Acute abdominal pain: causes, red flags and when to seek help

Acute abdominal pain is the label doctors use for tummy pain of recent onset. It can range from a nagging ache that began after lunch to a sudden, doubling-over pain that arrives in minutes. The word acute describes timing, not severity, so a mild but new pain still counts.

The abdomen holds the stomach, bowel, liver, gallbladder, pancreas, kidneys, bladder and, in women, the womb and ovaries. Pain can come from any of them, or from the abdominal wall itself. Because the organs sit close together, the pain is rarely a perfect map. What helps most is where the pain started, where it travelled, what it feels like, and what else is happening at the same time.

A clinician will usually sort the cause into one of three buckets: self-limiting problems that need only time and fluids, problems that need a scan or specialist but not an operation tonight, and problems that need surgery or intensive treatment urgently. The aim of the early assessment is to find out which bucket you are in.

The NHS stomach ache page pairs everyday patterns with their usual explanation, and the same logic is how most clinicians start. The table below follows that approach and adds the conditions the NHS lists as less common.

Appendicitis is swelling and infection of the appendix, and the NHS describes it as needing urgent hospital treatment. The pain typically starts in the middle of the abdomen around the belly button and, after a few hours, settles in the lower right side, getting worse when you move, cough or press on it. Some people feel it slightly better with the knees drawn up. If the appendix bursts, the pain can briefly ease and then return as severe pain across the whole abdomen.

Gallstones are very common and often silent. They become painful when a stone blocks a bile duct, causing pain in the middle of the tummy or under the right ribs that can be severe, constant, and last longer than 30 minutes. The NHS lists sudden severe pain, pain spreading to the back with vomiting, a very high temperature or shivering, and yellow skin or eyes as reasons for 999 or A&E.

Other causes that tend to need prompt hospital assessment include a bleeding stomach ulcer or one that has perforated, inflamed pancreas, obstructed or twisted bowel, inflamed or infected diverticula, infected kidney with a blocked stone, and, in a woman who could be pregnant, an ectopic pregnancy.

The NHS separates stomach ache into two levels of urgency. The lists below reproduce what its stomach ache page says, so that you can match your own symptoms to the right route.

• Call 999 or go to A&E if the pain came on very suddenly or is severe, or if it hurts when you touch your tummy.

• Call 999 or go to A&E if you are vomiting blood or the vomit looks like ground coffee.

• Call 999 or go to A&E if your stool is bloody, or black, sticky and extremely smelly.

• Call 999 or go to A&E if you cannot pass urine, or cannot poo or pass wind.

• Call 999 or go to A&E if you have chest pain, cannot breathe, or have diabetes and are vomiting; also if someone has collapsed.

• Ask for an urgent GP appointment or contact NHS 111 if the pain is getting much worse, does not go away or keeps coming back, or you have bloating that persists.

• Seek urgent advice too if you have trouble swallowing food, are pregnant, are losing weight without trying, suddenly pass urine more or less often, find peeing suddenly painful, bleed from the bottom, have unusual vaginal bleeding or discharge, or diarrhoea that has not eased after a few days.

• Do not drive yourself to A&E; ask someone else to drive or call 999 and bring your medicines.

Expect questions about when the pain began, exactly where it started, whether it has moved, and how it behaves with eating, movement, coughing or passing a stool. Doctors ask whether it is constant or comes in waves, whether you have vomited and what the vomit looked like, whether your bowels have opened and passed wind, and whether there is a change in urine. They also ask about your periods and the chance of pregnancy, recent travel or unusual food, previous operations (which can cause adhesions), medicines such as anti-inflammatory painkillers, alcohol, and any family history of bowel disease.

On examination a doctor will look at your general condition, temperature, pulse and blood pressure and then feel the tummy gently, checking for tenderness, swelling and whether pressing causes pain that is worse on release or tensing of the muscles. These signs help separate simple cramping from inflammation of the lining of the abdominal cavity. A rectal or pelvic examination may be offered when relevant.

Not everyone needs tests. A mild illness with a clear cause may be managed on history and examination alone. When tests are needed, those the NHS pages list include blood tests, a urine sample, an ultrasound scan or a CT scan to look for swelling, and a pregnancy test if pregnancy is possible. For gallstones the NHS names ultrasound and blood tests, and for stomach ulcers it names a breath test for H pylori, a stool sample, blood tests and sometimes gastroscopy.

Because there is no single test that always shows appendicitis, doctors may decide to observe you in hospital for a few hours to see how symptoms evolve, as the NHS explains, or proceed directly to surgery if the picture is clear.

For pain that is mild, fits a known pattern such as constipation or a stomach bug, and has none of the red flags above, the NHS suggests speaking to a pharmacist about the likely cause, which treatments might help, and medicines for constipation or indigestion. Small sips of fluid, rest and a bland diet are usual.

Avoid taking strong painkillers or laxatives if severe pain is building: they can mask a developing problem and may interfere with assessment. If pain worsens, spreads, or one of the signs in the red flag list appears, change your plan and seek urgent help rather than waiting for the next day.

Mild, short-lived pain is usually handled by a pharmacist or GP. Urgent pain goes through NHS 111 or an urgent GP slot, and severe or sudden pain through 999 or A&E, where surgeons, radiologists and anaesthetists work together. A hospital admission may lead to a surgical review within hours.

Recurring or persistent tummy pain without an emergency feature is often investigated through the GP, who may arrange blood tests, stool tests and, where indicated, referral to gastroenterology or gynaecology. Some people choose to see a private specialist for faster scanning or a second opinion; any new severe, sudden pain should still go through emergency routes.