Acute appendicitis

Acute appendicitis

1. Epidemiology

   • 10% population will develop it
   • Commonest between 10 and 20.
     • Uncommon before 2 years
   • A normal appendix is removed at 10-20% of appendicectomies.

2. Pathophysiology

   • An obstructed system gets infected.
     • Cholangitis and pyelonephritis are similar in this respect.
     • Faecolith or enlarged piece of lymphoid tissue ? response to viral illness.
       • Much rarer causes are caecal cancer and carcinoid tumours

3. Clinical features

   • Initially colicky midgut pain
     • Peritonitic pain as the inflammation spreads to involve the parietal peritoneum.
       • Associated with fever, anorexia, N+V
         • Pain before the vomiting usually. Constipation rather than D
   • Abdo tenderness, guarding, rebound and percussion tenderness.
     • Rovsing's sign positive
       • Palpation of the left iliac fossa makes the pain worse as the peritoneum is being stretched.
     • Tenderness on digital rectal exam.
       • Inflammatory fluids, maybe pus tracked into the pouch of Douglas.
     • Psoas sign
       • Pain on extending the hip
       • Retrocaecal appendix
     • Cope sign
       • Pain on flexion and int flexion of R hip
       • Appendix in close relation to obturator internus
   • Appendix mass
     • Walled off by the omentum and small bowel, and then presents.
       • Usually occurs 72 after the inflammation begins/onset of symptoms.
       • Palpable mass
         • Gets better with Abx, or abscess that requires drainage.
           • Elective appendicectomy 3 months later (Ochsner-Sherren regimen).
             • 20% may develop recurrent appendicitis otherwise.

4. Operation details

   • Need to know the basic operation.

5. Differential diagnosis

   • RIF mass
     • Appendix mass
       • Gynae mass - ovarian cyst
         • Caecal cancer
           • Soft tissue tumour e.g. sarcoma
             • LN mass
               • TB
                 • Actinomycoses
                   • Transplant kidney
                     • Iliac aneurysm
   • RIF pain
     • Ectopic pregnancy
       • Acute appendicitis
         • PID
           • Ovarian cyst
             • Perforated PU
               • Meckel's
                 • UTI
                   • Ureteric colic
                     • Mesenteric adenitis
                       • Crohn's disease
                         • Caecal cancer
   • Periumbilical (colicky pain)
     • SBO
       • Early appendicitis
         • Ischaemic bowel
           • Mesenteric adenitis
             • Pancreatitis

6. Investigations

   • CT scan
     • Decreases false negative operation rate, but increases delay