Acute Abdominal Pain in Pregnancy:

Diagnosis and Management Conservative

vs. SurgicalAndrea Lausman MD, FRCSC

Maternal Fetal Medicine SpecialistSt. Michael’s Hospital

University of Toronto - Assistant Professor March 19, 2013

Objectives

1. History, Physical, Investigations: • How they differ in pregnancy

2. Differential Diagnosis of acute abdominal pain

3. Diagnostic Imaging: US/ CT/ MRI

4. A review of some of the more common causes of acute abdomen in pregnancy

5. In the Operating Room• Laparoscopy vs. Laparotomy• Issues specific to pregnancy

Scope of the Problem

• Definition of Acute Abdomen: – S&S of intra-peritoneal disease best treated surgically

• ~1/500 women need non-obstetrical abdominal surgery during pregnancy

• Most common non-obstetrical surgical emergencies:1. Acute appendicitis2. Cholecystitis3. Intestinal Obstruction4. Pancreatitis5. Trauma

• “Earlier diagnosis means better prognosis” Sir Zachary Cope 1921

• Weigh risks and benefits of diagnostic modalities and therapies for both mother and fetus

History• P – Pain: onset, duration, intensity, character • Q - Quality• R – Radiates• S – Severity• T - Time

• Gestational age

• Associated symptoms – All frequent in normal pregnancy : – Nausea & vomiting– Constipation– Increased frequency of urination– Pelvic / Abdominal discomfort

Physical• Peritoneal signs are often absent in pregnancy

– lifting and stretching of the anterior abdominal wall– underlying inflammation has no direct contact with the parietal peritoneum– precludes muscular response or guarding that is expected

• The uterus can obstruct and inhibit the movement of the omentum to an area of inflammation

• < 24 weeks – document FHR

• >24 weeks - A reassuring tracing allows the evaluation to continue at an appropriate pace

• Monitoring for contractions:– Throughout the evaluation period– After definitive treatment

Investigations

• Labs: – ↑WBC (T2 <16, T3 <20-30 in early labour)

• Ultrasound

• CT

• MRI

Ultrasound

• Safe

• Relatively high sensitivity and specificity

• Test of choice for most ob/gyn causes of abdo pain

• Also useful first line test for many non-gyne conditions

Risk of Ionizing Radiation

• Risk based on gestational age and radiation dose – 1 rad = 1 cGy

• First trimester: all or nothing phenomenon

• Most sensitive time for CNS teratogenesis is 10-17 wks

• In T2 and T3 – risk is childhood haematologic malignancy– Background risk is 0.2-0.3% of childhood cancer and leukemia – Increased

risk by 0.06% per rad of exposure

• No single study should exceed 5 rads

• Accepted cumulative dose of ionizing radiation in pregnancy is 5-10 rads

Estimated Fetal Exposure from Some Common Radiologic Procedures

ProcedureFetal

Exposure

Chest radiograph (2 views) 0.02-0.07 mrad

Abdominal film (single view) 100 mrad

Intravenous pyelography >1 rad*

Hip film (single view) 200 mrad

Mammography 7-20 mrad

Barium enema or small bowel series 2-4 rad

CT scan head or chest  

CT scan abdomen and pelvis 3.5 rad

CT pelvimetry 250 mrad

MRI

• Safe in pregnancy for mother or fetus

• Becoming standard of care for investigation of placental implantation abnormalities, and further delineation of fetal anomalies

• Issue is contrast media

CLINICAL PRACTICE – March 2006• Canadian Family Physician; Motherisk Update• Safety of gadolinium during pregnancy Garcia-Bournissen F, Shrim A, Koren G

There is no evidence that

points to Gadolinium being

unsafe in pregnancy although no

centres in Canada use Gd in

pregnancy

Differential Diagnosis

Acute Abdomen in

Pregnancy

Pregnancy Related

Non-Gyne

GI GU Vascular

Gyne

Adnexal Accident,

fibroid Degeneration…

Difficult Diagnosis

• Expanding uterus dislocates other intra-abdominal organs

• High prevalence of nausea, vomiting and abdominal pain in pregnancy

• General reluctance to operate in pregnancy

Treatment

• Conservative…

• Surgical– Laparoscopy– Laparotomy

• Obstetrical issues:– Preterm labour– Intra-op monitoring– Tocolysis– Paeds– Delivery

Appendicitis

Appendicitis• Most common non-obstetric cause of surgical emergency in

pregnancy

• Incidence: 1 in 500-2000

• Pregnancy does not affect the overall incidence of appendicitis, but severity may be increased in pregnancy

• Appendicitis more common in T2 (40% of cases)

• Majority present with classic RLQ pain

• 25% of pregnant women will perforate– Don’t delay O.R. >24 hrs, ↑ perforation rate from 0% to 66%– Perforation occurs 2x more often in the T3 than T1,2

History

• Most reliable symptom is RLQ pain

• Nausea is present in nearly all cases

• Vomiting present in two thirds of patients

• Anorexia is present in only 1/3 – 2/3 of pregnantpatients, while it is present almost universally inNon-pregnant patients

Physical• Direct abdominal tenderness most common

– T1: Tenderness well localized in RLQ– T2, T3: tenderness may change location: right periumbilical

area, RUQ, diffuse

• Classic Signs:– Rebound present in 55-75% of patients– Abdominal muscle rigidity in 50-65%– Psoas sign observed less frequently in pregnancy– The Rovsig sign as frequent in pregnancy as non-pregnancy

state

• Rectal tenderness is usually present, particularly in the first trimester

• Fever and tachycardia are variably present; not sensitive signs

• Uterine activity due to localized peritonitis is common

Investigations

• US is imaging of choice– Accuracy is greatest in T1; in T2 and T3 up to

40% normal appendix rate

• General Laboratory Investigations:– Elevated WBC– Neutrophils often >80% – Urinalysis: Pyuria is observed in 10-20%

Treatment• Surgical: Laparotomy or laparoscopy

• If the appendix appears normal remove it because:(1) Early disease may be present despite its grossly normal

appearance (2) Diagnostic confusion can be avoided if the condition recurs

Laparotomy Incision– Right mid-transverse incision directly over the point of

maximal tenderness vs. Lower abdominal midline incision to accommodate unexpected surgical findings and the possibility of the need for cesarean delivery

• Tilt the operating table 30° to the patient's left

Acute appendicitis and Diffuse Peritonitis (Perforation)

• Cefuroxime, ampicillin, metronidazole, oxygen pre-op

• Depending on G.A. consider CS as fetal loss rate up to 20-36%

• Pre-op intubation and ventilation in cases of hypovolemia

• Copious irrigation and use of intra-peritoneal drain

Morbidity

• Perforation and abscess formation are more likely to occur in pregnant patients

• The rate of generalized peritonitis relates directly to the interval of time from symptom onset to diagnosis

• Maternal and fetal morbidity and mortality rates increase once perforation occurs

• Fetal mortality is dependant on if perforation is present: 20-35% vs. 1.5% is no perf

• PTL/PTD is common – 5-14%, up to 50% in T3

• Maternal mortality should be <1%

Acute Cholecystitis

Acute Cholecystitis

• Incidence in pregnancy is 1:600-1:10,000

• Second most common cause of acute abdomen in pregnancy

• Cholelithiasis is the cause in 90% of cases

• Incidence of cholelithiasis in pregnant women having routine OB scans is 3.5-10%

History and physical examination

• Previous history; dyspepsia, intolerance of fatty foods

• RUQ/ mid-epigastrium pain; may radiate to the back

• Nausea & Vomiting ~ 50% of cases

• Fever occasionally

• Direct tenderness usually present in RUQ, Rebound tenderness is rare

• Cholecystitis can mimic appendicitis in the third trimester

Investigations

• Blood tests are of limited value

– ↑ WBC, ↑ ALP – normal in pregnancy

– AST/ALT may help distinguish cholecystitis from hepatitis

– Amylase elevated transiently ~1/3; high amylase suggests pancreatitis

– Lytes: if persistent vomiting

Investigations

• Ultrasound is diagnostic

– Gall bladder calculi: present in> 95% with acute cholecystitis

– Wall thickening >3mm– Pericholecystic fluid– Sonographic Murphy’s sign– Dilation of intra and extra-hepatic ducts in common bile

duct obstruction

• If a radionucleotide scan of the gallbladder is needed, the radiation dose is not prohibitive

Treatment• Supportive: Intravenous fluids, Nasogastric suction

Non-surgical Management increases risk of:

• Recurrence in pregnancy if episode occurs:– T1 92%– T2 64%– T3 44%

• Gallstone pancreatitis ~13% (Fetal loss rate 10-60%)• ↑ SA, ↑PTL, ↑PTD

• A percutaneous drainage procedure may be indicated in select patients in order to defer definitive surgery

Surgical Management

• Has been source of much controversy

• Recently immediate surgical management is used more widely because:

1. Reduced use of medications2. Recurrence rate in pregnancy is 44-92%, depending on

trimester3. Shorter hospital stay4. ↓ risk of developing life-threatening complication: perforation,

sepsis, peritonitis

• “Laparoscopy or laparotomy – depends on GA and surgeon skill”

Choledocholithiasis• 1/1200 patients require intervention • ERCP uses 2-12 rads…

ERCP: • Risk of bleeding = 1.3%• Risk of pancreatitis = 3.5%

• Options are common bile duct exploration at time of laproscopic cholecystectomy or ERCP followed by cholecystectomy – no studies comparing the two

Bowel Obstruction

Bowel Obstruction

• Third most common cause of acute abdomen in pregnancy: 1:1500 – 1:16,000

• Etiology:1. Adhesions – 60-70% of cases

2. Volvulus ~25% of cases (much higher than non-pregnant)• Risk of cecal volvulus is highest at times of rapid changes in uterine

size (16-20 wks, and 32-36 wks)• Any redundant or abnormally mobile cecum is raised out of the

pelvis and allows for rotation around a fixed point• Small bowel volvulus is more common in T3 and PP

3. <5% of time: Intussusception, incarcerated hernia, cancer, diverticulosis etc.

History

• Crampy abdominal pain ~90% – Constant or periodic, mimicking labor– Pain may radiate to the flank, imitating pyelonephritis – The severity of pain may not reflect the severity of

disease

• Vomiting

• Obstipation

Physical findings• Classic distended tender abdomen with high-pitched bowel

sounds is the exception in pregnancy

• Uterus/cervix/adnexa share the same visceral innervation as the lower ileum, sigmoid colon and rectum - separating GI and Gyn sources of pain is often difficult

• Abdominal tenderness may be absent

• Bowel sounds are often normal upon presentation

• A tender cystic mass can sometimes be palpated

• Rebound tenderness, fever, and tachycardia occur late in the course

Laboratory Studies

• Leukocytosis may be present• Electrolyte abnormalities • Hemoconcentration • Elevated serum amylase levels

• X-Ray– Abdominal Plain film - best initial study– Sequential films may be needed – Air-fluid levels, progressive bowel dilation

Treatment Conservative• Fluid and electrolyte replacement• NG suction• Enema

Surgical• Midline abdominal incision• Decompress the bowel• Relieve obstruction• Resect nonviable tissue

Prognosis • Maternal Mortality ~6%• Fetal mortality ~26%• Bowel strangulation requiring resection ~23%

Pancreatitis

Pancreatitis• 1:1000 – 1:3000 pregnancies• Usually late in T3, or PP – may be due to increased intra-

abdominal pressure on the biliary ducts

• Etiology– Cholelithiasis – 67-100% of cases– Abdominal surgery– Blunt abdominal trauma– Infection– Penetrating duodenal ulcer– Hyperparathyroidism– Hyperlipidemic pancreatitis

• Associated with pregnancy– Preeclampsia – damage to microvasculature– AFLP

History

• Sudden, severe epigastric pain radiating to the back

• Postprandial nausea and vomiting

• Fever

Physical

• Patient in the ‘fetal position’ – due to severe pain

• Hypoactive bowel sounds (paralytic ileus)

• Jaundice

• Epigastric tenderness is the most reliable physical finding

• Peritoneal signs are minimal or absent

• Pulmonary findings in ~10% - can lead to ARDS

Laboratory Studies• Amylase

– During normal pregnancy, amylase levels are slightly elevated

• Lipase – better predictor than amylase

• Hyperglycemia

• Hyperbilirubinemia

• Hypocalcemia

• Hemoconcentration

• Electrolyte abnormalities

• Ultrasound of the upper abdomen

Ranson’s Criteria

On Admission:

• Age > 55• WBC > 16 • Glucose > 10• LDH > 350 • AST > 250

At 48 hours After Admission:• Hct drop > 10%• BUN increase > 1.79• Ca < 2 • Arterial pO2 < 60 • Base deficit (24 - HCO3) > 4

• Fluid needs > 6L

Prediction of Mortality• <5 – 15%• 5-9 40%• >9 100%

Treatment • Bowel rest – npo, NG suction, IV fluids

• Fluid/electrolyte resuscitation

• Analgesics:– demerol doesn’t cause spasm of sphincter of Oddi

• Anti-spasmodics

• Antibiotics if fever or sepsis is present

• ERCP, endoscpic sphincterotomy can be used to treat gallstone pancreatitis

• Surgery for refractory cases

Prognosis

• Acute symptoms last for ~6 days

• Maternal mortality rate ranges from 0-37%

• Perinatal mortality rate is ~ 10%

• The risk of perinatal death increases with the severity of disease

Trauma in Pregnancy

Trauma in Pregnancy

• Occurs in 6-7% of pregnancies

• Penetrating– Gunshot wounds– Stab wounds

• Blunt trauma– MVA– Physical abuse, Sexual Abuse– Accidental Falls

Maternal Injury

• Gravid uterus changes the location of abdominal organs

• 25% of pregnant women with blunt trauma will have hemodynamically significant hepatic or splenic injuries due to increased vascularity

• In penetrating trauma maternal death rate is lower than non-pregnant (~3.9% vs 12%) because the uterus ‘protects’ intra-abdominal organs

• Uterine rupture: most often at the fundus

Fetal Injury

• Direct fetal injury occurs in <1% of blunt trauma

• Direct fetal injury occurs in up to 90% of blunt trauma

• Fetal skull and brain injury more common in T3 when the head is engaged in the pelvis

• Deceleration injury to the fetal had can also occur

• Most common cause of fetal death is maternal death

• Fetal mortality 3-38%: abruption, shock, maternal death

Placental Abruption

• CTX > thAn 1 in 10 minutes is associated with 20% risk of diagnosed placental abruption

• Initiate CTG monitoring asap at >24 weeks; at least 4-6 hrs

• Risk of abruption exists for several days post-trauma

• Up to 40% of severe MVA’s are associated with abruption

• Minor trauma can result in abruption in 2-3%

• 10-30% of trauma victims have evidence of feto-maternal hemorrhage

Management

• ABC’s

• Rapid maternal respiratory support

• Evaluate the fetus once mother is stable: CTG

• Left lateral decubitus

• US

• Fetal monitoring for at least 4 hrs,then prn

• Surgical exploration prn +/- CS

ATLS in Pregnancy

Surgical Management

• Exploratory Laparotomy

• Delivery of fetus if direct uterine injury or fetal injury

Prevention Techniques

• Seat Belts

• Airbags

Gynecologic Causes of Acute Abdomen: Adnexal Masses

• Incidence in Pregnancy = 2%

• Most are functional cysts

• Expectant Mgmt for those <6cm – 82-94% resolution

• Torsion:– ~4% of adnexal masses will tort

Adnexal Torsion

• Pregnancy predisposes to adnexal torsion

• 1 in 5 adnexal torsions occurring during pregnancy

• Associated with an ovarian mass in 50-60% -most often a dermoid

• Occurs on R > L, by a ratio of 3:2

• Occurs most frequently in the first trimester

Treatment

• Surgical

• Conserve as much ovarian tissue as possible

• If the tissue is necrotic - unilateral salpingo-oophorectomy

• Partial torsion:– Conservative management - Untwist the pedicle, remove the cyst,

and stabilize the ovary

• If removal of the corpus luteum is necessary prior to 10 weeks of gestation needs progesterone supplementation

In the Operating Room

Pre-Op Decision Making

• Laparoscopy has the same indications as the non-pregnant patient

• Approach is based on skill of surgeon and availability of staff/ equipment

• Benefits of Laparoscopy:– ↓ post-op pain– ↓ post-op ileus– ↓ LOS– Faster return to work

Concerns r.e. Laparoscopy

• Trocar insertion

• CO2 insufflation

• Technical ability to get exposure

• Altered physiology of pneumoperitoneum

• Decreased venous return

• Can be used in all trimesters

• With increasing experience with this technique, there are fewer barriers

• Reports of successful appendectomy and cholecystectomy in the third trimester

Benefits in the Pregnant Patient

• ↓ fetal depression due to less narcotic use

• ↓ risk of wound complications

• ↓ post-op maternal hypoventilation

• ↓ risk of VTE due to early mobilization

• ↓ uterine irritability leads to less SA and PTL

Technical Issues

• Patient positioning– Left lateral decubitus

• Initial Port Placement– Hassan/ Verres, Optical trocar – adjust location to fundal height,

previous incisions and experience of surgeon

• Place trocars under direct visualization according to fundal height

• Insufflation to 10-15mmHg– No evidence of long-term detrimental effects of CO2

pneumoperitoneum

• Intra-op CO2 monitoring should be used– Theoretical risk of fetal acidosis due to

pneumoperitoneum; has been seen in animal studies, but not documented in the human fetus

• VTE Prophylaxis (pneumoperitoneum increases venous stasis)– Intra-op/ Post-op pneumatic compression stockings– Early post-op ambulation

Peri-Operative Care

• Obstetrical Consultation

• Fetal Heart Rate Monitoring – pre and post-op documentation of FHR / NST

• Tocolytics– No literature supports prophylactic use of tocolytics– Consider if S&S of PTL– Need OB consult for meds/ dosing etc

Conclusions

• Laparoscopy is safe in all trimesters of pregnancy

• The Veress needle can be used – depends on surgeon experience with ‘alternate site’ entries

• Pressure of 12-15mmHg – less than uterine ctx.

• Laparoscopy decreases maternal morbidity, LOS, fetal depression (due to less narcotic use)

Summary

• The incidence of acute abdominal pain in pregnancy which requires surgery is ~1/500

• It is important to keep a broad differential diagnosis as signs, symptoms and investigations can all altered due to pregnancy

• Diagnostic Imaging is safe in pregnancy

• Surgical options include laparotomy and laparoscopy