Acute appendicitis

Epidemiology:

• Most common surgical emergency
• Lifetime incidence of 6%

Pathogenesis:

Gut organisms invade the appendix wall after lumen obstruction by:

Lymphoid hyperplasia

Faecalith (a small, hard mass of faeces)

Filarial worms

There may be impaired ability to prevent invasion, brought about by improved hygiene (so less exposure to gut pathogens), the so called ‘hygiene hypothesis’.

Symptoms:

• As inflammation begins – central abdominal colic
• Once peritoneum inflamed – pain shifts to RIF and becomes more constant
• Anorexia
• Constipation
• Vomiting (occasionally)
• Diarrhoea (occasionally)

Signs:

• Tachycardia

• Pyrexia (37.5˚-38.5˚)
• Shallow breathing
• Furred tongue
• Coughing hurts
• Lying still

Signs in RIF:

• Tenderness
• Guarding
• Rebound tenderness
• Painful PR on right

Differential dx (in no particular order):

• Ectopic pregnancy
• Mesenteric adenitis (inflammation of mesenteric lymph nodes)
• Food poisoning
• Diverticulitis
• Salpingitis (inflammation of one/both Fallopian tube(s))
• Cholecystitis (inflammation of the urinary bladder)
• Perforated ulcer
• Crohn’s disease
• Cystitis

Acute appendicitis

Management:

• Prompt appendicectomy
• 3 doses IV A/Bs starting 1 hr pre-op decreases wound infections (Metronidazole 1g/8h + Cefuroxime 1.5g/8h)

Complications:

• Perforation leading to peritonitis (with later infertility in girls)
• Appendix mass (inflamed appendix surrounded by omentum)
• Appendix abscess

Appendicitis in pregnancy:

• 1 in 2000 pregnancies
• Pain/tenderness is higher due to displacement of appendix by uterus
• Appendicectomy is well tolerated but foetal mortality approaches 30% after perforation.