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Vermiform Appendix
Professor Mahmoud Al-Mukhtar MD FRCS(Eng,Glasg & Dublin) FACS
The vermiform appendix :
This organ is considered to be a vestigial organ but its importance in clinical surgery results from its
propensity for inflammation, which results in the clinical syndrome known as (acute appendicitis). Acute
appendicitis is the most common cause of an ‘acute abdomen’ in young adults in routine general surgical
practice.
Surgical Anatomy :
1. Macroscopic anatomy :
The vermiform appendix is present only in humans, certain anthropoid apes and the wombat. It is a blind
muscular tube with mucosal, , muscular and serosal layers. Morphologically, it is the undeveloped distal end
of the large caecum found in many lower animals. At birth, the appendix is short and broad at its junction
with the caecum, but differential growth of the caecum produces the typical tubular structure by about the
age of 2 years. During childhood, continued growth of the caecum commonly rotates the appendix into a
retrocaecal but intraperitoneal position. In approximately one quarter of cases, rotation of the appendix does
not occur, resulting in a pelvic, subcaecal or paracaecal position. The position of the base of the appendix is
constant, being found at the confluence of the three taeniae coli of the caecum, which fuse together to form
the outer longitudinal muscle coat of the appendix. At operation, use can be made of this to find an elusive
appendix, as gentle traction on the taeniae coli, particularly the anterior taenia, will lead the operator to the
base of the appendix.
2. Microscopic anatomy :
The average length is between (7.5-10) cm. Crypts are present but are not numerous. In the base of the
crypts lie Argentaffin cells (Kulchitsky cells),which may give rise to carcinoid tumours (see below). The
appendix is the most frequent site for carcinoid tumours, which may present with appendicitis due to
occlusion of the appendiceal lumen. The submucosa contains numerous lymphatic aggregations or follicles.
AcuteAppendicitis :
Recognition of acute appendicitis as a clinical entity is attributed to Reginald Fitz, afterwards, Charles
McBurney described the clinical manifestations of acute appendicitis including the point of maximum
tenderness in the right iliac fossa that now bears his name. The incidence of appendicitis seems to have risen
greatly in the first half of this century with up to 16% of the population undergoing appendicectomy. In the
past 30 years, the incidence has fallen dramatically in these countries, such that the individual lifetime risk
of appendicectomy is 8.6% - 6.7% among males and females respectively. Acute appendicitis is relatively
rare in infants, and becomes increasingly common in childhood and early adult life, reaching a peak
incidence in the teens and early 20s. After middle age, the risk of developing appendicitis is quite small. The
incidence of appendicitis is equal among males and females before puberty. In teenagers and young adults,
the male/female ratio increases to 3:2 at age 25, thereafter, the greater incidence in males declines. The
incidence of appendicitis is lowest in societies with a high dietary fibre intake to rise. This is in contrast to
the dramatic decrease in the incidence of appendicitis in western countries observed in the past 30 years. No
reason has been established for these paradoxical changes; however, improved hygiene and a change in the
pattern of childhood gastrointestinal infection related to the increased use of antibiotics may be responsible.
While appendicitis is clearly associated with bacterial proliferation within the appendix, no single organism
is responsible. A mixed growth of aerobic and anaerobic organisms is usual.
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The initiating event causing bacterial proliferation is controversial. Obstruction of the appendix lumen has
been widely held to be important, and some form of luminal obstruction, either by a faecolith or a stricture,
is found in the majority of cases. A faecolith is composed of inspissatedfaecal material, calcium phosphates,
bacteria and epithelial debris. Rarely, a foreign body is incorporated into the mass. The incidental finding of
a faecolith is a relative indication for prophylactic appendicectomy. Obstruction of the appendiceal orifice
by tumour, particularly carcinoma of the caecum, is an occasional cause of acute appendicitis in middle-
aged and elderly patients. Intestinal parasites, particularly Oxyuris vermicularis (pinworm), can proliferate
in the appendix and occlude the lumen.
Pathology :
Obstruction of the appendiceal lumen seems to be essential for the development of appendiceal gangrene
and perforation. Yet, in many cases of early appendicitis, the appendix lumen is patent despite the presence
of mucosal inflammation and lymphoid hyperplasia. Occasional clustering of cases among children and
young adults suggests an infective agent, possibly viral, which initiates an inflammatory response. Seasonal
variation in the incidence is also observed, with more cases occurring between May and August in northern
Europe than at other times of the year. Lymphoid hyperplasia narrows the lumen of the appendix, leading to
luminal obstruction. Once obstruction occurs, continued mucus secretion and inflammatory exudation
increase intraluminal pressure obstructing lymphatic drainage. Oedema and mucosal ulceration develop with
bacterial translocation to the submucosa. Resolution may occur at this point either spontaneously or in
response to antibiotic therapy. If the condition progresses, further distension of the appendix may cause
venous drainage obstruction
Muscularis propria and submucosa, producing acute appendicitis.contamination of the peritoneal cavity.
Alternatively, the greater omentum and loops
of small bowel become a obstruction and ischaemia of the appendix wall.With ischaemia, bacterial invasion
occurs through the dherent to the inflamed appendix, walling off the spread of peritoneal contamination, and
resulting in a phlegmonous mass or paracaecal abscess. Rarely, appendiceal inflammation resolves, leaving
a distended mucus-filled organ termed a mucocele of the appendix..It is the potential for peritonitis that is
the great threat of acute appendicitis. Peritonitis occurs as a result of free migration of bacteria through an
ischaemic appendicular wall, the frank perforation of a gangrenous appendix or the delayed perforation of an
appendix abscess. Factors that promote this process include extremes of age, immunosuppression, diabetes
mellitus and faecolith obstruction of the appendix lumen, a free-lying pelvic appendix and previous
abdominal surgery that 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 and systemic sepsis syndrome.
Clinical diagnosis :
History :
The classical features of acute appendicitis begin with poorly localised colicky abdominal pain. This is due
to mid-gut visceral discomfort in response to appendiceal inflammation and obstruction.
The pain is frequently first noticed in the peri-umbilical region and is similar to, but less intense than, the
colic of small bowel obstruction. Central abdominal pain is associated with anorexia, nausea and usually one
or two episodes of vomiting that follow the onset of pain. Anorexia is a useful and constant clinical feature,
particularly in children. The patient often gives a history of similar discomfort that settled spontaneously. A
family history is also useful as up to one-third of children with appendicitis have a first-degree relative with
a similar history With progressive inflammation of the appendix, the parietal peritoneumin of the right iliac
fossa becomes irritated, producing more intense, constant and localised somatic pain that begins to
predominate. Patients often report this as an abdominal pain that has shifted and changed in character.
Typically, coughing or sudden movement exacerbates the right iliac fossa pain.The classic visceral–somatic
sequence of pain is present in only about half of those patients subsequently proven to have
acute appendicitis. Atypical presentations include pain that is predominantly somatic or visceral and poorly
localised. Atypical pain is more common in the elderly, in whom localisation to the right iliac fossa is
unusual. An inflamed appendix in the pelvis may never produce somatic pain involving the anterior
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abdominal wall, but may instead cause suprapubic discomfort and tenesmus.In this circumstance, tenderness
may be elicited only on rectal examination and is the basis for the recommendation that a rectal examination
should be performed on every patient who presents with acute lower abdominal pain.
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Risk factors for perforation of the appendix :
1. Extremes of age
2. Immunosuppression
3. Diabetes mellitus
4. Faecolith obstruction
5. Pelvic appendix
6. Previous abdominal surgery
During the first 6 hours, there is rarely any alteration in temperature or pulse rate. After that time, slight
pyrexia (37.2–37.7°C) with a corresponding increase in the pulse rate to 80 or
90 is usual. However, in 20% of patients, there is no pyrexia or tachycardia in the early stages. In children, a
temperature greater than 38.5°C suggests other causes, e.g. mesenteric adenitis. Typically, two clinical
syndromes of acute appendicitis can be discerned, acute catarrhal (non-obstructive) appendicitis and acute
obstructive appendicitis. The latter is characterised by a much more acute course. The onset of symptoms is
abrupt, and there may be generalised abdominal pain from the start. The temperature may be normal and
vomiting is common, so that the clinical picture may mimic acute intestinal obstruction. Once recognised,
urgent surgical intervention is required because of the more rapid progression to perforation.
Abdominal Signs :
The diagnosis of appendicitis rests more on thorough clinical examination of the abdomen than on any
aspect of the history or laboratory investigation. The cardinal features are those of an unwell patient with
low-grade pyrexia, localised abdominal tenderness, muscle guarding and rebound tenderness at the right
iliac fossa. Inspection of the abdomen may show limitation of respiratory movement in the lower abdomen.
The patient is then asked to point to where the pain began and to where it moved (the pointing sign). Gentle
superficial palpation of the abdomen, beginning in the left iliac fossa moving 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 over the site of maximum tenderness will elicit rebound
tenderness. Deep palpation in the left iliac fossa may cause pain in the right iliac fossa (Rovsing’s sign)
which is helpful in supporting a clinical diagnosis of appendicitis. Occasionally, an inflamed appendix lies
on the psoas muscle, and the patient, often a young adult, will lie with the right hip flexed for pain relief
(the psoas sign). Spasm of the obturator internus is sometimes demonstrable when the hip is flexed and
internally rotated. If an inflamed appendix is in contact with the obturator internus, this manoeuvre will
cause pain in the hypogastrium (the obturator sign) Cutaneous hyperaesthesia may be demonstrable in the
right iliac fossa, but is rarely of diagnostic value.
Special features according to position of the appendix :
1. Retrocaecal appenditis :
Rigidity is often absent, and even application of deep pressure may fail to elicit tenderness (silent appendix),
the reason being that the caecum, distended with gas, prevents the pressure exerted by the hand from
reaching the inflamed structure. However, deep tenderness is often present in the loin, and rigidity of the
quadratus lumborum may be in evidence. Psoas spasm, due to the inflamed appendix being in contact with
that muscle, may be sufficient to cause flexion of the hip joint. Hyperextension of the hip joint may induce
abdominal pain when the degree of psoas spasm is insufficient to cause flexion of the hip.
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2. Pelvic appenditis :
Occasionally, early diarrhoea results from an inflamed appendix being in contact with the rectum. When the
appendix lies entirely within the pelvis, there is usually complete absence of abdominal rigidity, and often
tenderness over McBurney’s point is also lacking. In some instances, deep tenderness can be made out just
above and to the right of the symphysis pubis. However in either conditions we should try to :
A- Signs to elicit in appendicitis :
1.Pointing sign.
2.Rovsing’s sign.
3.Psoas sign.
4.Obturator sign.
Summary box 67.3
B-Clinical signs in appendicitis :
1.Pyrexia.
2. Localised tenderness in the right iliac fossa.
3.Muscle guarding.
4.Rebound tenderness.
Summary box 67.2
C- Symptoms of appendicitis :
1.Peri-umbilical colic.
2.Pain shifts to the right iliac fossa.
3.Anorexia.
4.Nausea.
A per rectal examination reveals tenderness in the rectovesical pouch or the pouch of Douglas, especially on
the right side. Spasm of the psoas and obturator internus muscles may be present when the appendix is in
this position. An inflamed appendix in contact with the bladder may cause frequency of micturition. This is
more common in children.
3. Postileal appendicitis :
In this case, the inflamed appendix lies behind the terminal ileum. It presents the greatest difficulty in
diagnosis because the pain may not shift, diarrhoea is a feature and marked retching may occur. Tenderness,
if any, is ill defined, although it may be present immediately to the right of the umbilicus.
Special features according to age :
1. Infants :
Appendicitis is relatively rare in infants under 36 months of age and, for obvious reasons, the patient is
unable to give a history. Because of this, diagnosis is often delayed, and thus the incidence of perforation
and postoperative morbidity is considerably higher than in older children. Diffuse peritonitis can develop
rapidly because of the underdeveloped greater omentum, which is unable to give much assistance in
localising the infection.
2. Children :
It is rare to find a child with appendicitis who has not vomited. Children with appendicitis usually have
complete aversion to food.
3. The elderly :
Gangrene and perforation occur much more frequently in elderly patients. Elderly patients with lax
abdominal walls or obesity may harbour a gangrenous appendix with little evidence of it, and the
clinical picture may simulate subacute intestinal obstruction. These features, coupled with other co-existant
medical conditions, produce a much higher mortality for acute appendicitis in the elderly.
4. The obese :
Obesity can obscure and diminish all the local signs of acute appendicitis. Delay in diagnosis, coupled with
the technical difficulty of operating in the obese, makes it wiser to consider operating through a midline
abdominal incision. Laparoscopy is particularly useful in the obese as it may obviate the need for a large
abdominal incision.
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5. Pregnancy :
Appendicitis is the most common extrauterine acute abdominal condition in pregnancy, with a frequency of
1/1500–2000 pregnancies. Diagnosis is complicated by delay in presentation as early non-specific symptoms
are often attributed to the pregnancy. Obstetric teaching has been that the caecum and appendix are
progressively pushed up to the right upper quadrant of the abdomen as pregnancy develops during the
second and third trimesters. However, pain in the right lower quadrant of the abdomen remains the cardinal
feature of appendicitis in pregnancy. Fetal loss occurs in 3–5% of cases, increasing to 20% if perforation is
found at operation.
Differential diagnosis of acute appendicitis :
Although acute appendicitis is the most common abdominal surgical emergency, the diagnosis can be
extremely difficult at some times. There are a number of common conditions that it is wise to consider
carefully and, if possible, to exclude. The differential diagnosis differs in patients of different ages; in
women, additional differential diagnoses are diseases of the female genital tract.
1. Children :
The diseases most commonly mistaken for acute appendicitis are acute gastroenteritis and mesenteric
lymphadenitis. In mesenteric lymphadenitis, the pain is colicky in nature and cervical lymph nodes may be
enlarged. It may be impossible to clinically distinguish Meckel’s diverticulitis from acute appendicitis. The
pain is similar; however, signs may be central or left sided. Occasionally, there is a history of antecedent
abdominal pain or intermittent lower gastrointestinal bleeding. It is important to distinguish between acute
appendicitis and intussusception. Appendicitis is uncommon before the age of 2 years, whereas the median
age for intussusception is 18 months. A mass may be palpable in the right lower quadrant, and the preferred
treatment of intussusception is reduction by careful barium enema. Henoch–Schonlein purpura is often
preceded by a sore throat or respiratory infection. Abdominal pain can be severe and can be confused with
intussusception or appendicitis. There is nearly always an ecchymotic rash, typically affecting the extensor
surfaces of the limbs and on the buttocks. The face is usually spared. The platelet count and bleeding time
are within normal limits. Microscopic haematuria is common. Lobar pneumonia and pleurisy, especially at
the right lung base,
Henoch–Schonlein purpura, pancreatitis, torsion/rupture/ infarction of mesenteric or
ovarian cyst may give rise to right-sided abdominal pain and mimic appendicitis. Abdominal tenderness is
minimal, pyrexia is marked, and chest examination may reveal a pleural friction rub or altered breath sounds
on auscultation. A chest radiograph is diagnostic.
2. Adults :
Terminal ileitis in its acute form may be indistinguishable from acute appendicitis unless a doughy mass of
inflamed ileum can be felt. An antecedent history of abdominal cramping, weight loss and diarrhoea
suggests regional ileitis rather than appendicitis. The ileitis may be non-specific, due to Crohn’s disease or
Yersinia infection. Yersinia enterocolitica causes inflammation of the terminal ileum, appendix and caecum
with mesenteric lymphadenopathy. If suspected, serum antibody titres are diagnostic, and treatment with
intravenous tetracycline is appropriate. If Yersinia infection is suspected at operation, a mesenteric lymph
node should be excised and divided, with half one submitted for microbiological culture (including
tuberculosis) and other half for histopathological examination. Ureteric colic does not commonly cause
diagnostic difficulty, Ureteric colic does not commonly cause diagnostic difficulty, as the character and
radiation of pain differs from that of appendicitis. Urinalysis should always be performed, and the presence
of red cells should prompt a supine abdominal radiograph. Renal ultrasound or intravenous urogram is
diagnostic. Right-sided acute pyelonephritis is accompanied and often preceded by increased frequency of
micturition. It may cause difficulty in diagnosis, especially in women. The leading features are tenderness
confined to the loin, fever (temperature 39°C) and possibly rigors and pyuria. In perforated peptic ulcer, the
duodenal contents pass along the right paracolic gutter to the right iliac fossa. As a rule, there is a history of
dyspepsia and a very sudden onset of pain that starts in the epigastrium and passes down the right paracolic
gutter. In appendicitis, the pain starts classically in the umbilical region. Rigidity and tenderness in the right
iliac fossa are present in both conditions but, in perforated duodenal ulcer, the rigidity is usually greater in
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the right hypochondrium. An erect chest radiograph will show gas under the diaphragm in 70% of patients.
Testicular torsion in a teenage or young adult male is easily valuable when there is diagnostic difficulty. On
the part of the patient may lead the unwary examiner to suspect appendicitis unless the scrotum is examined
in all cases. Acute pancreatitis should be considered in the differential diagnosis of all adults suspected of
having acute appendicitis and, when appropriate, should be excluded by serum or urinary amylase
measurement. Rectus sheath haematoma is a relatively rare but an easily missed differential diagnosis. It
usually presents with acute pain and localised tenderness in the right iliac fossa, often after an episode of
strenuous physical exercise. Localised pain without gastrointestinal upset is the rule. Occasionally, in an
elderly patient, one taking anticoagulant therapy, a rectus sheath haematoma may present as a mass and
tenderness in the right iliac fossa after minor trauma.
3. Adult female :
Most of diseases in childbearing age in females often mimics acute appendicitis. A careful gynaecological
history should be taken in all women with suspected appendicitis, concentrating on menstrual cycle, vaginal
discharge and possible pregnancy. The most common diagnostic mimics are pelvic inflammatory disease
(PID), Mittelschmerz, torsion or haemorrhage of an ovarian cyst and right-sided ruptured ectopic pregnancy.
A. Pelvic inflammatory disease :
PID comprises a spectrum of diseases that include salpingitis, is increasing, and the diagnosis should be
considered in every young adult female. Typically, the pain is lower than in appendicitis and is bilateral. A
history of vaginal discharge, dysmenorrhea and burning pain on micturition is a helpful differential
diagnostic point. The physical findings include adenexal and cervical tenderness on vaginal examination.
When suspected, a high vaginal swab should be taken for Chlamydia trachomatis and Neisseria
gonorrhoeae culture, and the opinion of a gynaecologist should be obtained. Treatment is usually a
combination of Ofloxacin and Metronidazole. Transvaginal ultrasound can be particularly helpful in
establishing the diagnosis. When serious diagnostic uncertainty persists, diagnostic laparoscopy should be
undertaken.
B. Midcycle pain (Mittelschmerz) :
Midcycle rupture of a follicular cyst with bleeding produces lower abdominal and pelvic pain. Systemic
upset is abdominal and pelvic pain. Systemic upset is rare, a pregnancy test is negative, and symptoms
usually subside within hours. Occasionally, diagnostic laparoscopy is required. Retrograde menstruation
may cause similar symptoms.
C. Torsion/haemorrhage of a right-sided ovarian cyst :
This can prove a difficult differential diagnosis. When suspected, pelvic ultrasound and a gynaecological
opinion should be sought. If encountered at operation, untwisting of the involved adnexa and ovarian
cystectomy should be performed, if necessary, in women of childbearing age. Documented visualisation of
the contralateral ovary is an essential medico-legal precaution prior to oophorectomy for any reason.
D. Right-sided ruptured ectopic pregnancy :
It is unlikely that a ruptured ectopic pregnancy, with its well-defined signs of haemoperitoneum, will be
mistaken for acute appendicitis, but the same cannot be said for a right-sided tubal abortion, or still more for
a right-sided unruptured tubal pregnancy. In the latter, the signs are very similar to those of acute
appendicitis, except that the pain commences on the right side and stays there. The pain is severe and
continues unabated until operation.Usually, there is a history of a missed menstrual period, and a urinary
pregnancy test may be positive. Severe pain is felt when the cervix is moved on vaginal examination. Signs
of intraperitoneal bleeding usually become apparent, and the patient should be questioned specifically
regarding referred pain in the shoulder. Pelvic ultrasonography should be carried out in all cases in which an
ectopic pregnancy is a possible diagnosis.
4. Elderly :
A. Sigmoid diverticulitis :
In some patients with a long sigmoid loop, the colon lies to the right
of the midline, and it may be impossible to differentiate between sigmoid colon diverticulitis and
appendicitis. Abdominal CT scanning is particularly useful in this setting and should be considered in the
management of all patients over the age of 60 years. A trial of conservative management with intravenous
fluids and antibiotics is often appropriate, with a low threshold for explorative laparotomy in the face of
deterioration or lack of clinical response.
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B. Intestinal obstruction :
The diagnosis of intestinal obstruction is usually clear; the subtlety lies
in recognising acute appendicitis as the occasional cause in the elderly. As with diverticulitis, intravenous
fluids, antibiotics and nasogastric decompression should be started, with an early resort to explorative
laparotomy.
C. Carcinoma of the caecum :
When obstructed or locally perforated, carcinoma of the caecum may mimic or cause obstructive
appendicitis in adults. A history of antecedent discomfort, altered bowel habit or unexplained anaemia
should raise suspicion. A mass may be palpable and barium enema is diagnostic.
5. Rare differential diagnoses :
A. Preherpetic pain of the right 10th and 11th dorsal nerves
is localized over the same area as
that of appendicitis. It does not shift and is associated with marked hyperaesthesia. There is no intestinal
upset or rigidity. The herpetic eruption may be delayed for 3–8 hours.
B. Tabetic crises
are now rare. Severe abdominal pain and vomiting are common during the crisis.
Other signs of tabes confirm the diagnosis.
C. Spinal conditions
are sometimes associated with acute abdominal pain especially in children
and the elderly. These may include tuberculosis of the spine, metastatic carcinoma, osteoporotic vertebral
collapse and multiple myeloma. The pain is due to compression of nerve roots and may be aggravated by
movement. There is rigidity of the lumbar spine whereas intestinal symptoms are absent.
D.The abdominal crises of porphyria and diabetes mellitus
need to be remembered. A urinalysis
should be undertaken in every abdominal emergency.
E. In cyclical vomiting of infants or young
children there is a history of previous similar attacks
and abdominal rigidity is absent. Acetone is found in the urine but is not diagnostic as it may accompany
starvation.
F. Typhlitis or leukaemic ileocaecal syndrome
is a rare but potentially fatal enterocolitis
occurring in immunosuppressed patients.
G. Gram-negative or clostridial (especially Clostridium septicum septicaemia
) can be rapidly
progressive. Treatment is with appropriate antibiotics and haematopoietic factors. Surgical intervention is
rarely indicated.
Investigations :
The diagnosis of acute appendicitis is essentially a clinical one; however, a decision to operate based on
clinical suspicion alone can lead to the removal of a normal appendix in 15–30% of cases. The premise that
it is better to remove a normal appendix than to delay diagnosis does not stand up to close scrutiny,
particularly in the elderly. A number of clinical and laboratory-based scoring systems have been devised to
assist diagnosis. The most widely used is the Alvarado score. A score of 7 or more is strongly predictive of
acute appendicitis. In patients with an equivocal score (5–6), abdominal ultrasound or contrast-enhanced CT
examination further reduces the rate of negative appendicectomy. Abdominal ultrasound examination is
more useful in children and thin adults, particularly if gynaecological pathology is suspected, with a
diagnostic accuracy in excess of 90%. Contrast-enhanced CT scan is most useful in patients in whom there
is diagnostic uncertainty, particularly older patients, in whom acute diverticulitis, intestinal obstruction and
neoplasm are other likely differential diagnoses. Selective use of CT scanning may be cost-effective by
reducing both the negative appendicectomy rate and the length of hospital stay.
Preoperative investigations in appendicitis :
A. Routine :
1. Full blood count.
2. Urinalysis.
3. Virology screen for hepatitis and HIV.
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B. Selective :
1. Pregnancy test.
2. Urea and electrolytes.
3. Supine abdominal radiograph.
4. Ultrasound of the abdomen/pelvis.
5. Contrast-enhanced CT scan of the GIT.
Treatment of Acute appendicitis :
The treatment for acute appendicitis is appendicectomy. There is a perception that urgent operation is
essential to prevent the increased morbidity and mortality of peritonitis. While there should be no
unnecessary delay, all patients, particularly those most at risk of serious morbidity, benefit by a short period
of intensive preoperative preparation. Intravenous fluids, sufficient to establish adequate urine output
(catheterisation is needed only in the very ill), and appropriate antibiotics should be given. There is ample
evidence that a single preoperative dose of antibiotics reduces the incidence of postoperative wound
infection. When peritonitis is suspected, therapeutic intravenous antibiotics to cover Gram-negative bacilli
as well as anaerobic cocci should be given. Hyperpyrexia in children should be treated with salicylates in
addition to antibiotics and intravenous fluids. With appropriate use of intravenous fluids and parenteral
antibiotics, a policy of deferring appendicectomy after midnight to the first case on the following morning
does not increase morbidity. However, when acute obstructive appendicitis is recognised, operation should
not be deferred longer than it takes to optimize the patient’s condition.
Appendicectomy :
Claudius Amyand successfully removed an acutely inflamed appendix from the hernial sac of a boy in 1736.
The first surgeon to perform deliberate appendectomy for acute appendicitis was Lawson Tait in May 1880.
The patient recovered; however, the case was not reported until 1890. Meanwhile, Thomas Morton was the
first to diagnose appendicitis, drain the abscess and remove the appendix with recovery, publishing his
findings in 1887. Appendectomy should be performed under general anaesthetic with the patient supine on
the operating table. When a laparoscopic technique is to be used, the bladder must be empty
(ensure that the patient has voided before leaving the ward). Prior to preparing the entire abdomen with an
appropriate antiseptic solution, the right iliac fossa should be palpated for a mass. If a mass is felt, it may, on
occasion, be preferable to adopt a conservative approach. Draping of the abdomen is in accordance with the
planned operative technique, taking account of any requirement to extend the incision or convert a
laparoscopic technique to an open operation.
A. Conventional appendectomy :
When the preoperative diagnosis is considered reasonably certain, the incision that is widely used for
appendectomy is the so called gridiron incision (gridiron: a frame of cross-beams to support
a ship during repairs). The gridiron incision (described first by McArthur) is made at right angles to a line
joining the anterior superior iliac spine to the umbilicus, its centre being along the
line at McBurney’s point. If better access is required, it is possible to convert the gridiron to a Rutherford
Morison incision by cutting the internal oblique and transverses muscles in the line of the incision.
In recent years, a transverse skin crease (Lanz) incision has became more popular, as the exposure is better
and extension, when needed, is easier. The incision, appropriate in length to the size and obesity of the
patient, is made approximately 2 cm below the umbilicus centred on the midclavicular-midinguinal line.
When necessary, the incision may be extended medially,with retraction or suitable division of the rectus
abdominis muscle.
B: Laparoscopic appendectomy :
Summary box 67.5