Appendix 1

د.ليث نايف

الجراحه العامه/المرحلة الرابعه
كلية طب الكندي/جامعة بغداد
THE VERMIFORM APPENDIX
Acute appendicitis (AA) is the most common cause of an: acute abdomen" in young adults.

ANATOMY;

It’s a blind muscular tube with mucosa, submucosa, muscular & serosal layer. During childhood, continued growth of the caecum commonly rotates the appendix into a retrocaecal intraperitoneal position(74%).In 25% of cases, rotation doesnt occur, resulting in a pelvic(21%), subcaecal(1.5%), or paracaecal(2%) position, it also may be preileal(1%) or postileal(0.5%).Rarely it can be found near the gall bladder or in the LIF(situs inversus).
The appendicular artery is a branch of the lower division of the ileocolic artery. It's an "end artery", thrombosis of which results in necrosis of the appendix (gangrenous appendicitis).
Lymphatic drainage of the appendix empty into ileocaecal LN.

MICROSCOPIC ANATOMY

Appendix varies in length& circumference. The length is 7.5-10 cm.Lumen has multiple longitudinal folds of mucous membrane lined by columnar cells (colonic mucosa). Crypts are present, in its base lie argentaffin cells which may give rise to carcinoid tumour. The submucosa contains numerous lymphatic aggregations or follicles.

ACUTE APPENDICITIS

It is relatively rare in infants, common in childhood& early adult life. Peak incidence in the teens & early 20s. Low incidence after middle age. Incidence is equal among males& females before puberty, but in teenagers &young adults, the M;F ratio rise to 3;2.

AETIOLOGY

As with diverticulitis, the incidence of appendicitis is lowest in societies with a high dietary fiber intake. In developing countries that are adopting a more refined carbohydrates, western type diet, the incidence continues to rise, although dramatic decrease in the incidence in Western countries. However improved hygiens may be responsible.
A mixed growth of aerobic & anaerobic organisms is usual in appendices.
Obstruction of the appendix lumen held to be important which is either by faecolith or stricture. Occasionally obstruction of the appendiceal orifice by tumour ex. Carcinoma of the caecum is an occasional cause of AA in middle age & elderly. Intestinal parasites (oxyuris vermicularis can occlude the lumen.


PATHOLOGY
Obstruction of the lumen is essential for development of the appendiceal gangrene &perforation. Yet in many early appendicitis, the lumen is patent despite the presence of mucosal inflammation &lymphoid hyperplasia. An infective agent, possibly viral may be implicated.
Lymphoid hyperplasia narrows the lumen of the appendix leading to luminal obstruction. Mucous secretion& inflammatory exudation increase intraluminal pressure with lymphatic obstruction. Oedema&mucosal ulceration develop with bacterial translocation to the submucosa.
At this point resolution may occur spontaneously or by antibiotics.
If the condition progresses, further distension of the appendix causes venous obstruction& ischaemia of the appendix wall. Bacterial invasion occur through muscularis propria& submucosa, producing AA. Finally ischaemic necrosis of the wall produces gangrenous appendicitis, with bacterial contamination of the peritoneal cavity.
Alternatively the greater omentum & loops of small bowel adherent to the inflamed appendix, walling off the spread of peritoneal contamination resulting in a phlegmonous mass or paracaecal abscess.
Peritonitis occurs as a result of free migration of the bacteria through an ischemic appendicular wall, through frank perforation of a gangrenous appendix or delayed perforation of an appendix abscess.

Risk factors for perforation of the appendix:

Extreme of age
Immunosuppresion
Diabetes Mellitus
Fecolith obstruction
Pelvic appendix
Previous abdominal surgery that limit the greater omentum function
CLINICAL DIAGNOSIS:
HISTORY
1- Periumbilical pain, it is poorly localised and colicky (visceral pain)
2- Anorexia, nausea& usually one or two episodes of vomiting.
3- With progressive inflammation, the parietal peritoneum in the RIF become irritated producing more intense, constant& localized somatic pain. Typically coughing or sudden movement exacerbates the R.I.F pain .This visceral- somatic sequence of pain is present in 50% of AA. Atypical pain is more common in the elderly in whom localization to the RIF is unusual.
4- During first 6hrs there is no change in temp. Or PR .After that pyrexia (37.2-37.8C) with increase in PR> 80 or 90 is usual.
Typically 2 clinical types of AA: Acute catarrhal (non obstructive) ´ obstructive type. The latter characterized by much more acute course. Once recognized, urgent surgical intervention is required because of the more rapid progression to perforation.


SIGNS:
The diagnosis of AA rests on clinical examination than on any aspect of the history or Lab. Investigation.
1- Low grade pyrexia.
2- Localised abdominal tenderness on the RIF.
3- Muscle guarding & Rebound tenderness.
4- May be limitation of respiratory movement in the lower abdomen.
5- The patient can point where the pain begun& where it moved (Pointing sign). 6- Deep palpation of the LIF may cause pain in the RIF (Rovsing sign).
7- Occasionally inflamed appendix lies on the psoas muscle& patient will lie with the Rt hip flexed for pain relief (Psoas sign).
8- If inflamed appendix is in contact with obturator internus, so when hip is flexed& internally rotated, the patient will experienced pain in the hypogastrium (Obturator sign).

SPECIAL FEATURES ACCORDING TO POSITION OF THE APPENDIX:

RETROCAECAL:
1- Rigidity is often absent.
2- Deep pressure may fail to elicit tenderness the reason being that the caecum distended with gas, prevents the pressure exerted by the hand from reaching the inflamed structure.
3- However deep tenderness in the loin& rigidity of quadratus lumborum may be present.
4- Psoas spasm with flexion of the hip joint, hyperextension of hip joint may induce abdominal pain.

PELVIC:

1- Early diarrhea occasionally occurs when inflamed appendix being in contact with rectum.
2- Complete absence of rigidity& often no tenderness over Mc Burney point.
3- Deep tenderness can be made out just above & to the Rt of the symphysis pubis.
4- Rectal examination (PR) reveals tenderness in the rectovesical pouch or pouch of Douglas.
5- Spasm of psoas or obturator internus muscles may be present.
6- When appendix in contact with the bladder may cause frequency of micturition.

POSTILEAL:
Appendix lies behind the terminal ileum, it presents the greatest difficulty in diagnosis because:
1- The pain may not shift.
2- Diarrhea is a feature.
3- Marked retching may occur.
4- Tenderness is ill defined; it may be present to the RT of umbilicus.


SPECIAL FEATURES ACCORDING TO AGE
INFANTS:
1-Appendicitis is rare in infants under 36 months of age.
2- Diagnosis is often delayed & thus the incidence of perforation& postoperative morbidity is high than in older children.
3-Diffuse peritonitis can develop rapidly due to underdeveloped greater omentum which is unable to give much assistance in localising the infection.

CHILDREN:

1- Rare to find a child with AA who has not vomited.
2- Usually complete aversion to food.
3- They dont sleep during the attack.
4- Bowel sounds are completely absent in the early stages.

THE ELDERLY:

Gangrene& perforation occur much more frequently in elderly. Lax abdominal wall or obesity gives little evidence of it &clinical picture may simulate subacute IO. These features, coupled with concident medical condition produce a high mortality in the elderly.

THE OBESE:

Obesity can obscure& diminish all the local signs of AA. Delay in diagnosis coupled with operative technical difficulties makes it wiser to consider midline abdominal incision.

PREGNANCY:

AA is the most common extrauterine abdominal condition in pregnancy with a frequency of 1 in 1500 to 1 in 2000 pregnancies. Early non specific signs are often attributed to the pregnancy. As pregnancy develops during the 2nd& 3rd trimester, the caecum& appendix are pushed to the Rt upper quadrant of the abdomen, However pain in the Rt lower quadrant remains the cardinal feature of AA in pregnancy. Fetal loss occurs in 3-5% of cases increasing to 20% in perforated AA.


DIFFERENTIAL DIAGNOSIS
CHILDREN:
1-ACUTE GASTROENTERITIS: There is intestinal colic, diarrhea& vomiting but localised tenderness doesnt usually occur. There is often a history of other family member being affected. Postileal AA may mimic this condition, thus hospital admission &observation, if serious doubt persist, Laparoscopy or surgical exploration may be indicated.

2-MESENTRIC LYMPHADENITIS; colicky pain, the Pt may be completely free from pain between attacks which last few minutes. Cervical LN may be enlarged. Shifting tenderness when the child turns on to his Lt side may be present. If doubt exist, exploration is advisable.

3-MECKELS DIVERTICULITIS; the pain is similar to AA, however signs may be central or Lt sided. History of intermittent lower GI bleeding.

4-INTUSSUSCEPTION; AA is uncommon before age of 2 where as median age of the intussusception is 18 mths. A mass may be palpable in the Rt lower quadrant, reduced by barium enema.

5-HENOCH-SCHONLEIN PURPURA; Often preceded by a sore throat or respiratory infection, sever abdominal pain, always there is ecchymotic rash mainly at extensor surfaces of the limbs& buttocks. Microscopic hematuria is common. Platelets count & bleeding time are normal.
6-LOBAR PNEUMONIA& PLEURISY; Especially the Rt base may give rise to Rt sided abdominal pain, abdominal tenderness is minimal, marked pyrexia, may be pleural rub, altered breath sound, a chest radiography is diagnostic.

ADULTS:

1-TERMINAL ILEITIS; May be indistinguishable from AA unless doughy mass can be felt. History of abdominal cramping, wt loss& diarrhea suggest regional ileitis which may be due to crohns or yersinia infection.

2-URETERIC COLIC; Character&radiation of pain differs from that of AA. Urinalysis should always be performed. KUB or IVU is diagnostic.

3-RIGHT SIDED ACUTE PYELONEPHRITIS; is accompanied or preceded by increased frequency of micturition. Tenderness confined to the loin, fever (39C) & may be rigor& pyrexia.

4-PERFORATED PEPTIC ULCER; The duodenal contents pass along the paracolic gutter to the right iliac fossa.
There is a history of dyspepsia, very sudden onset of pain that starts in the epigastrium& passes to the RIF. Rigidity& tenderness are present in both conditions, but in PPU the rigidity usually greater in the Rt hypochondrum. An erect CXR will show gas under diaphragm in 70% of pts.


5-TESTICULAR TORSION; in a teenage or young adult male, pain may be referred to the RIF. The scrotum is odematus & red with tender testis.

6-ACUTE PANCREATITIS; Excluded by serum or urinary amylase level.

7-RECTUS SHEATH HEMATOMA; It's rare, but easily missed. Acute pain& localised tenderness in the RIF without GI upset often after episode of strenuous exercise. In an elderly it may occur when anticoagulant therapy taken.

ADULT FEMALE:

In women of childbearing age, the pelvic disease most often mimic AA, so careful gynecological history should be taken in all cases of suspected AA.

1-PELVIC INFLAMMATORY DISEASES (PID): It includes salpingitis endometritis& tubo-ovarian sepsis. Typically the pain is lower than in AA& is bilateral. History of vaginal discharge, dysmenorrhea, burning micturition is helpful diagnostic points. On PV cervical tenderness. High vaginal swab should be taken. Transvaginal U/s is helpful
2-MITTELSCHMERZ: Mid-cycle rupture of ovarian follicular cyst with bleeding can produce lower abdominal& pelvic pain. Systemic upset is rare. Pregnancy test is negative. Symptoms usually subside within hours.

3-TORSION/HEMORRHAGE OF AN OVARIAN CYST; Pelvic U/S& gynecol. Opinion should be sought.

4-ECTOPIC PREGNANCY; Its unlikely that a ruptured ectopic pregnancy with sign of haemoperitonium will be mistaken for AA, but Rt sided tubal abortion or unruptured tubal pregnancy may be difficult except that the pain commences on the Rt side& stays there, the pain is sever& continue till operation. Usually there is a history of a missed period. Pregnancy test may be positive. Severe pain is felt when the cervix is moved in vaginal examination. Pelvic U/S is helpful

ELDERLY;

1-SIGMOID DIVERTICULITIS; in some patients with long sigmoid loop, the colon lies to the Rt of midline & it may be impossible to differentiate between diverticulitis & appendicitis. Abdominal CT is useful. A trial of conservative treatment with IVF& antibiotics is often benefit. If no response or deterioration, exploratory laparotomy is performed.

2- INTESTINAL OBSTRUCTION; Diagnosis of I.O is usually clear

3-CARCINOMA OF THE CAECUM; May mimic or cause obstructive AA. Altered bowel habit. Unexplained anaemia should raise suspicion. Mass may be palpable. Barium enema is diagnostic

RARE DIFFERENTIAL DIAGNOSIS;

1-PREHERPETIC PAIN OF THE Rt 10th or 11th DORSAL NERVE: Pain doesnt shift, marked hyperesthesia, no intestinal upset, Herpetic eruption after few hrs
2-TABETIC CRISIS;
3-SPINAL CONDITIONS: TB of the spine, Metastatic cancer, Osteoporosis, Multiple myeloma
4-PORPHYRIA& DM
5-TYPHLITIS OR LEUKEMIC ILEOCAECAL SYNDROME









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