The vermiform appendix is considered by most to be a vestigial organ, its importance in surgery is only due to its tendency for inflammation resulting in the syndrome called acute appendicitis .
Acute appendicitis is the most common cause of an “acute abdomen” in young adults.
Appendectomy is the most frequently performed urgent abdominal operation
Despite extraordinary advances in the modern radiographic imaging & laboratory investigations, the diagnosis of appendicitis remains essentially clinical requiring a mixture of observation, surgical science & clinical sense.
The vermiform appendix is present only in mammals.
The position of the appendix is variable:
- Retrocecal 74%.
- Pelvic 21%.
- Postileal 5%.
- Paracecal 2%.
- Subcecal 1.5%.
- Preileal 1%.
The position of the base of the appendix is constant, being found at the confluence of the 3 taenia coli of the cecum which fuse to form the outer longitudinal muscle coat of the appendix.
The mesentery of the appendix (mesoappendix) arises from the lower surface of the mesentery of the terminal ileum.
The appendicular artery , a branch of the lower division of the ileocolic artery lie in the free border of the mesoappendix. It is an “end-artery”, thrombosis of which results in necrosis of the appendix (gangrenous appendicitis).
Acute appendicitis is relatively rare in infants, becomes increasingly common in childhood & early adult life, reaching a peak incidence in the teens & early 20s.
After middle age, the risk of developing acute appendicitis in the future is quite small.
Etiology: There is no unifying hypothesis regarding the etiology of acute appendicitis.
While appendicitis is associated with bacterial proliferation within the appendix, no single organism is responsible, mixed growth of aerobic & anaerobic organisms is usual.
Obstruction of the appendix lumen is important, some form of luminal obstruction by either a fecolith or stricture is found in the majority of cases.
Obstruction of orifice by tumor (carcinoma of the cecum) is a cause of acute appendicitis, in middle age & elderly.
Obstruction of the lumen is essential for development of appendiceal gangrene & perforation.
In early appendicitis, the lumen is patent despite mucosal inflammation & lymphoid hyperplesia.
In children & young adults, an infective agent possibly viral initiates the inflammatory process, which within the narrow lumen of the appendix leads to luminal obstruction.
Once obstruction occurs, continued mucus secretion & inflammatory exudation increase intraluminal pressure, obstructing lymphatic drainage.
Edema & mucosal ulceration develop with bacterial translocation to the submucosa.
Resolution could occur at this point, whether spontaneous or in response to antibiotic therapy.
Progression of the condition leads to further distension of the app. Causing venous obstruction & ischemia of the app. Wall.
With ischemia, bacterial invasion occurs through the muscularis propria & submucosa.
Finally, ischemic necrosis of the appendix wall produces gagrenous appendicitis , with free bacterial contamination of the peritoneal cavity.
Alternatively, the greater omentum & loops of small intestine become adherent to the inflamed app., walling off the spread of peritoneal contamination resulting in appendicular mass or paracecal abscess.
Rarely, appendiceal inflammation resolves leaving a distended mucus filled organ termed mucocele of the appendix.
The great threat of acute appendicitis is the potential for peritonitis , factors which promote this process: 1) extremes of age, 2) immunosupression, 3) D.M., 4) fecolith obstruction of the appendix lumen, 5) a free lying pelvic appendix, & 6) previous abdominal surgery which limits the ability of the greater omentum to wall off the spread of peritoneal contamination.
In these situations a rapidly deteriorating clinical course is accompanied by signs of diffuse peritonitis & systemic sepsis syndrome.
Clinical diagnosis - History
Pain shifts to right iliac fossa
Clinical features of appendicitis
The classical features of acute appendicitis begin with poorly localized colicky abdominal pain, due to midgut visceral discomfort in response to appendiceal inflammation.
Pain is frequently first noticed in the periumbilical region, associated with anorexia, nausea, once or 2 episodes of vomiting. Anorexia is constant feature especially in children.
With progressive inflammation, the parietal peritoneum in the rt. iliac fossa becomes irritated, producing intense more localized, constant somatic pain . Typically, cough or sudden movement exacerbates the rt. iliac fossa pain.
This typical sequence is present in 50% of cases. Atypical presentation is common: elderly (no localization), pelvic app. (no somatic pain, suprapubic discomfort & tenesmus).
No fever during the first 6 hours, then slight pyrexia (37.2-37.7), pulse rate (80-90).
Typically, 2 clinical syndromes of acute appendicitis: acute catarrhal (nonobstructive) & acute obstructive appendicitis . The latter is characterized by a much more acute course, the onset of symptoms is abrupt, with more tendency for perforation.
Clinical diagnosis - Signs
Localized tenderness in the rt. iliac fossa
Clinical signs of appendicitis
Signs to elicit in appendicitis
The diagnosis of acute appendicitis depends on clinical examination rather than history or investigations.
The main features : unwell patient, low grade fever.
Patient is asked to point where the pain began & to where it moved, (pointing sign).
Superficial palpation starting from the left iliac fossa, anticlockwise to the right iliac fossa, will detect muscle guarding over the point of maximum tenderness, classically McBurney’s point .
Asking the patient to cough or gentle percussion rebound tenderness.
Deep palpation over the left iliac fossa pain in the right iliac fossa (Rovsing’s sign).
If the appendix lies over the psoas muscle the patient will lie with the right hip flexed for pain relief (Psoas sign).
If the appendix is in contact with the obturator internus muscle, flexion & internal rotation of the hip pain in the hypogastrium (Obturator sign).
Special features – according to position of the appendix
Rigidity is often absent, even on deep pressure (silent appendix), as the cecum (distended with gas prevents the pressure exerted by the hand to reach the appendix.
+ve deep tenderness in the loin, with +ve psoas sign & pain on hyperextension of the hip joint.
Early diarrhea (rectal irritation), -ve abdominal rigidity, P/R: shows tenderness in the rectovesical or Douglas pouch. +ve psoas & obturator signs. If appendix is in contact with urinary bladder frequency of micturition.
Special features – according to age
Rare before 3 years, patient is unable to give history, diagnosis is often delayed, high incidence of perforation & morbidity.
Rapid diffuse peritonitis as the greater omentum is not developed no localization of infection.
Gangrene & perforation occur more frequently, the clinical picture may simulate subacute intestinal obstruction.
Coincident medical conditions produce higher mortality.
Obesity may obscure local signs of acute appendicitis, causing delay in diagnosis, technical operative difficulty may necessitate midline incision.
Appendicitis with pregnancy
Appendicitis is the most common extrauterine acute abdominal condition in pregnancy.
Early non-specific symptoms are often attributed to the pregnancy leading to delayed diagnosis.
The cecum & appendix are pushed to the right upper abdominal quadrant atypical site of pain & tenderness.
The inflamed appendix may induce uterine irritation & contractions abortion.
Fetal loss occurs in 3-5% of cases, increasing to 20% if perforation is found at operation.
Torsion/ruptured ovarian cyst
Rectus sheath hematoma
Elderly Female Adult Children
Acute gastroenteritis :
Intestinal colic, diarrhea, vomiting, but no localized tenderness, history of affection of other family member.
Postileal appendicitis mimic this condition, thus hospital admission & careful observation are necessary. If serious doubt, laparoscopy or surgical intervention may be indicated.
The pain is colicky in nature, patient is completely free in between attacks, which lasts for few minutes, cervical lymph nodes may be enlarged.
Shifting tenderness if the child turns to the left side is convincing evidence.
It represents a common diagnostic difficulty in children, if doubt exploration is advised.
It may be impossible to distinguish from acute appendicitis, pain may be central or left sided, previous attacks of abdominal pain or anemia.
It is important to differentiate between both conditions.
Appendicitis is uncommon between <2 years, the median age for intussusception is 18 months.
A mass may be palpable in the right lower quadrant.
The preferred treatment for intussusception is reduction by a careful barium enema.
Often preceded by sore throat or respiratory infection. Nearly always ecchymotic rash in the extensor surface of the limbs & buttocks, the face is usually spared.
Lobar pneumonia & pleurisy:
Especially at the right lung base, abdominal tenderness is minimal, pyrexia marked, chest examination reveals pleural friction rub or altered breath sounds. Chest x-ray is diagnostic.
May be nonspecific, due to Crohn’s disease or Yersinia infection.
In its acute form, may be indistinguishable from acute appendicitis unless a doughy mass of inflamed ileum can be felt.
Previous history of abdominal cramping, weight loss & diarrhea suggests regional ileitis rather than appedicitis.
Does not commonly cause diagnostic problem, the character & radiation of pain is different.
Differentiate by urine analysis, plain abdominal x-ray film.
Renal U/S or I.V.P. is diagnostic.
Right-sided acute pyelonephritis:
Accompanied & often preceded by increased frequency of micturition.
The leading features: tenderness confined to the loin, fever (39), rigors & pyuria.
Perforated peptic ulcer:
Duodenal contents pass along the paracolic gutter to the right iliac fossa.
History of dyspepsia & very sudden onset of pain, which starts in the epigastrium & passes down the right paracolic gutter.
Rigidity & tenderness in the right iliac fossa as appendicitis, but is usually greater in the right hypochondrium.
Plain x-ray erect shows air under diaphragm.
In teenager or young adult, easily missed, pain can be referred to the right iliac fossa.
Patient may be shy to reveal, missed if the testis were not examined.
Should be suspected in any adult with acute abdomen.
Serum & urinary amylase are diagnostic.
Rectus sheath hematoma:
Rare, acute pain & tenderness in right iliac fossa, no gastrointestinal upset.
Usually after vigorous exercise, or trauma to a patient on anticoag.
Pelvic disease in women of child-bearing period most often simulates acute appendicitis.
A careful gynecological history should be taken in all women with suspected acute appendicitis concentrating on menstrual cycle, vaginal discharge & possible pregnancy.
Condition that poses greatest difficulty in young women.
Typically the pain is lower than in appendicitis & is bilateral.
History of vaginal discharge & dysmenorrhea are helpful points.
Opinion of gynecologist may be helpful.
If uncertain, diagnostic laparoscopy should be undertaken.
Midcycle rupture of a follicular cyst with bleeding produces lower abdominal & pelvic pain, typically midcycle.
Systemic upset is rare, pregnancy test is –ve, symptoms usually subsides within hours.
Occasionally, diagnostic laparoscopy is required.
Torsion/hemorrhage of an ovarian cyst
Can be difficult diagnostic problem.
When suspected, pelvic U/S & gynecological opinion should be sought.
If encountered at operation, ovarian cystectomy should be performed, with visualization of the contralateral ovary.
A ruptured ectopic pregnancy can be easily differentiated from acute appendicitis, well defined signs of hemoperitoneum.
But right sided tubal abortion or right sided unruptured tubal pregnancy are difficult to differentiate.
Signs are similar to acute appendicitis except for:
1) History of missed period.
2) Pain starts in the right iliac fossa & stays there.
3) Pain is severe & continues until operation.
4) Severe pain is felt if the cervix is moved on vaginal examination.
5) Pregnancy test is +ve.
6) Signs of intraperitoneal bleeding with pain referred to the shoulder. Pelvic U/S should be carried out if suspected.
If long sigmoid loop, colon lies to the right of midline, may be impossible to differentiate between diverticulitis & appendicitis.
May be history of chronic constipation, colonic troubles.
If suspected, investigations & conservative treatment with fluids & antibiotics should be started.
Signs of I.O. are clear.
Cons. treatment with I.V. fluids, antibiotics & nasogastric decompression is started.
Carcinoma of the cecum:
When obstructed or perforated, may mimic or cause obstructive appendicitis.
History of discomfort, altered bowel habit or unexplained anemia should raise suspicion.
A mass may be palpable, barium enema & colonoscopy are diagnostic.
The diagnosis of acute appendicitis is essentially clinical.
-Full blood count.
-Pregnancy test (females in child bearing period).
-Plain abdominal x-ray (int. obstruction or renal colic).
The treatment of acute appendicitis is appendectomy.
Urgent operation is essential to prevent the increased morbidity & mortality of peritonitis.
There should be no unnecessary delay except for correction of unstable general condition (adequate U.O.P., pyrexia & preoperative preparation of elderly patient).
Single preoperative dose of antibiotics is usually sufficient to prevent wound infection.
If peritonitis is suspected, therapeutic I.V. antibiotics for Gram-negative & anerobic bacteria should be given.
Either conventional open operation or laparoscopic technique.
Laparoscopic: nasogastric tube & empty bladder.
Palpation for mass in R.I.F.
Incision: grid-iron, Rutherford Morison, Lanz.
Technique of appendectomy.
- Edema of the cecal wall.
-Base of the app. severely inflamed.
-Gangrenous app. base.
-Drainage of the peritoneal cavity ??
The valuable aspect of laparoscopy in the management of suspected appendicitis is as a diagnostic tool, especially in women of child-bearing age.
Problems encountered during appendectomy
A normal appendix is found:
This demands careful exclusion of other possible diagnoses, particularly terminal ileitis, Meckel’s diverticulitis & tubal or ovarian causes in women.
It is usual to remove the appendix to avoid future diagnostic problems, even though the appendix is macroscopically normal.
Approximately a quarter of seemingly normal appendices show microscopic evidence of inflammation.
The appendix cannot be found:
The cecum should be mobilized & the tenia coli traced to their confluence before the diagnosis of absent appendix is made.
An appendicular tumor is found:
Tumors <2.0 cm. in diameter can be removed by appendectomy.
Larger tumors should be treated by right hemicolectomy.
An appendix abscess is found: & appendix cannot be removed easily.
Should be treated by local peritoneal toilet & drainage of any abscess, with I.V. antibiotics.
Appendicitis complicating Crohn’s disease:
Patient operated for appendicitis found to have concomitant Crohn’s disease of the ileocecal region.
Provided the cecal wall is healthy at the base of the appendix, appendectomy can be performed without increasing the risk of enterocutaneous fistula.
Rarely the appendix is involved with the Crohn’s disease, a conservative approach may be undertaken, with a trial of I.V. steroids & systemic antibiotics to resolve the acute inflammatory process.
Failure of resolution of an appendix mass or continuing spiking fever indicates pus in the appendix mass.
U/S or abdominal CT scan identify the possibility of percutaneous drainage, if unsuccessful, laparotomy through a midline incision.
Management of an appendix mass
If the condition of the patient is satisfactory, the standard treatment is the conservative Ochsner-Sherren regimen.
The inflammatory process is already localized & surgery is difficult & may be dangerous.
It may be impossible to find the appendix & a fecal fistula may form.
So, non-operative program is advised, to be prepared to operate if clinical deterioration occurs:
1) A rising pulse rate.
2) Increasing or spreading abdominal pain.
3) Increasing size of the mass.
4) Vomiting or increase gastric aspirate.
Careful record of the vital signs, regular abdominal examination, extent of the mass, it is helpful to mark the limits of the mass on the skin. A nasogastric tube with I.V. fluids & antibiotics therapy.
Clinical improvement is usually evident within 24-48 hrs. in 90% of cases.
Appendix should be removed after an interval of 6-8 weeks.
Relatively uncommon & reflect the degree of peritonitis that was present at the time of operation.
Most common, occurs in 5-10% of all cases.
Presents with pain & erythema of the wound on the fourth or fifth postop. day.
Treatment: by wound drainage & antibiotics, the organisms responsible are usually gm –ve & anerobic bacteria.
Rare after the use of perioperative antibiotics.
Postoperative spiking fever, malaise & anorexia 5-7 days postoperatively.