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Appendicitis: Causes and symptoms

Appendicitis: Causes and symptoms

Most of us have heard of appendicitis – it is, after all, the most common abdominal surgical emergency in the world, with 50,000 operations to remove appendixes performed each year in the UK alone (i). Many of us may even know that appendicitis means inflammation of the appendix. But what is the appendix exactly, and what role does it play in the body?
Your appendix is a small, narrow structure, much like a closed-ended tube or pouch, that’s usually anything from five to 10cm long with muscular walls similar to those found in your intestines. This small tube or pouch protrudes from a part of your bowel called the caecum that’s usually found on the right side of your abdomen where the small intestine becomes the large intestine.
Though it contains some immune tissue, we still don’t really know what the appendix’s function is. Scientists used to think it may have helped our ancestors digest certain foods that we no longer eat today. But according to Patient UK some experts have more recently suggested the appendix may contain a supply of helpful digestive bacteria, and that it may be important for the development of the immune system in babies and young children (ii). However, surgically removing an appendix doesn’t do anybody any medical harm – which suggests we’re still rather in the dark as to why we have them in the first place.

How common is appendicitis?

One of the most common causes of acute abdominal pain in children and in adults (and also one of the most common non-obstetric surgical emergencies in pregnant women) (i), appendicitis is thought to affect around one in seven people in the UK at some point in their life (ii). You can develop appendicitis at any age, though you’re most likely to be affected during your teens, 20s or 30s, and least likely when you’re very young or very old (iii).
Meanwhile women are thought to have a slightly higher risk of developing appendicitis than men, plus it’s much more common in western countries than other parts of the world (ii). In fact, it’s quite rare in rural areas of the developing world, which is why it’s often suggested that appendicitis may have something to do with eating a typical Western diet that’s relatively low in fibre.

Appendicitis symptoms

Most cases of appendicitis are classed as acute – that is, they begin suddenly and get worse very quickly. Chronic appendicitis, on the other hand, isn’t so common and is much less understood. However, some people experience chronic symptoms that stop and start and don’t escalate. Even if you think you have chronic rather than acute appendicitis, it’s still serious as it could progress to being acute, so it’s always advisable to see your GP without delay.
Symptoms of appendicitis can vary, but typical cases start with a dull pain around the centre of the abdomen that moves to the lower right abdomen, where it becomes much sharper and more painful, especially when you cough or move suddenly. This pain will usually get worse over just a few hours. Meanwhile you may also experience other symptoms, including:

  • Pain and abdominal tenderness when you touch the lower right-hand side of your abdomen (even very gentle touch can be very painful).

  • Nausea and vomiting

  • Lack of appetite

  • Raised temperature

  • Constipation 

  • Diarrhoea 

  • Bloating

  • Frequent urination

  • General feeling of unwellness

If left untreated, appendicitis can progress and the appendix can burst (perforate), which is something that happens to between 16 and 30 per cent of people with appendicitis (iv). If this happens it will cause severe pain in the entire abdomen. If you think you might have a burst appendix, call 999 for an ambulance immediately, as it’s highly likely you’ll need emergency surgery to remove it.

Could it be something else?

Several other conditions have similar symptoms to those of appendicitis, which can make diagnosing appendicitis tricky. Some of these include:

There are, however, a few indications that can suggest abdominal pain is caused by appendicitis rather than any of the above conditions. First, apply pressure to the area that hurts. If it feels worse when you release the pressure, there’s a good chance the pain is caused by appendicitis. Other tell-tale signs include your pain getting worse when you cough, and pain felt on your lower right side when you put pressure on your lower left side.
If you’re having the above-mentioned symptoms – even if you’re not sure they could be appendicitis – see or speak to a doctor as soon as you can (call NHS 111 or 999 if you think your appendix might have burst).

What causes appendicitis?

According to the NHS it’s not completely clear what causes appendicitis, though in many cases it might be the result of a blockage of the entrance to the appendix (vi). This blockage can be caused by remnants of indigestible foods that have been passing through the intestines or bits of hard stools called appendix stones. It can also be caused by lymphoid hyperplasia, which is the process by which lymph glands become swollen in response to infections (in this case, lymph glands in the appendix wall can swell up when there is an infection somewhere else in the body – an upper respiratory infection, for instance).
Other conditions that can cause appendicitis include:

  • Colitis

  • Cystic fibrosis

  • Parasites

  • Tumours (very rarely a cancer of the appendix or caecum may cause a blockage)

Meanwhile if someone in your family has had appendicitis your risk of developing it too may be almost three times higher than that of someone who has no family history of appendicitis (vi). Scientists have also pointed out that the time of year may somehow be a factor, since cases of appendicitis tend to peak during the summer months (vi).

Appendicitis complications

Appendiceal rupture (a burst appendix) is the main complication of appendicitis. Once it starts to become swollen, the appendix becomes infected with bacteria and gradually fills with pus. If you don’t get treatment, the appendix can eventually burst and the bacteria can spill out into the abdominal cavity. This can cause a serious condition called peritonitis (inflammation of the peritoneum, the membrane that lines the abdomen), which in turn can cause sepsis – also a very serious and potentially life threatening condition that needs urgent treatment.
Other complications include an abdominal abscess – a collection of pus that develops after an appendix bursts – and small bowel obstruction. These are all very good reasons to seek treatment for appendicitis earlier rather than later (that is, before your appendix bursts).

Appendicitis treatment

There’s no official test for appendicitis, so if you have the symptoms and your doctor isn’t sure about your condition after examining you, you may need a series of tests including blood tests, urine tests, ultrasound scans, CT scans or X-rays.
Once diagnosed, the standard treatment for acute appendicitis is to have an operation to have it removed (appendectomy). This will often be performed quickly, as your doctor will want to have your appendix removed before it bursts and causes complications. Laparoscopic appendectomy is the procedure where the appendix is removed via keyhole surgery, which has benefits over open surgery including shorter recovery times. This operation involves inserting a mini camera into a small cut in the abdomen, with tiny surgical instruments inserted through other small cuts used to remove the appendix.
However, open surgery – which involves making a larger cut in the abdomen – may be more suitable in some cases, including where the appendix has burst or when there is a lot of inflammation in the appendix and abdomen. Whichever operation you have, you will usually be given antibiotics beforehand to help treat any infection in your appendix. If your appendix has burst you may also need a longer course of antibiotics after it has been removed.

Appendicitis complications

As with any type of surgery there are risks involved with having an appendectomy – though these are thought to be far less problematic than not having surgery, which can be fatal. The main risks include bleeding, bruising, constipation and wound infection. All of these risks are temporary – there aren’t usually any long-term complications associated with having your appendix removed.

Are there any alternatives to surgery?

Some people can be treated for appendicitis with antibiotics instead of surgery. This isn’t routinely offered, but it may be helpful in cases of diagnostic doubt where it’s possible that appendicitis may not be the cause of symptoms, for instance, or for people who want to avoid having surgery for some reason or other. In these cases antibiotics are usually prescribed for home use over seven to 10 days.
However, there are drawbacks to this approach as antibiotic treatment isn’t always successful, plus even when they do work your symptoms could keep coming back and you may need an operation eventually anyway (according to Frimley Health NHS Foundation Trust, antibiotic treatment fails in 10 per cent of cases, while around 12 - 24 per cent of people who have appendicitis have it again after having had antibiotic treatment previously (vii)).

Can appendicitis be prevented?

There’s no real way to protect yourself against appendicitis, though the fact that it’s less common in some parts of the world does suggest that eating plenty of high-fibre foods might in some way help reduce your risk of developing it (high-fibre foods include most fruits and vegetables, whole grains, beans, lentils, nuts and seeds).
Meanwhile if you do have your appendix removed in hospital by keyhole surgery, you may be allowed to go home 24 hours after your operation if the surgery was uncomplicated. Your hospital doctor or nurse should give you advice on pain relief to use at home, as you will usually experience some pain and bruising at first (though this should start to improve within a couple of days or so). If you had regular instead of dissolvable stitches, they’ll have to be removed at your GP surgery after seven to 10 days. Meanwhile you should be well enough to start getting back to normal within a few weeks.
If you had open surgery, or your keyhole surgery was complicated, you may need to stay in hospital for up to a week before you’re well enough to go home. You may also not be able to go back to work for four to eight weeks, depending on what type of job you do.
If you experience constipation as a complication of having surgery, your GP can prescribe medication if you need it – you may also want to try drinking plenty of fluids and eating lots of high-fibre foods until you’re back to normal. There’s more information on managing constipation in our guide to constipation causes
You may also want to consider supporting your recovery by taking a multivitamin and mineral supplement, as well as a high-strength fish oil supplement, as both can benefit your overall health. Fish oils, for instance, are widely thought to help relieve inflammation, plus a multivitamin may come in useful especially if you’re not managing to eat quite as healthily as usual when you come home from hospital (check out our multivitamin guide to find out which type of multi would suit you).
Finally there’s more on what you can do to boost your recovery from an appendectomy or any other operation, plus steps you can take to prepare for surgery, in our post-operative recovery guide.

Need more information?

We have lots more information on a wide range of conditions that cause pain in the pain section of our pharmacy health library.


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  6. Rentea RM, St Peter SD, Synder CL. (2017) "Pediatric appendicitis: state of the art review." Pediatr Surg Int. 33(3):269-283. Available at:

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Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.

Our Author - Christine Morgan


Christine Morgan has been a freelance health and wellbeing journalist for almost 20 years, having written for numerous publications including the Daily Mirror, S Magazine, Top Sante, Healthy, Woman & Home, Zest, Allergy, Healthy Times and Pregnancy & Birth; she has also edited several titles such as Women’ Health, Shine’s Real Health & Beauty and All About Health.

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