Tx : Maternal stabilization (glucose infusion, reversal of coagulopathy) and emergent delivery
Definition of Acute Abdomen
Stedman's Medical Dictionary, 27th Edition defines acute abdomen as "any serious acute intra-abdominal condition attended by pain, tenderness, and muscular rigidity, and for which emergency surgery must be considered.”
Incidence of acute abdomen during pregnancy is 1 in 500-635
# 1 Acute Appendicitis
# 2 Acute Cholecystitis
Challenges of Diagnosis
Nausea, vomiting, and abdominal pain are common in the normal obstetric population. N/V are most common in weeks 4-16.
Expanding uterus dislocates other intraabdominal organs.
Leukocytosis (10-20K) and anemia are common in normal pregnancies and thus, not as predictive of infection or blood loss.
Which conditions require urgent surgical management in pregnancy?
Perforated duodenal ulcer
Spontaneous visceral rupture
Ovarian or uterine torsion
Timing of Surgery
1 st trimester (wks 1-12)
12% SAb rate
2 nd trimester (wks 13-26)
0 - 5.6% SAb rate
5% rate of preterm labor
3 rd trimester (wks 27-40)
30-40% rate of preterm labor
U/S: No known adverse effects.
X-ray: Presence of adverse effects depends on total radiation dose.
CT: Presence of adverse effects depends on total radiation dose.
MRI: No known adverse effects.
ERCP: Only recommended for therapeutic use, not for routine imaging.
Radiation during pregnancy
Use of ERCP in Pregnancy American Society for Gastrointestinal Endoscopy Guidelines
ERCP should only be used when therapeutic intervention is intended (usually for biliary pancreatitis, choledocholithiasis, or cholangitis).
Several studies have confirmed the safety of ERCP in pregnancy.
With precautions, fetal exposure is well below the 5- to 10-rad level.
Kahaleh et al. reported an estimated fetal radiation exposure of 40 mrads (range 1-180 mrad).
Precautions for reducing radiation exposure:
Lead shields placed under the pelvis and lower abdomen, remembering that the x-ray beam originates from beneath the pt.
Use of brief ''snapshots'' of fluoroscopy to confirm cannula position and CBD.
Minimize total fluoroscopy time.
Reducing Radiation in Pregnancy
X-ray: PA exposures lowers the radiation dose by 2 to 4 mrad compared with the traditional AP exposures because the uterus is located in an anterior pelvic position.
CT: Narrow collimation and wide pitch (the patient moves through the scanner at a faster rate) results in a slightly reduced image quality, but provides a large reduction in radiation exposure.
Sequelae of Radiation in Pregnancy
May cause failure of implantation, malformation, growth retardation, CNS abnormalities, or fetal loss.
Exposure <10 rads (100 mGy) does not the risk of fetal death, malformation, or developmental delay.*
Highest risk of radiation damage during embryonic period of organogenesis (weeks 3-9).
*International Commission on Radiological Protection.
Childhood Leukemia and Radiation
The background rate of leukemia in children is about 3.6 per 10,000.
Exposure to one or two rad increases this rate to 5 per 10,000.
Use of contrast in pregnancy
Crosses the placenta
Can produce transient effects on the developing fetal thyroid gland, although clinical sequelae from brief exposures have not been reported.
May be used when indicated.
Crosses the placenta.
Because of limited experience with this agent, gadolinium is currently not recommended for use in the pregnant patient unless the potential benefit justifies the potential risk to the fetus.
Animal studies have shown an risk of spontaneous abortion and skeletal and visceral anomalies.
MRI as an imaging modality
Electromagnetic field induced changes in proton spin
Theoretical risks to fetus
Induction of local electric fields and currents
Radiofrequency radiation results in heating of tissue
American College of Radiology Paper on MRI Safety
MRI should only be used in pregnancy when:
The information requested from the study cannot be obtained from nonionizing means.
The information is needed to care for the pt and fetus during pregnancy.
The ordering MD does not feel it is prudent to delay diagnosis until after pregnancy.
MRI in Pregnancy
No studies have shown adverse effects on the fetus or the outcome of the pregnancy.
However, arbitrarily MRI is NOT usually performed in the 1 st trimester 2/2 to this being the period of organogenesis.
When MRI is used, informed consent must include the possibility that a previously undiagnosed fetal abnormality may be found.
"No single diagnostic procedure results in a radiation dose that threatens the well-being of the developing embryo and fetus." -- American College of Radiology
Appendicitis #1 Cause of Acute Abdomen
Accounts for 25% of the operative indications for non-obstetric surgery antepartum.
Appendicitis is NOT more common during pregnancy.
Incidence is approximately equal in all three trimesters.
Signs and Symptoms
RLQ pain: Most reliable sx
Anorexia and vomiting: Not sensitive nor specific.
Direct RLQ tenderness: ~100%
Rebound tenderness: 55-75% of pts
Abdominal muscle rigidity: 50-65% of pts
Psoas sign: Observed less frequently.
All findings are less common in 3 rd trimester due to laxity of abdominal wall muscles.
If the point of maximal tenderness shifts medially with repositioning on the left lateral side, the etiology is generally adnexal or uterine (vs appendiceal).
Historically, many references have reported appendiceal displacement.
In 2003, a study by Hodjati et al showed that pregnancy did NOT change appendiceal location.
Degree of displacement, if any, is likely due to different extents of cecal fixation.
WBC: Absolute number not reliable given leukocytosis of pregnancy.
Differential: levels of band cells can be reliable indication of infection.
U/A: Caution as 20% of pts have pyuria or hematuria with appendicitis due to extraluminal irritation of the ureter (rather than due to a UTI).
1 st Line Imaging for Appendicitis
Graded compression U/S
80% sensitive: non-perforating appendicitis
28% sensitive: perforated appendicitis
3 rd trimester accuracy is lower due to technical difficulties.
* Doris et al (meta-analysis).
2 nd Line Imaging for Appendicitis
Up to 100% sensitivity*
No known adverse effects on fetus, but cost and availability may be prohibitive.
Fielding and Chin (2006). *Values are from small study of 45 pregnant pts.
Risks for Mother and Fetus
66% risk of perforation if surgery delayed by >24 hrs from presentation.
Negative laparotomy rates of up to 35% are considered acceptable in the pregnant population (vs 15% in non-pregnant population).
Fetal mortality of 1.5%
Fetal mortality of 20-35%
Maternal mortality of 1%
83% risk of preterm contractions due to localized peritonitis.
In all cases, the rate of premature delivery is highest in the 1 st week post-op.
Augustin and Majerovic (2006).
Recommendations for Diffuse Peritonitis
IV Cefuroxime, ampicillin, metronidazole, and oxygen pre-operatively.
Immediate C-section can be considered, depending on gestational age of fetus.
Preoperative intubation and ventilation in cases of fetal hypoxia.
Augustin and Majerovic (2006).
Acute Cholecystitis # 2 Cause of Acute Abdomen
Pathophysiology: Hormones and biliary disease
Estrogen in pregnancy cholesterol synthesis, hepatic cholesterol uptake, catabolism of cholesterol to bile acids Bile supersaturation & cholesterol stones
Progesterone in pregnancy bile stasis and GB contraction in response to CCK
Cholelithiasis is the cause of cholecystitis in pregnant pts in 90% of cases
Incidence of cholelithiasis in pregnancy is 3.5-10%
Only 30-40% of pregnant pts with gallstones are symptomatic
Augustin and Majerovic (2006).
Presentation and Diagnosis
Symptoms: Basically identical in pregnant and non-pregnant pts
Labs: Bilirubin, +/- Transaminases, Alkaline phosphatase is non-specific as it is normally in pregnancy
Imaging: U/S has an accuracy of 95-98% of detecting acute cholecystitis and choledocolithiasis
Initial Management of Cholecystitis
Nasogastric decompression if necessary
Surgical Management of Cholecystitis
Cholecystectomy is now recommended as the primary treatment for cholecystitis because of:
Recurrence rate during pregnancy of 44-92%, depending on date of 1 st presentation
Reduced use of medications
Shorter hospital stay and fewer hospitalizations
Elimination of risk of subsequent gallstone pancreatitis
Minimizing development of potentially life-threatening complications such as perforation, sepsis, and peritonitis
Augustin and Majerovic (2006).
Other Indications for Cholecystectomy During pregnancy
Choledocolithiasis (after ERCP)
Recurrent symptomatic cholelithiasis
Several studies have found the incidence of SAb, preterm labor, or premature delivery to be higher in pts treated non-operatively than in those undergoing cholecystectomy.
However, no prospective trial has been done to determine the best management for recurrent biliary colic.
Laparotomy vs Laparoscopy?
Choosing Surgical Technique
Currently considered 1 st line approach.
Always preferred approach when diffuse peritonitis is present, as it is associated with a lower complication rate than laparoscopy in this setting.
First offered in 1991 for pregnant patients for appendectomy and cholecystectomy.
Many new studies show this technique to be safe in pregnancy for routine appendicitis, especially during the 2 nd trimester.
Can help r/o salpingitis, adnexal mass, or ectopic pregnancy when dx is uncertain.
Recommendations to improve safety of laparoscopy during pregnancy
Obstetrical consultation should be obtained preoperatively.
When possible, operative intervention should be deferred until 2 nd trimester.
Procedure should be performed with pt in supine, left lateral decubitus position and degree of reverse Trendelenburg should be minimized.
Open Hasson technique should be used to prevent puncture of uterus.
Pneumoperitoneum pressures should be minimized to 8-12 mm Hg with maximum 15 mm Hg.
Administration of tocolytic agents and perioperative monitoring of fetal heart tones should be considered.
Pneumatic compression devices should always be used as both pneumoperitoneum and the condition of pregnancy are a risk for venous stasis.
Halkik et al (2006).
Optimizing Delivery *Understanding what the consulting obstetrician is doing for your patients*
Use of Tocolytics for Preterm Labor
Delay delivery so that corticosteroids can be administered.
Prolong pregnancy when there are underlying, self-limited causes of labor, such as pyelonephritis or abdominal surgery, that are unlikely to cause recurrent PTL.
Use is limited to <34 weeks gestation
Types of Tocolytics I
Terbutaline (Beta-2 agonist)
Mechanism : Agonist at myometrium causing relaxation
Meta-analysis showed # of births within subsequent 48 hrs but no change in # of births within subsequent 7 days
Mechanism : Unknown, likely competes with calcium reducing myometrial contractility
Cochrane review concluded that this drug did not significantly reduce the proportion of women delivering within 48 hrs.
Types of Tocolytics II
Nifedipine (Calcium channel blocker)
Mechanism : Directly blocks influx of Ca ions
Meta-analysis showed # of births within 48 hrs as compared to terbutaline as well as # of births within subsequent 7 days.
Indomethacin (Cyclooxygenase inhibitor)
Mechanism : Blocks production of prostaglandins
Small studies indicate effectiveness for prolonging time to delivery
Use of corticosteroids to improve fetal outcomes in premature delivery
Two doses of 12 mg betamethasone IM given 24 hrs apart.
Benefit of therapy is initially observed 18 hrs after the first dose with maximal benefit 48 hrs after the first dose.
Benefits include reduction in the incidence of:
Neonatal respiratory distress syndrome
Steroids and peritonitis?
“ Glycocorticosteroids administered during the initial phase of experimental diffuse peritonitis display favorable action decreasing animal mortality rate regardless of the dose. However, glycocorticosteroids given in the developed septic syndrome decrease the pro-inflammatory cytokine serum concentration regardless of the dose, still not affecting the animal mortality rate.”
Modzelewski et al (2002).
“ Acute Fatty Liver of Pregnancy.” Up-to-date.
Augustin, G and M Majerovic. Non-obstetrical acute abdomen during pregnancy . European J of Obstetrics, Gynecology, and Reproductive Biology 2006; 131: 4-12.
Brooks et al. The Pregnant Surgical Patient . ACS Surgery: Principles and Practice.
Curet, MJ. Special problems in laparascopic surgery: previous abdominal surgery, obesity, and pregnancy. Surg Clinic North Am 2000; 80: 1093-1110.
“ Ectopic Pregnancy.” Up-to-date.
Fielding, JR and BM Chin. Magnetic Resonance Imaging of Abdominal Pain during Pregnancy . Top Magn Resonance Imaging 2006; 17: 409-416.
Halkic et al. Laparascopic management of appendicitis and symptomatic cholelithiasis during pregnancy. Langenbacks Arch Surg 2006; 391: 467-471.
“ HELLP Syndrome.” Up-to-date.
“ Inhibition of preterm labor.” Up-to-date.
Kahaleh et al. Safety and efficacy of ERCP in pregnancy. Gastrointestinal Endoscopy 2004; 60: 287-292.
Modzelewski et al. Tests for the usefulness of glucocorticosteroids in treatment of experimental peritonitis . Pol Merkur Lekarski 2002; 69: 228-231.
Murray et al. Diagnosis and treatment of ectopic pregnancy . CMAJ 2005; 73: 905.
Pedrosa et al. MR Imaging of Acute Right Lower Quadrant Pain in Pregnant and Nonpregnant Patients. Radiographics 2007; 27: 721-753.