What are the steps to diagnose appendicitis?

Diagnosing Appendicitis: A Structured Approach

Begin with clinical assessment focusing on characteristic symptoms (periumbilical pain migrating to right lower quadrant, anorexia, nausea/vomiting, fever) and physical examination findings (right lower quadrant tenderness, guarding, positive psoas sign), then proceed to diagnostic imaging for most patients, except young males under 40 with classic presentation. 1

Step 1: Clinical Assessment

History - Key Features to Identify

• Classic pain pattern: Vague periumbilical pain that migrates to the right lower quadrant 2, 3
• Associated symptoms: Anorexia, nausea, and intermittent vomiting (note: vomiting before pain makes appendicitis unlikely) 2
• Low-grade fever 3
• Timeline: This constellation of symptoms diagnoses approximately 90% of cases 3

Physical Examination - Critical Findings

• Right lower quadrant tenderness and guarding 4, 2
• Positive psoas sign (increases likelihood of appendicitis) 2
• Fever 2
• Absence of these findings (no migration of pain, no right lower quadrant pain, no guarding, no fever) makes appendicitis less likely 2

Laboratory Evaluation

• White blood cell count 4
• Urinalysis (to exclude urinary tract pathology) 4
• Pregnancy test for all females of childbearing potential 1

Clinical caveat: Scoring systems (e.g., Alvarado score) can aid documentation but should never replace clinical judgment 1

Step 2: Diagnostic Imaging - The Standard of Care

Diagnostic imaging is now the standard for most patients with suspected acute appendicitis. 1

Who Gets Imaging?

• All patients presenting with acute abdominal pain consistent with appendicitis 1
• Exception: Male patients aged <40 years with classical history and physical findings may proceed directly to surgery 1
• All female patients should undergo diagnostic imaging 1
• All children, particularly those aged <3 years, when diagnosis is uncertain 1

Imaging Modality Selection

Adults:

• CT with IV contrast only (no oral or rectal contrast) is the recommended imaging procedure 1
• CT sensitivity: 90.8%, specificity: 94.2% 4

Pregnant patients (first trimester):

• Ultrasound or MRI to avoid ionizing radiation 1
• If these studies are non-diagnostic, consider laparoscopy or limited CT scanning 1

Children:

• CT is preferred for definitive diagnosis 1
• Ultrasound is a reasonable alternative to avoid ionizing radiation (sensitivity: 87.1%, specificity: 89.2%) 4
• No prospective randomized comparisons exist between CT and ultrasound in pediatric populations 1

Step 3: Post-Imaging Management

If Imaging is Positive for Appendicitis

• Proceed to surgical intervention or consider antibiotics-first approach based on CT findings 3
• Initiate antimicrobial therapy promptly 1

If Imaging is Negative but Clinical Suspicion Remains

Critical step: There is a measurable false-negative rate with imaging 1

• Hospital or emergency department observation to evaluate symptom evolution over time 1
• 24-hour follow-up is mandatory for all discharged patients (even by telephone if necessary) 1
• Re-examination and possibly re-imaging if no improvement occurs 1
• Consider diagnostic laparoscopy if clinical suspicion persists 1

Special Populations Requiring Heightened Vigilance

• Extremes of age (very young and elderly) 5
• Pregnant women - should undergo timely surgical intervention to decrease complications 6
• Immunocompromised patients - should undergo timely surgical intervention 6

Common Pitfalls to Avoid

• Do not rely solely on scoring systems - they are documentary devices that should not replace clinical suspicion 1
• Do not discharge patients without 24-hour follow-up plans - false-negative imaging occurs and other conditions may manifest 1
• Do not skip imaging in females of childbearing age - atypical presentations are more common 1
• Do not use oral or rectal contrast for CT - IV contrast alone is recommended 1
• Do not assume adult CT protocols apply to all pediatric ages - children have different peritoneal fat distributions 1

Clinical Pathway Implementation

Hospitals should establish standardized clinical pathways involving surgeons, emergency physicians, radiologists, and other relevant specialists to ensure comprehensive management from presentation through discharge 1. These pathways reduce unnecessary operations, decrease antibiotic use, shorten hospital stays, and improve patient outcomes 1.