Benign Prostatic Hyperplasia (BPH): This is the most common cause of urine retention in men, especially those over the age of 50. The enlarged prostate gland can compress the urethra, leading to obstruction of urine flow.

Urinary Tract Infections (UTIs): Especially in women, UTIs can cause irritation and inflammation of the bladder and urethra, leading to urine retention.
Neurogenic Bladder: Conditions such as diabetes, stroke, or spinal cord injuries can damage the nerves that control bladder function, resulting in urine retention.
Medication Side Effects: Certain medications, such as anticholinergics, antihistamines, and decongestants, can cause urine retention as a side effect.
Constipation: Severe constipation can put pressure on the urethra, leading to urine retention.

Spinal Cord Compression: A serious condition that requires immediate attention, spinal cord compression can cause urine retention due to nerve damage.
Cauda Equina Syndrome: A rare but serious condition where the nerves in the lower spine are compressed, leading to urine retention, among other symptoms.
Post-Renal Transplantation Complications: In patients who have undergone kidney transplantation, urine retention can be a sign of a serious complication, such as ureteral obstruction or rejection.

Bladder Neck Contracture: A rare condition where the bladder neck becomes scarred and narrowed, causing urine retention.
Urethral Stricture: A rare condition where the urethra becomes narrowed due to scarring, leading to urine retention.
Multiple Sclerosis: A chronic condition that can cause nerve damage, leading to urine retention in some cases.
Rabdomyolysis: A rare condition where muscle breakdown leads to the release of toxins, which can cause urine retention.