Appendicitis

Appendicitis

·        = Acute Suppurative Appendicitis

·        Lifetime incidence = 6%

·        Most common surgical emergency

·        Incidence declining (?­Hygiene ® ¯pathogen exposure)

·        Gut organisms invade appendix wall after lumen obstruction

·        If suspected then nil by mouth.  If no diarrhoea or vomiting then no immediate danger of dehydration

·        If you diagnose it, or if you don‟t, you‟ll be wrong 50% of the time!

Symptoms & Signs

·        Very difficult to diagnose – considerable variety in presentation 

·        Fever: 37.5 – 38.5. Typically low grade. Higher if perforated. Swinging fever more typical of an abscess

·        Pain:

o  Initially: central abdominal colic (obstructed appendix and ­lumen pressure)

o  Ball-valve relief of obstruction often leads to colicky pain

o  Once peritoneum inflamed: constant RIF pain.

o  If perforated: generalised tenderness, maybe distension.  If really sick, abdomen may not be hard

o  However, considerable variation – pain may stay central, may be situated elsewhere in abdomen

o  Lying on back and lying still, coughing hurts (peritonitis) 

o  Push on left side ® hurts more on right 

o  Evoking pain: cough or hop on right leg. In a child, look for tenderness and guarding – not rebound – won‟t let anyone touch them after that.

·        Systemic signs:

o  Kids: vague pain, off food (won‟t eat favourite food), diarrhoea, vomiting

o  Elderly: shocked, confused, no pain

o  Anorexia, maybe vomiting

o  Constipation or diarrhoea

o  Tachycardia (not always)

·        May be urinary symptoms and signs: especially in children with appendix in the pelvis – e.g. dysuria, white cells in urine (always do dipstick)

Differential

·        Appendicitis may co-exist with acute tonsillitis, pneumonia, UTI or even gastro-enteritis

·        Salpingitis in female, ectopic pregnancy, food poisoning, diverticulitis, cholecystitis, perforated ulcer, cystitis, Crohn‟s disease, inflammation of Meikels diverticulum (if operate and appendix OK, always check a metre up the small bowel), radiation of torsion of right testis, strangulated inguinal hernia, pyelonephritis

Pathology

·        Pathogenesis: Obstruction of the lumen (faecal, tumour, worms) ® ­intraluminal pressure ® ischaemia and bacterial invasion ® inflammation ® ­oedema

·        Macroscopic appearance: congested, dull, fibropurulent exudate on serosa, luminal abscess, gangrene, rupture

·        Microscopic appearance: neutrophils in mucosa, submucosa and muscularis propria, necrosis +/-abscess

Treatment

·        If not sure, observe: it will get better or worse

·        Supportive care: IV, NG, restore hydration

·        Appendicectomy

·        Metronidazole + cefuroxime (reduce wound infection)

Children

·        Anatomic variations:

o   Typical site only 30 – 40% of time 

o   PR: pain on right side ® retrocaecal appendix (30%). Pain may radiate up right flank. May be no abdominal tenderness 

o   Pelvic (23%).  If in contact with bladder ® sterile pyuria.  If in contact with sigmoid ® diarrhoea

·        Course accelerated: 

o   Tiny lumen, ­inflammation, perforate quickly

o   Dehydration, tachycardia and shock

o   Board-like abdomen after resuscitation

·        Treatment:

o   Resuscitation first: HG, IV, antibiotics 

o   Operate when: ­urine output, ¯temperature, ¯pulse rate. Anaesthetics ® vasodilation and cardiac depression ® ¯¯ BP if not well hydrated

Complications

·        Wound infection

·        Perforation ® peritonitis ® infertility in girls (Þ lower threshold for surgery in girls)

·        Abscess

·        Bowel obstruction (related to perforation ® adhesions)

Other Disorders of the Appendix

·        Mucocoele of the appendix: dilation of the appendiceal lumen by mucus duct hyperplasia (either benign or malignant)

·        Pseudomyxoma peritonei: „Jelly Belly‟. Mucinous cystadenocarcinoma invading the peritoneum, fills with tenacious semisolid mucus. Treated with serial resection