GI - Acute Appendicitis

Question 1

Definition

Answer 1

Inflammation of vermiform appendix ranging from oedema to ischaemic necrosis and perforation

Question 2

epidemiology

Answer 2

• 6% lifetime incidence, commonest surgical emergency,

- Peaks in childhood, incidence decreases thereafter

Question 3

Differential

Answer 3

• GI: cholecystitis, diverticulitis, Meckel’s diverticulitis (if normal appendix on appendicectomy- should looke for this), mesenteric adenitis, Crohn’s
• Gynae: cyst accident (torsion, rupture, haemorrhage), salpingitis/PID, ruptured ectopic
• Renal: ureteric stones, UTI, pyelonephritis
• Urological: testicular torsion

Question 4

Pathogenesis/Aetiology

Answer 4

• Obstruction of the appendix: faecolith (most common), lymphoid hyperplasia (post viral), tumour (caecal Ca or carcinoid), worms (ascaris lumbricoides, schisto)
• Gut organisms: infection behind obstruction - oedema - ischaemia - necrosis - perforation
• Peritonitis
• Abscess
• Appendix mas

Question 5

Clinical features - early vs late inflammation

Answer 5

• Early = appendiceal irritation: visceral pain is poorly localised, nociceptive info travels in the sympathetic afferent fibres that supply the viscous, pain referred to the dermatome corresponding to the spinal cord entry level of these sympathetic fibres. (Append = midgut = lesser splanchnic nerve (T10-11) = umbellicus
• Later inflammation = parietal peritoneum irritation = pain localised in RIF
• *The pain moves, doesn’t radiate

Question 6

Clinical features- symptoms

Answer 6

• Colicky abdo pain (may be localised), worse with movement
• Anorexia
• Nausea (vomiting rarely prominent
• fever
• Constipation/diarrhoea

Question 7

Clinical features- signs

Answer 7

• Low grade pyrexia (37.5-38.5)
• Increased HR, shallow breathing
• Guarding and tenderness at McBurney’s point + percussion tenderness
• Appendix mass may be palpable in RIF
• Pain PR suggests pelvic appendix

Question 8

What special signs should you perform?

Answer 8

• Rovsing’s sign: RIF fossa pain on palpation of LIF
• Psoas sign: RIF pain with extension of right hip (suggests inflamed appendix abutting psoas major muscle in retrocaecal position)
• Cope sign: flexion + internal rotation of R hip. If painful, appendix is lying close to obturator internus
• Have poor predictive value alone, must be combined with rest of examination
• *Females: should do pelvic exam to assess for potential gynae pathology

Question 9

Ix: lab tests

Answer 9

• Diagnosis is principally clinical
• Bloods: FBC, CRP, amylase, G&S, clotting
• Urine: dip test (exclude UTI), sterile pyuria (may indicate bladder irritation), ketones (anorexia), HCG for ladies

Question 10

Ix: imaging and others

Answer 10

• Trans abdo USS: good in children (less radiation and they’re skinnier)
• CT scan (more common in older pts) - good for identifying potential malignancy/source of problem
• Diagnostic laparotomy

Question 11

Mx protocol

Answer 11

• Fluids
• ABX: cef + met
• Analgesia: paracetamol, NSAIDS, codeine phosphate
• Certain diagnosis: appendicectomy (open or lap)
• Uncertain diagnosis: active observation

Question 12

Complications

Answer 12

• Appendix mass: inflamed appendix with adherent covering of omentum/small bowel
• Appendix abscess: results if appendix mass doesn’t resolve/get fixed - enlarges
• Perforation: common if faecolith in kids (Dx often delayed) - can lead to peritonitis