What causes difficulty passing urine?

You may notice a slow or weak stream, a delay before urine starts, straining, stopping and starting, or a feeling that the bladder has not emptied. Benign prostatic hyperplasia is a common presentation of difficulty passing urine in people with a prostate, because an enlarged prostate can press on the urethra. Prostatitis can cause difficulty along with pelvic discomfort, burning, fever, or pain during ejaculation. A urinary tract infection may irritate the urinary passage, while a kidney stone can obstruct flow and cause severe side or groin pain. Less commonly, bladder or prostate cancer can affect urinary function; difficulty passing urine alone does not identify cancer.

Some medicines, constipation, previous urinary procedures, and nerve conditions can also interfere with bladder contraction or relaxation. The pattern, speed of onset, pain, fever, blood in urine, and your medicines help a clinician identify the likely cause.

Arrange a medical assessment if the problem is new, persistent, or getting worse. A clinician may ask about your stream, urgency, pain, bowel symptoms, medicines, and previous prostate or urinary problems. Testing can include an examination, urine testing, blood tests, or checking how much urine remains after you try to empty your bladder. Do not stop prescribed medicines without advice, and avoid repeatedly straining to force urine out. Note when symptoms occur and whether you have fever, blood, pain, or leakage.

Seek urgent medical care if you cannot pass urine, especially with lower abdominal swelling or severe discomfort. Prompt assessment is also needed for fever or chills with urinary difficulty, severe side or back pain, vomiting, visible blood in urine, confusion, or new weakness or numbness. Complete blockage can overstretch the bladder and may affect the kidneys, so do not wait for it to resolve on its own.

Could a prostate, infection, stone, medicine, or nerve problem explain my symptoms? Do I need a urine test or a bladder scan? What changes should make me seek urgent help?