Urinary retention is a clinical manifestation of BPH, characterized by increased obstruction up to a certain level, inability to empty the bladder of all urine during urination, and the appearance of bladder residual urine. The BPH is a disease in which the prostate enlarges in size, destroys the normal structure and causes a series of dysfunctions due to different degrees of glandular and/or fibrous and muscular tissue hyperplasia caused by disorders of sex hormone metabolism in the elderly. 1, physical examination: If the patient is weak, pale, drowsy, high blood pressure, fast pulse, deep breathing should be thought of the possibility of uremia. Abdominal examination may reveal enlarged kidneys with spinal rib angle pressure pain, indicating that secondary hydronephrosis has developed. The suprapubic area should be examined for an engorged bladder, and a smooth, soft, nodular bladder surface for urinary retention. Patients with a long history must be noted for comorbid cancer, hemorrhoids, stricture of the prepuce, and normal urethra. Rectal palpation: Firstly, the anal canal sphincter tone is understood, and neurogenic bladder should be thought of with a flaccid anal canal. The prostate enlarges, the middle groove disappears, the surface is smooth, and the hyperplastic nodules seen histologically are generally free of nodular changes on finger palpation because of the pseudo-envelope formed by the outer peripheral band. The enlargement of the prostate can be asymmetrical on both sides, and if the enlarged portion protrudes into the bladder, rectal palpation may not reach the upper edge of the prostate. The texture of the prostate can be soft or hard, depending on the proportion of glandular components and fibrous smooth muscle. If the prostate is irregularly enlarged, nodular or even hard as a stone, the possibility of prostate cancer should be thought of. The physical examination should monitor whether the reflexes of the bulbocavernosus muscle, lower limb movement and perception are normal to detect possible neuropathy. 2. Blood and urine tests should be performed to assess the patient’s kidney function and to rule out the possibility of urinary tract infection. Because infections in any part of the male reproductive or urinary system can cause difficulty in urination, some symptoms of BPH resemble prostatitis and can easily lead to misdiagnosis. 3.Ultrasound examination (also used for prostate cancer diagnosis) can monitor the size of the prostate for the patient. In addition, with a pressure-sensitive sensing device, the doctor can measure the force of the urine flow when the patient strains to urinate. A decrease in the force of the urine flow often indicates the possibility of BPH in the patient. 4. Nephrography (intravenous injection of contrast followed by urological x-ray) is mainly used for the diagnosis of kidney and ureteral disease, although it also has some diagnostic value for BPH. Through pyelogram, the doctor can detect any blockage or abnormal strictures in the patient’s entire urinary tract. Urethral strictures at the level of the prostate will be highly suggestive of the possible presence of BPH. 5. Through cystoscopy we can directly detect strictures or blockages in the patient’s urethra. Before performing a cystoscopy, we should first inject an amount of anesthetic into the urethra through the urethral orifice and then insert a probe equipped with a search light into the patient’s urethra so that we can search for the stricture in the patient’s urethra through the monitor. Reduction in bladder volume: Bladder volume is the amount of urine in the bladder when there is an urge to urinate and an urgent need to urinate. Under normal circumstances, the amount of urine expelled at one time is the bladder capacity. Residual urine is the amount of residual urine that is not expelled from the bladder after urination. When there is residual urine, the amount of urine expelled is not equal to the bladder capacity. In this case, bladder capacity = the amount of urine expelled at one time and the amount of residual urine. The capacity of a normal bladder is about 400m1. In inflammatory bladder disease, the bladder capacity is below 200m1. In tuberculous bladder, the volume can be as small as 10m1. Incomplete bladder emptying: When the bladder is full in a normal adult male, the volume is about 250ml; in a female, it is about 300ml; the residual urine after urination should be less than 10%. If the urinary function is abnormal, resulting in excessive residual urine, or even complete inability to urinate, then urinary retention is considered. Depending on the urgency of the symptoms, it can be divided into acute and chronic urinary retention. There are symptoms of incomplete urination. Acute urinary retention: Sudden complete inability to urinate, bladder enlarges and must be catheterized immediately. For example, if a woman has occasional urinary retention after childbirth, a urinary catheter can be left in place for one to two weeks. In patients with benign prostatic hyperplasia, it is already difficult to urinate, and if you take medications that affect bladder contraction (such as antihistamines used for colds and nasal congestion), it may cause the bladder to go on strike. Some patients also suffer from blocked nerve pathways, such as a stroke or injury to the cremaster. Once symptoms such as increased nocturia are detected, it is important to visit a regular urology department in a state-run hospital with a urological specialty and undergo relevant tests; once the diagnosis is confirmed, a professional urologist will need to follow formal treatment principles and develop a treatment plan that is appropriate for the patient’s specific situation.