Definition of appendicitis
-inflammation of the vermiform appendix, most likely due to obstruction of the lumen of the appendix (by faecolith, normal stool, infective agents, lymphoid hyperplasia)
Symptoms of appendicitis
- sudden
- abdominal pain starting in the mid-abdomen and later localising in the right lower quadrant
- associated fever, anorexia, nausea, vomiting
- pain aggravated by cough, steady pain
Different appendix positions:
- retrocaecal appendix can cause flank or back pain
- retroileal appendix can cause testicular pain due to irritation of the spermatic artery or ureter
- pelvic appendix can cause suprapubic pain
- paracolic long appendix with tip inflammation in the right upper quadrant may cause pain in this region
Diagnosis of appendicitis
- acute severe right iliac fossa pain
- poorly localised central abdominal pain that becomes localised to the right lower quadrant
- anorexia, nausea, vomiting
- perforated appendix = signs of shock/sepsis, guarding, palpable mass
-psoas sign - flexred right hip
Risk factors for appendicitis
- low dietary fibre
- improved personal hygiene (frequent use of antibiotics, hygienic conditions = imbalance of GI microbiota flora= modified response to viral infection = trigger appendicitis
- smoking
Aetiology of appendicitis
- obstruction of the lumen of the appendix; faecolith (hard mass of faecal matter), normal stool, or lymphoid metaplasia
- neuroimmune aetiology in some cases
Pathophysiology of appendicitis
- lumen distal to the obstruction starts to fill with mucus and acts as a closed-loop obstruction = distension, increased intraluminal pressure
- overtime, resident bacteria in the appendix rapidly multuply- Bacteriodes fragilis, Escherichia coli
- distension of the lumen of the appendix causes reflex anorexia, nausea, vomiting, visceral pain
- as pressure of the lumen > venous pressure, small venules/capilaries become thrombosed but arterioles remain open = appendix engorged and congested
- once the small arterioles are thrombosed, the anti-mesenteric border become ischaemic, infarction and perforation
- bacteria leaks from dying walls, pus forms around appendix
Management of appendicitis
- emergency appendicectomy
- if sepsis= critical care
- preoperative resus
- maintain high level of suspicion of appendicitis in pregnant women, after 1st trimester, RUQ or right flank pain can occur
Scoring system for appendicitis
AIR = Appendicitis Inflammatory Response
AAS = Adult Appendicitis Score
Investigations for appendicitis
-use of initial blood tests, history, examination and scoring system to determine whether imaging required
Imaging- abdominal US or CT, MRI in pregnant if US inconclusive
- high risk patients <40 may go straight to surgery without imaging
- if >40, should have imaging
- low-risk discharged
-urinalysis to rule out UTI (NOT to diagnose)
-raised WBCs, neutrophils
-raised CRP (seen >12hrs)
-
-leukocytosis shift
