Appendicitis

Question 1

What is appendicitis?

Answer 1

Acute inflammation of the appendix usually from obstruction of the lumen.

Question 2

What is the aetiology of appendicitis?

Answer 2

Gut organisms invade the appendix wall after lumen obstruction by lymphoid hyperplasia (e.g. from viral infection), faecolith, or filarial worms (a parasitic roundworm). Obstruction means the appendix fills with mucus, which leads to increased intra-appendix pressure and thrombosis or occlusion of its small vessels. Occlusion leads to ischaemia necrosis. Gut organism invasion leads to oedema and perforation.

Question 3

What are the risk factors of appendicitis? (x2)

Answer 3

(1) Western diet, lower in fibre leading to right-sided feacal reservoir and reduced faecal transit time. (2) Hygiene hypothesis – there may be an impaired ability to prevent invasion, brought about by improved hygiene and less exposure to pathogens

Question 4

What is the epidemiology of appendicitis: Age? Incidence?

Answer 4

Highest incidence 10-20 years. Most common surgical emergency (6% lifetime incidence).

Question 5

Why is appendicitis rare before 2 y/o?

Answer 5

The appendix is cone shaped with a larger lumen.

Question 6

What are the symptoms of appendicitis? (x5)

Answer 6

o PAIN: early peri-umbilical pain, moving to the RIF as the peritoneum becomes involved. Pain is aggravated by moving, deep breathing and coughing.

o Nausea and vomiting (but rare as pain normally precedes vomiting)

o Anorexia

o Usually constipated, though diarrhoea may occur.

o Low grade pyrexia.

Question 7

What are the signs of appendicitis? (x3 +3)

Answer 7

o Localised tenderness, guarding, and rebound tenderness in the RIF (peritonism)

o Tachycardia

o Pyrexia

o ROVSING’S SIGN: pain higher in RIF than LIF when the LIF is pressed

o PSOAS SIGN: pain on extending hip if retrocaecal appendix

o COPE SIGN: pain on flexion and internal rotation of right hip if appendix in close relation to obturator internus.

Question 8

What is rebound tenderness?

Answer 8

Called Blumberg sign: pain upon removal of pressure rather than application of pressure to the abdomen.

Question 9

What is peritonism?

Answer 9

NOT to be confused with peritonitis. Peritonism is localised inflammation of the peritoneum.

Question 10

What is retrocaecal appendix?

Answer 10

Inflamed appendix behind the caecum.

Question 11

What is McBurney’s point? Pain?

Answer 11

1/3 of the distance from the ASIS to the umbilicus: corresponds to the most common location of the base of the appendix where it is attached to the caecum. This is where pain localises in appendicitis.

Question 12

What investigations are there for appendicitis? (x3)

Answer 12

o BLOODS: neutrophil leucocytosis and elevated CRP.

o ULTRASOUND: not always able to visualise the appendix.

o CT: high diagnostic accuracy and is useful if the diagnosis is unclear. It reduces negative appendicectomy rate.

Question 13

What are the features of appendicitis on USS?

Answer 13

Aperistaltic, thick-walled, at least 6mm in diameter under compression. May be able to visualise an appendicolith (not present in all cases), and echogenic (whiter-looking) fat which is non-specific and indicates inflammation (see photo).

Question 14

What is appendicolith?

Answer 14

Calcified deposit within the appendix that is find in some cases of acute appendicitis: aetiology is unknown, but some case reports suggest gallstone or foreign body.

Question 15

How is an appendicolith identified in USS?

Answer 15

Posterior acoustic shadowing

Question 16

What would a perforated appendix look like in USS?

Answer 16

Pericaecal fluid collection (black) or discontuity in the wall of the appendix.

Question 17

How may the clinical picture of appendicitis differ when appendix is retrocaecal or retroperitoneal? (x3)

Answer 17

May cause flank or RUQ pain; caecum (which sits anteriorly) may prevent eliciting tenderness upon even deep palpation; there may be increased tenderness on the right on PR (rectal examination).

Question 18

What may you see in the clinical picture of a CHILD with appendicitis?

Answer 18

May not eat their favourite food.

Question 19

What may you see in the clinical picture of an octogenarian (80s) with appendicitis?

Answer 19

No pain, but in a shocked, confused state.

Question 20

Appendicitis and pregnancy? 5 differences from appendicitis in normal individuals.

Answer 20

Occurs in 1/1000 pregnancies. Mortality is higher. Perforation is more common. Foetal mortality is higher. Pain is often less well localised. Signs of peritonism are less obvious.

Question 21

What are the treatment options for appendicitis? (x3)

Answer 21

o Appendicectomy

o Antibiotics: piperacillin/tazobactam – given pre-operatively and post-operatively to prevent wound infections, but longer if perforated

o Laparoscopy: not recommended in cases of suspected gangrenous perforation as the risk of abscess formation is higher

Question 22

What are the complications of appendicitis? (x3)

Answer 22

PERFORATION: more common if a faecolith is present and in younger children because the diagnosis is often delayed – leading to peritonitis; APPENDIX MASS: occurs when the appendix is not removed early during infection, and the inflamed appendix adheres to surrounding omentum and intestines forming a palpable lump; APPENDIX ABSCESS: if an appendix mass fails to resolve, this can form.

Question 23

How is appendix mass treated? (x2)

Answer 23

Conservative management – NBM and antibiotics. Colonoscopy/laparoscopy to rule out tumour.

Question 24

How is appendix abscess treated?

Answer 24

Drainage (surgical or percutaneous under US/CT-guidance), OR antibiotics alone.

Question 25

Why does pain in appendicitis migrate?

Answer 25

Internal organs and the VISCERAL PERITONEUM have no somatic innervation, so the brain attributes the visceral signals to a physical location whose dermatome corresponds to the same entry level in the spinal cord. Early inflammation irritates the structure and walls of the appendix, so a colicky pain is referred to the mid-abdomen (classically peri-umbilical). As the inflammation progresses and irritates the PARIETAL PERITONEUM, the somatic, lateralised pain settles at McBurney’s point.

Question 26

What is the foregut, midgut and hindgut?

Answer 26

Fore – proximal to 2nd part of duodenum; Mid – to 2/3 along transverse colon, Hind – to rectum.

Question 27

What is the somatic referral of pain in the foregut, midgut and hindgut?

Answer 27

Fore – epigastrium, mid – periumbilical, hind – suprapubic.

Question 28

What is the arterial blood supply of the foregut, midgut and hindgut?

Answer 28

Fore – coeliac axis, Mid – superior mesenteric, Hind – inferior mesenteric.

Question 29

What is the prognosis of appendicitis?

Answer 29

Recovery is usually 10-28 days, though can take longer if peritonitis occurs. If appendicitis resolves spontaneously, it remains controversial whether an elective interval appendicectomy should be performed to prevent a recurrent episode of appendicitis.

Question 30

How may presentation of appendicitis be different in thin patients?

Answer 30

Pain can be localised in the midline rather than RIF as caecum often shifted to the midline by the slimness of the patient.

Question 31

What is an appendicectomy?

Answer 31

Removal of an appendix.

Question 32

What are the indications for an appendicectomy?

Answer 32

Appendicitis.

Question 33

What are the possible complications of an appendicectomy?

Answer 33

Surgical site infection – leading to abdominal or pelvic abscess which requires drainage or antibiotics.

Question 34

When is appendicectomy done electively?

Answer 34

If patient has had appendicitis for a while and recovered on antibiotics, you would operate electively in 6 weeks once inflammation has reduced, as chance of recurrence is high.