Original ArticlesBenign prostatic hyperplasia: an overview
Section snippets
Epidemiology
Potential risk factors for BPH include age, race, ethnicity, family history, cigarette smoking, and chronic disease (hypertension, coronary artery disease, and diabetes mellitus), although the literature on risk factors is sparse. The incidence of BPH increases with increasing age, especially after the fifth decade2, 3 as noted above, and is highest in African Americans and lowest in native Japanese. However, the incidence in Japanese and Chinese is increased in immigrant populations in Western
Etiology
The causative factors of BPH in man have been intensively studied and several theories suggested. In general, the 2 most important factors are aging and the presence of functional testes. These factors are the key to development of BPH, although they appear to be nonspecific.11
The prostate consists of a network of glandular elements embedded in stroma, with androgen being the most important factor for prostatic growth. Free plasma testosterone enters prostatic cells, where at least 90% is
Pathophysiology and clinical manifestations
The anatomic location of the prostate at the bladder neck enveloping the urethra plays an important role in the pathophysiology of BPH, but it is known that the severity of obstructive voiding symptoms is not correlated only with the size of the prostate. Two prostatic components play a role in bladder outlet obstruction (BOO) and development of lower urinary tract symptoms: dynamic and static.
The static component of BPH is related to increased prostate tissue mass. Progressive nodular
Alpha-adrenergic receptor subtypes
Caine et al.25 first reported in 1975 using in vitro pharmacologic studies that there is a predominance of α1 receptors in the human prostate. Receptor autoradiography showed α1 to α2 ratio of 3.9:1. The α2-adrenoreceptors are mainly localized to the epithelium and blood vessels.26 It is therefore concluded that the principal control of the prostate is via the action of α1 receptors, which are mainly localized within the stromal compartment of the prostate. These results provide the scientific
Diagnosis
A detailed medical history, including symptom assessment using the American Urological Association symptom score, a physical examination, and laboratory tests (urinalysis, kidney function tests, and possibly prostate-specific antigen [PSA] measurement) is all that is needed to diagnose BPH and rule out other diagnoses. A history of prior instrumentation, prostatic surgery, trauma, or urethritis may suggest urethral stricture. Pain in the bladder or penis may indicate the presence of a bladder
Treatment
Men with moderate symptoms of BPH are the best candidates for medical treatment, whereas surgery is usually indicated for patients with severe symptoms. Men with mild symptoms may be followed by watchful waiting as they do not usually need treatment. However, sometimes there is a dissociation between symptomatic and urodynamic improvement. Treatment modalities are summarized in Table I
Conclusions
BPH is a disease that affects millions of men. As life expectancy increases, more and more men will seek treatment for obstructive lower urinary tract symptoms. Therefore, urologists face the challenge of finding better ways to improve the quality of life of these patients and relieve their symptoms. To this end, better understanding of the etiology and epidemiology of BPH is needed. Also, minimally invasive therapies need to be studied further and compared to the gold standard.
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