Sudden urgent need to pee: causes, red flags and when to get it checked

The bladder normally stores urine quietly until you choose to go. In urgency, the bladder muscle contracts at the wrong time, or the nerves signalling fullness are over-sensitive. Irritants such as infection, stones, caffeine or inflammation can provoke this.

• Overactive bladder: urgency, frequency and sometimes urge incontinence without infection.

• Urinary tract infection: urgency with burning pain, cloudy or smelly urine and sometimes fever.

• Caffeine, alcohol, fizzy drinks, artificial sweeteners and high fluid intake.

• Menopause and vaginal atrophy, with urgency, recurrent infections and discomfort.

• Enlarged prostate in men, with urgency alongside weak stream and nocturia.

• Constipation and pelvic floor problems.

• Diabetes, medicines such as diuretics, and neurological conditions such as multiple sclerosis, Parkinson disease or stroke.

• Bladder stones, interstitial cystitis (bladder pain syndrome) and bladder cancer, which are less common but important.

Blood in the urine, bladder or pelvic pain, incomplete emptying or retention, repeated infections, new bowel and bladder symptoms with back pain or leg weakness, unexplained weight loss, a history of pelvic radiotherapy or a smoking history warrant further tests.

• Call 999 or go to A&E: new loss of bladder and bowel control with back pain and numbness between the legs, or inability to pass urine with pain.

• Same-day GP: urgency with fever, loin pain or blood in urine.

• GP within weeks: urgency persisting over a few weeks despite simple measures.

• Routine: urgency linked to a high caffeine or fluid intake.

The doctor asks about onset, frequency, leakage, nocturia, fluid and caffeine intake, pain, blood, bowel habit, pregnancy and childbirth history, menopause, medicines and neurological symptoms. They examine the abdomen and in women the pelvic floor, in men the prostate.

• Urine dipstick and culture: to look for infection or blood.

• Blood tests: glucose or HbA1c and kidney function.

• Bladder diary: to see the pattern, volumes and triggers.

• Ultrasound with post-void residual: to check emptying.

• Cystoscopy or urodynamics: in selected people with persistent or complicated symptoms.

Bladder training, gradually extending the time between toilet visits, is the first-line treatment. Reduce caffeine, alcohol and fizzy drinks, avoid drinking too much or too little, treat constipation, lose excess weight, and do pelvic floor exercises. Vaginal oestrogen helps menopausal changes in suitable women. Medicines and nerve stimulation treatments are available if lifestyle measures are not enough.

The NHS route is a GP and continence service, with urology or urogynaecology for persistent cases. Private urology and urogynaecology clinics offer urodynamics and treatments such as botulinum toxin.