Appendicitis

Appendicitis

1. Epidemiology

   • Primarily adolescents and young adults, uncommon in over the age of 55yrs. The female/male ratio is 1.2:1.5. Incidence of acute appendicitis approaches 20% in some reports, there has been a notable decline in the incidence for all age groups over the past 30yrs. Genetic, dietary, and infectious factors are associated. Appendiceal inflammation results from luminal obstruction of the appendiceal orifice, lymphoid hyperplasia, fecolith, or filarial worms. This inflammation allows for invasion of GI organisms through the appendix wall. There may also be impaired ability to prevent invasion

2. Symptoms & Signs

   • Diagnosis not always straight forward. Pain is the most important symptom; In general, as inflammation begins, there is central abdominal colic as a result of stimulation of the visceral pain fibers. Once the peritoneum becomes inflamed, the pain shifts to RLQ and becomes more constant Also: Tachycardia, lying still, flushing, foetor, low-grade fever, leukocytosis, anorexia, vomiting, diarrhea, constipation

3. Abdo pain referral

   • Foregut: proximal to 2nd part of duodenum, somatic referral – upper abdo, arterial supply - coeliac axis
   • Midgut: 2nd part of duodenum to 2/3 along tranverse colon, somatic referral – middle abdo, arterial supply – superior mesenteric
   • Hindgut: 2/3 along transverse colon distally, somatic referral – lower abdo, arterial supply – inferior mesenteric

4. Examination

   • RLQ point tenderness (^ pain on palpation) or rebound tenderness (^ pain on release) may be present. Rovsing’s sign (pain more in the RLQ than the LLQ when the LLQ is pressed. RLQ pain may also be elicited on rectal exam. In women, do a vaginal examination: Does she have cervical motion tenderness or discharge. RE - EXAMINE frequently if unsure of diagnosis

5. Differential diagnosis

   • Ectopic pregnancy, mesenteric adenitis, cystitis, cholecystitis, diverticulitis, salpingitis, menstrual cramps, crohn’s disease, ovarian cyst or abscess, kidney stone, meckel’s diverticulitis

6. Investigations

   • Wbc— leukocytosis, urinalysis— WBC ’s and bacteria indicating bladder infection (can be misleading); RBC s which may suggest kidney stone. Pregnancy test. AXR— usually demonstrates a paucity of gas in the RLQ , may see fecolith. Abdo CT— highly sensitive for appendiceal inflammation (thickening of appendiceal wall) but can not always separate acute and chronic inflammation. Abdo USS— sensitive for evaluation of ovarian cyst or abscess, hydrosalpinx

7. Alvarado Score

   • Poor sensitivity but shows important features to monitor. Features: Migration of pain =1, Nausea/vomiting =1, Anorexia =1, RIF tenderness =2, Rebound pain =1, Temp >37.3C =1, WCC>10x10*9/L =2, Neutrophil count >75% =1. Total score: if 4 or less =diag unlikely, 5-6 =observe, 7+ =operation needed

8. Complications of acute appedicitis

   • Perforation, appendix mass (when an inflamed appendix becomes covered with omentum or loops of small bowel), appendix abscess (if an appendix mass fails to resolve. Signs include enlargement of the mass or pt becoming toxic (pain^; temperature^; pulse^; WBC ^)

9. Treatment

   • Mass: Usually conservative— NPO and antibiotics (eg cefuroxime IV and metronidazole IV ). Mark out the size of the mass, drain if it develops into an abscess. If the mass resolves some perform an interval (ie delayed) appendicectomy.
   • Abscess: Usually drainage, either surgical or percutaneous (under radiological guidance). Antibiotics alone may bring about resolution, eg in >90% of children. Surgical treatment Once decision is made to operate, make patient NPO and hydrate with NS. Metronidazole + cefuroxime 1 to 3 doses IV starting 1h pre-op, reduces wound infections
   • Appendectomy : Laporascopically or through a RLQ incision at McBurney’s Point (one-third the distance between the anterior superior iliac crest and the umbilicus). Metronidazole + cefuroxime 1 to 3 doses IV starting 1h pre-op, reduces wound infections. Laparoscopic appendectomy reduces recovery time and incidence of wound infections, but increases risk of intra-abdominal abscesses. If the appendix is perforated, most advocate closing the fascia but leaving the wound open for closure by secondary intention