Acute Abdomen in Pregnancy

Kate Pettit, MS III

June 18, 2007

The Most Important Equation

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10-14 yrs

15-19 yrs

20-24 yrs

25-29 yrs

30-34 yrs

35-39 yrs

40-44 yrs

45-54 yrs

0 20 40 60 80 100 120 140

c

How old are your prospective pregnant patients?

CDC 2004

Live Births per 1,000 Women

Avg Age at First Birth in

US:

25.1 yrs

DDx of Abdominal Pain in Pregnancy

Divided into three categories:

1) Conditions incidental to pregnancy

2) Conditions associated with pregnancy

3) Conditions due to pregnancy

Conditions Incidental to Pregnancy

Acute appendicitis Acute pancreatitis Peptic ulcer Gastroenteritis Hepatitis Bowel obstruction Bowel Perforation Herniation Meckel’s Diverticulitis Toxic megacolon Pancreatic pseudocyst Ovarian cyst rupture Adnexal torsion Ureteral calculus

Rupture of renal pelvis Ureteral obstruction SMA syndrome Thrombosis/infarction Ruptured visceral artery

aneurysm Pneumonia Pulmonary embolus Intraperitoneal hemorrhage Splenic rupture Abdominal trauma Acute intermittent porphyria Diabetic ketoacidosis Sickle Cell Disease

Conditions Associated with Pregnancy

Acute pyelonephritisAcute cystitisAcute cholecystitisAcute fatty liver of pregnancyRupture of rectus abdominus muscleTorsion of pregnant uterus

Conditions Due to Pregnancy

Ectopic pregnancy Septic abortion with peritonitis Acute urinary retention due to retroverted uterus Round ligament pain Torsion of pedunculated myoma Placental abruption Placenta percreta HELLP Syndrome Acute Fatty Liver of Pregnancy Uterine rupture Chorioamionitis

Ectopic Pregnancy

Classic Symptoms Abdominal pain Amennorrhea Vaginal Bleeding

Diagnosis Transvaginal U/S (TVS)

Presence of a true gestational sac at 4.5 to 5 wks is the 1st sign of IUP.

Cardiac activity is first detected at 5.5 to 6 weeks.

Serum quantitative HCG Absence of an intrauterine

gestational sac at hCG concentrations >1500-2000 IU/L suggests an ectopic or nonviable intrauterine pregnancy

Management Option of medical vs surgical

management if pt is hemodynamically stable and no rupture has occurred.

Emergent surgical management if rupture has occurred and/or patient is hemodynamically unstable

Prognosis Ruptured ectopic pregnancies

account for 4- 10 percent of all pregnancy related deaths.

HELLP SyndromeHemolysis – Elevated Liver Enzymes – Low Platelets

Incidence: 1 in 1K pregnancies Timing: Majority diagnosed at

28-36 wks Labs: Plts, AST/ALT,

indirect bili, haptoglobin, schistocytes on peripheral Smear

Management: Emergent delivery for

pregnancies > 34 weeks, nonreassuring fetal status, severe maternal disease (multiorgan dysfunction, DIC, liver infarction or hemorrhage, ARF, or abruptio placenta)

Delayed delivery in stable pregnancies <34 wks after administration of corticosteroids

Sign/Sx Frequency

Proteinuria 87

HTN (>140/90) 85

RUQ/Epigastric pain 40-90

Nausea/Vomiting 29-84

Headache 33-60

Visual changes 10-20

Jaundice 5

Acute Fatty Liver of Pregnancy

Incidence: Rare (1 in 7K – 16K deliveries) Timing: 2nd half of pregnancy (usually 3rd tri)

Sxs: N/V (75%), epigastric abdominal pain (50%), anorexia, jaundice +/- signs of pre-eclampsia

Labs: PT, PTT, AST/ALT, Cr, glucose, +/- WBC, +/- Plts

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.”

Epidemiology

Incidence of acute abdomen during pregnancy is 1 in 500-635

# 1 Acute Appendicitis

# 2 Acute Cholecystitis

Challenges of Diagnosis

Symptoms Nausea, vomiting, and abdominal pain are common

in the normal obstetric population. N/V are most common in weeks 4-16.

Physical Exam Expanding uterus dislocates other intraabdominal

organs. Labs

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?

TraumaAcute appendicitisIntestinal obstructionPerforated duodenal ulcerSpontaneous visceral ruptureEctopic pregnancyOvarian or uterine torsion

Timing of Surgery

1st trimester (wks 1-12)12% SAb rate

2nd trimester (wks 13-26)0 - 5.6% SAb rate5% rate of preterm labor

3rd trimester (wks 27-40)30-40% rate of preterm labor

Imaging Options

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 PregnancyAmerican 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

Iodinated contrast: 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. Gadolinium:

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

MechanismElectromagnetic field induced changes in

proton spinTheoretical risks to fetus

Induction of local electric fields and currentsRadiofrequency 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 1st 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

Appendicitis

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 3rd

trimester due to laxity of abdominal wall muscles.

Adler Sign

If the point of maximal tenderness shifts medially with repositioning on the left lateral side, the etiology is generally adnexal or uterine (vs appendiceal).

Appendiceal Location

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.

Laboratory Evaluation

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).

1st Line Imaging for Appendicitis

Graded compression U/S80% sensitive: non-perforating appendicitis28% sensitive: perforated appendicitis3rd trimester accuracy is lower due to

technical difficulties.

* Doris et al (meta-analysis).

2nd Line Imaging for Appendicitis

CT 94% sensitivity 94% specificity

MRI Up to 100%

sensitivity* 96% specificity* 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).

Non-perforated appendix Fetal mortality of 1.5%

Perforated appendix 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 1st week post-op.

Augustin and Majerovic (2006).

Recommendations for Diffuse Peritonitis

1) IV Cefuroxime, ampicillin, metronidazole, and oxygen pre-operatively.

2) Immediate C-section can be considered, depending on gestational age of fetus.

3) 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

Epidemiology

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

IV hydrationBowel restPain controlAntibioticsFetal monitoringNasogastric 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 1st 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)Gallstone PancreatitisRecurrent 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.

Curet (2000).

Laparotomy vs Laparoscopy?

Choosing Surgical Technique

Laparotomy Currently considered 1st

line approach. Always preferred

approach when diffuse peritonitis is present, as it is associated with a lower complication rate than laparoscopy in this setting.

Laparoscopy 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 2nd trimester.

Can help r/o salpingitis, adnexal mass, or ectopic pregnancy when dx is uncertain.

Recommendations to improve safety of laparoscopy during pregnancy

1) Obstetrical consultation should be obtained preoperatively.2) When possible, operative intervention should be deferred until

2nd trimester.3) Procedure should be performed with pt in supine, left lateral

decubitus position and degree of reverse Trendelenburg should be minimized.

4) Open Hasson technique should be used to prevent puncture of uterus.

5) Pneumoperitoneum pressures should be minimized to 8-12 mm Hg with maximum 15 mm Hg.

6) Administration of tocolytic agents and perioperative monitoring of fetal heart tones should be considered.

7) 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

PurposeDelay 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

Magnesium sulfate 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

Administration: 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 Intraventricular hemorrhage Necrotizing enterocolitis Mortality

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).

References

“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.