In a 70‑year‑old patient with new‑onset right lower quadrant abdominal pain, what is the appropriate urgent evaluation, diagnostic work‑up, and initial management?

Right Lower Quadrant Pain in a 70-Year-Old: Urgent Evaluation and Management

Obtain CT abdomen and pelvis with IV contrast immediately—this is the mandatory first-line imaging study for any elderly patient presenting with new-onset RLQ pain, as it achieves 95% sensitivity and 94% specificity for appendicitis while identifying critical alternative diagnoses in 23–45% of cases. 1, 2

Why Elderly Patients Require Urgent CT Imaging

Atypical Presentations Are the Rule

• Only 50% of patients over 65 years present with classic RLQ abdominal pain, 17% have fever, and 43% lack leukocytosis—making clinical diagnosis unreliable 1
• Normal laboratory values do not exclude surgical emergencies in elderly patients, as inflammatory markers are frequently falsely reassuring 1, 2, 3
• Delayed diagnosis is common and catastrophic: mortality rates after emergency surgery are 1.6% in patients <65 years, 9.7% in those 65–79 years, and 17.8% in those >80 years 1

The Broad Differential Demands Comprehensive Imaging

While appendicitis remains the leading surgical cause (accounting for ~50% of RLQ pain presentations), elderly patients have a fundamentally different disease spectrum 1, 2:

High-priority surgical diagnoses:

• Right-sided colonic diverticulitis (8% of RLQ pain cases)—can precisely mimic appendicitis 2, 3
• Colorectal malignancy causing obstruction (accounts for ~60% of large bowel obstructions in elderly patients) 2, 3, 4
• Bowel obstruction (small or large bowel, ~3% of presentations) 2
• Mesenteric ischemia—must be considered in elderly patients with cardiovascular disease, especially when pain is disproportionate to physical findings 2, 4

Other critical diagnoses CT will identify:

• Perforated appendicitis with abscess formation 1, 2
• Complicated diverticulitis with perforation or abscess 1
• Ureteral stone disease 2
• Epiploic appendagitis 2
• Infectious/inflammatory colitis including typhlitis 2

The CT Protocol

Use CT abdomen and pelvis with IV contrast 1, 2, 3:

• IV contrast is essential for optimal diagnostic accuracy 3
• Oral contrast may be added for better bowel luminal visualization but is not mandatory 3
• CT identifies conditions requiring hospitalization or invasive treatment in 41% of patients with non-appendiceal diagnoses, with 22% undergoing surgical or image-guided intervention 2

Why Not Ultrasound First?

Do not start with ultrasound in a 70-year-old patient 2, 3:

• Ultrasound sensitivity ranges widely (21–95.7%) depending on operator experience and patient body habitus 3
• The appendix is not visualized in 20–81% of cases, creating diagnostic uncertainty 3
• Equivocal ultrasound results require CT anyway, resulting in diagnostic delay without avoiding radiation 3
• Ultrasound cannot reliably evaluate for the broader differential diagnoses critical in elderly patients (malignancy, ischemia, complicated diverticulitis) 2, 3

Immediate Management While Awaiting Imaging

Initiate these measures urgently 3, 5:

• NPO status
• IV fluid resuscitation
• Nasogastric decompression if signs of obstruction (distension, vomiting)
• Broad-spectrum antibiotics if sepsis or perforation suspected
• Surgical consultation—do not delay this while awaiting imaging

Critical Red Flags in History and Examination

Specifically assess for 1, 2, 3:

• Prior abdominal surgery (adhesive small bowel obstruction has 85% sensitivity for adhesions) 3
• Last bowel movement and flatus passage (obstruction indicators) 3
• Rectal bleeding or unexplained weight loss (colorectal malignancy) 2, 3
• Cardiovascular disease history (mesenteric ischemia risk) 2
• Disproportionate pain to physical findings (ischemia) 2
• Hip flexion weakness or pain with hip extension (psoas abscess or retroperitoneal pathology) 5

Common Pitfalls to Avoid

• Do not wait for "classic" symptom evolution—atypical presentations are the norm in elderly patients, and delays increase perforation risk and morbidity 1, 2
• Do not rely on clinical scoring systems alone—the Alvarado score has not improved diagnostic accuracy and shows mixed results guiding CT use 1
• Do not assume normal labs exclude pathology—many elderly patients with serious infection or perforation have normal inflammatory markers 1, 2, 3
• Do not perform ultrasound first in elderly patients—proceed directly to CT 2, 3
• The negative appendectomy rate based on clinical determination alone is unacceptably high at 25% 1, 2