What is the assessment and treatment for suspected appendicitis in pregnant women?

Assessment and Treatment for Suspected Appendicitis in Pregnant Women

In pregnant women with suspected acute appendicitis, abdominal ultrasound should be used as the initial imaging modality, followed by MRI if results are equivocal or inconclusive. 1

Clinical Presentation and Diagnostic Challenges

• Appendicitis is the most common non-obstetric surgical emergency during pregnancy, occurring in approximately 1 in 766 pregnancies 2
• Diagnosis can be challenging due to anatomical and physiological changes of pregnancy that may alter the typical presentation of appendicitis 3, 4
• Key clinical symptoms that are significantly more frequent in pregnant women with appendicitis include:
  • Uterine contractions
  • Diffuse or periumbilical pain migrating to the right lower abdominal quadrant 2
• Common symptoms such as abdominal pain, nausea, vomiting, and laboratory findings (leukocyte count, CRP, body temperature) may not be as helpful in establishing the correct diagnosis during pregnancy 2

Diagnostic Imaging Algorithm

1. First-line imaging: Abdominal Ultrasound

   • The Infectious Diseases Society of America (IDSA) recommends abdominal ultrasound as the initial imaging modality for pregnant women with suspected appendicitis 1
   • Ultrasound is preferred due to absence of radiation exposure to the fetus 1
   • Be aware that ultrasound is operator-dependent and has a high rate of equivocal results in pregnant women (median 95% in studies) 1

2. Second-line imaging: MRI

   • If ultrasound is inconclusive or negative but clinical suspicion remains high, MRI should be the next imaging modality 1
   • MRI is highly sensitive and specific for diagnosing appendicitis during pregnancy 1
   • The IDSA notes that "the conditional imaging strategy suggested (US, then MRI for equivocal results) would likely yield the same results as an MRI only" 1
   • MRI avoids radiation exposure while providing excellent diagnostic accuracy 1

3. CT considerations

   • CT should be avoided when possible due to radiation exposure to the fetus 1
   • In settings where MRI is not readily available and diagnosis is urgent, low-dose CT may be considered as a last resort 1

Management Approach

• Surgical intervention

  • Prompt surgical intervention is recommended once appendicitis is diagnosed to prevent perforation 3, 4
  • Delay in diagnosis and treatment may lead to increased maternal and fetal risk 3, 5
  • Laparoscopic appendectomy is considered safe during pregnancy and preferable to open surgery 6
  • Surgery should not be delayed more than 24 hours from admission to avoid complications 6

• Analgesia

  • Paracetamol (acetaminophen) is the first-line analgesic for pregnant women with appendicitis at a dose of 500-1000 mg every 6-8 hours, not exceeding 4 grams in 24 hours 6

• Antibiotic therapy

  • Prophylactic antibiotics are recommended in all laparotomies during pregnancy when appendicitis is suspected 2
  • Initial intravenous antibiotics with subsequent conversion to oral antibiotics is recommended for cases managed non-operatively 1

Potential Complications and Outcomes

• Both perforated appendicitis and negative appendectomy during pregnancy are associated with increased risk of premature delivery 3
• Fetal loss risk varies by trimester:
  • First trimester: Up to 33% risk of spontaneous abortion following appendectomy 2
  • Second trimester: Approximately 14% risk of premature delivery 2
  • Third trimester: Lower risk of pregnancy complications compared to earlier trimesters 2

Key Considerations

• An aggressive surgical approach may be warranted despite the risk of negative appendectomy, as delay in diagnosis can lead to perforation with increased maternal and fetal morbidity 5, 4
• Multidisciplinary team approach involving obstetricians, surgeons, and radiologists is essential for optimal management 7
• The combination of symptoms and clinical judgment remains vital in deciding which patients need surgical treatment, even with advanced imaging techniques 2