What are the signs of appendicitis?

Signs of Appendicitis

The classic presentation of appendicitis includes periumbilical pain migrating to the right lower quadrant, right lower quadrant tenderness with guarding, anorexia/nausea/vomiting, and fever, though this complete triad is present in only a minority of patients. 1, 2

Classic Clinical Signs

Pain Characteristics

• Periumbilical pain that migrates to the right lower quadrant is one of the strongest discriminators for appendicitis in adults 1, 2
• Right lower quadrant pain is the most reliable sign for ruling in acute appendicitis in adults 3
• Pain typically begins as vague periumbilical discomfort before localizing to the right lower quadrant over hours 2
• The pain location can vary with anatomical position of the appendix—atypical locations may present with epigastric or other non-classic pain patterns 4

Physical Examination Findings

• Right lower quadrant tenderness (at McBurney's point, located one-third the distance from the anterior superior iliac spine to the umbilicus) is a key finding 5, 3
• Abdominal rigidity and guarding are among the best signs for ruling in acute appendicitis in adults 3
• Rebound tenderness indicates peritoneal irritation and is commonly present 4
• Rovsing sign (pain in the right lower quadrant when palpating the left lower quadrant) occurs when pressure displaces gas and fluid, causing peritoneal irritation at the inflamed appendix 5, 3
• Psoas sign (pain with hip extension) suggests retrocecal appendix location 3
• Obturator sign (pain with internal rotation of the flexed hip) suggests pelvic appendix location 5, 3

Associated Symptoms

• Anorexia, nausea, and intermittent vomiting are classic associated symptoms 1, 2
• Low-grade fever is present, though reported rates vary from 30% to 80% in different populations 1, 2
• Decreased or absent bowel sounds are reliable findings, particularly in children 3

Age-Related Variations

Elderly Patients (≥65 years)

• The typical triad of migrating right lower quadrant pain, fever, and leukocytosis is infrequently observed in elderly patients 1
• Signs of peritonitis are more common, including abdominal distension, generalized tenderness and guarding, rebound tenderness, and palpable abdominal mass 1
• Symptoms may mimic ileus or bowel obstruction 1
• Elderly patients have significantly higher rates of complicated/perforated appendicitis (18-70%) compared to younger patients (3-29%) 6
• Comorbidities and concurrent medications may mask or complicate the clinical presentation 1

Laboratory Findings

• Leukocytosis (elevated white blood cell count) is common but not diagnostic on its own 1, 7
• Elevated C-reactive protein (CRP) is frequently present; when two or more inflammatory variables are increased, appendicitis is likely 1
• Normal inflammatory markers have high negative predictive value (100% in some studies) for excluding appendicitis 1
• In elderly patients, elevated CRP >101.9 mg/L may indicate perforation (AUC 0.811) 1
• Procalcitonin has diagnostic value for identifying complicated appendicitis (AUC 0.94) 1

Imaging Signs

CT Findings

• Appendiceal diameter ≥7 mm (some studies use 8.2-8.5 mm cutoff) 1, 2
• Presence of appendicoliths/fecaliths predicts perforation with odds ratio of 2.47-2.67 1, 8, 2
• Periappendiceal fat stranding 1
• Absence of intraluminal gas 1
• Focal wall defect has highest specificity (98.8%) for perforation 1
• CT has sensitivity of 90-100% and specificity of 94.8-100% for diagnosing appendicitis 1, 5, 7

Ultrasound Findings

• Non-compressible appendix >6 mm diameter 7
• Ultrasound has average sensitivity of 87.1% and specificity of 89.2%, though visualization rates vary (35-65%) 1, 7
• Bedside ultrasound shows mean sensitivity of 90% and specificity of 95% 1

MRI Findings

• MRI demonstrates 96% sensitivity and 96% specificity for appendicitis diagnosis 1, 5
• Particularly useful in pregnant patients 5

Plain Radiography

• Fecal loading sign (cecum distended with stool containing innumerable punctate lucencies) has sensitivity of 97.05% and specificity of 85.33% 1
• This sign disappears after appendectomy 1

Critical Clinical Pitfalls

• Do not rely on clinical signs and symptoms alone for diagnosis, especially in elderly patients—imaging is essential 1
• Scoring systems (Alvarado score) are useful for excluding appendicitis (low scores) but should not be used alone for diagnosis 1
• Atypical presentations occur in approximately 50% of patients, requiring lower threshold for imaging 1
• Female patients of childbearing age have more atypical presentations and lower diagnostic accuracy on ultrasound (false-positive rate 35.5% vs 6.2% in men) 1
• Obesity significantly reduces diagnostic accuracy of ultrasound, with false diagnosis rates of 34.4% in obese men vs 6.2% in non-obese men 1
• Delayed presentation increases perforation risk—elderly patients typically present later with higher perforation rates 1, 6