INTRODUCTION
A 62-year-old man returns home from playing bingo, complaining of midline abdominal pain. He denies being hit or suffering any other trauma. Over the next few hours the pain does not remit but becomes more severe and is localized to the lower right quadrant. He also develops nausea and vomiting. He denies diarrhea and has not had similar episodes. The patient lies down in bed, and over the next 24 hours, the pain worsens and he develops fever and chills and is brought to the emergency center. On examination, he has a temperature of 102°F and appears ill. His abdomen is mildly distended and has hypoactive bowel sounds. The abdomen is diffusely tender to palpation, particularly in the right lower quadrant.
· What is the most likely diagnosis?
· What additional tests would help in making an accurate diagnosis?
Summary: A 62-year-old man complains of midline abdominal pain. He denies being hit or suffering any other trauma. Over the next few hours, the pain worsens and is localized to the lower right quadrant. He also develops nausea and vomiting and, after 24 hours, develops fever and chills and an acute abdomen.
· Most likely diagnosis: Acute appendicitis.
· Additional diagnostic tests: CT scan of the abdomen and pelvis.
CLINICAL CORRELATION
Introduction
This older man has a typical picture of a ruptured appendicitis with sepsis. He originally had mild right lower quadrant abdominal pain, but it worsened, and after 24 hours he developed fever and chills. Perhaps the most worrisome finding on physical examination is that he "appears ill." He probably has sepsis, which is a systemic condition of infection-mediated illness. The chills probably reflect bacteremia. The emergency physician should expeditiously manage this situation, because delay could lead to morbidity or mortality, particularly in a geriatric patient. The blood pressure is not mentioned, but the patient could be in septic shock. Treatment should be addressed in a systematic manner: airway, breathing, and circulation (ABC) with oxygen administered, two large-bore intravenous lines (IVs), volume repletion for the probable volume depletion and sepsis, blood cultures, urine culture, and antibiotic therapy aimed at gram-negative bacilli and anaerobic bacteria. Blood work to be obtained includes a complete blood count and a chemistry panel to assess electrolytes and serum creatinine for kidney function. After stabilization, the patient should be taken to the operating room. If the diagnosis is unclear, a CT scan of the abdomen sometimes can help distinguish other abdominal pathologies, such as diverticulitis.
Approach to Appendicitis
Definitions
Appendicitis: Inflammation of the vermiform appendix.
Diverticulitis: Inflammation of an outpouching of the diverticulum.
Diverticulosis: A condition of outpouching of the large bowel near the taeniae coli where the blood vessels penetrate. Complications include hemorrhage (lower gastrointestinal bleeding) and inflammation.
Approach to Appendicitis and Diverticulitis
Discussion
Appendicitis
Acute appendicitis is a common disease in Western countries and is uncommon in Africa and Asia. The incidence of the disease in the United States has fallen considerably over the last 30 years; however, it remains the most common abdominal emergency in childhood, adolescence, and early adult life. Fewer than 5 percent of cases of acute appendicitis occur in patients over age 60 years.
The pathologic process begins on the mucosal surface of the appendix, and there is often an element of obstruction of the appendicular lumen by a fecalith. This may lead to pressure necrosis of the mucosa and invasion of the appendicular wall by bacteria. Common causes of obstruction include elongation or kinking of the appendix, adhesions, and neoplasias such as carcinoma and carcinoid tumors, both of which are rare. Some cases spontaneously resolve, but more commonly, infection of the wall of the appendix progresses, leading to impairment of its blood supply. When the pathologic process has extended throughout the wall of the appendix to involve the parietal peritoneum, the pain and tenderness are classically over the McBurney point at the site of the appendix. The pathologic process may continue and produce gangrene, perforation, and more generalized peritonitis. Once perforation has occurred, the advancing bacteria may be controlled by the ability of the omentum to wall off the inflammation; alternatively, the peritonitis may become more widespread. In advanced appendicitis, a mass may develop; alternatively, generalized peritonitis may lead to the septic inflammatory response syndrome (SIRS), ultimately with the development of multiple organ failure and death.
The site of the pain in appendicitis may vary. When the appendix is retrocecal in position, somatic pain may be perceived in the flank and loin rather than in the right lower quadrant. Anorexia is an almost invariable symptom in association with appendicitis. The presence of hunger usually eliminates this diagnosis. In association with anorexia, nausea is common and tends to proceed to vomiting. Diarrhea sometimes occurs and may be a result of the appendix lying in a pelvic position.
Laboratory investigations commonly performed include the peripheral white blood cell count, which may be elevated with a predominance of polymorphonuclear leukocytes. The urinalysis is usually normal. A CT scan of the abdomen may show thickening of the appendix with periappendicular inflammation and the presence of intraperitoneal fluid.
The differential diagnosis includes acute gastroenteritis, which typically has vomiting and diarrhea as prominent symptoms and abdominal pain that is less well defined. Intestinal obstruction must be considered and typically presents with vomiting and abdominal distention. Mesenteric adenitis may mimic appendicitis closely but is associated with a generalized viral illness and causes less severe pain. Inflammation of Meckel diverticulum may produce symptoms remarkably similar to those of appendicitis, and laparoscopy or laparotomy may be needed for the diagnosis. Crohn disease may closely simulate appendicitis; affected patients generally have intestinal obstruction, and usually conservative management is the best therapy. Gynecologic disorders such as pelvic inflammatory disease with cervical motion tenderness and adnexal tenderness may present similarly to appendicitis. Ureteral colic is associated with pain and tenderness of the flank area, radiating to the groin region. Other conditions include acute diverticulitis, colonic carcinoma, acute cholecystitis, and pancreatitis.
Appendicitis in the elderly may have a more rapid course. Gangrene and perforation are more common in those over age 60 years, and this may be due to a delay in diagnosis. A classic picture of the appendicitis may be lacking, and the pain may be a less prominent feature. Overall, although there has been a decline in the incidence of peritonitis, paradoxically, it has increased among the elderly. Thus, appendicitis should be at the forefront of the differential diagnosis in males with right lower quadrant pain and tenderness.
The treatment of uncomplicated appendicitis is surgical, consisting of an appendectomy. The abdomen is opened, and if the appendix is found to be normal in the absence of any other pathology, it should be removed prophylactically. At the present time, most appendixes are removed laparoscopically rather than in an open operation.
Diverticulitis
Diverticuli are blind pouches involving the bowel. They result from herniation of the mucosa through the circular muscle at the site of small penetrating blood vessels. Their walls consist of an outer layer of serosa and an inner mucosa. There is no muscle in the wall of the diverticulum. Diverticular disease is associated with increased intraluminal pressure in the large intestine with hypertrophy of both circular and longitudinal muscle layers. Diverticula can occur anywhere in the large bowel and small bowel but are found most commonly in the sigmoid colon. Muscle hypertrophy predates the development of diverticula and results in a narrowing of the bowel and, consequently, an increase in the intraluminal pressure.
Diverticular disease may produce central or left lower quadrant abdominal pain together with an alteration in bowel habit with occasional rectal bleeding. The diagnosis is confirmed by barium enema or colonoscopy, which will show muscle thickening and multiple diverticula with small orifices emerging through the colonic wall. Diverticular disease of the colon is common in Western countries and rare in central Africa, the Middle East, the Far East, and the Pacific islands. The incidence of the disease in Japan is increasing, possibly because of the adoption of a more westernized diet. African Americans residing in the United States now have an incidence of the disease equal to that of the white population. Epidemiologic studies support the concept that the disease is not racially determined but is related to changes in the environment and to dietary factors. Postmortem studies in the Western countries report an incidence of about 40 percent overall and one as high as 60 percent in those over age 60 years.
Acute or chronic inflammation within a diverticulum is designated diverticulitis. It is estimated that the approximately 20 percent of patients with diverticulosis will manifest diverticulitis. Localized inflammation, or even perforation and peritonitis, may occur. Pneumaturia, resulting from a colovesical fistula, may occur, and on occasion, fecal material may be passed in the urine. CT imaging of the abdomen remains the primary method of diagnosing the acute process, whereas barium enema and endoscopic examinations are relatively contraindicated during acute infection.
Known complications of diverticulitis include bleeding, abscess formation, peritonitis, and fistula formation. Colonic obstruction also can occur. The treatment of diverticulitis includes broad-spectrum antibiotics, intravenous fluids, and nothing by mouth until the condition settles. Frank peritonitis or abscess formation usually requires surgical intervention, commonly involving excision of the affected area, such as a sigmoid colectomy. Postoperatively, patients should be instructed to eat a high-residue diet and drink plenty of liquids.
COMPREHENSION QUESTIONS
[7.1] A 20-year-old woman presents with the sudden development of nausea, vomiting, and right lower abdominal pain. Physical examination finds a mild fever, and laboratory evaluation finds an increased peripheral leukocyte count. She is taken to surgery, where an appendectomy is performed. Which one of the following histologic changes is most likely to be present in her appendix?
A. Amorphic mucinous material within the lumen
B. Caseating granulomas within the periappendiceal fat
C. Hyperplastic lymphoid follicles within the lamina propria
D. Multinucleated giant cells within the epithelium
E. Numerous neutrophils within the muscular wall
[7.2] A 61-year-old woman presents with nausea, vomiting, and the sudden onset of left-sided abdominal pain. Physical examination finds a low-grade fever, and laboratory evaluation finds increased numbers of neutrophils in her peripheral blood. What is the most likely diagnosis?
A. Appendicitis
B. Cholecystitis
C. Colitis
D. Diverticulitis
E. Pancreatitis
[7.3] Which one of the clinical findings listed below is most likely to be present in an older individual with diverticulosis?
A. Abdominal colic caused by intestinal obstruction
B. Iron deficiency anemia caused by chronic blood loss
C. Megaloblastic anemia caused by vitamin B12 deficiency
D. Steatorrhea caused by malabsorption of fat
E. Chronic diarrhea caused by decreased absorption of protein
ANSWERS
[7.1] E. The histologic hallmark of acute inflammation, such as that seen with acute appendicitis, is the presence of numerous acute inflammatory cells, namely, neutrophils. Therefore, histologic sections of an appendix surgically removed from an individual with acute appendicitis will reveal numerous neutrophils within the muscular wall. The inflammation can be so marked that it causes complete destruction of the muscular wall, which can lead to perforation and peritonitis.
[7.2] D. Acute inflammation of diverticula (diverticulitis) will produce the sudden onset of left-sided abdominal pain accompanied by fever and peripheral leukocytosis (mainly neutrophils). These clinical signs are essentially the same as those seen with acute appendicitis except that the abdominal pain is on the left side rather than the right side. As such, diverticulitis sometimes is referred to as left-sided appendicitis.
[7.3] B. Diverticulosis refers to the presence of numerous diverticula in the colon. The diverticula usually are located in the sigmoid colon in older individuals. Although they may become inflamed and produce signs of acute diverticulitis, more often they produce chronic blood loss as a result of chronic bleeding, which will lead to heme-positive stools and iron deficiency anemia.
PATHOLOGY PEARLS
· Appendicitis usually is a 24-hour disease with periumbilical pain localizing to the right lower quadrant.
· The primary treatment of appendicitis is surgical.
· Appendicitis continues to have high morbidity and mortality in older patients.
· Diverticula usually involve the left colon, particularly the sigmoid colon.
· Diverticulitis presents as left lower abdominal pain, fever, and nausea and vomiting.
· CT imaging is helpful in diagnosing both acute appendicitis and diverticulitis.
REFERENCES
Liu C, Crawford JM. The gastrointestinal tract. In: Kumar V, Assas AK, Fausto N, eds. Robbins and Cotran pathologic basis of disease, 7th ed. Philadelphia: Elsevier Saunders, 2004:854-856, 870-872.
Silen AW. Acute appendicitis and peritonitis. In: Kasper DL, Fauci AS, Longo DL, et al. Harrison's principles of internal medicine, 16th ed. New York: McGraw-Hill, 2004:1805-1806.
Copyright © 2006 by the McGraw-Hill Companies, Inc. All rights reserved.
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