Appendicitis in Pregnancy Scott Nguyen Elmhurst Hospital

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Appendicitis in Pregnancy

• Scott Nguyen
• Elmhurst Hospital Center
• October 29, 2003

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Epidemiology

• Same risk as general population
• 1/1500 1/2000 Pregnancies
• 30 1st Trimester
• 45 2nd Trimester
• 25 3rd Trimester

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Maternal Physiology

• Gravid uterus will compress IVC in supine
  position
• Decreases venous return, preload, CO up to 25
• Pts should be placed in left lateral tilt
  position
• Hypervolemic state
• Pt w/ signs of hypovolemia (sepsis) significantly
  volume depleted (30-50 blood volume)
• Anemia
• Typical Hcts 30-35 (d/t increased intravascular
  volume in pregnancy)
• Hypercoagualable state
• Increase in coagulation factors, venous stasis of
  pregnancy -gt 4-6x risk of thromboembolic
  complications
• Uterus limits ability of omentum migration
• Decreased ability to wall off infection

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The Mortality of appendicitis complicating
pregnancy is the mortality of delay- Babler,
1908

• 1908 study 24 maternal, 40 fetal mortality in
  pregnancy
• Increased complications of appendicitis in
  pregnancy d/t delay in diagnosis

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Presentation

• Appendix location cephalad
• 12 weeks -- McBurneys point
• 24 weeks Iliac crest
• 36 weeks RUQ quadrant
• Peritoneal signs often absent
• d/t lifting of abdominal wall by uterus
• Nausea, vomiting, anorexia nonspecific
• Fever in less than majority
• Elevated WBC normal in pregnancy
• 15K in 1st 2nd trimesters
• 20 30K at labor
• lt10K more reassuring

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Position of AppendixBaer et al, 1932
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Differential Diagnosis

• Nonobstetric
• Pyelonephritis
• Urinary calculi
• Cholecystitis
• Cholelithiasis
• Pancreatitis
• Gastroenteritis
• Mesenteric Adenitis
• Pneumonia
• Meckels Diverticulum
• Peptic Ulcer Disease

• Obstetric
• Preterm Labor
• Placental Abruption
• Chorioamnionitis
• Adnexal Torsion
• Ectopic Pregnancy
• Pelvic Inflammatory Disease
• Round ligament pain
• Uterine rupture

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Graded Compression US

• Scan RLQ w/ increasing pressure
• to push bowel loops away
• Empty cecum of gas and fluid
• Sonographic Criteria
• Noncompressible, gt 7mm appendiceal diameter
• Mural thickening gt 3mm
• Presence of appendicalith

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Ultrasound

• Nonpregnant
• Sensitivity 84, Specificity 90
• Pregnant -
• Lim et al 1992, 42 pts
• Sensitivity 100, Specificity 96
• Advanced gestation inadequate evaluation in 3
  pts, gt35 wks
• gt Easy, safe diagnostic tool, but operator
  dependent

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CT in pregnancy

• gt90 sensitive, gt95 specific
• Risk of ionizing radiation???
• Most studies based from Atomic bomb victims in
  Japan
• gt Cumulative dose of 5 rad considered safe

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Radiation Exposure in Pregancy

• No increase in risk of pregnancy loss
• CNS abnormalities
• Risk during 10-17 wks gestation
• gt 10 rad increased risk for mental retardation,
  microcephaly
• Should delay non-urgent radiographs gt 17wks
• Malignancies
• Very small increase in malignancies, mostly
  leukemia
• 2 rad, malignancy risk increases from 3.6/10,000
  (baseline population) to 5/10,000
• Gene mutations
• Very small increase in incidence of gene
  mutations
• 50-100 rad needed to double baseline mutation rate

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• "No single diagnostic procedure results in a
  radiation dose that threatens the well-being of
  the developing embryo and fetus."
• -- American College of Radiology
• "Fetal risk is considered to be negligible at 5
  rad or less when compared to the other risks of
  pregnancy, and the risk of malformations is
  significantly increased above control levels only
  at doses above 15 rad.
• - National Council on Radiation Protection
• "Women should be counseled that x-ray exposure
  from a single diagnostic procedure does not
  result in harmful fetal effects. Specifically,
  exposure to less than 5 rad has not been
  associated with an increase in fetal anomalies or
  pregnancy loss."
• - Amer College of Obstetricians and
  Gynecologists

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Helical CT

• gt 90 sensitive, gt95 specific
• Radiation dose 0.3 rad
• Quicker
• Case series 7 pts only
• Torbati et al, 2002

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Surgery

• Lower threshold for surgery as consequences of
  delay are severe
• Accepted negative appendectomy rate 25-35
• In 2nd, 3rd trimester pregnancies - gt 40
  negative
• Delay in surgery gt 24 h after presentation
  marked increase in rate of perforation
• 0 vs 66 in study of 12 pts (7 perf) Horowitz
  et al 1995
• Perforation occurs twice as often in 3rd
  trimester as 1st or 2nd
• Undoubtedly d/t more difficultly in diagnosis

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Consequences

• Fetal Mortality
• Unperforated appendicitis 3-5
• Perforated appendicitis 20-30
• Preterm contractions common 83
• Preterm labor and delivery uncommon 5-14
• Tocolytics not shown to be helpful
• Maternal Mortality
• Unperforated 0.1
• Perforated 4
• Associated w/ later gestation, diffuse
  peritonitis d/t perforation

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Surgery Anesthetic considerations

• Increased complications associated w/ primary
  disease or surgical procedure NOT anesthesia
• IV/Inhaled anesthetics have NOT been associated
  w/ teratogenicity
• But potential teratogens best avoided hold off
  elective surgery until 2nd trimester
• Local/Regional anesthetics NO association w/
  fetal malformations
• Risk of hypotension decrease uterine blood flow
• Minimize w/ adeq fluids, lateral position

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Surgical Approach

• Incision over point of maximal tenderness
• Midline incision if diffuse peritonitis, or doubt
  about diagnosis
• Tilt table 30 to left
• Minimize uterine manipulation to decrease risk of
  irritability and preterm labor
• External fetal monitoring especially if
  perforation

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Laparoscopic Appendectomy
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Laparoscopy

• Experience limited, but safe so far
• Also useful in diagnosis
• Earlier mobilization, postoperative recovery -
  fewer thromboembolic complications
• Lower postoperative narcotic use less fetal
  depression
• Shorter hospital stay

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Problems

• Technically more difficult in late 2nd and 3rd
  trimesters
• Risk of uterine injury w/ trochar placement
  --Open technique should be used
• Potential for decreased uterine blood flow d/t
  pneumoperitoneum
• Fetal carbon dioxide absorbtion fetal acidosis
• gt Should maintain intraabd pressure lt12 mm Hg,
  minimize operative time
• Potential fetal exposure to smoke CO from
  cautery or lasers
• Smoke should immed be evacuated from abd
• Potential for uterine irritation from
  electrocautery

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Laparoscopic Appendectomy

• Bisharah et al, 2003