I. Acute appendicitis
Acute appendicitis is one of the most common diseases in abdominal surgery, and most patients can seek timely medical attention and obtain good treatment results. However, sometimes the diagnosis is quite difficult, and some serious complications can occur when not handled properly. To date, acute appendicitis still has a mortality rate of 0.1-0.5%, so it is still worth paying attention to how to improve the efficacy and reduce misdiagnosis.
Causes: Although acute appendicitis is often manifested as a purulent infection caused by varying degrees of bacterial attack on the appendiceal wall, its pathogenesis is a more complex process, summarized by the following factors.
(a) Obstruction of the appendiceal lumen: The lumen of the appendix is narrow and elongated, and the distal end is closed at the first end, so the obstruction of the lumen is the basis for acute appendicitis. Under normal circumstances, the contents of the appendiceal cavity come from the cecum and can be completely discharged by peristalsis of the appendiceal wall, but if different factors cause obstruction of the lumen, this normal emptying ability is blocked. According to statistics, about 70-80% of the pathology of gangrenous appendicitis can be found in the presence of obstructive factors in the appendiceal lumen. The site of obstruction is mostly in the root of the appendix, but of course it can also be in the middle and distal segments of the appendix, and the causes of obstruction are.
1. Hyperplasia of lymphatic Shanghai vesicles: The submucosa of the appendix has abundant lymphatic tissue, and any cause of swelling of these tissues can cause narrowing of the appendiceal lumen. About 60% of acute appendicitis in adolescents is induced by swelling of lymphoid tissue. It has been observed that the occurrence of appendicitis is closely related to the number of lymphatic vesicles in the appendix.
2, fecal stone obstruction: about 35%, fecal stone is the main cause of acute appendicitis in adults. Fecal stone is the appendix cavity by the feces, bacteria and secretions mixed, concentrated, mostly a, about the size of a soybean. When a larger fecal stone is embedded in the narrow part of the appendix, obstruction can occur.
3, other foreign bodies: about 4%, such as food residues, parasitic worms and eggs, can cause appendiceal cavity obstruction.
4.Appendix itself: when congenital factors or inflammatory adhesions in the abdominal cavity can make the appendix twisted and folded, and compression by cords and swellings can narrow the appendiceal cavity.
5, cecum and appendix wall lesions: inflammation of the cecum wall near the opening of the appendix, tumors and the appendix itself polyps, overlapping, etc. can lead to the obstruction of the appendix lumen.
After the obstruction of appendiceal lumen, a large amount of mucus is retained in the lumen, which gradually increases the pressure inside the lumen, and the excessive pressure can compress the mucosa, causing necrosis and ulceration, creating conditions for bacterial invasion. If the intracavitary pressure continues to increase, the appendiceal wall is also pressurized, firstly, the venous return is blocked, venous thrombosis is formed, the appendiceal wall is edematous and ischemic, and the intracavitary bacteria can penetrate into the abdominal cavity. In severe cases, the artery is also blocked, causing necrosis of part or even the whole appendix.
(2) Bacterial infection: There are a large number of bacteria in the appendix cavity, including aerobic and anaerobic bacteria, and the species are the same as those in the colon, mainly Escherichia coli, Enterococcus and Bacteroides fragilis. Bacteria invade the appendix wall in the following ways.
1, direct invasion: bacteria invade from the ulcer on the mucosal surface of the appendix, and gradually develop to all layers of the appendiceal wall, causing purulent infection.
2.Hematogenous infection: bacteria reach the appendix via blood circulation, and the incidence of acute appendicitis can be increased in children with upper respiratory tract infections.
(3) Spread of adjacent infections: Acute inflammation of the organs surrounding the appendix, which spreads directly to the appendix, can cause appendicitis secondary to this route, which is less common.
(iii) Nervous reflexes: Stomach and intestinal dysfunction of various causes can reflexively cause spasmodic contractions of the appendiceal ring muscle and appendiceal artery. The former can aggravate the obstruction of the appendiceal lumen and make the drainage more poor, while the latter can lead to ischemia and necrosis of the appendix, accelerating the onset and development of acute appendicitis.
Types of pathology
(A) Types: Acute appendicitis can be broadly divided into three types pathologically, representing different stages of inflammation development.
1. Acute simple appendicitis: the appendix is mildly swollen with plasma membrane congestion accompanied by a small amount of fibrinous exudate. There may be small ulcers and bleeding spots in the appendiceal mucosa and a small amount of inflammatory exudate in the abdominal cavity. There is edema and neutrophilic leukocyte infiltration in all layers of the appendiceal wall, most notably in the mucosa and submucosa. Inflammation of the organs and tissues surrounding the appendix was not yet evident.
2. Acute purulent (cellulitis) appendicitis: the appendix is significantly swollen and thickened, the plasma membrane is highly congested, and the surface is covered with purulent exudate. The mucosal surface of the appendix is ulcerated and enlarged, pus accumulates in the lumen, and small abscesses are also formed in the wall. There is purulent exudate in the abdominal cavity, and the inflamed appendix is wrapped by the greater omentum and the adjacent intestinal canal, limiting the development of inflammation.
3. Acute perforated (gangrenous) appendicitis: all or part of the appendiceal wall is fully necrotic, the plasma membrane is dark red or blackish purple, and the area may be perforated. Most of the perforations are in the distal part of the appendix where blood flow is poor, but also in the local part directly compressed by fecal stones, and the perforations may form periappendiceal abscesses or complicate diffuse peritonitis. At this time, most of the appendiceal mucosa is ulcerated and the pus in the lumen is bloody.
(II) Ending: It can also be roughly divided into three possibilities
1. Dissipation of inflammation: Simple appendicitis can be dissipated and completely cured by non-surgical treatment, but a few patients can be left with scars and even narrowing of the lumen, which can become the basis of re-occurrence. Some patients with purulent appendicitis can form a local restrictive abscess after conservative treatment, which will be cured by absorption.
2.Limited infection: In purulent appendicitis and perforated appendicitis, the infection can be confined to the periappendiceal area, or appear as a limited inflammatory mass, or form a periappendiceal abscess. Most patients can be completely absorbed after treatment, but in some cases, the abscess gradually increases and can even break down, causing serious consequences.
3.Infection spread: When perforation occurs before acute appendicitis is wrapped by the omentum, it can cause diffuse peritonitis, and improper treatment can form residual abscesses in the abdominal cavity such as subphrenic abscesses in light cases, or life-threatening in heavy cases. In rare patients, bacterial emboli can enter the portal vein with blood flow to cause inflammation, and furthermore, abscesses can be formed in the liver, and patients develop severe sepsis with clinical phenomena such as high fever, jaundice, and hepatomegaly.
Second, special types of appendicitis
1.Pediatric acute appendicitis
(a) Pediatric acute appendicitis is not uncommon clinically, but the incidence is lower than that of adults. According to the statistics of general hospitals, pediatric acute appendicitis under 12 years of age accounts for about 4-5% of the total number of acute appendicitis.
(b) Compared with adults, pediatric acute appendicitis develops rapidly, is serious, has a high perforation rate, and has many complications. Perforation occurs in almost 100% of acute appendicitis in infants within one year of age, 70-80% within two years of age, and 50% at five years of age. The mortality rate of acute appendicitis in pediatric patients is 2-3%, which is on average 10 times higher than that of adults.
(c) The large omentum of the pediatric population is not well developed and has poor ability to limit inflammation, and nearly 80% of children are seen with varying degrees of septic peritonitis.
(d) Clinical symptoms are atypical, with gastrointestinal reactions being more prominent, sometimes with frequent vomiting as the initial primary symptom. Individual children have a high fever of 39-40°C at the onset of the disease, and some have persistent diarrhea as the main manifestation.
(e) Upper respiratory tract infections, tonsillitis, and acute enteritis may be triggering factors for pediatric acute appendicitis, resulting in more atypical clinical manifestations of acute appendicitis and easy misdiagnosis.
(f) Pediatric physical examination is often uncooperative, and it is not easy to determine whether there is pressure pain in the abdomen and the extent and degree of pressure pain. The cooperation of the child and the family must be obtained urgently, and repeated examinations and careful comparisons must be made to obtain more accurate results.
(vii) After the diagnosis is confirmed, the appendix should be surgically removed immediately, and the preoperative preparation and postoperative comprehensive treatment should be strengthened to reduce the occurrence of complications.
2.Acute appendicitis in the elderly
(a) With the aging of our population, the number of acute appendicitis in elderly people over 60 years old has increased, accounting for about 10% of the total number of acute appendicitis and 10% of adults over 40 years old.
(b) The elderly often suffer from various major organ diseases such as coronary heart disease, and the mortality rate of acute appendicitis is higher and increases with the gradual increase in age. According to statistics, the mortality rate of acute appendicitis is 17% in the age group of 60-69 years, 40% in the age group of 70 years or older, and 13.3% in those who have immediate surgery within 12 hours of onset.
(C) the elderly have low resistance, appendiceal wall, vascular sclerosis, about 30% of patients have perforated appendix at the time of consultation. In addition, the large omentum of the elderly has atrophied, and the inflammation is not easily confined after perforation, so there is more chance of combined purulent peritonitis.
(D) The clinical manifestations are atypical, the elderly have low responsiveness, the abdominal pain is not obvious, and there are often no metastatic features. Since the abdominal muscles have atrophied, even if the appendix has been perforated, the signs of peritoneal irritation are not obvious. Sometimes, after the formation of periappendiceal abscess, a mass has appeared in the right lower abdomen, but it is not accompanied by acute inflammatory manifestations, which is clinically very similar to a malignant tumor in the ileocecal region.
(v) Elderly people often have coexisting cardiovascular diseases, chronic lung diseases, gastrointestinal diseases and metabolic diseases such as diabetes mellitus, and the symptoms of these diseases may be confused with the clinical manifestations of acute appendicitis, making the diagnosis more difficult.
(vi) Advanced age is not a contraindication to surgery. Except for simple appendicitis which can be treated conservatively under close observation, other types of appendicitis must be treated surgically. However, the preoperative preparation and postoperative treatment should be strengthened to ensure the safety of surgery and reduce the occurrence of postoperative complications.
3.Acute appendicitis during pregnancy
(a) The incidence of acute appendicitis in pregnancy: domestic obstetrics hospital statistics appendicitis in pregnancy accounts for about 0.1% of pregnant women, general hospitals account for 2% of the total number of appendicitis. The majority of cases occur between the ages of 25-35, and about 80% are in the middle and late stages of pregnancy.
(B) Due to the physiological changes in pregnant women, once the appendicitis occurs its risk is greater than the average adult. According to statistics, the mortality rate of pregnant women with acute appendicitis during pregnancy is 2%, which is 10 times higher than the average patient, and the mortality rate of the fetus is about 20%.
(c) As the uterus increases, the position of the appendix and appendix changes, and the appendix is displaced upward while its tip rotates in an anti-clockwise direction. Sometimes the appendix and appendix are displaced outward and backward, partially covered by an enlarged uterus. (Figure 6)
(d) During pregnancy, due to congestion of the pelvic organs, inflammation develops more rapidly and there is more chance of perforation of the appendix after inflammation. The chance of combined diffuse peritonitis is also increased because the large wind membrane is pushed to one side, which does not easily limit the development of inflammation.
(e) The clinical manifestations of acute appendicitis in the early stages of pregnancy are the same as those of general appendicitis, but in the middle and late stages of pregnancy, the location of abdominal pain and pressure pain is also elevated, and the muscle tension is not obvious, so it is easy to be misdiagnosed clinically.
(6) The treatment of acute appendicitis in pregnancy should, in principle, be based on the safety of the pregnant woman. For those who develop appendicitis in the third trimester, in principle, it is the same as that in non-pregnancy, and emergency removal of the appendix is best. The diagnosis and treatment of acute appendicitis in the prenatal and perinatal periods are more complicated and should be studied and handled together with obstetricians.
4.Ectopic acute appendicitis
In most people, the appendix has descended into the right iliac fossa at birth. If the embryo develops abnormally, the appendix can lodge in any part of the abdominal cavity. When acute inflammation occurs in the abnormally located appendix, there is some difficulty in diagnosis. The more common ectopic appendixes in clinical practice are pelvic location, subhepatic location and left side location.
(a) Low (pelvic) acute appendicitis: due to excessive descent of the appendix or lack of fixation of the right hemicocele, the appendix may be located below the iliac spine line or even enter the pelvic cavity completely, the clinical estimate of the incidence of pelvic acute appendicitis is about 4.8-7.4%, manifesting as metastatic abdominal pain, only that the abdominal pain site and pressure area are lower, and the muscle tension is also lighter. During the course of the disease, rectal irritation symptoms such as increased bowel movements and anal swelling may occur; or bladder irritation symptoms such as urinary frequency and urgency may occur. The treatment of low appendicitis is the same as that of general appendicitis, and the appendix should be removed by emergency surgery. During surgery, the location of the appendix and the appendix should be carefully explored, and the inflammatory adhesions should be separated so that the appendix is completely free and then removed.
(b) High (subhepatic) acute appendicitis: In congenital incomplete intestinal rotation and descent, the cecum and appendix may stay under the liver; in acquired appendix with excessive length, the tip may also extend under the liver. In subhepatic appendicitis, abdominal pain, pressure and muscle tension are confined to the right upper abdomen, which is often mistaken for acute cholecystitis in clinical practice. If necessary, an ultrasound examination of the abdomen should be performed, and if it is confirmed that the gallbladder is of normal size with clear contours and there is no foreign body echo in the gallbladder cavity, high appendicitis should be considered, and once the diagnosis is confirmed, the appendix should be removed urgently.
(iii) Left-sided acute appendicitis: due to congenital abdominal visceral ectopic, the appendix can be located in the left lower abdomen; acquired free appendix, which can also move and adhere fixed in the left lower abdomen, and the appendix is subsequently fixed in the left iliac fossa. Left-sided acute appendicitis is rare and has the same pathological type and pathogenesis as right-sided acute appendicitis, with metastatic left lower abdominal pain, and pressure and muscle tension limited to the left medullary fossa. When considering the possibility of left-sided acute appendicitis, a careful physical examination and X-ray of the chest and abdomen should be performed, and the appendix can be removed through an oblique incision in the left lower abdomen after confirmation of the diagnosis.
The lowest point is the second month of gestation; the highest point is the eighth month of gestation.
III. Chronic appendicitis
(I) Concept
The diagnosis of chronic appendicitis is not yet fully unified, and there are still differences of opinion as to whether it can be treated as an independent disease in clinical practice. In practice, the pathology of chronic appendicitis and the clinical chronic appendicitis do not always match each other. For example, in incidental resection of a normally asymptomatic appendix for examination, a significant proportion of the appendix is pathologically chronically inflamed. While the pathological examination of the appendix after resection with typical clinical manifestations is chronic appendicitis, the patient has an unsatisfactory postoperative outcome, while the pathological examination of the appendix does not confirm the presence of chronic inflammation, but the symptoms are completely relieved after surgery. Of course, the clinical manifestations, pathological diagnosis and surgical outcome of chronic appendicitis are completely consistent in most patients, so it should be recognized that chronic appendicitis is a clinically independent disease.
(ii) Classification
Clinically, chronic appendicitis is broadly classified into two types.
(i) Primary chronic appendicitis: It is characterized by an insidious onset, slow development of symptoms, and a long duration of illness, ranging from a few months to several years. There is no history of acute attacks at the beginning of the disease, and there are no recurrent acute attacks during the course of the disease.
(b) Secondary chronic appendicitis: characterized by the onset of the first acute appendicitis, which is cured by non-surgical treatment or remits on its own, and then remains with clinical symptoms that remain untreated for a long time and can have another or several acute attacks during the course of the disease.
(iii) Treatment
Surgical treatment is the only effective method, but special care should be taken when deciding to perform appendectomy.
(a) After the diagnosis of chronic appendicitis is confirmed, in principle, surgery should be performed to remove the pathological appendix, especially in patients with a history of acute attacks. For patients with doubtful diagnosis or senior patients with serious coexisting diseases, non-operative treatment should be temporarily carried out and followed up in the outpatient clinic.
(2) If the appendix is found to be basically normal in appearance during surgery, the abdomen should not be easily closed after removing only the appendix, and the tissues and organs near the appendix such as the ileocecal region, the last meter of the ileum, the small intestine mesentery and its lymph nodes should be carefully examined. Female patients should also explore the pelvis and adnexa carefully to prevent misdiagnosis and missed diagnosis.
(iii) Each patient should be followed up for a period of time after surgery to understand the actual outcome after removal of the appendix. The final diagnosis of chronic appendicitis is not pathology, but the complete resolution of symptoms after surgery. Patients who are still symptomatic after surgery should be examined thoroughly to find out the real cause, and should not be easily treated symptomatically as postoperative intestinal adhesions.