Appendicits

This is the most common indication for abdominal surgery in children.

Appendicitis is acute inflammation of the appendix

Epidemiology

-          About 5% of the population will have appendicitis at some point

-          Most commonly occurs in the 2^nd and 3^rd decades, but can occur at any age

-          Appendicitis in pregnancy

o   Occurs in 1/1000 pregnancies

§ This is not more common than the general population, however, it carries a greater risk of mortality

§ Risk of mortality is greatest after 20 weeks gestation

§ Perforation occurs in 15-20% of cases

·         Fetal mortality without perforation – 1.5%

·         Fetal mortality with perforation – 20-30%

§ As pregnancy advances, the position of the appendix changes, thus pain is usually poorly localised, and signs of peritonitis are usually less obvious

§ If appendicitis is suspected in pregnancy is should be investigated quickly with laparotomy by an experienced surgeon

Pathology

Results from obstruction of the appendical lumen. Typically from lymphoid tissue hyperplasia, but also sometimes from faeces, foreign body or worms.

-          Once obstructed, there can be:

o   Bacterial overgrowth

o   Distension

o   Ischaemia

o   Inflammation

-          If untreated, there may be:

o   Necrosis

o   Perforation

§ Sometimes, this is contained by the greater omentum, in which case, and appendical abscess may form

o   Gangrene

Clinical features

-          Pain – typically episgastric or periumbilical, before localising to the RLQ

§ Pain migration occurs due to the different innervations of the layers. The viscera (i.e. the appendix tissue itself) is innervated by the splanchnic nerves, which are poorly localising, and localise to the centre of the abdomen. Once the peritoneum becomes involved, different nerve pathways are activated, and the pain can be more closely localised. These differences are due to the different embryological derivations of the layers of the gut.

o   Peritonitis if present– classic peritonitis pain of wasboard rigidity – as the pain is exacerbated by the slightest movement (e.g. rolling, coughing, even breathing)

o   Rebound tenderness at McBurney’s point – press at this point does not elicit pain, but relieve the pressure (the ‘rebound’) elicits pain (or elicits more pain than the initial pressing)

§ Mcburney’s Point –2/3’s of the way along an imaginary line from the umbilicus to the anterior superior iliac spine on the right hand side

o   Rovsing’s Sign – pain felt in the LRQ when the LLQ is palpated

o   Psoas sign –increased pain during passive extension of the right hip

o   Obturator sign –pain felt on passive internal rotation of the flexed hip

-          Nausea

-          Vomiting

-          Anorexia

-          Low grade fever

-          The above classical symptoms only appear in <50% of patients. There are lots of other presentations!

o   Pain is less likely to be localised in children

o   Bowel movements – often less frequent, or absent especially if peritonitis is present

o   Urine dipstick – may show WBCs and/or RBCs

Diagnosis

-          If classical signs / symptoms are present, then diagnosis if often clinical

o   Delaying diagnosis in these patients can be life-threatening – delaying treatment increases the risk of perforation and peritonitis

o   The Alvarado Score is a way of scoring suspected appendicitis clinically to identify those who may need surgery. BUT in trials, it has proved no more effective than good clinical judgement. However, it may still be useful when making assessment

§ Alvarado score more accurate in Men and Children

Alvarado Score

Criteria	Score	Criteria	Score
Pain migration	1	Nausea / Vomiting	1
Anorexia	1	RLQ Tenderness	2
Rebound tenderness	1	Temp >37.3	1
WCC > 10x109 / L	2	Neutrophil Count >75%	1

-          <4 – appendicitis unlikely

-          5-6 – observe

-          >7 - operate

Investigations

In atypical and non-urgent presentations, laparotomy can be avoided, and other
investigations instead performed.

-Contrast CT – is useful, but can take time to organise. Good sensitivity and
specificity, and able to diagnose other differentials

-USS – can
identify appendicitis, but not good at identifying other causes

-Laparatomy – don’t be afraid to perform a diagnostic laparotomy if necessary

Management

-APPEDICECTOMY! – don’t be afraid to treat quickly. Delaying
treatment increases mortality. The negative appendicectomy rate is
about 10%

oContraindicated in IBD involving the caecum. Also may
be unsuitable in very elderly or severely ill patients.

§In patients who can’t undergo surgery, IV antibiotics
are beneficial. They are not curative, but reduce
mortality by 50% and thus buy some time.

Complications

-Perforation
± peritonitis

-Abscess formation 

Notes by Tom Leach