The Appendix. Dr. Naser El-Hammuri

Transcription

1 The Appendix Dr. Naser El-Hammuri

2 Anatomy and Function The relationship of the base of the appendix to cecum remains constant, whereas the tip can be found in a retro-cecal, pelvic, sub-cecal, pre-ileal, or right peri-colic position. The three taenia coli converge at the junction of the cecum with the appendix (useful landmark to identify appendix) Appendix length vary from 1cm 30cm (most appendices are 6cm 9cm) Appendix is a immunologic organ that actively participate in secretion of immunoglobulins, particularly (IgA)

3 Anatomy and Function Appendix is an integral component of gut associated lymphoid tissue (GALT) system, however, its function is not essential and appendectomy is not associated with any predisposition to sepsis or any manifestation of immune compromise.

4 Incidence Life time rate of appendectomy is 12% for men and 25% for women, with approximately 7% of all people undergoing appendectomy for appendicitis Rate of appendectomy for appendicitis is 10 per 10,000 patients per year Appendicitis is most frequently seen in patients in their second through fourth decades of life with mean age of 31.3 years Slight male to female predominance (M:F 1.3:1) The rate of misdiagnosis of is significantly higher among women than men (22.2 vs 9.3%)

5 Etiology and Pathogenesis Obstruction of the lumen is the dominant causal factor in acute appendicitis Fecaliths are the usual cause of appendiceal obstruction Less common causes: - Hypertrophy of lymphoid tissue - Inspissated barium from previous x-ray study - Tumors - Vegetable and fruits seeds - Intestinal parasites

6 Etiology and Pathogenesis The predictable sequence of events leading eventually to appendiceal rupture: Proximal obstruction of appendiceal lumen Closed loop obstruction Continuing normal secretion by appendiceal mucosa rapidly produce distension, (lumen capacity of normal appendix is only 0.1 ml, secretion as little as 0.5 ml raises the lntra-luminal pressure to 60 cm H2O) Distension of the appendix stimulates nerve endings of afferent stretch fibers producing vague, dull, diffuse in the mid-abdomen or lower epigastrium

7 Etiology and Pathogenesis Sudden distension stimulates peristalsis resulting in abdominal cramps that may superimpose on the visceral pain early in the course of acute appendicitis As distention continues from continued mucosal secretion and from rapid multiplication of resident bacteria of appendix Distension of this magnitude causes reflex nausea and vomiting and diffuse visceral pain become more severe As pressure on organ increases, venous pressure is exceeded

8 Etiology and Pathogenesis Capillaries and venules get occluded while arteriolar inflow continues resulting in engorgement and vascular congestion Inflammatory process involves the serosa of appendix and in turn the parietal peritoneum in the region, producing the characteristic shift in pain to right lower quadrant Impairment of arterial supply result in mucosal integrity compromise allowing bacterial invasion Infarct develop in areas with poorest blood supply

9 Etiology and Pathogenesis As distension, bacterial invasion, compromise of arterial supply and infarction progress, perforation occurs, usually through one of the infarcted areas on the antimesenteric border Perforation generally occur just beyond the point of obstruction Some episodes of acute appendicitis may subside spontaneously

10 Bacteriology The principal organisms seen in normal appendix, in acute appendicitis and in perforated appendicitis are Escherichia Coli and Bacteroides Fragilis Appendicitis is polymicrobial infection

11 Clinical Manifestations Symptoms Pain is the prime symptom of acute appendicitis, initially diffusely centered in lower epigastrium or umbilical area, moderately severe with intermittent cramping superimposed After a period varying from 1 12 hours (usually 4 6 hours) the pain localizes to right lower quadrant This classic pain sequence is usual but not invariable Variation in the anatomic location of the appendix responsible for many of the variations in the principal locus of the somatic phase of the pain

12 Clinical Manifestations E.g. long appendix with inflamed tip in left lower quadrant causes pain in this area - Retro-cecal appendix cause flank or back pain - Pelvic appendix causes supra pubic pain - Malrotation somatic component of pain is felt at site where the cecum has been arrested in rotation Anorexia nearly always accompanies appendicitis Vomiting 75% of appendicitis, once or twice and caused secondary to neural stimulation and ileus

13 Clinical Manifestations History of obstipation beginning prior to onset of abdominal pain Diarrhea in some patients (children) Sequence of symptoms - Anorexia is the first symptom (95% of cases) - Followed by abdominal pain - Then vomiting (if vomiting precedes onset of pain, the diagnosis of appendicitis should be questioned)

14 Clinical Manifestations Signs Physical signs are determined principally by the anatomic position of the inflamed appendix, as well as if the organ has already ruptured when the patient is first examined Vital signs minimally changed by uncomplicated appendicitis Patient with appendicitis prefer to lie supine, with thighs, particularly the right thigh, drawn up, as motion cause pain

15 Clinical Manifestations Signs Right lower quadrant signs Tenderness maximal at or near McBurney s point Referred or indirect rebound tenderness indicating localized peritoneal irritation Rovsing s sign Cutaneous hyperasthesia in the area supplied by spinal nerves on the right at T10, T11, and T12 (elicited by needle prick or by gently picking up the skin between forefinger and thumb

16 Clinical Manifestations Signs Muscular resistance to palpation to abdominal wall roughly parallels the severity of inflammatory process, early in disease guarding, if present, consists mainly of voluntary guarding. As peritoneal irritation progresses, muscle spasm increases and becomes largely involuntary, i.e. reflex rigidity due to contraction of muscles directly beneath the inflamed parietal peritoneum

17 Clinical Manifestations Signs Physical signs also depends on the anatomical site of the appendix Retro-cecal appendicitis, the anterior abdominal findings are less striking, with tenderness mainly in the flank Pelvic appendicitis, abdominal findings may be entirely absent, and signs may be missed if rectal examination is not done Psoas sign Obturator sign

18 Laboratory Findings Mild leukocytosis (10,000 18,000), in uncomplicated appendicitis, with polymorphonuclear predominance Higher level of leukocytosis in patients with perforated appendicitis Urine analysis (WBC or RBC may be seen in case of ureteral or bladder irritation) Beta HCG

19 Imaging Studies Plain Films Done to R/O other pathology Abnormal gas pattern (none specific) Fecalith CXR basal pneumonia Barium enema

20 Imaging Studies / Ultrasonography Blind-ending, none-peristaltic, bowel loop originating from cecum None compressible, with anteroposterior diameter of 6mm or greater Presence of appendicolith Thickening of appendiceal wall and peri-appendiceal fluid (demonstration of easily compressible blind ending tubular structure measuring 5 mm or less in diameter excludes the diagnosis of appendicitis)

21 Imaging Studies / Ultrasonography If appendix not visualized and there is no peri-cecal fluid or mass, study is considered inconclusive U/S is also used to evaluate remainder of abdominal cavity to establish alternative diagnosis Sonographic diagnosis of acute appendicitis - Sensitivity 55 96% - Specificity 85 98%

22 Imaging Studies / CT scan High resolution helical tomography Appendix appears dilated with thickened wall Evidence of inflammation with, dirty fat, thickened mesoappendix Phlegmon Fecalith Sensitivity 92 97% Specificity 85 94%

23 Imaging Studies / CT scan Some studies demonstrated that computed tomography resulted in drop in the rate of negative appendectomies from 19 to 12% Other study demonstrated drop in negative appendectomies in women from 24 to 5% The rational approach is the selective use of CT scan (CT scan and Alvarado score)

24 Alvarado Scale Manifestations Value Symptoms Signs Migration of pain Anorexia Nausea/Vomiting RLQ tenderness Rebound Elevated temperature Laboratory Values Leukocytosis Left shift 2 1

25 Alvarado Scale for diagnosis of Appendicitis Score of 9 10 almost certain to have appendicitis, no further work up needed Score of 7 8 high likelihood of appendicitis Score 5 6 compatible but not diagnostic of appendicitis, CT scan is appropriate for this group Score 0 4 extremely unlikely (but not impossible), It is difficult to justify CT scan expenses and radiation in this group

26 Differential Diagnosis Acute Mesenteric Adenitis Upper respiratory tract infection is present or has recently subsided Pain usually diffuse, and tenderness not sharply localized Rigidity is rare Generalized lymphadenopathy may be noted Relative lymphocytosis If still in doubt, exploration

27 Differential Diagnosis Acute Gastroenteritis Nausea, vomiting with perfuse diarrhea Hyper-peristaltic abdominal cramps precede the watery stool Abdomen is relaxed between cramps, and there are no localizing signs Salmonella gastroenteritis can cause more intense localized pain, associated with rebound tenderness Chills and fever are common Leukocyte count is normal

28 Differential Diagnosis Disease of Male Urogenital System Torsion of the testis and epididymitis, and Seminal vesiculitis Meckel s Diverticulitis Located within the distal two feet of ileum Cause clinical picture similar to appendicitis and need requires same treatment

29 Differential Diagnosis Intussusception Important to differentiate intussusception from acute appendicitis as treatment is different Appendicitis is rare under age of 2 years, while nearly all cases of idiopathic intussusception occur in children younger than 2 years Sudden colicky abdominal pain, infant is well between attacks Bloody mucoid stool Sausage shape mass may be palpable in RLQ As intussusception progresses distally, the RLQ feels abnormally empty Treatment, if no peritonitis, is by barium reduction

30 Differential Diagnosis Crohn s Disease Manifestation of acute regional enteritis Fever, RLQ pain and tenderness Diarrhea, and infrequency of anorexia, nausea and vomiting favor a diagnosis of enteritis but not sufficient to exclude appendicitis Perforated Peptic Ulcer Simulate appendicitis if the spilled gastroduodenal contents gravitate down the right gutter To the cecal area and if perforation spontaneously seals, minimizing upper abdominal findings

31 Differential Diagnosis Colonic Lesion Diverticulitis or perforated cecal tumor, or that portion of sigmoid that lies on the right side May be impossible to distinguish from acute appendicitis This entities should be considered in older patients CT scanning is often helpful in making the diagnosis

32 Differential Diagnosis Epiploic Appendigitis Results from infarction of cecal appendages secondary to torsion Symptoms may be minimal, or there may be continuous pain in the area corresponding to the contour of the colon Pain shift is unusual No diagnostic sequence of symptoms, patient doesn t look ill, nausea and vomiting are unusual Localized tenderness with marked rebound

33 Differential Diagnosis Urinary tract infection Acute pyelonephritis on the right side Chills, right costovertebral angle tenderness, pyuria, and bacteriuria are usually sufficient to make diagnosis Uretral Stone May simulate retro-cecal appendicitis Pain referred to labia, scrotum, or penis Hematuria and / or absence of leukocytosis Pyelography and CT scan without contrast confirm diagnosis

34 Differential Diagnosis Primary Peritonitis In patients with nephrotic syndrome, cirrhosis, and endogenous or exogenous immunosuppression Mimic diffuse peritonitis secondary to ruptured appendicitis Diagnosed by peritoneal aspiration, if only gram positive cocci are seen on the gram smear, peritonitis is primary and treated with antibiotics, if flora are mixed or gram negative, secondary peritonitis should be suspected

35 Differential Diagnosis Henoch-Schonlein Purpura Syndrome usually occurs 2 3 weeks after streptococcal infection Abdominal pain Joint pains Purpura Nephritis

36 Differential Diagnosis Yerisinosis Human infection with Yersinia enterocolitica or Y. pseudotubercolosis is transmitted through food contaminated by feces or urine Yersinia infection cause variety of clinical syndromes including: - Mesenteric adenitis - Ileitis - Colitis - Acute appendicitis Many of the infections are mild and self-limited, but some lead to systemic septic course Organism sensitive to tetracyclines, streptomycin, ampicillin, and kanamycin

37 Differential Diagnosis Yerisinosis A preoperative suspicion of the diagnosis should not delay the operative intervention because appendicitis caused by yerisenia can t be distinguished from appendicitis from other causes Copylobacter jejuni (stool culture) Salmonella Typhimurium infection (serology)

38 Differential Diagnosis Gynecologic disorders Pelvic Inflammatory disease Usually bilateral, if confined to right side can mimic appendicitis Nausea and vomiting 50% of cases Pain and tenderness are lower Motion of the cervix is exquisitely painful Intracellular diplococci may be demonstrable of smear of the purulent vaginal discharge

39 Differential Diagnosis Gynecologic disorders Rupture Graafian Follicle / mittelschmerz Mid point of menstrual cycle (mittelschmerz) Brief mild lower abdominal pain Pain and tenderness are rather diffuse Leukocytosis and fever are minimal or absent

40 Differential Diagnosis Gynecologic disorders Ruptured Ectopic Pregnancy Rupture of right tubal or ovarian pregnancies can mimic appendicitis Recent menstrual changes Pelvic mass with elevated levels of Beta HCG Vaginal examination reveals cervical motion and adnexal tenderness Leukocyte count may be elevated Drop in hematocrit Culdocentesis is diagnostic

41 Differential Diagnosis Gynecologic disorders Twisted Ovarian Cyst Mass on abdominal examination U/S and CT scan can be diagnostic Torsion requires emergent operation, if torsion is complete or long standing, the pedicle undergoes thrombosis and the ovary and tube become gangrenous and require resection Leakage of ovarian cyst resolves the problem

42 Acute Appendicitis in Young Diagnosis more difficult than in adult History Gastrointestinal upset is common in children Rapid progression to rupture and inability of underdeveloped greater omentum to contain a rupture leads to significant morbidity Children younger than 5 years Negative appendectomy rate 25 & compared to 10% in children 5 12 years of age Appendiceal perforation rate of 45% compared to 20%

43 Acute Appendicitis in Elderly Incidence of appendicitis in this elderly is lower Rapid progression to perforation Co-morbid disease

44 Acute Appendicitis During pregnancy Incidence 1 in 2000 pregnancies More frequent during first two trimesters Nausea and vomiting after first trimester or new onset nausea and vomiting Abdominal pain and tenderness will be present, while rebound and guarding are less frequent due to laxity of abdominal muscles WBC count elevation above the normal pregnancy levels, 15,000 20,000 If diagnosis in doubt, do U/S or laparoscopy The performance of operation during pregnancy carries the risk of premature labor of 10 15%. Risk is similar for both negative laparotomy and appendectomy for simple appendicitis Fetal mortality risk increases from 3 5% in early appendicitis to 20% in perforation

45 Treatment Adequate hydration Correct electrolytes abnormalities Antibiotics Appendectomy - Conventional - Laparoscopic

46 Tumors Appendiceal malignancies are extremely rare Primary appendiceal cancer is diagnosed in % of appendectomy specimens Less than 50% of cases are diagnosed at operation Most series report that Carcinoid is most common appendiceal malignancy, however, recent review from the National Cancer institute s Surveillance found that mucinous adenocarcinoma (37% of total cases) to be the most common followed by carcinoid (33%)

47 Tumors Carcinoid Yellow firm bulbar mass in the appendix should raise suspicion of appendiceal carcinoid Appendix is the most common site of Gastrointestinal Carcinoid Carcinoid syndrome rarely associated Tumor can result in obstruction and appendicitis Majority of tumor is located in the tip, malignant potential is related to size Appendectomy is the treatment if smaller than 1cm For tumors 1cm and extending in the mesoappendix or tumors larger than 1.5 cm right hemicolectomy should be performed

48 Tumors Adenocarcinoma Rare neoplasm Three subtypes - Mucinous adenocarcinoma - Colonic adenocarcinoma - Adenocarcinoid Appendicitis is the most common form of presentation, early perforation Mass or ascites (may) Or discovered during operation Treatment is right hemicolectomy

49 Mucocele Progressive enlargement of appendix from intraluminal accumulation of mucoid substance Four histologic subtypes (type dictates course of disease and prognosis) - Retention cyst - Mucosal Hyperplasia - Cyst-adenoma - Cyst-adenocarcinoma Mucocele of benign etiology treated by appendectomy