Appendicitis

Appendicitis


Hello. This presentation will focus on acute appendicitis. The learning objectives are as given below. Here’s a brief outline of what we’ll be talking about today with regards to appendicitis. Here’s a common clinical scenario. A 35-year-old gentleman with no past medical history of note comes to the emergency department with a two day history of abdominal pain which was initially diffuse in nature but is now localized primarily to the right iliac fossa. The pain was accompanied by a fever as well as nausea and vomiting. Physical exam reveals a guarded abdomen with a diffuse tenderness but with increased pain in the right iliac fossa. There is no rebound tenderness. Rovsing’s sign, obturator sign, and psoas sign are all negative. What are the next steps to take in the management of this patient? Epidemiology– globally appendicitis is one of the most frequent causes of an acute abdomen as well as one of the most common indications for abdominal surgery. In general, it has a higher incidence in individuals aged 10 to 19 years with most cases occurring between 10 to 30 years of age. The incidence is also slightly greater in males than females. Statistics vary depending on the institutions and countries where the data is gathered. Overall mortality is approximately 0.1% for non-perforated cases and 5% for perforated cases. The rate of perforation is 12% in the general population presenting with appendicitis. The rate of perforation is increased in infants and the elderly most commonly because of their atypical presentation and late presentations, which correspond to a higher mortality rate. The base of the appendix is located at the base of the cecum where the tinea coli converge approximately two centimeters below the ileocecal valve. There is more anatomic variation in the tip. The appendix usually has an intraperitoneal location 70% of the time, either anterior or retrocecal. However, if it has a pelvic, retroileal, or retrocolic position, the patient may present with atypical symptoms. Unlike the diverticula of diverticular disease, the appendix is a true diverticulum in that it contains all layers of the colonic wall– mucosa, submucosa, muscularis, and the serosal covering. Most appendixes are 6 to 9 centimeters long. The appendix itself is a hollow organ that opens into the cecum. Its main function appears to be immunological– secretion of immunoglobulin A. And its lining is interspersed with lymphoid follicles. The amount of this lymphoid tissue increases throughout p puberty and then remains constant for a decade before declining. There’s almost no lymphoid tissue left by the age of 60. The blood supply of the appendix comes mainly from the appendicular artery, a branch of the ileocolic artery. The obstruction of the narrow lumen of the appendix is the primary etiology of acute appendicitis. The obstruction is usually caused by fecaliths, calculi, lymphoid hyperplasia, infectious processes, or benign malignant tumors. Fecaliths are found in 90% of gangrenous appendicitis with rupture, but only in 40% of cases with simple appendicitis. Age is also related to the cause of the obstruction. In the young, lymphoid hyperplasia due to infection is a common cause, whereas in the elderly, fecaliths or neoplasia are more common causes. Regardless of the etiology of the obstruction, the appendiceal mucosa continues to secrete. Without an outlet, the lumen quickly fills with mucus, and the appendix distends. It is this distension that first causes the dull, diffuse pain seen early in the course of appendicitis. As the pressure continues to increase, small blood vessels are occluded. This causes the appendix to initially become ischemic and then necrotic. The ischemia also renders the appendix susceptible to bacterial invasion by normal gut flora. Common organisms involved in appendicitis include E. coli, Peptostreptococcus, Bacteroides, and Pseudomonas. The invasion of the wall of the appendix causes an inflammatory reaction and a fibrinous exudate on the serosal surface of the appendix. Once this progresses and involves the parietal peritoneum, it causes a sharper, more localized pain in the right iliac fossa that corresponds to the classical migratory pain in appendicitis. Eventually, a combination of all these factors– distension, ischemia, infection, and inflammation– leads to perforation of the appendix. Some evidence suggests that an increased duration of symptoms, greater than 48 hours before surgery, increases the likelihood that the appendix is perforated. A high fever, greater than 39.4, and an elevated white blood cell count, greater than 15,000, also point towards a perforation. The more significantly elevated the white blood count, the more likely that a perforation has occurred. Presentation– the most common symptoms of appendicitis include abdominal pain, anorexia, nausea, vomiting, and the classic symptom of pain migration from an initially diffuse or periumbilical pain to one focused around the right iliac fossa. The symptoms of abdominal pain, anorexia, and nausea are found in most patients. However, the textbook history of periumbilical pain that migrates to the right lower quadrant only occurs in 50% of patients. Furthermore, the location of the tip of the appendix affects where the pain is felt. A retrocecal appendix can cause flank or back pain. A pelvic appendix can cause suprapubic pain. And a retroileal appendix can cause testicular pain. Pain classically associated with appendicitis at McBurney’s point, which is 2/3 of the distance from the umbilicus to the anterior superior iliac spine, is seen with an anterior appendix. In the majority of cases, anorexia is generally the first symptom followed by abdominal pain, then nausea and vomiting, and finally fever. Signs– in general, patients will be keen to remain as still as possible preferring to remain supine and voluntarily guarding their abdomen. Agitation of the abdomen such as coughing, Dunphy’s sign, increases pain. Other classical signs include Rovsing’s sign where palpation of the left iliac fossa causes pain in the right iliac fossa. The obturator sign is pain on internal rotation of the hip and suggests a pelvic appendix. The psoas sign is pain on extension of the right hip and suggests a retrocecal appendix. Perforation is associated with an increase in pain and an abdomen that is rigid and diffusely tender. Lab findings– leukocytosis with a neutrophilic shift is commonly seen in most patients with appendicitis. Significant leukocytosis, greater than 20,000, suggests complicated appendicitis with abscess or perforation. However, it is important to note that more than 10% of patients with appendicitis may present with a normal leukocyte count. In general, imaging is not necessary if the diagnosis of appendicitis is certain. However, in certain populations such as children, older adults, or women of childbearing age, their diagnosis may be unclear. The modalities of choice are either ultrasound or CT. Ultrasound has a sensitivity of 85% and a specificity of 90%. So although it cannot rule out appendicitis in a patient with abdominal pain, it is a useful adjunct for patients where there is diagnostic uncertainty. CT has a sensitivity and specificity greater than 90% for the diagnosis of acute appendicitis. Key findings on CT include an appendix greater than 7 millimeters in diameter, circumferential wall thickening, appendicolith, or periappendiceal fat stranding. It is important to note that if a patient has a very short duration of symptoms, many of the characteristic findings on CT related to inflammation may not have yet developed. Either oral or IV contrast may be used. And some studies indicate that using oral contrast in overweight or obese patients improves sensitivity and specificity. Management– appendectomy is the gold standard of care for patients with appendicitis who present within 24 to 72 hours after the onset of symptoms and can be performed either laparoscopically or by the traditional open laparotomy. A meta-analysis found the following benefits of laparoscopy– lower rate of wound infections, less pain on postoperative day one, shorter duration of hospital stay, and shorter time to return of bowel function. It also found these downsides– higher rate of intra-abdominal abscesses, longer operative time, and higher cost. If the appendix looks normal, it should still be removed. But it is important to exclude common alternative causes of abdominal pain intraoperatively if possible. Meckel’s diverticulum, Crohn’s disease, mesenteric lymphadenopathy, ovarian torsion, and hernias should all be excluded. Prophylactic antibiotics have an important role to play in the management. In acute appendicitis, a single pre-operative dose is sufficient to prevent wound infection. In perforated appendicitis, empiric, broad-spectrum antibiotics should be started and then narrowed once final cultures and sensitivities are known. A third generation cephalosporin plus metronidazole is generally used until no clinical signs of infection remain, which typically takes five to seven days. In patients who present five days after symptoms have started, immediate surgery is associated with increased morbidity. In these individuals, the initial treatment should be antibiotics, IV fluids, and bowel rest. If imaging shows an abscess, then CT or ultrasound guided drainage can be performed. If these patients do not improve clinically after several days of non-operative treatment, then immediate appendectomy is warranted. If patients do improve with initial non-operative management, an interval appendectomy is still carried out approximately six weeks after symptoms first started. This is mainly to prevent recurrence of appendicitis, which can be as high as 25% as well as to exclude appendiceal neoplasms. Older adults should undergo colonoscopy after treatment, as colon cancer is detected in 5% of cases. Important differential diagnoses– in children, you should be concerned about intussusception, Meckel’s diverticulum, gastroenteritis, and mesenteric lymphadenitis. In adults, pyelonephritis, inflammatory bowel disease, and diverticulitis. In women, consider pelvic inflammatory disease, tubo-ovarian abscesses, ruptured ovarian cysts, ovarian torsion, or ectopic pregnancy. In the elderly, don’t forget about bowel obstruction, diverticulitis, malignancies, and perforated ulcers. In summary– in general, acute appendicitis is the most common cause of an acute abdomen and should therefore remain in the list of differentials for most patient populations. Not all patients will present with the classic symptoms and may need further radiologic testing with abdominal CT scan with IV contrast to clinch diagnosis. However, if the diagnosis is clear based on history, physical exam, and lab testing, no further radiological investigation is needed before an appendectomy. An appendectomy, either laparoscopically or open, is the gold standard for patients with acute appendicitis. Even for patients who have been treated non-operatively due to the presence of an abscess or symptoms that have lasted for more than five days, an interval appendectomy still performed six to eight weeks after the symptoms have resolved.

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