Appendicitis is inflammation of the appendix, an anatomically blind pouch connected to the caecum.

It is a common cause of surgical emergency, and is the most common cause of an acute abdomen in children, with an incidence around 3-4 children per 1000. It can occur at any age, although it is less common at the two extremes of age.

Appendicitis is caused by obstruction of the lumen of the appendix, usually by a faecolith. This obstruction allows a build up of intraluminal fluid which distends the appendix, with a resultant blockage in lymph and venous drainage. Ischaemic injury consequentially allows bacterial invasion of the appendiceal wall and additional inflammatory oedema and exudation further exacerbates the drainage problems. This can result in an appendix abscess if pus collects around it, or perforation of the appendix with possible deadly consequences. A ruptured appendix will leak feacal matter into the abdomen causing peritonitis and will lead to septicaemia and death if untreated.

As with any condition, a detailed history and examination is important. A number of other conditions can mimic appendicitis including mesenteric adenitis, an inflamed Meckel's diverticulum and Crohn's disease. Along with its many imitators, the variable positioning of the appendix can make diagnosis difficult.

A history may be difficult to illicit from the patient and so third parties are always important when evaluating a child. Appendicitis in a child is the same as appendicitis in an adult but children are not always able to express themselves as easily.

History

The most common mnemonic used for pain is SOCRATES:

  • The site of pain in appendicitis will typically begin centrally, moving over to the right iliac fossa (RIF) within a number of hours. A point of particular tenderness can be localised 1/3's of the way between the anterior superior iliac spine and the umbilicus, and is known as McBurney's point.
  • It is an acute presentation and thus onset of the pain is generally over a 24-48 hour period.
  • The pain can be described as colicky in character.
  • The radiation of pain to the RIF is the most discriminating feature of a patient's history.
  • It is always important to consider additional symptoms, particularly anorexia, nausea/vomiting and fever, in suspected appendicitis. Loss of appetite is a very useful screening question to ask. Sore tummies in children are very common but the appendicitis child rarely wants anything to eat.
  • There is no particular association with timing.
  • Patients commonly demonstrate a reluctance to move with shallow breathing as movement can exacerbate the pain. Coughing may also hurt.
  • Pain may not be severe to begin with but once localisation occurs and/or peritonism develops, pain levels will increase and there will be particular tenderness over the RIF.

As with all children:

  • Any problems urinating?
  • In all boys: Is there any testicular pain?
  • In pubertal girls: Is there any chance they could be pregnant? Are they sexually active? Last menstrual period?
  • When was their last stool? Was it hard? Was it loose? Was it sore?

Examination

Some key points to the abdominal examination in a child with suspected appendicitis:

  • How does the child walk into the examination room or get onto the bed? The child who comfortably walks over to you standing tall and upright is very unlikely to have appendicitis. The child who walks hunched over, like 'an old man', you must be thinking of peritonitis. Obviously appendicitis is much more likely in this case.
  • Do they look unwell? Kids with appendicitis generally aren't nagging mum for food, running about or climbing on chairs.
  • Where is the pain exactly? Is it in the right iliac fossa? Is there true guarding?
  • If they have pain in a number of areas, e.g. both LIF and RIF, designate each a number and ask 'Which is more painful, 1 or 2?'
  • Always, always, always examine the testicles in a boy with a sore abdomen. These kids will always be embarrassed and may be pretending the pain is a little higher. A testicular torsion is something not to be missed.

Special tests

Three such tests are Rovsing's sign, obturator test and the psoas sign. It is important to know at least Rovsing's sign.

  • Rovsing's sign is positive if palpation of the left iliac fossa induces pain in the RIF. It is a demonstration of peritonism and is often a useful discriminator clinically.
  • The obturator test, or 'Cope's test', involves flexion and internal rotation of the right hip. A positive result is if this manoeuvre causes pain in the RIF, said to be the result if obturator internus muscle is in close relation to an inflamed pelvic appendix.
  • The psoas sign is performed by asking the patient to lie on their left hand side and then extending the right hip. An inflamed retrocaecal or pelvic appendix close to the right psoas muscle is irritated by this movement. This causes pain in the RIF.

It is also important to look out for signs of peritonitis which include abdominal tenderness, guarding and rigidity and a reluctance to move. Peritonitis is a result of perforation of the appendix and is associated with a higher degree of mortality and complications.

Appendicitis is commonly a clinical diagnosis but a few investigations can be useful and may be necessary to exclude other differential diagnoses.

Investigations

- A full blood count should be ordered to look for a raised white blood cell (WBC) count. Group & save should be taken for any possible surgical presentation.

- Urine dipstix and microscopy and culture should be performed to exclude infection.

- An abdominal ultrasound can be used if the diagnosis is in doubt and can be used to rule out ovarian pathology.

- Appendicitis itself is not apparent on an abdominal plain flim but X-ray may help to make diagnoses such as intestinal obstruction, constipation and intussusception less likely.

Appendicitis is largely a clinical diagnosis, but the Alvarado appendicitis score is occasionally used as a useful scoring system for assessing the likelihood of appendicitis. It can be tallied up after a full history, examination and some initial blood tests have been taken.

 

Alvarado score

A score lower than 5 suggests appendicitis is less likely, with a score greater than 8 suggesting a high probability of appendicitis.

Management

Surgery is the mainstay of treatment for appendicitis although pain management is also key.

Prior to surgery patients need to be kept nil by mouth and will be given intravenous fluids, antibiotics and analgesia. Metronidazole 500mg/8h and cefuroxime 1.5g/8h, 1 to 3 doses IV starting 1 hour pro-op, reduces wound infections. A longer course would be indicated in perforation. Appendicectomy can then be performed either by open surgery or laparoscopically.

Open surgery uses the traditional Gridiron incision over McBurney’s point, at a 90̊ angle to the line from the umbilicus to the anterior superior iliac spine. Laparoscopic surgery involves 3 small incisions and has many advantages over open surgery including decreased postoperative pain, better aesthetic result, and a lower incidence of wound infection and dehiscence.

Sometimes patients are managed with fluids and antibiotics with frequently re-assessed and then an elective appendicectomy is arranged for a number of weeks later.

If an abscess has formed, a drain will need to be inserted to first drain the pus and the appendix is later removed.

Hints and Tips

In a surgeon's eyes there is no such thing as a grumbling appendix!

Rebound tenderness isn't nice and it's not a good idea to perform it on a child as they will associated you with the extreme pain and may not allow you to examine them further! Instead you can ask them to cough or, as I was advised, get them to jump up and down. The inflamed appendix will rub on the surrounding tissues and peritoneum and can replicate the pain.

In pregnancy, pain and tenderness are higher because of the displacement of the appendix by the enlarging uterus. NB: A pregnancy test should always be performed on females to rule out ectopic pregnancy.

Attempt to involve a child in a history in order to gain their trust and speak at a level appropriate to their age.

Sometimes it is necessary to perform an examination out of order so that important aspects are covered before a child becomes uncooperative, e.g. listening to a child's chest or abdomen while they are quiet.

Growth charts are very important, always think about them and/or ask to see it.

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