Benign prostatic hyperplasia diagnosis and treatment guide I. The basics of benign prostatic hyperplasia. (a) Definition Benign prostatic hyperplasia is one of the most common benign diseases causing urinary disorders in middle-aged and elderly men. The main manifestations are histological hyperplasia of the interstitial and glandular components of the prostate, anatomical enlargement of the prostate, clinical symptoms dominated by lower urinary tract symptoms, and urodynamic obstruction of the bladder outlet. (ii) EpidemiologyThe incidence of histologic BPH increases with age, usually occurring initially after the age of 40 years [2], to >50% by the age of 60 years and up to 83% by the age of 80 years. Similar to the histologic presentation, symptoms such as dyspareunia increase with age. Approximately 50% of men with histologically diagnosed BPH have moderate to severe lower urinary tract symptoms. Some studies have shown that it appears that Asians are more prone to moderate-to-severe BPH-related symptoms than Americans. (iii) Etiology Two important conditions must be present for the development of BPH: increasing age and functioning testes. Domestic scholars investigated 26 elderly eunuchs of the Qing Dynasty and found that the prostate had become completely inaccessible or significantly atrophied in 21 of them [5]. However, the specific mechanism by which BPH occurs is unclear and may be caused by a balanced disruption of epithelial and mesenchymal cell proliferation and apoptosis. Associated factors are: androgens and their interaction with estrogens, interaction of prostatic mesenchymal a glandular epithelial cells, growth factors, inflammatory cells, neurotransmitters and genetic factors. (iv) Pathology McNeal divided the prostate into peripheral zone, central zone, migratory zone and periurethral glandular area. All BPH nodules occur in the migratory zone and periurethral glandular region [1]. Early nodules in the periurethral glandular region are exclusively mesenchymal in composition; whereas early nodules in the migratory zone show mainly hyperplasia of glandular tissue with a relative decrease in the amount of mesenchyme. Smooth muscle in the interstitial tissue is also an important component of the prostate. These smooth muscles and the periurethral tissue of the prostate are innervated by adrenergic nerves, cholinergic nerves, or other enzymatic transmitters, with the adrenergic nerves playing a major role. There are abundant G receptors, especially αl receptors, in the prostate and bladder neck [6-7], and activation of this adrenergic receptor can significantly increase prostatic urethral resistance. The anatomical envelope of the prostate and lower urinary tract symptoms are closely related. Due to the presence of this envelope, the hyperplastic gland is compressed and bulges out into the urethra and bladder thereby increasing urinary tract obstruction. After prostate enlargement, the enlarged nodules compress the rest of the gland to form a “surgical envelope” with a clear demarcation between the two. The prostate gland can still be detected by post-operative rectal examination and imaging after surgical removal of the hyperplastic part, leaving the compressed gland. (E) Pathophysiological changes of prostatic hyperplasia lead to lengthening of the posterior urethra, pressure deformation, narrowing and increased urethral resistance, causing bladder hypertension and related symptoms during voiding. With the increase of bladder pressure, compensatory hypertrophy of the bladder forcing muscle occurs and instability of the forcing muscle and causes symptoms related to the urinary storage phase. If the obstruction is not relieved for a long time, the forceps muscle loses its compensatory capacity. The main causes of upper urinary tract changes secondary to BPH, such as hydronephrosis and renal impairment, are urinary retention due to bladder hypertension and ureteral reflux. (F) Clinical manifestations, diagnosis and treatment BPH mainly presents clinically with bladder irritation symptoms, obstructive symptoms and related comorbidities. Various symptoms may appear sequentially or develop progressively throughout the course of the disease. The diagnosis is based on symptoms, physical examination, especially rectal examination, imaging, urodynamic examination and endoscopy, etc. The treatment of BPH mainly includes observation and waiting, pharmacological treatment, minimally invasive treatment and surgical treatment. The aim of treatment is to improve the quality of life of patients while protecting renal function. The choice of specific treatment methods should be based on the severity of the patient’s symptoms, combined with various auxiliary examinations, local medical conditions and patient compliance.