What are the signs and symptoms of acute appendicitis?

Signs and Symptoms of Acute Appendicitis

The classic presentation of acute appendicitis includes periumbilical pain that migrates to the right lower quadrant, anorexia/nausea/vomiting, right lower quadrant tenderness with guarding, and low-grade fever, though this complete triad occurs in only a minority of patients. 1, 2, 3

Cardinal Clinical Features

Pain Characteristics

• Periumbilical pain migrating to the right lower quadrant is one of the strongest discriminating features for appendicitis in adults 1, 2
• Right lower quadrant pain is the most consistent finding, though location may vary with appendiceal position 1, 2, 4
• Pain typically develops over hours and becomes progressively worse 3

Associated Gastrointestinal Symptoms

• Anorexia is a classic early symptom that precedes other findings 1, 2, 3
• Nausea and intermittent vomiting commonly occur after pain onset 1, 2
• Vomiting that occurs before pain onset makes appendicitis less likely 5

Physical Examination Findings

Most Reliable Signs in Adults

• Right lower quadrant tenderness is nearly universal 1, 4
• Abdominal rigidity strongly suggests appendicitis and indicates peritoneal irritation 2, 4
• Guarding (involuntary muscle contraction) is highly predictive across age groups 2, 5, 4
• Rebound tenderness indicates peritoneal inflammation 1, 2, 4

Specialized Physical Examination Signs

• McBurney point tenderness (approximately one-third the distance from anterior superior iliac spine to umbilicus) is a key finding but has limited specificity alone 2, 5
• Rovsing sign (pain in right lower quadrant when left lower quadrant is palpated) suggests peritoneal irritation at the appendix 2, 5
• Psoas sign (pain with hip extension) suggests retrocecal appendix location 2, 5, 4
• Obturator sign (pain with internal rotation of flexed hip) suggests pelvic appendix 2, 5, 4

Most Reliable Signs in Children

• Absent or decreased bowel sounds are highly predictive 5, 4
• Positive psoas sign is more reliable in pediatric patients 5, 4
• Positive obturator sign has high specificity in children 5, 4
• Positive Rovsing sign is particularly useful for ruling in appendicitis 5, 4
• Difficulty walking combined with focal right lower quadrant pain is significantly associated with pediatric appendicitis 5

Fever and Vital Signs

• Low-grade fever is present in 30-80% of cases, though absence does not exclude appendicitis 1, 2
• High fever (>38°C) combined with other findings increases diagnostic certainty 5, 4

Laboratory Findings

White Blood Cell Count

• Leukocytosis (WBC >10,000/mm³) is common but not diagnostic alone, with positive likelihood ratio of only 1.59-2.7 2, 5
• WBC >10,000/mm³ combined with CRP ≥8 mg/L has a positive likelihood ratio of 23.32 5
• The combination of elevated WBC with left shift has positive likelihood ratio of 9.8 5

Inflammatory Markers

• Elevated C-reactive protein (CRP ≥10 mg/L) has positive likelihood ratio of 4.24 2, 5
• When two or more inflammatory variables are increased, appendicitis is likely 1, 2
• Normal inflammatory markers have 100% negative predictive value in some studies for excluding appendicitis 1, 2
• Very high CRP (>101.9 mg/L) in elderly patients suggests perforation 1

Age-Specific Variations

Elderly Patients (>65 Years)

• The typical triad of migrating pain, fever, and leukocytosis is infrequently observed in elderly patients 1, 2
• Signs of peritonitis are more common: abdominal distension, generalized tenderness and guarding, rebound tenderness, and palpable abdominal mass 1, 2
• Many elderly patients present with signs consistent with ileus or bowel obstruction 1
• Comorbidities and concurrent medications may mask or complicate the clinical presentation 1, 2
• Elderly patients have significantly higher rates of complicated appendicitis (18-70%) and perforation 6

Pediatric Patients (<5 Years)

• Atypical presentations are more frequent in young children 1
• Classic symptoms are less reliable and only moderately reproducible between clinicians 1
• Delayed presentation is common, contributing to higher perforation rates 1

Pregnant Patients

• Peritoneal signs may be less reliable due to anatomic displacement of the appendix 5
• Presentation may be atypical as pregnancy progresses 7

Critical Clinical Pitfalls

Diagnostic Limitations

• Approximately 50% of patients present atypically, requiring lower threshold for imaging 2
• Only a minority of patients have all typical signs and symptoms together 1, 7
• Clinical signs and symptoms alone should never be used for diagnosis—imaging is essential, especially in elderly patients 1, 2
• Scoring systems like Alvarado are useful for excluding appendicitis with low scores but should not be used alone for diagnosis 1, 2

Gender-Specific Considerations

• 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) 2

Body Habitus Impact

• Obesity significantly reduces diagnostic accuracy of ultrasound, with false diagnosis rates of 34.4% in obese men vs 6.2% in non-obese men 2

Diagnostic Approach Based on Clinical Findings

High Clinical Suspicion

When patients present with fever >38°C, guarding, and WBC ≥10,100/mm³, this creates a prediction rule with only 1% missed appendicitis rate in children 5

Intermediate Clinical Suspicion

Patients with some but not all classic findings require imaging (CT for adults, ultrasound for children) rather than proceeding directly to surgery 5, 4

Low Clinical Suspicion

Patients with Alvarado scores <5 may be considered for discharge with 24-hour follow-up, though 8.4% of patients with appendicitis had scores below 5 in some studies 5

When to Suspect Perforation

Clinical Signs of Complicated Appendicitis

• Prolonged symptom duration (>48-72 hours) significantly increases perforation risk 3, 4
• Generalized peritonitis with diffuse tenderness and rigidity 1, 2
• Palpable abdominal mass suggests abscess or phlegmon formation 1, 2
• Rebound tenderness has highest positive predictive value (65%) for complicated appendicitis in children 5