Saturday, May 6, 2017

Benign Prostatic Hyperplasia



Introduction
Although most men older than age 50 have some prostatic enlargement, with benign prostatic hyperplasia (BPH), the prostate gland enlarges sufficiently to compress the urethra and cause some overt urinary obstruction. Depending on the size of the enlarged prostate, the age and health of the patient, and the extent of obstruction, BPH is treated symptomatically or surgically.

Causes
Recent evidence suggests a link between BPH and hormonal activity. As men age, production of androgenic hormones decreases, causing an imbalance in androgen and estrogen levels and high levels of dihydrotestosterone, the main prostatic intracellular androgen. Other causes include neoplasm, arteriosclerosis, inflammation, and metabolic or nutritional disturbances.
Whatever the cause, BPH begins with changes in periurethral glandular tissue. As the prostate enlarges, it may extend into the bladder and obstruct urinary outflow by compressing or distorting the prostatic urethra. BPH may also cause a pouch to form in the bladder that retains urine when the rest of the bladder empties. This retained urine may lead to calculus formation or cystitis.

Signs and symptomsSigns and symptoms of BPH depend on the extent of prostatic enlargement and the lobes affected.

Urinary symptoms
Characteristically, the condition starts with a group of symptoms known as prostatism: reduced urinary stream caliber and force, difficulty starting micturition (straining), feeling of incomplete voiding and, occasionally, urine retention. As obstruction increases, urination becomes more frequent, with nocturia, incontinence and, possibly, hematuria.
Physical examination reveals a visible midline mass (distended bladder) that represents an incompletely emptied bladder; rectal palpation discloses an enlarged prostate. The examination may also detect secondary anemia and, possibly, renal insufficiency secondary to obstruction.

Later effects
As BPH worsens, complete urinary obstruction may follow infection. Complications include infection, renal insufficiency, hemorrhage, and shock.

Diagnosis
Signs and symptoms and a rectal examination are usually sufficient for a diagnosis. Other test findings help to confirm it.
  • Excretory urography may indicate urinary tract obstruction, hydronephrosis, calculi or tumors, and filling and emptying defects in the bladder.
  • Elevated blood urea nitrogen and serum creatinine levels suggest impaired renal function.
  • Urinalysis and urine culture show hematuria, pyuria and, when the bacterial count exceeds 100,000/┬Ál, urinary tract infection.
  • With severe symptoms, a cystourethroscopy is definitive, but this test is performed only immediately before surgery to help determine the best procedure. It can show prostate enlargement, bladder wall changes, and a raised bladder.
Treatment
Treatment depends on the cause, severity of the obstruction and the status of the patient. 

Conservative therapy includes prostate massages, sitz baths, fluid restriction for bladder distention, and an antimicrobial for infection. Regular ejaculation may help relieve prostatic congestion.
Pharmacological measures: Urine flow rates can be improved with alpha-adrenergic blockers, such as terazosin, tamsulosin, and prazosin. These drugs relieve bladder outlet obstruction by preventing contractions of the prostatic capsule and bladder neck. Finasteride may also reduce the size of the prostate in some patients.

Surgery is the only effective therapy to relieve acute urine retention, hydronephrosis, severe hematuria, recurrent urinary tract infections, and other intolerable signs and symptoms.
A transurethral resection may be performed if the prostate weighs less than 2 oz (57.2 g). In this procedure, a resectoscope removes tissue with a wire loop and electric current. In high-risk patients, continuous drainage with an indwelling urinary catheter alleviates urine retention.
Alternatively, large prostates can be removed by one of two surgical approaches:
  • suprapubic (transvesical) resection: most common and useful when prostatic enlargement remains within the bladder
  • retropubic (extravesical) resection: allows direct visualization; potency and continence are usually maintained.
Balloon dilatation of the prostate is ineffective. Transurethral microwaves (heat therapy) are now being used in some patients. Their efficacy lies between that of the use of an alpha1-adrenergic blocker and surgery.

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