What are the criteria for diagnosing appendicitis? Leucocytosis, left shift, and PCR: 2 or more altered exams indicate higher risk; 3 normal crite...

What are the criteria for diagnosing appendicitis?

Leucocytosis, left shift, and PCR: 2 or more altered exams indicate higher risk; 3 normal criteria indicate low risk.
Radiography: rarely makes the diagnosis, quick and available exam, aids in differential diagnoses such as volvulus, intussusception, and nephrolithiasis. Radiographic signs include paralytic ileus in the right lower quadrant, fecalith in the appendix, blurring in the psoas region, and pneumoperitoneum. None of these signs are sensitive or specific enough to conclude the diagnosis.
Ultrasound: no radiation exposure, sensitivity and specificity vary greatly in studies. Abdominal ultrasound can show a normal appendix as a compressible tubular structure with a maximum diameter of 5 mm. Appendicitis is characterized by a blind-ended, immobile, non-compressible structure with anechoic mucosa, echogenic muscular wall thickening, and diameter > 6 mm. Other findings include fluid collections, phlegmon, and appendicolith. Color Doppler can show increased blood flow in the inflamed appendix, known as the 'ring of fire'. Diagnostic criteria include diameter > 6 mm, pain on compression, fecalith in the lumen, and peritoneal fluid around the appendix. Sensitivity ranges from 75-90% and specificity from 86-100%. Difficulties include non-visualization of the appendix in 25-35% of cases and the tip of the appendix may not be observed.
CT scan: considered the best exam for diagnosing appendicitis. Sensitivity ranges from 87-100% and specificity from 95-100%. It is the most reliable imaging exam for acute appendicitis. The Alvarado score is 4-6 and includes the presence of fecaliths inside the appendix, blurring of the surrounding fat, and dilation of the lumen with fluid inside the appendix. CT scan has higher sensitivity than ultrasound and similar specificity. It can also aid in other diagnoses. Disadvantages include radiation exposure, longer duration (when oral contrast is used), and potential side effects of intravenous contrast such as nephropathy or allergic reaction. The cost is high, but it can decrease unnecessary hospitalizations and appendectomies, and allow for early diagnosis in specific populations (e.g. elderly patients).
MRI: no radiation exposure, time-consuming, less available and expensive. It is safe for pregnant women, but gadolinium contrast should be avoided in the first trimester. It can visualize a large appendix and easily confirm the diagnosis.
Diagnostic scores: Alvarado score (1986) and Mantrels score. The Alvarado score includes migration of pain, anorexia, nausea or vomiting, tenderness in the right lower quadrant, rebound tenderness, elevation of temperature, leukocytosis, and left shift. The accuracy is affected by gender and age, and scores below 3 indicate a very low risk of appendicitis, while scores of 7 or higher indicate appendicitis in 93% of men and 78% of women.
Other diagnostic methods include laparoscopy, which is both diagnostic and therapeutic but invasive as a diagnostic method and mainly performed in women. According to the American College of Radiology guidelines, appendicitis can be diagnosed clinically, but imaging increases the sensitivity and specificity of the diagnosis. In general, CT scan is the most accurate imaging exam to evaluate suspected appendicitis and alternative etiologies of lower right quadrant abdominal pain. In children, ultrasound is the preferred initial exam as it is almost as accurate as CT scan for diagnosing appendicitis without ionizing radiation exposure. In pregnant women, increasing data supports the use of MRI after equivocal or inconclusive ultrasound results.
Diagnosis: appendicitis should be considered as a differential diagnosis in any patient with epigastric, umbilical, or right lower quadrant/flank pain. Complementary exams include laboratory tests and imaging.
Treatment: drainage and appendectomy have been the standard treatment for over 100 years, with advancements in laparoscopy, single-port, and robotic techniques. Antibiotic therapy is not a consensus.