appendicitis appendicitis appendicitis is inflammation of the appendix. symptoms commonly include right lower abdominal pain, nausea, vomiting, and decreased appetite. however, approximately 40% of people do not have these typical symptoms. severe complications of a ruptured appendix include widespread, painful inflammation of the inner lining of the abdominal wall and sepsis. appendicitisother namesepityphlitisan acutely inflamed and enlarged appendix, sliced lengthwise.specialtygeneral surgerysymptomsperiumbilical or right lower abdominal pain, vomiting, decreased appetitecomplicationsabdominal inflammation, sepsisdiagnostic methodbased on symptoms, medical imaging, blood testsdifferential diagnosismesenteric adenitis, cholecystitis, psoas abscess, abdominal aortic aneurysmtreatmentsurgical removal of the appendix, antibioticsfrequency11.6 million (2015)deaths50,100 (2015) appendicitis is caused by a blockage of the hollow portion of the appendix. this is most commonly due to a calcified "stone" made of feces. inflamed lymphoid tissue from a viral infection, parasites, gallstone, or tumors may also cause the blockage. this blockage leads to increased pressures in the appendix, decreased blood flow to the tissues of the appendix, and bacterial growth inside the appendix causing inflammation. the combination of inflammation, reduced blood flow to the appendix and distention of the appendix causes tissue injury and tissue death. if this process is left untreated, the appendix may burst, releasing bacteria into the abdominal cavity, leading to increased complications. the diagnosis of appendicitis is largely based on the person's signs and symptoms. in cases where the diagnosis is unclear, close observation, medical imaging, and laboratory tests can be helpful. the two most common imaging tests used are an ultrasound and computed tomography (ct scan). ct scan has been shown to be more accurate than ultrasound in detecting acute appendicitis. however, ultrasound may be preferred as the first imaging test in children and pregnant women because of the risks associated with radiation exposure from ct scans. the standard treatment for acute appendicitis is surgical removal of the appendix. this may be done by an open incision in the abdomen (laparotomy) or through a few smaller incisions with the help of cameras (laparoscopy). surgery decreases the risk of side effects or death associated with rupture of the appendix. antibiotics may be equally effective in certain cases of non-ruptured appendicitis. it is one of the most common and significant causes of abdominal pain that comes on quickly. in 2015 about 11.6 million cases of appendicitis occurred which resulted in about 50,100 deaths. in the united states, appendicitis is one of the most common cause of sudden abdominal pain requiring surgery. each year in the united states, more than 300,000 people with appendicitis have their appendix surgically removed. reginald fitz is credited with being the first person to describe the condition in 1886. signs and symptoms location of mcburney's point (1), located two thirds the distance from the umbilicus (2) to the right anterior superior iliac spine (3) the presentation of acute appendicitis includes acute abdominal pain, nausea, vomiting, and fever. as the appendix becomes more swollen and inflamed, it begins to irritate the adjoining abdominal wall. this leads to the localization of the pain to the right lower quadrant. this classic migration of pain may not be seen in children under three years. this pain can be elicited through signs, which can feel sharp. pain from appendicitis may begin as dull pain around the navel. after several hours, pain will usually transition towards the right lower quadrant, where it becomes localized. symptoms include localized findings in the right iliac fossa. the abdominal wall becomes very sensitive to gentle pressure (palpation). there is pain in the sudden release of deep tension in the lower abdomen (blumberg's sign). if the appendix is retrocecal (localized behind the cecum), even deep pressure in the right lower quadrant may fail to elicit tenderness (silent appendix). this is because the cecum, distended with gas, protects the inflamed appendix from pressure. similarly, if the appendix lies entirely within the pelvis, there is typically a complete absence of abdominal rigidity. in such cases, a digital rectal examination elicits tenderness in the rectovesical pouch. coughing causes point tenderness in this area (mcburney's point), called dunphy's sign. causes location of the appendix in the digestive system 3d model of appendicitis. acute appendicitis seems to be the result of a primary obstruction of the appendix. once this obstruction occurs, the appendix becomes filled with mucus and swells. this continued production of mucus leads to increased pressures within the lumen and the walls of the appendix. the increased pressure results in thrombosis and occlusion of the small vessels, and stasis of lymphatic flow. at this point, spontaneous recovery rarely occurs. as the occlusion of blood vessels progresses, the appendix becomes ischemic and then necrotic. as bacteria begin to leak out through the dying walls, pus forms within and around the appendix (suppuration). the result is appendiceal rupture (a 'burst appendix') causing peritonitis, which may lead to sepsis and in rare cases, death. these events are responsible for the slowly evolving abdominal pain and other commonly associated symptoms. the causative agents include bezoars, foreign bodies, trauma, lymphadenitis and, most commonly, calcified fecal deposits that are known as appendicoliths or fecaliths. the occurrence of obstructing fecaliths has attracted attention since their presence in people with appendicitis is higher in developed than in developing countries. in addition an appendiceal fecalith is commonly associated with complicated appendicitis. fecal stasis and arrest may play a role, as demonstrated by people with acute appendicitis having fewer bowel movements per week compared with healthy controls. the occurrence of a fecalith in the appendix was thought to be attributed to a right-sided fecal retention reservoir in the colon and a prolonged transit time. however, a prolonged transit time was not observed in subsequent studies. diverticular disease and adenomatous polyps was historically unknown and colon cancer was exceedingly rare in communities where appendicitis itself was rare or absent, such as various african communities. studies have implicated a transition to a western diet lower in fiber in rising frequencies of appendicitis as well as the other aforementioned colonic diseases in these communities. and acute appendicitis has been shown to occur antecedent to cancer in the colon and rectum. several studies offer evidence that a low fiber intake is involved in the pathogenesis of appendicitis. this low intake of dietary fiber is in accordance with the occurrence of a right-sided fecal reservoir and the fact that dietary fiber reduces transit time. diagnosis appendicitis as seen on ct imaging diagnosis is based on a medical history (symptoms) and physical examination, which can be supported by an elevation of neutrophilic white blood cells and imaging studies if needed. histories fall into two categories, typical and atypical. typical appendicitis includes several hours of generalized abdominal pain that begins in the region of the umbilicus with associated anorexia, nausea, or vomiting. the pain then "localizes" into the right lower quadrant where the tenderness increases in intensity. it is possible the pain could localize to the left lower quadrant in people with situs inversus totalis. the combination of pain, anorexia, leukocytosis, and fever is classic. atypical histories lack this typical progression and may include pain in the right lower quadrant as an initial symptom. irritation of the peritoneum (inside lining of the abdominal wall) can lead to increased pain on movement, or jolting, for example going over speed bumps. atypical histories often require imaging with ultrasound or ct scanning. signs aure-rozanova's sign: increased pain on palpation with finger in the right inferior lumbar triangle (can be a positive blumberg's sign). bartomier-michelson's sign: increased pain on palpation at the right iliac region as the person being examined lies on their left side compared to when they lie on their back. dunphy's sign: increased pain in the right lower quadrant with coughing. hamburger sign: the patient refuses to eat (anorexia is 80% sensitive for appendicitis) kocher's sign (kosher's sign): from the person's medical history, the start of pain in the umbilical region with a subsequent shift to the right iliac region. massouh's sign: developed in and popular in southwest england, the examiner performs a firm swish with their index and middle finger across the abdomen from the xiphoid process to the left and the right iliac fossa. obturator sign: the person being evaluated lies on her or his back with the hip and knee both flexed at ninety degrees. the examiner holds the person's ankle with one hand and knee with the other hand. the examiner rotates the hip by moving the person's ankle away from their body while allowing the knee to move only inward. a positive test is pain with internal rotation of the hip. psoas sign, also known as "obraztsova's sign", is right lower-quadrant pain that is produced with either the passive extension of the right hip or by the active flexion of the person's right hip while supine. the pain that is elicited is due to inflammation of the peritoneum overlying the iliopsoas muscles and inflammation of the psoas muscles themselves. straightening out the leg causes pain because it stretches these muscles, while flexing the hip activates the iliopsoas and causes pain. rovsing's sign: pain in the lower right abdominal quadrant with continuous deep palpation starting from the left iliac fossa upwards (counterclockwise along the colon). the thought is there will be increased pressure around the appendix by pushing bowel contents and air toward the ileocaecal valve provoking right-sided abdominal pain. rosenstein's sign (sitkovsky's sign): increased pain in the right iliac region as the person is being examined lies on their left side. perman's sign: in acute appendicitis palpation in the left iliac fossa may produce pain in the right iliac fossa. blood and urine test while there is no laboratory test specific for appendicitis, a complete blood count (cbc) is done to check for signs of infection. although 70–90 percent of people with appendicitis may have an elevated white blood cell (wbc) count, there are many other abdominal and pelvic conditions that can cause the wbc count to be elevated. due to its low sensitivity and specificity, on its own, wbc is not seen as a good indicator of appendicitis. a urinalysis generally does not show infection, but it is important for determining pregnancy status, especially the possibility of an ectopic pregnancy in women of childbearing age. the urinalysis is also important for ruling out a urinary tract infection as the cause of abdominal pain. the presence of more than 20 wbc per high-power field in the urine is more suggestive of a urinary tract disorder. imaging in children the clinical examination is important to determine which children with abdominal pain should receive immediate surgical consultation and which should receive diagnostic imaging. because of the health risks of exposing children to radiation, ultrasound is the preferred first choice with ct scan being a legitimate follow-up if the ultrasound is inconclusive. ct scan is more accurate than ultrasound for the diagnosis of appendicitis in adults and adolescents. ct scan has a sensitivity of 94%, specificity of 95%. ultrasonography had an overall sensitivity of 86%, a specificity of 81%. ultrasound ultrasound image of acute appendicitis abdominal ultrasonography, preferably with doppler sonography, is useful to detect appendicitis, especially in children. ultrasound can show the free fluid collection in the right iliac fossa, along with a visible appendix with increased blood flow when using color doppler, and noncompressibility of the appendix, as it is essentially walled-off abscess. other secondary sonographic signs of acute appendicitis include the presence of echogenic mesenteric fat surrounding the appendix and the acoustic shadowing of an appendicolith. in some cases (approximately 5%), ultrasonography of the iliac fossa does not reveal any abnormalities despite the presence of appendicitis. this false-negative finding is especially true of early appendicitis before the appendix has become significantly distended. also, false-negative findings are more common in adults where larger amounts of fat and bowel gas make visualizing the appendix technically difficult. despite these limitations, sonographic imaging with experienced hands can often distinguish between appendicitis and other diseases with similar symptoms. some of these conditions include inflammation of lymph nodes near the appendix or pain originating from other pelvic organs such as the ovaries or fallopian tubes. ultrasounds may be either done by the radiology department or by the emergency physician. ultrasound showing appendicitis and an appendicolith ultrasound of a normal appendix for comparison a normal appendix without and with compression. absence of compressibility indicates appendicitis. computed tomography a ct