Appendicitis

Question 1

Anatomy of the appendix

Answer 1

The appendix (or vermiform appendix; also cecal [or caecal] appendix; vermix; or vermiform process) is a blind-ended tube connected to the cecum, from which it develops in the embryo. The cecum is a pouchlike structure of the colon, located at the junction of the small and the large intestines.

Question 2

Pathophysiology of appendicitis

Answer 2

• The appendix base thus lies in the right iliac fossa, close to McBurney’s point.
• initiated by luminal obstruction caused by impacted faeces or a faecolith.
• appendicitis is more common with a low dietary fibre intake
• the mucosa becomes inflamed first. Inflammation eventually extends through the submucosa to involve the muscular and serosal (peritoneal) layers
• fibrinopurulent exudate on the serosal surface extends to any adjacent peritoneal surface, e.g. bowel or abdominal wall, causing localised peritonitis
• By this stage the necrotic glandular mucosa sloughs into the lumen, which becomes distended with pus
• Finally, the end-arteries supplying the appendix thrombose and the infarcted appendix becomes necrotic or gangrenous at the distal end and the appendix begins to disintegrate.
• Perforation soon follows and faecally contaminated contents spread into the peritoneum

Question 3

Clinical features of appendicitis

Answer 3

• poorly localised, colicky central abdominal visceral pain
• inflammation advances over the ensuing 12–24 hours, it progresses through the appendiceal wall to involve the parietal peritoneum (innervated somatically)
• local peritonitis can be elicited, i.e. tenderness, guarding and rebound tenderness

Question 4

Other presentations of acute appendicitis

Answer 4

• If appendix lies in the pelvis near the rectum, it may cause local irritation and diarrhoea
• If lies near the bladder or ureter, inflammation may cause urinary frequency, dysuria and (microscopic) pyuria, i.e. leucocytes in the urine
• These findings may be mistakenly interpreted as urinary tract infection
• An inflamed appendix near the Fallopian tube causes pelvic pain suggestive of an acute gynaecological disorder such as salpingitis or torsion of an ovarian cyst
• older patients, a gangrenous or perforated appendix is more likely to be contained by greater omentum or loops of small bowel.
• In the elderly, an appendix abscess is often walled off by loops of small bowel

Question 5

Making the diagnosis of appendicitis

Answer 5

Cardinal features of acute appendicitis

• Abdominal pain for less than 72 hours
• Vomiting 1–3 times
• Facial flush
• Tenderness concentrated on the right iliac fossa
• Anterior tenderness on rectal examination
• Fever between 37.3 and 38.5°C
• No evidence of urinary tract infection on urine microscopy

Question 6

Special points in the history and examination

Answer 6

• Acute appendicitis typically runs a short course, between a few hours and about 3 days. If symptoms have been present for longer, appendicitis is unlikely unless an ‘appendix mass’ has developed.
• A recent or current sore throat or viral-type illness, particularly in children, favours a diagnosis of mesenteric adenitis (inflammation of mesenteric lymph nodes analogous to viral tonsillitis).
• Urinary symptoms suggest urinary tract infection but may also occur with pelvic appendicitis.
• Several signs (e.g. Rovsing’s sign—pressure in the left iliac fossa causing pain in the right iliac fossa) are said to point to a diagnosis of appendicitis but all are unreliable.
• One useful test is to ask the child to stand, then to hop on the right leg. If this can be achieved, there is unlikely to be significant peritoneal inflammation.
• Rebound tenderness was traditionally demonstrated by palpating deeply, then suddenly releasing the hand.
• However, this can cause excessive and unexpected pain. A kinder and more precise method is to perform gentle percussion in the right iliac fossa.

Question 7

Differential diagnosis

Answer 7

• Mesenteric adenitis is a self-limited inflammatory process that affects the mesenteric lymph nodes in the right lower quadrant. Its clinical presentation mimics that of acute appendicitis
• Yersinia ileitis (Yersinia enterocolitica (bacterial species in the family Enterobacteriaceae that most often causes enterocolitis, acute diarrhea, terminal ileitis, mesenteric lymphadenitisand inflamed)
• Meckel’s diverticulum

Question 8

Scoring system for appendicitis

Answer 8

Question 9

Management of suspected appendicitis

Answer 9

The ‘grumbling’ appendix

• Recurrent bouts of right iliac fossa pain are often labelled ‘grumbling appendix’.
• These children may have several abortive admissions for abdominal pain and it may eventually be justifiable to remove the appendix to allay parental anxiety.
• A non-inflamed appendix containing a faecolith or threadworms (assumed to have caused the pain) is often found. The pain will be cured in no more than half.

Question 10

Complications of appendicitis

Answer 10

Intraperitoneal complications:

• Appendix stump blow-out—spillage of colonic contents into the peritoneal cavity
• Generalised peritonitis—perforated or gangrenous appendix, virulent organisms, late presentation or diagnosis
• Abscesses—local, pelvic, subhepatic, subphrenic
• Retained faecolith causing chronic local infection
• Haematoma due to slippage of a vascular ligature or a mesenteric or omental tear

Early or late (even many years later)

• Intestinal obstruction due to adhesions

Late:

• Incisional hernia

Question 11

Technique of appendicectomy

Answer 11

• Increasingly, laparotomy is being replaced by laparoscopic diagnosis and surgery, but the principles are similar.
• Surgeons performing appendicectomy need to be aware of possible appendiceal neoplasms, present in 0.5—0.9% of appendec­tomies.
• Most are innocent carcinoid-type tumours but others are mucinous adenocarcinomas.