Prostate gland enlargement become a serious problem when it severely interferes with your ability to empty your bladder. If this is the case, you will need surgery.

Complications of enlarged prostate include acute urinary retention. Acute urinary retention is a sudden, painful inability to urinate. This may occur after you have taken an over-the-counter decongestant medication for allergies or a cold.

When you are unable to urinate at all, your doctor may thread a tube (catheter) through your urethra into your bladder. Or, your doctor may put in a suprapubic tube — a catheter that drains your bladder through the lower abdomen. The type of catheter you need will depend on your particular circumstances. Some men with an enlarged prostate require surgery or other procedures to relieve urinary retention.
Urinary tract infections (UTIs): Some men with an enlarged prostate end up having surgery to remove part of the prostate to prevent frequent urinary tract infections.

Bladder stones- These are mineral deposits that can cause infection, bladder irritation, blood in the urine and obstruction of urine flow and are generally caused by the inability to completely empty the bladder. Bladder damage… This occurs when the bladder hasn’t emptied completely over a long period of time. The muscular wall of the bladder stretches and weakens and no longer contracts properly. Often, symptoms of bladder damage improve after prostate surgery or other treatment, but not always.

Kidney damage…is caused by high pressure in the bladder due to urinary retention. This high pressure can directly damage the kidneys or allow bladder infections to reach the kidneys. When an enlarged prostate causes obstruction of the kidneys, a condition called hydronephrosis — a swelling of the urine-collecting structures in one or both kidneys — may result. Most men with an enlarged prostate don’t develop these complications. However, acute urinary retention and kidney damage in particular can be serious health threats when they do occur.