather than a standalone disease.

• Internal Structure of the Penis:

  • The penis contains two chambers called the corpora cavernosa that run its entire length.

  • These chambers are filled with spongy tissue containing smooth muscles, fibrous tissues, spaces, veins, and arteries.

  • The corpora cavernosa are surrounded by a membrane called the tunica albuginea.

  • The urethra, the channel for urine and ejaculate, runs along the underside of the corpora cavernosa and is surrounded by the corpus spongiosum.

• Mechanism of Erection:

  • An erection begins with sensory and/or mental stimulation.

  • Impulses from the brain and local nerves cause the smooth muscles of the corpora cavernosa to relax.

  • This relaxation allows blood to flow through the arteries and fill the spaces in the spongy tissue.

  • Bood creates pressure in the corpora cavernosa, causing the penis to expand.

  • The tunica albuginea helps trap the blood within the corpora cavernosa to sustain the erection.

  • The erection ends when penile muscles contract to stop the inflow of blood and open the veins for blood outflow.

Pathophysiology and Causes of ED

• ED occurs when the precise sequence of nerve impulses (brain, spinal column, area around the penis) and muscle/vascular responses is disrupted.

• Contributing Factors:

  1. Diseases: Diabetes, high blood pressure, nerve disease or damage, Multiple Sclerosis (MS), atherosclerosis, and heart disease affect the nerves, arteries, and tissues necessary for an erection.

  2. Lifestyle: Smoking, alcohol consumption, being excessively overweight, and lack of exercise contribute to vascular problems and heart disease.

  3. Surgery: Procedures for prostate or bladder cancer can injure the nerves and arteries near the penis.

  4. Medications: Side effects from common drugs including blood pressure medications, antihistamines, antidepressants, appetite suppressants, and the ulcer drug cimetidine.

  5. Psychological Factors: Stress, anxiety, depression, low self-esteem, and fear of sexual failure.

  6. Hormonal Abnormalities: Low levels of testosterone.

Diagnosis and Treatment of ED

• Diagnosis involves a patient medical history, physical examination, and laboratory tests.

• Treatment (from least to most invasive):

  • Lifestyle changes.

  • Replacing medications that cause ED side effects.

  • Psychotherapy for psychological causes.

  • Oral Medications: Sildenafil (Viagra), Vardenafil hydrochloride (Levitra), and Tadalafil (Cialis). These are phosphodiesterase (PDE) inhibitors that enhance the effects of nitric oxide to relax smooth muscles and increase blood flow.

  • Injectable Medications: Drugs injected into the penis to cause vasodilation and blood engorgement. Side effects include aching in the penis/testicles, burning in the urethra, redness, minor bleeding, or priapism (a persistent, painful erection).

  • Surgery (Most invasive): Implantation of a device to cause erection, reconstruction of arteries to increase flow, or blocking veins that allow blood to leak from penile tissues.

Renal Failure

• The kidneys are glands located in the abdominal region above the pelvis on both sides of the body.

• Key functions of the kidneys include:

  • Filtering excess water and waste from the bloodstream.

  • Producing urine to flush away toxins.

  • Maintaining a critical balance of fluids and electrolytes in the body.

• Renal failure is a serious condition where the kidneys are unable to filter waste, produce urine, or maintain fluid balance, often following cellular death. Left untreated, the buildup of toxins can affect the brain and heart and may be fatal.

Types and Symptoms of Renal Failure

• Acute Renal Failure: A sudden onset caused by underlying problems like dehydration, injury to the kidney, or overuse of pain medications such as Tylenol (acetaminophen) or Advil (ibuprofen).

• Chronic Renal Failure: A progressive and more serious condition resulting from long-term diseases like diabetes and hypertension.

• The condition may initially be asymptomatic, with symptoms appearing slowly as urea levels in the blood rise (uremia).

• Systemic Effects and Symptoms:

  • Encephalopathy (brain dysfunction).

  • Pericarditis (inflammation of the heart lining).

  • Decreased muscle function.

  • Anemia: Failing kidneys produce less erythropoietin, the hormone required to stimulate bone marrow for Red Blood Cell (RBC) production. Fewer RBCs mean less oxygen is carried, leading to general tiredness.

  • Acidosis: With less oxygen, cells use anaerobic metabolism, increasing acid production. Lungs may attempt to compensate through hyperventilation to blow off $CO_2$ (carbon dioxide).

  • Edema: Fluid deposits in tissues or organs like the lungs, affecting breathing.

  • Reduced urine output and increased thirst.

Diagnosis and Management of Renal Failure

• Diagnostic Testing:

  • Chemical testing for Blood Urea Nitrogen (BUN), creatinine, and Glomerular Filtration Rate (GFR) to measure waste buildup. GFR specifically measures the rate at which blood is filtered.

  • Protein level testing; protein in the urine indicates kidney damage.

  • Measurement of electrolyte concentrations in the blood and urine.

• Treatment and Management:

  1. Prevention: Managing diabetes and high blood pressure.

  2. Dietary Restrictions: Limiting intake of potassium (which can cause heart problems, found in bananas and apricots) and phosphorus (which can cause bone problems, found in milk and cheese).

  3. Medication:

     • Phosphorus-lowering medications.

     • Erythropoietin or darbepoetin (Aranesp) to stimulate RBC production.

     • Iron supplements for RBC production.

  4. Dialysis: When kidneys fail completely, dialysis is the only option other than kidney transplantation.