APPENDICITIS

Introduction – Appendix is a blind muscular tube with mucosal, submucosal, muscular  & serous layers. At birth the appendix is short & broad at its junction with caecum but differential growth of the caecum produces the typical tubular structure by about the age of two years. During childhood continued growth of the caecum commonly rotates the appendix into a retrocaecal but intraperitoneal position.

figure:Appendix

Position of the appendix –according to the position of the tip

1)       Retrocaecal -74%

2)       Pelvic         -21%

3)       Para caecal -2%

4)       Sub caecal  -1.5%

5)       Pre ileal      -1%

6)       Post ileal     -.5%

Position of the base of the appendix is constant being found at the confluence of the three taeniae colli of the caecum which fuse to form the outer longitudinal muscle coat of the appendix.The mesentery of the appendix arise from the lower surface of the mesentery or the terminal ileum and itself a subject to great variation.

The average length of the appendix is between 7.5 and 10 cm.

ACUTE APPENDICITIS

Incidence – Acute appendicitis is rare in infant and becomes increasingly common in childhood and early adult life, reaching a peak incidence in the teen and early 20s. After middle age the risk of developing appendicitis is quite small. The incidence is equal among male and female before puberty.

Aetiology –There is no unifying hypothesis regarding the aetiology of acute appendicitis. Decrease dietary fibre & increased consumption of refined carbohydrate may be important.

Appendicitis due to bacterial proliferation, no single organism is responsible but a mixed growth of aerobic and anaerobic organism is usual.

Obstruction of the appendix lumen has been widely held to be important, either by a faecolith or a stricture is found in majority of cases. Faecolith is composed of inspissated faecal material, calcium phosphate, bacteria & epithelial debris. The incidental findings of faecolith is a relative indication for prophylactive appendicectomy. A fibrotic stricture of the appendix usually indicates previous appendicitis that resolves without surgical intervention.

PATHOLOGY – Obstruction of the appendiceal lumen seems to be essential for the development of appendiceal gangrene & perforation. Once obstruction occur contineous mucous secretion & inflamatory exudates increased intra-luminal pressure, obstructing lymphatic drainage. Oedema and mucosal ulceration develop with bacterial translocation to the sub mucosa. If condition progress, further distension of the appendix may cause venous obstruction and ischaemia of the appendix wall. With ischaemia, bacterial invasion occur through the muscularis  propria and sub mucosa producing acute appendicitis. Finally ischaemic necrosis of the appendix wall produces gangrenous appendicitis with free bacterial contamination of the peritoneal cavity. Alternatively the greater omentum & loops of small intestine adherent to the  inflamed appendix, walling off the spread of  peritoneal contamination and resulting in a phlegmonass mass or para caecal abscess. Peritonitis occurs as a result off free migration of bacteria through an ischaemic appendicular wall, the frank perforation off the gangrenous appendix or the delayed perforation of an appendix abscess.

RISKFACTORS FOR PERFORATIONOF APPENDIX

1)       Extremes of age .

2)       Immuno suppression

3)       Diabetes Mellitus

4)       Faecolith obstruction

5)       Pelvic appendix

6)       Previous abdominal surgery

SYMPTOMS OF APPENDICITIS

Peri umbilical colic

Pan shifted to RIF

Anorexia

Nausea, vomiting

CLINICAL SIGNS

Pyrexia

Localized tenderness in RIF

Muscle guarding

Rebound tenderness

SIGNS TO ELICIT IN APPENDICITIS

Pointing sign

Rovsing’s sign

Psoas sign

Obturator sign

DIFFERENTIAL DIAGNOSIS

Children

Gastro enteritis

Mesenteric adenitis

Meckel’s diverticulitis

Intussusception

Henoch-Schonlein purpura

Lobar pneumonia

Adult

Regional enteritis

Ureteric colic

Perforated peptic ulcer

Torsion of the testes

Pancreatitis

Restus sheath haematoma

    Adult female

    Pelvic inflamatory disease

    Pyelonephritis

    Ectopic pregnancy

Torsion/ rupture of ovarian cyst

Endometriosis

   

Elderly

    Diverticulitis

    Intestinal obstruction

    Colonic carcinoma

    Torsion Appendix epiploicae

    Mesenteric infarction

    Leaking aortic aneurysm

    INVESTIGATION

    Routine

    Full blood count

    Urinalysis

    Selective

    Pregnancy test

    Urea & electrolytes

    Supine abdominal radiograph

    Ultrasound of the abdomen/ pelvis

    Contrast enhanced CT scan of the abdomen

TREATMENT- The treatment of acute appendicitis is appendicectomy. Appendicectomy may be performed by conventional open operation or by using laparoscopic techniques.

PROBLEMS ENCOUNTERED DURING APPENDICECTOMY

1)       A normal appendix is found

2)        Appendix can not be found

3)       Appendicular tumour is found

4)       Appendix abscess is found and the appendix can not be removed easily

Complications of acute appendicitis

1) Appendicular lump

2) Appendicular abscess

3) Gangrenous appendix

4) Burst appendix

5) Pelvic abscess

 

Pelvic abscess-  Pelvic abscess formation is an occasional complication of appendicitis and can occur irrespective of

the position of the appendix within the peritoneal cavity. The most common presentation is a spiking pyrexia several days following appendicitis. Pelvic pressure or discomfort associated with loose stool or tenesmus is common. Rectal examination reveals a boggy mass in the pelvis, anterior to the rectum, at the level of the peritoneal reflection. Pelvic ultrasound or CT scan will confirm. Treatment is trans-rectal

drainage under general anaesthesia.