Acute Abdomen in Pregnancy

Acute Abdomen in Pregnancy
Anne Kennedy, MD
DIFFERENTIAL DIAGNOSIS
Common
  • Placental Abruption
  • Appendicitis
  • Renal Stone Disease
  • Pyelonephritis
  • Cholecystitis
Less Common
  • Torsion
  • Fibroid Degeneration
  • Trauma
Rare but Important
  • Uterine Rupture
  • HELLP Syndrome
ESSENTIAL INFORMATION
Helpful Clues for Common Diagnoses
  • Placental Abruption
    • Difficult diagnosis to make sonographically: Occult in up to 50% of cases
      • Acute clot is isoechoic to placenta, no flow on Doppler evaluation
      • Clot may be marginal, preplacental, retroplacental
  • Appendicitis
    • Appendix is displaced out of pelvis by enlarging gravid uterus
    • US
      • Blind ending, non-compressible tube
      • Diameter > 6 mm
      • Look for appendicolith: Echogenic focus with distal acoustic shadowing
      • May see echogenic periappendiceal fat from inflammation
      • May see focal fluid collection if ruptured
      • EV sonography very helpful when appendix drops into pelvis, behind pregnant uterus
    • CT
      • Same anatomic features
      • More sensitive for focal perforation, presence of appendicolith, inflammation of fat
    • MR
      • Increasingly used if US non-diagnostic as no ionizing radiation
      • T1, T2, T2 FS sequences (Gadolinium contraindicated in pregnancy)
      • Same anatomic features as seen with US or CT
  • Renal Stone Disease
    • Collecting system dilatation
    • Ureteric dilatation, particularly suspicious for stone if dilatation stops abruptly
      • Physiologic dilatation tapers at pelvic brim
    • Look for ureteric jets with color Doppler
      • Have patient in decubitus position with side of concern elevated
    • Measure intrarenal resistive indices (RI)
      • Physiologic caliectasis does not cause elevated RI
      • Look for difference of > 0.1 side-to-side
      • Not specific for renal stone disease, as can also be seen with other other acute renal conditions
    • Coronal MR, with heavily T2 weighted sequences, shows stones as low signal filling defects within column of high signal urine
  • Pyelonephritis
    • US
      • Enlarged kidney ± parenchymal edema
      • Look for complicating conditions such as abscess or pyonephrosis (an obstructed, infected system), which require drainage
    • CT
      • Delayed ± striated nephrogram
      • Focal areas of diminished enhancement on delayed images
  • Cholecystitis
    • Gallstones
    • Gallbladder wall thickening
    • Pericholecystic fluid
    • Positive sonographic Murphy sign
    • Remember that right upper quadrant pain and abnormal liver function tests may be seen in preeclampsia
Helpful Clues for Less Common Diagnoses
  • Torsion
    • Adnexal mass can undergo torsion in pregnancy
    • Maximum risk at 12-14 weeks and immediately postpartum
    • Look for
      • Ovarian or paraovarian mass as lead point
      • Echogenic stroma, ovarian enlargement, peripheral follicles from edema
      • Hemorrhage/necrosis/infarction
    • Use Doppler to assess flow
      • Lack of venous flow most suspicious finding
      • Documentation of flow does not exclude the diagnosis in presence of strong clinical suspicion or other imaging findings of concern
  • Fibroid Degeneration
    • Larger fibroids at greater risk for acute red (hemorrhagic) degeneration
      • Severe abdominal pain may mimic abruption
      • Often requires narcotic analgesia for control
    • Inhomogeneous echoes in center of fibroid
    • No flow in inhomogeneous area on Doppler interrogation
    • Placental implantation over large fibroid carries increased risk for abruption
      • Look for changes of abruption, as well as fibroid degeneration, in setting of acute pain
  • Trauma
    • Imaging evaluation should not be compromised because the patient is pregnant
    • When feasible, limit radiation exposure, or use US/MR if possible
    • Fetus at significant risk even if maternal injuries seem relatively minor
      • Placental shear injury → abruption, infarction
      • Maternal hypotension → decreased placental perfusion
      • Most fetal ischemic injury takes time to be visible on imaging
      • Wait 10-14 days post injury and consider performance of fetal MR to look for intracranial hemorrhage, ischemic encephalopathy
Helpful Clues for Rare Diagnoses
Aug 10, 2016 | Posted by in OBSTETRICS | Comments Off on Acute Abdomen in Pregnancy

Full access? Get Clinical Tree

Get Clinical Tree app for offline access