What are the signs for an appendicitis test?

Signs and Tests for Appendicitis

The diagnosis of appendicitis should not be based solely on clinical signs and symptoms, especially in elderly patients, but should include a combination of clinical evaluation, laboratory tests, and imaging studies when indicated.

Clinical Signs and Symptoms

• The classic presentation includes migration of pain from periumbilical area to right lower quadrant, accompanied by anorexia, nausea, vomiting, and fever, though this is present in only about 50% of cases 1
• Right lower quadrant tenderness is one of the strongest clinical indicators of appendicitis 2
• Rebound tenderness in the right iliac fossa is a significant finding that increases the likelihood of appendicitis 3
• Nausea and vomiting typically occur after the onset of pain; vomiting before pain makes appendicitis less likely 4
• Fever (>38°C) is present in 30-80% of cases, with higher temperatures suggesting possible perforation 2
• Atypical presentations are common in elderly patients, who may present with signs of ileus or bowel obstruction rather than the classic triad 2
• In elderly patients, peritoneal signs (abdominal distension, generalized tenderness and guarding, rebound tenderness) may be more prominent due to delayed presentation and higher rates of perforation 2

Laboratory Tests

• Leukocytosis with left shift is a valuable indicator but should not be used alone for diagnosis 2, 3
• CRP elevation is helpful, particularly when combined with other inflammatory markers 2
• Normal white blood cell count and CRP values together have a high negative predictive value (100% in some studies) for excluding appendicitis in elderly patients 2
• Elevated CRP >101.9 mg/L in elderly patients may suggest perforation (AUC 0.811) 2
• Procalcitonin has significant diagnostic value for identifying complicated appendicitis (AUC 0.94) 2
• Laboratory tests alone are insufficient for diagnosing appendicitis but should be used to complement clinical evaluation 2

Clinical Scoring Systems

• The Alvarado score includes: migration of pain, anorexia, nausea/vomiting, right lower quadrant tenderness, rebound tenderness, fever, leukocytosis, and left shift of neutrophils 5
• Alvarado score is useful for excluding appendicitis in low-risk patients but not recommended for confirming diagnosis 2
• In elderly patients, Alvarado scores ranging from 5-10 indicate high risk of appendicitis, with scores of 5-6 being common 2
• The AIR (Appendicitis Inflammatory Response) score and AAS (Adult Appendicitis Score) have better discriminating power than the Alvarado score in adults 2
• In pediatric patients, the Pediatric Appendicitis Score (PAS) includes right lower quadrant pain with coughing, hopping, or percussion, which is particularly relevant in children 2
• The AIR score outperforms both Alvarado and PAS in pediatric patients 2

Imaging Studies

• CT scan is the primary imaging modality for evaluating appendicitis in adults, with sensitivity of 85.7-100% and specificity of 94.8-100% 1
• CT with IV contrast but without enteral contrast has high sensitivity (90-100%) and specificity (94.8-100%) 1
• Ultrasound is preferred for children and women of childbearing age, though it has variable sensitivity (51.8-81.7%) and specificity (53.9-81.4%) 1
• MRI is particularly useful for pregnant patients, with both sensitivity and specificity of 96% 1
• When CT is used as a supplement to clinical assessment based on Alvarado criteria, sensitivity increases to 98.3% and specificity to 95.8% 6

Diagnostic Algorithm

1. Perform initial clinical evaluation focusing on classic symptoms and apply appropriate clinical scoring system 1
2. Stratify risk using clinical scores:
   • Low-risk patients may be observed without imaging 2
   • High-risk patients may proceed directly to surgical consultation 2
   • Intermediate-risk patients should undergo imaging studies 2
3. Select appropriate imaging based on patient characteristics:
   • CT with IV contrast for adults 1
   • Ultrasound for children and women of childbearing age 1
   • MRI for pregnant patients 1
4. Interpret findings considering appendiceal dilation (≥7mm), presence of appendicoliths, and periappendiceal inflammation 7

Special Considerations

• Elderly patients have higher rates of misdiagnosis and perforation due to atypical presentation 2
• Children under 5 years often present with atypical features and have higher rates of perforation 1
• Pregnant patients should not be diagnosed based on symptoms and signs alone; laboratory tests and inflammatory markers should always be included 2
• Appendicoliths, mass effect, or appendiceal dilation >13mm on CT suggest higher risk of treatment failure with antibiotics-first approach 7