APPENDICITIS Flashcards
Definition
acute inflammation of the appendix caused by an obstruction of the appendix, most commonly by lymphoid hyperplasia or fecalith.
Epidemiology
The most common urgent or emergent operations performed in the US
6-7% of population
M>F
80% between are 5-35 years of age
Less common in underdeveloped countries- might be due to Western high-fat, low fiber diet
Pathogenesis
Proximal luminal obstruction 🡪 bacterial overgrowth 🡪 inflammation/swelling 🡪 increased pressure 🡪impaired venous drainage🡪 localized ischemia + bacterial overgrowth with the risk of:
Gangrene and perforation- time to perforation is variable (hours-days)
Formation of a localized abscess (walled off by omentum)
Peritonitis- due to the release of bacterial inoculum to the abdominal cavity
Infections are polymicrobial and include both gram-negative bacteria and anaerobes. Most commonly: E. coli, Bacteroides fragilis, enterococci, Pseudomonas aeruginosa
ETIOLOGY
Children or young adult:
Hyperplasia of lymphoid follicles- often secondary to a viral infection (e.g. adenovirus, measles) or immunization
Adult:
Fibrosis/stricture,
Fecolith- obstructs the proximal lumen-
Obstructing neoplasm
Other causes: parasites, foreign body, fruits and vegetables
SIGNS AND SYMPTOMS
Most reliable feature is progression of signs and symptoms
Low grade fever (38ºC)🡪 rises the presence of a perforation
Abdominal pain then anorexia, nausea and vomiting, less commonly diarrhea
classic pattern of pain:
initially periumbilical; constant, dull, poorly localized,
then well localized pain over McBurney’s point
due to progression of disease from visceral irritation (causing referred pain from structures of the embryonic midgut, including the appendix) to irritation of parietal structures (somatic pain)
Tachycardia and mild dehydration may also be present
Atypical presentations:
Retroperitoneal appendicitis🡪 subacute presentation with flank or back pain
Appendiceal tip inflammation🡪 suprapubic pain that might be confused with a urinary tract infection
SOB🡪 due to multiple appendiceal abscesses that went undiagnosed
SIGNS
Abdominal examination typically reveals a quiet abdomen with tenderness and guarding on palpation of the right lower quadrant.
Rebound tenderness🡪 peritonitis
Diffuse abdominal wall rigidity/ diffuse rebound tenderness 🡪 strongly suggestive of perforation
Inferior appendix:
McBurney’s sign- Tenderness on a 1/3 of the distance from the anterior superior iliac spine (ASIS) to the umbilicus on the right side. McBurney’s sign is present whenever the opening of the appendix at the cecum is directly under McBurney’s point; therefore McBurney’s sign is present even when the appendix is in different locations
Rovsing’s sign- the presence of right lower quadrant pain on palpation of the left lower quadrant.
Retrocecal appendix:
Psoas sign (pain on flexion of hip against resistance or passive hyperextension of hip)
Pelvic appendix:
Obturator sign (flexion then external or internal rotation about right hip causes pain)
DDX
Children-
mesenteric adenitis (often seen after a recent viral illness)
Acute gastroenteritis
Meckel diverticulitis
Intussusception
IBD
Testicular torsion (males)
Females at age of fertility
Ruptured follicular cyst
Ruptured ectopic pregnancy
Endometriosis ovarian torsion
Pelvic inflammatory disease
Elderly:
Colonic carcinoma
Acute diverticulitis
COMPLICATIONS
Perforation (especially if >24 h duration)
Abscess, phlegmon
Pyelophlebitis
Infection of the portal vein
Danger of portal vein thrombosis
Radiograph shows gas in the portal vein.
Subphrenic abscess
Persistent postoperative fever
Diaphragm fixed on the right; right-sided pleural effusion
Tenderness over lateral seventh and eighth ribs
LAB
Mild leukocytosis with left shift (may have normal WBC counts in 10% of cases)
Higher leukocyte count with perforation
β-hCG to rule out ectopic pregnancy
Urinalysis- to exclude UTI.
IMAGING
Ultrasound: may visualize appendix, but also helps rule out gynecological causes – overall accuracy 90-94%, can rule in but CANNOT rule out appendicitis
CT scan– Gold standard! overall accuracy 94-100%, optimal investigation: showing an enlarged appendix (>7 mm in diameter) with a thickened, inflamed wall and mural enhancement.
Surrounding fluid or air🡪 suggest perforation
Type of CT:
Spiral CT after enema
Plain CT with contrast administration
MRI- usually used in pregnant women- excellent prediction.
Plain film- upright CXR, AXR: nonspecific and should not be used.
Pneumoperitoneum is usually not found, even in the presence of a perforation. Its presence should direct the diagnosis to other causes of perforation (e.g. diverticulitis or perforated ulcer).
TREATMENT
Acute uncomplicated appendicitis
Fluid resuscitation- Hydrate, correct electrolyte abnormalities
Broad-spectrum antibiotics- directed against gram-negative and anaerobic organisms.
cefazolin + metronidazole (no post-operative antibiotic unless perforated)
other choices: 2nd/3rd generation cephalosporin for aerobic gut organisms
should not be continued beyond a single pre-operative dose
Surgery (gold standard, 20% mortality with perforation especially in elderly). Can be either laparoscopic vs. open (remains a major point of controversy among surgeons)
Laparoscopy- allows:
examination of the entire peritoneal space (excluding other causes of acute abdomen)
quicker discharge (day after the surgery)
↓risk of infection
Open Surgery
Shorter duration of surgery
Lower operation costs
In high-risk patients with acute uncomplicated appendicitis, in which the risk of surgery is too high🡪 antibiotics alone + CT-guided drainage of abscess (if needed).
Perforated appendicitis
more aggressive resuscitation
antibiotic therapy should be initiated immediately (like non-perforated cases)
continued postoperatively for 4-7 days
surgery- both approaches are acceptable. A challenge even for the most experienced surgeon. Requires gentle handling of the friable appendix and inflamed periappendiceal tissues to avoid tissue injury.
large-volume irrigation🡪 for the clearance of infectious material (e.g. spilled fecal material).
Home discharge is only after normalization of bowel sounds and passage of flatus, WBC count and fever and restoration of tolerance to normal feeding.
postoperative abscess- is the most important complication.
Diagnosed with a CT scan with IV contrast administration
Treated with placing a percutaneous drain within the abscess cavity during the CT scan.
If CT drainage is not technically possible because of the location of the abscess, laparoscopic, transrectal, or transvaginal drainage is an alternative.
DELAYED PRESENTATION
Patients may occasionally present several days to even weeks after the onset of appendicitis
treatment for these patients is initially accomplished nonoperatively- Immediate exploration and attempted appendectomy may result in substantial morbidity
Fluid resuscitation
Broad-spectrum antibiotic therapy-
CT scan from detecting a phlegmon- if recognized🡪 CT guided percutaneous drainage. If drainage is not complete🡪 continues antibiotic therapy for 4-7 days.
‘Interval appendectomy’- is the ‘prophylactic’ removal of the appendix after the inflammation had passed, in order to avoid recurrent episodes. Today it is agreed that only patients with recurrent appendicitis should undergo interval appendectomy.
GENERAL COMMENTS
If the appendix is found normal during appendectomy:
Other causes should be searched for (Meckel’s diverticulum, stigmata of Crohn’s disease mesenteric adenitis, tubo-ovarian or salpingeal disease, such as ovarian torsion, tubo-ovarian abscess, endometriosis, or ruptured ovarian cysts, diverticulitis, and even gallbladder and the duodenum).
Controversy regarding the removal of the appendix even if normal- why?
In the presence of other morbidities (e.g. Crohn’s) it removes appendicitis from the differential diagnosis when the patient presents with recurrent right lower quadrant pain.
Gross normal appendix appearance might still have presence microscopic pathologies responsible for the clinical symptoms.
if localized abscess (palpable mass or large phlegmon on imaging and often pain >4-5 d), consider radiologic drainage + antibiotics x 14 d ± interval appendectomy in 6 wk (controversial)
colonoscopy in the elderly to rule out other etiology (neoplasm)
MORTALITY RATE
0.08% (non-perforated)
0.5% (perforated appendicitis)
