Part of the TeachMe Series

Acute Appendicitis

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Original Author(s): Hussain Aluzri
Last updated: 17th December 2018
Revisions: 17

Original Author(s): Hussain Aluzri
Last updated: 17th December 2018
Revisions: 17

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Acute appendicitis is inflammation of the appendix, a narrow blind-ended tube connected to the posteromedial end of the caecum(1, 2). It presents as abdominal pain and is a condition that often leads to abdominal surgery in children(3).


Appendicitis is most common in the 10-19 years age group and much more common in developing countries (1). However, it can occur at any age including in neonates. It is one of the most common causes of abdominal pain in young people and children, with more than 40,000 cases in both children and adults a year in England (1).


Appendicitis occurs when the appendix becomes acutely inflamed. It’s not entirely known why appendicitis occurs however it is thought to be due to the lumen of the appendix becoming blocked by a faecolith, normal faecal matter or lymphoid hyperplasia due to a viral infection(1).

Once obstructed, there is reduced blood flow to the tissue and bacteria is able to multiply. Due to the lumen being obstructed, the pressure within the appendix increases and this reduces venous drainage, resulting in ischaemia (3). If untreated the ischaemia can lead to necrosis and gangrene. At this stage, the appendix is at risk of perforating (3). It takes around 72hrs for perforation to occur from when the appendix becomes obstructed (3). Once the appendix perforates, bacteria and inflammatory cells are released into the surrounding structures. This then causes inflammation of the peritoneum and the child develops peritonitis causing diffuse abdominal pain (3).

Figure 1: Normal appendix (left) vs Inflamed appendix (right)

Risk factors

The following are risk factors for appendicitis:

  • Age (most common between 10 – 19 years)
  • Male sex (1).

Clinical features

It is important to remember that acute appendicitis can present atypically in infants and  young children.

The typical history will have the following features:

  • Anorexia
  • Normally afebrile or low-grade fever (5).
  • Other symptoms that may be present include vomiting (presents after onset of pain not before), anorexia, nausea and diarrhoea (6).
  • Gradual onset of pain in the periumbilical area which migrates to the right lower quadrant (RLQ).

    Right Lower Quadrant Pain

      The pain is referred to the umbilical region in the early stages because inflammation of the visceral peritoneum is poorly localised. This is because the visceral peritoneum has the same nerve supply as the viscera it invests and it is only sensitive to stretch and chemical irritation. As the appendix becomes more inflamed, the parietal peritoneum becomes irritated. The pain then becomes localised to the right iliac fossa because the parietal peritoneum is innervated by the same somatic nerve as the region of the abdominal wall that it lines

Atypical Pain and Symptoms

It is important to be aware that 40-45% of patients present with atypical pain(5).

Atypical pain may present in various ways.

        • Pelvic appendix – pain initially felt in RLQ, no visceral symptoms and pain on urination, may cause suprapubic pain (5). May present with profuse diarrhoea and pelvic pain.
        • Retrocaecal appendix – 15% cases present in this way. Pain may localise to psoas muscle, the flank or right upper quadrant (5).
        • Retroileal appendix – May cause testicular pain due to irritation of the spermatic artery or ureter (7).
        • An appendix which is long with tip inflammation in the left lower quadrant may cause pain in that area (7).

      Figure 2: Diagram showing different appendix positions

Other atypical symptoms that could be present which are important to be aware of are:

  • Vomiting before onset of pain – this can occur in patients with retrocecal appendices, inflammation of the appendix can cause irritation of the duodenum causing vomiting and nausea before pain occurs in the RLQ(5).
  • Diarrhoea –Atypical in appendicitis however if a patient’s appendix is in the pelvis then the inflammation can irritate the rectum. However, be mindful to ask about what they mean by diarrhoea because in appendicitis often the stools are soft, of small volume and frequent rather than watery in true diarrhoea(5).
  • Fever – A temperature of ≥38oC is not common and may be present when perforation has occurred (5).

If perforation has already occurred the child will present with:

      • Generalised abdominal pain
      • High heart rate
      • Temperature over 38oC (5).

Issues to be aware of:

A child under 6 years of age who has had symptoms for over 48 hours is more likely to be suffering from a perforated appendix (5).

It is important to note that younger patients do not often score as highly on the Paediatric Appendicitis Score (PAS, see below) because they may struggle to describe the migration of pain from the umbilical area to the RLQ and to localise the pain (5).

If a child cannot verbalise where the pain is or unable to communicate how they feel, then parents/caregivers can give information, however sometimes this can vary due to different perspectives (8). Pathological findings can be elicited by asking about eating, playing, sleeping and toilet habits and by observing the patient (8).

From examination

When examining a child, it is important to consider their age and their developmental stage and adapt the examination accordingly. The findings of the examination will differ depending on the age of the child.

It is important to be aware that during examination especially in younger children (under 6 years of age) there may not be tenderness in the RLQ (5). This may be due to perforation having already occurred before presentation resulting in more generalised pain due to peritonitis (5, 9).

General Examination

Firstly, the general state of the child is observed before examining their abdomen. The activity or withdrawal of the patient will give clues towards the diagnosis (5). If the patient can mobilise, observe the child’s gait.

Cardiovascular and respiratory examination

Examining the heart and lungs will help exclude differentials like a LRTI and basal pneumonia. It also gives an idea of the child’s overall state more than displaying signs of appendicitis. The patient may show signs of dehydration or be tachypnoeic or tachycardic (5).

Abdominal Examination

      • Expose the abdomen
      • Ask the child to point to where the pain is worst
      • Look for any abnormalities on the abdomen such as scars, rashes, swellings


          • Palpate furthest away from the site the child pointed to and work your way to the most painful area. Palpate with a gentle and light touch
          • Be aware for involuntary guarding. If present, it shows peritoneal irritation which is found in appendicitis and cannot be overcome by distraction unlike voluntary guarding which is due to fear of pain (5).
          • The child’s face should be watched throughout palpation to look for any facial expressions suggesting pain.
          • The most tender part of the abdomen can be found at McBurneys point in the RLQ. If a mass is palpable here, then this suggests the appendix has perforated (5).

        Figure 3 McBurney’s Point (1) – two thirds of the way between the umblicus (2) and the Anterior Superior Iliac Spine (3).

    • Rovsing sign (pain in the RLQ in response to left sided palpation or percussion) suggests peritoneal irritation (5).
    • Peritoneal irritation can be elicited by asking the child to jump, cough, tapping the feet or moving the bed whilst looking at the face of the child (8). Trying to detect peritoneal irritation by rebound tenderness may put the child in a lot of pain and the child may lose trust of the healthcare professional, so alternative ways can be used to detect peritoneal irritation (5).


      • Auscultate the abdomen for bowel sounds. If no bowel sounds are present this suggests constipation.

Genitourinary examination

Examine the groin and genitalia in males to exclude incarcerated hernia and acute testicular torsion.

Pelvic examination

In sexually active girls, pelvic inflammatory disease and other gynaecological disorders may be differentials as they can present similar to appendicitis (8). A pelvic examination may be considered.

Differential Diagnosis

Children may find it difficult to communicate their symptoms and may complain of vague abdominal pain therefore it is important to exclude other diagnoses.

Other GI causes of abdominal pain which are important to exclude are

  • Gastroenteritis – vomiting before pain is usually a symptom of gastroenteritis rather than appendicitis (5). Often presents with profuse watery diarrhoea which occurs after the abdominal pain (10).
  • Acute mesenteric adenitis – usually presents after an upper respiratory infection and abdominal pain is diffuse (10).
  • Constipation – patients may present with fewer than 3 complete stools a week and parents may say there is soiling (in children over the age of 1 years). Child may be distressed or be in pain when passing stool (11). However, this is a diagnosis of exclusion.
  • Crohns disease – major differential for appendiceal abscess or mass.
  • Intussusception – severe colicky abdominal pain. Stool may be mixed with blood and mucus (redcurrant stools) and there may be a sausage shaped mass in the abdomen in the RLQ (10, 12).

Other differentials to consider that cause abdominal pain

  • Urinary tract infection – pain and tenderness is in the suprapubic area and there is burning on urination with increased frequency and urgency (10). Can be excluded by performing a urine dipstick or MSU.
  • Ectopic pregnancy if female and sexually active – It is important to ask when the patient’s last menstrual cycle was (usually patient has missed a period). Presents with RLQ pain or pelvic pain. There will be some vaginal bleeding or spotting. Blood tests and urinalysis will show high levels of HCG and ultrasound will show a mass in the fallopian tubes (10).
  • Ovarian torsion – presents with RLQ pain, sometimes a mass is present in the RLQ. Ultrasound will show decreased blood flow and an ovarian cyst (10).
  • Basal pneumonia and pleurisy – pain may be referred to the abdomen.


Laboratory tests

Blood tests should be done initially to rule out other causes and help in diagnosis.

  • FBC – WCC becomes elevated in 70-90% of cases of acute appendicitis but can be elevated in other abdominal conditions as well (5). However, a normal WCC does not exclude appendicitis.
  • U+Es – electrolyte disturbances associated with GI issues are common
  • CRP and ESR – non-specific inflammation markers however also help in assessing whether presentation is due to infection/inflammation (13).

Pregnancy test should be done when the patient is a sexually active female adolescent to rule out pregnancy and ectopic pregnancy (14).

Urine dipstick to rule out UTI (14).

Imaging or invasive tests

Ultrasound scan may be performed to exclude other diagnoses such as ovarian torsion and ectopic pregnancy.

Risk scoring

The Paediatric Appendicitis Score (PAS) is used to assist in assessing the risk of appendicitis in children.

Feature PAS
Migration of pain 1
Anorexia 1
Nausea 1
Tenderness in the right quadrant 2
Elevated temperature 1
Leucocytosis 1
Shift of white cell count to the left 1
Coughing/hopping/percussion pain 2
Total 10


Low risk PAS (<4)

There is a low likelihood of appendicitis if the score is lower than 4. There is a higher negative predictive value (95%) if the child isn’t complaining of RLQ pain or pain on walking/jumping (15). With this score other differential diagnoses should be explored however this group of patients according to PAS do not have a score of zero, use clinical discretion to whether further assessment and imaging would aid diagnosis.

A score of 4-6

This indicates further monitoring is needed and should be used alongside clinical judgement of the child’s presentation, examination findings and assessment of the parents to determine whether admission is necessary (16).

Imaging in these patients will be helpful with diagnosis, ultrasound scan or MRI is used in paediatric patients (15).

High risk PAS (>6)

It is recommended the child is referred to the surgical team for blood tests to obtain the White Cell Count and to look for the presence of Leucocytosis and monitoring (15, 16). A PAS of 6 or greater does not confirm acute appendicitis but should be used alongside the clinical picture (16).


Initial Management

Suspected appendicitis in children needs immediate hospital admission as it is a medical emergency (17). There is a low threshold for admitting children and infants with suspected appendicitis. Research shows that young children with appendicitis have increased mortality due to delayed presentation and often have atypical signs and symptoms (18).

Acute management of patients with suspected appendicitis:

  • IV access
  • Fluid resuscitation
  • Contact surgical team to discuss IV antibiotics, whether to make the child NBM and if surgical intervention is needed*.

*if there is an appendix mass, conservative management is opted for (IV antibiotics and monitoring). If there is an improvement then an interval appendectomy is considered after at least 6 weeks. However, if during the monitoring the patient begins to deteriorate then surgical intervention will be considered sooner.

Surgical Management

Appendicitis is treated by surgical removal of the infected appendix (19). The surgery may be done by laparoscopy which is gold standard or by open incision at McBurney’s point (two thirds between the umbilicus and the anterior superior iliac spine)(17). Many studies suggest a laparoscopic approach leads to shorter hospital stays and a quicker return to baseline function (20). Pre-operative antibiotics may be given as they are associated with a reduction in surgical site infections (20).

Peri-op Care

In uncomplicated cases, the patient is usually discharged after 24-36 hours.

Post operatively ensure:

  • The patient is apyrexial
  • Sufficient oral intake
  • Adequate pain control (21).
  • The wound has no signs of inflammation/infection.

In patients where perforation has occurred, a longer hospital stay is needed for IV antibiotics (21). The WCC should be monitored during this time and should be within the normal range and the child should be apyrexial when considering discharge (21).


The most common complication of appendicitis is perforation. The rate of this occurring in young children is significantly increased and can be up to 97% (22). Perforation can cause other complications:

  • Appendix mass – the greater omentum reduces the spread of infection by surrounding and adhering to the appendix.
  • Abscess – an appendix mass may progress to an abscess.
  • Generalised peritonitis – infection of the lining of the abdominal and pelvic cavity due to the release of infected and faecal matter into the peritoneal cavity.
  • Sepsis – a serious complication of infection, the body’s inflammatory response which can result in reduced perfusion of organs and tissues.
  • Death – perforation is associated with increased mortality (22).



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