Inflammation of the wall of the appendix causes venous congestion, which may compromise arterial inflow, leading to ischemia and infarction. Microorganisms from the lumen of the appendix enter the submucosa through an ischaemic ulcer, causing liquefaction of the wall and ultimately perforation
Within a few hours , this localized condition may worsen because of thrombosis of the appendicular artery and veins, leading to perforation and gangrene of the appendix. As this process continues, a periappendicular abscess or peritonitis may occur
Laboratory tests are not specific for appendicitis but may be helpful to confirm diagnosis in patients with an atypical presentation.
Complete blood cell count
A mild elevation of WBCs (ie, >12,000/mL) is a common finding in patients with acute appendicitis. In these patients, leukocytosis occurs. Otherwise, the WBC count has low specificity for appendicitis, and a number of bacterial and viral diseases may also lead to leukocytosis.
In infants and elderly patients, a WBC count is especially unreliable because these patients may not mount a normal response to infection.
In pregnant women, the physiologic leukocytosis renders the CBC count useless for the diagnosis of appendicitis.
Urinalysis may be useful in differentiating appendicitis from urinary tract conditions.
Mild pyuria may occur in patients with appendicitis because of the relationship of the appendix with the right ureter. Severe pyuria is a more common finding in UTI
Proteinuria and hematuria suggest genitourinary diseases or hemocoagulative disorders
C-reactive protein (CRP) has been reported to be useful in the diagnosis of appendicitis. This protein is physiologically produced by the liver when bacterial infections occur and rapidly increases within the first 12 hours.
CRP lacks specificity and cannot be used to distinguish between sites of infection.
CRP levels greater than 1 mg/dL commonly are reported in patients with appendicitis. Very high levels of CRP in these patients indicate gangrenous evolution of the disease, especially if it is associated with leukocytosis and neutrophilia. However, CRP normalization occurs 12 hours after onset of symptoms.
Liver and pancreatic function tests (eg, transaminases, bilirubin, alkaline phosphatase, serum lipase, amylase) may be helpful to determine the diagnosis in patients with an unclear presentation.
According to a recent report, measurement of the urinary 5-5-hydroxyindoleacetic acid (U-5-HIAA) could be an early marker of appendicitis. The rationale of such measurement is related to the large amount of serotonin-secreting cells in the appendix.
In the cited report, U-5-HIAA levels increase significantly in acute appendicitis, decreasing when the inflammation shifts to necrosis of the appendix. Therefore, such decrease could be an early warning sign of perforation of the appendix.
CT scan with oral contrast medium or rectal Gastrografin enema may help in diagnosis. Intravenous contrast is not usually necessary. It may help differentiate between appendicitis and other pelvic pathologies.
The typical findings are a nonfilling appendix with distention and thickened walls of both the appendix and the cecum, enlarged mesenteric nodes, and periappendiceal inflammation or fluid.
Because of its cost, CT scans are generally reserved for patients with uncertain diagnosis or severe obesity.
Recently, helical CT scan has demonstrated high sensitivity and specificity in differentiating appendicitis from other conditions, and it may be cost efficient with regards to limiting the number of unnecessary operations.
Diagnostic laparoscopy may be useful in selected cases (eg, infants, elderly patients, female patients) to confirm the diagnosis. If findings are positive, such procedures should be followed by definitive surgical treatment at the time of laparoscopy.
Thousands of classic appendectomies (open procedure) have been performed in the last 2 centuries. Mortality and morbidity have gradually decreased, especially in the last few decades because of antibiotics, early diagnosis, and improvements in anesthesiologic and surgical techniques.
Since 1987, many surgeons have begun to treat appendicitis laparoscopically. This procedure has now been improved and standardized.
Certain contraindications exist for laparoscopic appendectomy. These contraindications are extensive adhesions, radiation or immunosuppressive therapy, severe portal hypertension, and coagulopathies. Laparoscopic appendectomy is contraindicated in the first trimester of pregnancy
If the surgeon finds a normal appendix, he or she is faced with a dilemma. At this point, other causes of the patient's condition should be ruled out, including ovarian pathology, Meckel diverticulum, sigmoid disease, and cholecystitis.
Regardless of the findings, the authors believe that appendectomy should be performed. The patient will have a RLQ incision, and, in the future, physicians who examine the patient may assume that an appendectomy has been performed and they will not include appendicitis in the differential diagnosis.
The nonoperative management of appendicitis with high doses of antibiotics is reported in some studies, but it seems to be effective in only 60% of patients. It may be useful (and should be considered) in rural areas or if a surgical facility is not in close proximity to the patient.