What are the key considerations in the management of acute appendicitis in pregnancy?

Acute Appendicitis in Pregnancy: Key Considerations

Acute appendicitis in pregnancy is least common in the third trimester, and surgical intervention rather than initial observation is recommended when diagnosis is suspected due to the high risk of perforation and subsequent complications. 1

Distribution and Incidence

• Acute appendicitis occurs with varying frequency across trimesters:
  • First trimester: 30-32% of cases
  • Second trimester: 38-44% of cases (most common)
  • Third trimester: 16-32% of cases (least common) 1

Diagnosis Challenges

Clinical Presentation

• Most helpful diagnostic clinical findings include:
  • Uterine contractions
  • Periumbilical pain migrating to the right lower quadrant 1, 2
• Leukocytosis is less reliable for diagnosis due to physiologic leukocytosis of pregnancy 1
• The Alvarado score may be lower in pregnant women (mean 6.7) compared to non-pregnant women (7.3), making clinical diagnosis more challenging 3

Imaging Recommendations

• First-line imaging: Abdominal ultrasound (high specificity but limited sensitivity) 1
• Second-line imaging: MRI (sensitivity 96%, specificity 97%) 1
• CT should be avoided due to radiation exposure 1

Management Approach

Surgical Intervention

• Surgical intervention is recommended when acute appendicitis is suspected in pregnancy rather than initial observation 1
• Delaying surgical intervention increases risks of:
  • Maternal morbidity
  • Fetal loss
  • Premature delivery 1
• Perforation rates significantly increase when symptoms exceed 24 hours (43% vs. 0%) 4

Surgical Approach

• Laparoscopic appendectomy is preferred when appropriate resources and skills are available 1
• Benefits of laparoscopy include:
  • Less post-operative pain
  • Lower wound infection rates
  • Fewer early deliveries 1
• However, laparoscopy carries a slightly increased risk of fetal loss compared to open appendectomy 1

Complications and Risks

Maternal Complications

• Higher rates of surgical wound infection in pregnant women (14.0%) compared to non-pregnant women (3.0%) 3
• Longer hospital stays for pregnant women (5.1 days vs. 1.7 days) 3
• Complications are most pronounced in third-trimester presentations 3

Fetal Complications

• Risk of spontaneous abortion: Up to 33% following appendectomy in the first trimester 1, 2
• Risk of premature delivery: 14-33% following appendectomy in the second trimester 1, 2
• Both perforated appendicitis and negative appendectomy are associated with high risk of premature delivery 5

Pitfalls and Caveats

1. Diagnostic Challenges: Pregnancy-related physiologic changes can obscure accurate diagnosis 4
2. Laboratory Limitations: No single laboratory finding is diagnostic for acute appendicitis during pregnancy 2
3. Timing is Critical: Perforation risk increases dramatically after 24 hours of symptoms 4
4. Negative Appendectomy Risks: Even negative appendectomies carry significant fetal risks 5
5. Third Trimester Presentation: Though least common, third trimester appendicitis is associated with poorer outcomes 3

Key Takeaways

• Prompt surgical intervention is essential when appendicitis is suspected in pregnancy
• Ultrasound followed by MRI (if needed) is the recommended imaging approach
• The classic symptom of periumbilical pain migrating to RLQ remains important for diagnosis
• Leukocytosis should not be heavily relied upon for diagnosis due to physiologic changes in pregnancy
• The risks of delayed diagnosis outweigh the risks of negative appendectomy