Tuesday, February 16, 2010
Appendicitis
2:54 AM | 
Diposkan oleh
Hermanto
Pathophysiol
ogy
Diagnosis
History
Physical Examination
Radiography
Barium Enema
Differential Diagnoses
Most patients with acute appendicitis are managed by prompt surgical removal of the appendix. A brief period of resuscitation is usually sufficient to ensure the safe induction of general anesthesia. Preoperative antibiotics cover aerobic and anaerobic colonic flora. For patients with nonperforated appendicitis, a single preoperative dose of antibiotics reduces postoperative wound infections and intra-abdominal abscess formation. Postoperative oral antibiotics do not further reduce the incidence of infectious complications in these patients. For patients with perforated or gangrenous appendicitis, we continue postoperative intravenous antibiotics until the patient is afebrile.
Open appendectomy
Open appendectomy is usually easily performed through a transverse right lower quadrant incision (Davis-Rockey) or an oblique incision (McArthur-McBurney).
Laparoscopic appendectomy
Laparoscopic appendectomy offers the advantage of diagnostic laparoscopy combined with the potential for shorter recovery and incisions that are less conspicuous.
ogy Obstruction of the lumen is the major cause of acute appendicitis. This may be due to fecalith or appendicolith, lymphoid hyperplasia, vegetable matter or seeds, parasites, or a neoplasm. The lumen of the appendix is small and this configuration may predispose to closed-loop obstruction. Obstruction of the lumen contributes to bacterial overgrowth, and continued secretion of mucus leads to intraluminal distention and increased wall pressure. Luminal distention produces the visceral pain sensation experienced by the patient as periumbilical pain. Subsequent impairment of lymphatic and venous drainage leads to mucosal ischemia. These findings in combination promote a localized inflammatory process that may progress to gangrene and perforation. Inflammation of the adjacent peritoneum gives rise to localized pain in the right lower quadrant. Although there is considerable variability, perforation typically occurs after at least 48 hours from the onset of symptoms and is accompanied by an abscess cavity walled-off by the small intestine and omentum. Rarely, free perforation of the appendix into the peritoneal cavity occurs that may be accompanied by peritonitis and septic shock and can be complicated by the subsequent formation of multiple intraperitoneal abscesses.
Diagnosis
History
The typical presentation begins with periumbilical pain (due to activation of visceral afferent neurons) followed by anorexia and nausea. The pain then localizes to the right lower quadrant as the inflammatory process progresses to involve the parietal peritoneum overlying the appendix. This classic pattern of migratory pain is the most reliable symptom of acute appendicitis.
Fever ensues, followed by the development of leukocytosis. These clinical features may vary.
Although most patients with appendicitis develop an adynamic ileus and absent bowel movements on the day of presentation, occasional patients may have diarrhea. Others may present with small bowel obstruction related to contiguous regional inflammation.
Fever ensues, followed by the development of leukocytosis. These clinical features may vary.
Although most patients with appendicitis develop an adynamic ileus and absent bowel movements on the day of presentation, occasional patients may have diarrhea. Others may present with small bowel obstruction related to contiguous regional inflammation.
Physical Examination
- Patients with acute appendicitis typically look ill and are lying still in bed.
- Low-grade fever is common (∼38°C).
- The exact location of the tenderness is directly over the appendix, which is most commonly at McBurney's point (located one third of the distance along a line drawn from the anterior
superior iliac spine to the umbilicus).
- Peritoneal irritation can be elicited on physical examination by the findings of voluntary and involuntary guarding, percussion, or rebound tenderness. Any movement, including coughing (Dunphy's sign), may cause increased pain.
- Other findings may include pain in the right lower quadrant during palpation of the left lower quadrant (Rovsing's sign), pain on internal rotation of the hip (obturator sign, suggesting a pelvic appendix), and pain on extension of the right hip (iliopsoas sign, typical of a retrocecal appendix).
- Rectal and pelvic examinations are most likely to be negative. However, if the appendix is located within the pelvis, tenderness on abdominal examination may be minimal, whereas anterior tenderness may be elicited during rectal examination as the pelvic peritoneum is manipulated. Pelvic examination with cervical motion may also produce tenderness in this setting.
If the appendix perforates :
- Abdominal pain becomes intense and more diffuse, and abdominal muscular spasm increases, producing rigidity.
- The heart rate rises, with an elevation of temperature above 39°C.
- The patient may appear ill and require a brief period of fluid resuscitation and antibiotics before the induction of anesthesia.
- Occasionally, pain may improve somewhat after rupture of the appendix, although a true pain-free interval is uncommon.
Laboratory Studies
- The white blood cell count is elevated with more than 75% neutrophils in most patients. A completely normal leukocyte count and differential is found in about 10% of patients with acute appendicitis.
- A high white blood cell count (>20,000/mL) suggests complicated appendicitis with either gangrene or perforation. A
- Urinalysis can also be helpful in excluding pyelonephritis or nephrolithiasis.
- Other blood tests are generally not helpful and are not indicated in the patient with suspected appendicitis.
Radiography
Barium Enema
- Failure of the appendix to fill during a barium enema has been associated with appendicitis, but this finding lacks both sensitivity and specificity because up to 20% of normal appendices do not fill.
- Ultrasonography has a sensitivity of about 85% and a specificity of more than 90% for the diagnosis of acute appendicitis.
- Ultrasonography has the advantages of being a noninvasive modality requiring no patient preparation that also avoids exposure to ionizing radiation.
- Computed tomography (CT) is commonly used in the evaluation of adult patients with suspected acute appendicitis. CT Scan has a sensitivity of about 90% and a specificity of 80% to 90% for the diagnosis of acute appendicitis among patients with abdominal pain.
- Classic findings include a distended appendix greater than 7 mm in diameter and circumferential wall thickening, which may give the appearance of a halo or target.
- As inflammation progresses, one may see periappendiceal fat stranding, edema, peritoneal fluid, phlegmon, or a periappendiceal abscess.
Differential Diagnoses
- Infants : pyloric stenosis.
- Preschool-aged children : Intussusception, Meckel's diverticulitis, and acute gastroenteritis.
- School-aged children : Gastroenteritis, inflammatory bowel disease, constipation
- Adults : pyelonephritis, colitis, and diverticulitis.
- Women : pelvic inflammatory disease (PID), tubo-ovarian abscess, ruptured ovarian cyst or ovarian torsion, and ectopic pregnancy.
Most patients with acute appendicitis are managed by prompt surgical removal of the appendix. A brief period of resuscitation is usually sufficient to ensure the safe induction of general anesthesia. Preoperative antibiotics cover aerobic and anaerobic colonic flora. For patients with nonperforated appendicitis, a single preoperative dose of antibiotics reduces postoperative wound infections and intra-abdominal abscess formation. Postoperative oral antibiotics do not further reduce the incidence of infectious complications in these patients. For patients with perforated or gangrenous appendicitis, we continue postoperative intravenous antibiotics until the patient is afebrile.
Open appendectomy
Open appendectomy is usually easily performed through a transverse right lower quadrant incision (Davis-Rockey) or an oblique incision (McArthur-McBurney).
Laparoscopic appendectomy
Laparoscopic appendectomy offers the advantage of diagnostic laparoscopy combined with the potential for shorter recovery and incisions that are less conspicuous.
