What are the clinical signs of acute appendicitis?

Clinical Signs of Acute Appendicitis

The most important clinical signs of acute appendicitis include abdominal pain that migrates from the periumbilical region to the right lower quadrant, localized tenderness in the right iliac fossa, positive Blumberg sign (rebound tenderness), and signs of systemic inflammation such as fever and leukocytosis. 1

Classic Presentation

• Periumbilical pain migrating to the right lower quadrant (RLQ)
• Loss of appetite (anorexia)
• Nausea and/or vomiting
• Fever (present in approximately 50% of patients)
• Leukocytosis (present in approximately 50% of patients)
• Abdominal rigidity
• Guarding over the RLQ 1, 2

Physical Examination Findings

• Localized tenderness at McBurney's point (located two-thirds of the way from the umbilicus to the anterior superior iliac spine)
• Positive Blumberg sign (rebound tenderness)
• Positive Rovsing sign (pain in RLQ when pressing the left lower quadrant)
• Positive psoas sign (pain with passive extension of the right hip)
• Positive obturator sign (pain with internal rotation of the flexed right hip)
• Absent or decreased bowel sounds 1, 3

Laboratory Findings

• Leukocytosis (elevated white blood cell count)
• Elevated C-reactive protein (CRP)
• Note: The absence of leukocytosis and normal CRP have a high negative predictive value, but their presence is non-specific 1

Important Considerations

Atypical Presentations

• Atypical presentations are common, especially in:

  • Young children (<5 years)
  • Elderly patients
  • Pregnant women (where the appendix is displaced upward by the enlarging uterus) 1, 4

• In elderly patients, more signs of peritonitis may be present, such as:

  • Abdominal distension
  • Generalized tenderness 1

Critical Caveat

It's important to note that pain may be the only consistent sign of acute appendicitis. In a significant proportion of patients (15.6% in one study), isolated rebound tenderness in the right lower quadrant may be the only sign, without fever, leukocytosis, or elevated CRP 5. Therefore, the absence of inflammatory signs does not exclude the diagnosis of appendicitis.

Diagnostic Scoring Systems

• The Alvarado score and Appendicitis Inflammatory Response score can help stratify patients as low, moderate, or high risk
• These scoring systems should not be used in isolation but can be useful for excluding appendicitis in patients with low probability 1, 3

Complications of Delayed Diagnosis

• Perforation (occurs in 17-32% of patients)
• Abscess formation
• Peritonitis
• Sepsis
• Increased morbidity and mortality 1, 3

Early diagnosis and prompt intervention are essential to minimize these complications. Over-reliance on a single diagnostic test rather than considering the entire clinical picture can lead to misdiagnosis 1.