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.
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