Definition and etiology
Acute appendicitis is an acute inflammation of the vermiform appendix of the cecum. The condition is among the most frequent causes of an acute abdomen and requires timely diagnosis, as delayed intervention can lead to severe complications and death. A separate category is complicated acute appendicitis, which presents with signs of infection spreading within the abdominal cavity: appendiceal infiltrate, periappiceal abscess, peritonitis, retroperitoneal phlegmon, and pylephlebitis.
The main causes of inflammation include:
- fecaliths (intestinal stones) and obstruction of the appendiceal lumen;
- helminthic invasion and food masses;
- lymphoid hyperplasia of the appendiceal wall;
- neoplasms;
- microbial seeding — E. coli, streptococci, bacteroids, and other pathogens.
Classification
Based on morphological changes, several forms of the disease are distinguished:
- Catarrhal — the initial stage with changes predominantly in the mucous membrane.
- Phlegmonous — acute inflammation with marked edema, pus accumulation, and fibrinous deposits on the serosa.
- Gangrenous — thrombosis of the vessels of the appendiceal mesentery with tissue necrosis; high risk of peritonitis and death.
- Secondary — an inflammatory reaction in the vessels of the vermiform appendix due to a disease of neighboring organs; appendectomy is generally not indicated.
- Empyema of the appendix — a variant of phlegmonous inflammation in which a scarring process or fecalith forms a closed cavity filled with pus.
Complications
The most significant complications include:
- perforation of the vermiform appendix;
- appendiceal infiltrate — detected preoperatively by ultrasound or CT or found intraoperatively (soft or dense);
- periappendiceal abscess;
- generalized peritonitis;
- pylephlebitis — suppurative thrombosis of the portal vein branches;
- retroperitoneal phlegmon.
Anatomical positions and differential diagnosis
The broad range of differential diagnoses is due to the variability in the location of the vermiform appendix. Clinical guidelines identify five main variants: ascending, medial, pelvic, retrocecal (retroperitoneal), and left-sided. The nature of pain depends on the location: in the pelvic variant, pain is localized in the lower abdomen and often mimics gynecological pathology; in the subhepatic variant, it resembles biliary colic; when close to the root of the mesentery, repeated vomiting frequently develops due to mesenteric irritation.
Acute appendicitis is differentiated from perforated gastric and duodenal ulcers, acute pancreatitis, complicated diverticulitis, ruptured ectopic pregnancy, ovarian apoplexy, pelvic inflammatory disease, renal colic, urinary tract infections, acute mesadenitis, and intestinal infections.
Clinical presentation and appendicular signs
Patients usually arrive via emergency services in a fetal position, complaining of severe abdominal pain. At the onset of the disease, the abdominal shape is unchanged; the abdomen is soft, moves with respiration, and tenderness and local tension are determined in the right iliac region. As the inflammation progresses, the right half of the abdomen lags behind during respiration.
According to clinical guidelines, the main appendicular signs are as follows:
- McBurney's sign — tenderness at the point between the umbilicus and the right anterior superior iliac spine.
- Blumberg's sign — intensification of pain upon sudden withdrawal of the hand after palpation of the right iliac region (a sign of peritoneal irritation.
- Voskresensky's sign ("shirt sign") — intensification of pain with a rapid slide of the hand over taut clothing from the epigastrium to the right iliac region.
- Rovsing's sign — the appearance of pain in the right iliac region upon jolting palpation in the left iliac and flank regions due to the displacement of gases toward the ileocecal junction.
Laboratory diagnostics
Laboratory workup is mandatory even if emergency surgery is planned:
- Complete blood count: leukocytosis, increase in polymorphonuclear neutrophils, accelerated ESR, elevation of C-reactive protein as markers of inflammation.
- Urinalysis to rule out urinary system pathology.
- Bacteriological examination of abdominal exudate with determination of pathogen susceptibility to antibiotics, especially in peritonitis, for selecting postoperative antibiotic therapy.
Surgical treatment
The standard treatment for acute appendicitis is appendectomy, performed via open or laparoscopic access. The stages of the intervention include:
- exploration of the abdominal cavity with assessment of effusion, organ status, and presence of peritonitis;
- visualization and mobilization of the vermiform appendix;
- transection and ligation of the appendiceal artery;
- removal of the appendix with stump management.
The removed specimen must be sent for histological examination. This is because the clinical presentation of acute appendicitis may be caused not only by inflammation but also by tumor processes of the vermiform appendix, including malignant neoplasms.
Key points
- Acute appendicitis is acute inflammation of the vermiform appendix requiring emergency diagnosis and surgical treatment.
- Morphological forms: catarrhal, phlegmonous, gangrenous, secondary, appendiceal empyema.
- Severe complications — perforation, peritonitis, periappendiceal abscess, pylephlebitis, retroperitoneal phlegmon.
- The clinical presentation depends on five variants of appendix localization, which determines a broad differential diagnosis.
- Key signs — McBurney's, Blumberg's, Voskresensky's, Rovsing's.
- Mandatory laboratory minimum: CBC, urinalysis, in peritonitis — exudate culture with antibiogram.
- Treatment standard — open or laparoscopic appendectomy.
- Histological examination of the removed appendix is mandatory to rule out tumor pathology.