What are the signs and symptoms of acute appendicitis?

Signs and Symptoms of Acute Appendicitis

The classic presentation of acute appendicitis includes periumbilical pain migrating to the right lower quadrant, anorexia/nausea/vomiting, and low-grade fever, though this complete triad occurs in only a minority of patients and should never be required for diagnosis. 1

Classic Clinical Presentation

Primary Symptoms

• Periumbilical pain migrating to the right lower quadrant is one of the strongest discriminators for appendicitis in adults and represents the most characteristic symptom pattern 1, 2
• Anorexia, nausea, and intermittent vomiting are classic associated symptoms that typically follow the onset of pain 1, 2
• Right lower quadrant pain with localized tenderness is the most common presenting complaint, though the pain pattern may vary 3, 4
• Low-grade fever is present in 30-80% of cases, meaning 20-70% of patients present without fever—absence of fever should never exclude appendicitis 5, 1

Physical Examination Findings

• Right lower quadrant tenderness with guarding is highly predictive, particularly when combined with other findings 1, 4
• Abdominal rigidity indicates established peritonitis and requires immediate surgical consultation 1, 4
• McBurney point tenderness (approximately one-third the distance from the anterior superior iliac spine to the umbilicus) is a key finding but has limited specificity when used alone 1
• Rovsing sign (palpation of the left lower quadrant elicits pain in the right lower quadrant) occurs when pressure displaces gas and fluid, causing peritoneal irritation at the inflamed appendix 1
• Psoas sign (pain with hip extension) suggests retrocecal appendix location 1, 4
• Obturator sign (pain with internal rotation of the flexed hip) suggests pelvic appendix 1, 4
• Rebound tenderness has the highest positive predictive value (65%) among clinical signs for predicting complicated appendicitis in children 6

Laboratory Findings

• Leukocytosis (WBC >10,000/mm³) is common but has limited diagnostic value alone with a positive likelihood ratio of only 1.59-2.7 6
• Elevated C-reactive protein (CRP ≥8-10 mg/L) has a positive likelihood ratio of 4.24 6
• The combination of WBC >10,000/mm³ AND CRP ≥8 mg/L is most powerful with a positive likelihood ratio of 23.32 and negative likelihood ratio of 0.03 6
• Normal inflammatory markers have high negative predictive value (100% in some studies) for excluding appendicitis 1

Age-Related Variations and Atypical Presentations

Pediatric Patients (<5 years)

• Atypical symptoms occur more frequently in children under 5 years, who often cannot articulate classic pain patterns 3
• Absent or decreased bowel sounds, positive psoas sign, positive obturator sign, and positive Rovsing sign are the most reliable physical findings for ruling in acute appendicitis in children 6, 4
• Delayed presentation is more common, contributing to higher perforation rates in the youngest children 3

Elderly Patients

• 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
• Comorbidities and concurrent medications may mask or complicate the clinical presentation 1
• Higher perforation rates (18-70% compared to 3-29% in younger patients) occur due to delayed diagnosis 5

Pregnant Patients

• Peritoneal signs may be less reliable due to anatomic displacement of the appendix by the gravid uterus 6
• Atypical presentations are more common in female patients of childbearing age 1

Critical Clinical Pitfalls

• Never rely on clinical signs and symptoms alone for diagnosis—imaging is essential, especially in elderly patients and those with atypical presentations 1, 6
• Atypical presentations occur in approximately 50% of patients, requiring a lower threshold for imaging 1
• The complete classic triad is present in only a minority of patients—do not require all elements for diagnosis 1, 2
• Scoring systems (Alvarado score) are useful for excluding appendicitis (low scores) but should not be used alone for diagnosis 1, 6
• 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
• Absence of fever, normal WBC, or normal CRP should never exclude appendicitis—early appendicitis may not yet demonstrate laboratory abnormalities 5, 6

Risk Stratification Approach

• Combine symptoms, physical examination signs, and laboratory results systematically using validated scoring systems (Alvarado, AIR, or Pediatric Appendicitis Score) to guide imaging decisions 6, 4
• The combination of fever >38°C, guarding, and WBC ≥10,100/mm³ creates a prediction rule with only 1% missed appendicitis rate in children 6
• Proceed with imaging (ultrasound in children, CT in adults) for intermediate-risk patients rather than relying on clinical assessment alone 6, 4
• High clinical suspicion warrants immediate surgical consultation even if imaging is inconclusive or negative 6