Episode 7: Medical and Surgical Emergencies in Pregnancy

The whole playing field changes with pregnant patients in the emergency department.  When you’re faced with one of the Medical and Surgical Emergencies in Pregnancy that we’ll cover in this episode, there are added challenges and considerations.  Dr. Shirley Lee and Dr. Dominick Shelton discuss a challenging case of a pregnant patient presenting to the emergency department with shortness of breath and chest pain. They review those diagnoses that the pregnant patient is at risk for and discuss the challenges of lab test interpretation and imaging algorithms in the pregnant patient. Next, they walk us through the management of cardiac arrest in the pregnant patient. In another case of a pregnant patient who presents with abdominal pain and fever, they discuss strategies to minimize delays in diagnosis to prevent serious morbidity and mortality. The pros and cons of abdominal ultrasound, CT and MRI are reviewed as well as the management of appendicitis, pyelonephritis and septic abortion in pregnant patients.

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Written Summary and blog post by Lucas Chartier, edited by Anton Helman August 2010

Cite this podcast as: Lee, S, Shelton, D, Helman, A. Medical and Surgical Emergencies in Pregnancy. Emergency Medicine Cases. August, 2010. https://emergencymedicinecases.com/episode-7-medical-and-surgical-emergencies-in-pregnancy/. Accessed [date].

Medical and Surgical Emergencies in Pregnancy are very challenging. These patients’ symptoms can be misleading or confused with normal pregnancy, their vital signs are normally altered, the physical exam can often be more difficult, their lab values are harder to interpret and imaging algorithms for pregnant patients are very complicated. In addition, they generally have worse outcomes than non-pregnant patients. In this episode, Dr. Lee and Dr. Shelton answer questions such as: how is the pregnant patient with suspected pulmonary embolism worked up and treated? How are ACLS protocols different for pregnant patients? How and when should emergency physicians perform emergency C-sections? How is the presentation of appendicitis different in pregnant patients? What are the risks to the fetus of CT pulmonary angiogram vs. VQ scan? What is the role of MRI for diagnosing appendicitis in pregnant patients? Is gadolinium contrast contraindicated in pregnancy? How can we minimize radiation exposure to our pregnant patients? Which pregnant patients with UTI should be admitted to hospital? What are the best antibiotic choices for asymptomatic bacteruria, cystitis and pyelonephritis in pregnant patients? Do we need to do a BhCG on every woman of childbearing age who presents to the ED? How is septic abortion diagnosed and best managed? and many more……

MEDICAL AND SURGICAL EMERGENCIES IN PREGNANCY

Causes of chest pain or SOB for which pregnant patients are at higher risk than nonpregnant patients

• Pulmonary embolus (PE), peri‐partum cardiomyopathy, myocardial infarction, aortic dissection and mitral stenosis

Vital signs changes in pregnancy

• Increase in heart rate (by 10‐15bpm) and respiratory rate (up to 24/min), decreased blood pressure with a nadir in the 2nd trimester (due to volume redistribution and decreased peripheral vascular resistance – down to sBP of 90), and supine hypotension syndrome (where the gravid uterus compresses the inferior vena cava and prevents venous return, easily corrected by placing the patient in the left lateral decubitus position)

Murmurs in pregnancy

• Can be physiologic secondary to hyperdynamic state and volume overload, sometimes creating a higher cardiac‐thoracic ratio; pathologic murmurs to think about in pregnant patients presenting with chest pain and/or shortness of breath: diastolic murmur – mitral stenosis (most common valvular abnormality in pregnancy) and new aortic regurgitation (indicating possible aortic dissection); systolic murmur – tricuspid regurgitation (can occur in massive PE)

D‐dimer in pregnancy

• Quite useless as its utility for PE is in low‐risk patients, which pregnant patients are not by virtue of their pregnancy (moderate risk at least); d‐dimer also becomes increasingly positive in normal pregnant patients (50% are positive in the first trimester increasing to almost 100% in 3rd trimester), and takes a full 4‐6wks postpartum before returning to baseline level)

Update 2014: Recent evidence suggests that post-partum women are at risk for thromboembolic events up to 12 weeks after delivery (NEJM, 2014)

Algorithm for suspected Pulmonary Embolism in Pregnancy

• If patient stable, get Doppler ultrasound (70% of pregnant patients with PE have a DVT, and 85% of them in the left leg): if positive, investigations are stopped and patient treated; if negative (iliac vein DVTs are frequent in pregnancy, but not seen on Doppler examination), further imaging must be undergone.
  • In one study, in FIRST‐TRIMESTER pregnant patients with LEFT leg symptoms and calf CIRCUMFERENCE >2cm more in affected leg, 70% have a DVT. Full PDF
• If patient unstable, get definitive imaging study.

CT scan vs V/Q scan to rule out pulmonary embolism in pregnancy

• CT scan delivers less ionizing radiation to fetus (1 to 2‐3rad, which is below the teratogenic cutoff of 5‐10rad), but delivers a significant radiation dose to the mother’s breast issue, putting her at increased risk for breast cancer; less accurate in pregnant patients than in non‐pregnant patients (possibly due to inconsistent uptake of contrast from inferior vena cava compression), but has the advantage over V/Q of providing alternate diagnoses

• V/Q scan delivers more radiation to fetus (difference even greater the earlier in the pregnancy), and can result in “non‐conclusive” scan for which a CT scan needs to be performed subsequently; radiation dose can be minimized in pregnancy by using a 1/2 dose perfusion scan and only using ventilation imaging if the perfusion scan is abnormal

• Both are carcinogenic and increase the likelihood of the fetus developing leukemia later on in life; all in all, however, missing a PE is probably more dangerous than the radiation dose necessary to diagnose it

Management of Pulmonary Embolism in Pregnancy

• Low‐molecular weight heparin (LMWH) right away and throughout pregnancy, with unfractionated heparin (UFH) only for unstable patients and/or possible thrombolysis candidates, imminent delivery or recent surgery or C‐section; coumadin is prohibited due to teratogenic potential

Additional FOAMed Resource: Jeff Kline on ER Cast talks pulmonary embolism in pregnancy

Changes to ACLS in pregnancy

• Defibrillation is safe for the fetus and should be used for witnessed arrest; good CPR is essential for optimal fetal flow; epinephrine (although it decreases uteroplacental circulation) can be used; thrombolysis has only been reported in case reports so decision must be individualized

• Positioning: left lateral decubitus is not practical, so put towels under the patient’s right side in order to tilt the patient 20‐30° towards the left; have a dedicated team member manually displace the uterus to the left side and superior

• Emergency C‐section (during cardiac arrest) must be considered early and completed within 5min of arrest; hence the “4‐minute rule” (4 minutes maximum to start C‐section); this might save the fetus, but it is mainly done to save the mother by decreasing the physiologic demand.
  • Procedure: while CPR is ongoing, make vertical incision through all the abdominal wall layers from epigastrium to pubic symphysis, then perforate uterus at fundus and extend incision vertically down with scissors by inserting 2 fingers in the uterine cavity to separate it from the fetus, deliver the fetus, then hold the baby below the mother, clamp the cord and cut it.

Important differential diagnoses of 1st trimester abdominal pain and fever

• Appendicitis (most common non‐obstetric surgery in pregnancy)
• urinary tract infection and pyelonephritis
• ovarian torsion
• pelvic inflammatory disease (which can present without fever or cervical motion tenderness in pregnancy, and incidence decreases after 1st trimester)

The immaculate conception

• Studies show that 7‐15% of women who assure it’s IMPOSSIBLE they are pregnant end up being pregnant, so all women of childbearing age who present with abdominal pain should have a β‐hCG drawn, regardless of their stated date of last menstrual period and usual regularity

Appendicitis considerations in pregnancy

• Non‐specific signs of both appendicitis and pregnancy can be written off as being “normal” (nausea, vomiting, anorexia); peritoneal signs may be delayed or absent due to the desensitization of the abdominal wall caused by stretching

• Despite the belief that pregnancy displaces the inflamed appendicitis to the RUQ, newer studies show that the appendix is located in the RLQ in the majority of patients, and most still present with RLQ pain and tenderness; the same proportion of pregnant as non‐pregnant patients present with an atypical location (15%)

• Alvarado appendicitis score has not been validated in pregnancy:
  • Migration of pain to RLQ (1 point), RLQ tenderness (2pts) and rebound pain (1pt), anorexia or acetone in urine (1pt for either or both), nausea or vomiting (1pt), fever (1pt), WBC>10,000 (2pts) with left shift [>75% neutrophils] (1pt)
  • 8pts: very probably appendicitis

Ultrasound in suspected appendicitis in pregnancy

• Although it is very operator dependent, is especially not accurate for ruptured appendicitis and is not useful after 35wks gestational age (due to the difficulties of doing graded compression because of the gravid uterus),it is still the initial modality of choice due to its safety.

Other imaging modalities for abdominal pain in pregnancy

• CT scan: plain CT has been shown to be just as sensitive as contrast CT in the diagnosis of appendicitis in the general population; contrast should be avoided in pregnancy, if possible, even though there is no risk of teratogenicity (only fetal hypothyroidism in animal studies using very high contrast doses).
• MRI scan: might be more appropriate than CT scan, although there is very low to nil availability in most centres; gadolinium (MRI contrast) has been shown to cross the placenta in animal studies; it is controversial whether there is harm to the fetus from gadolinium contrast.

Complications of appendicitis in pregnancy

• Non‐perforated appendicitis carries a 5% fetal loss rate, and this jumps to 30% for ruptured appendicitis, as well as increased rates of pre‐term labour (on top of a 4% death rate for the mother herself if perforation!)

Cystitis, UTI and pyelonephritis in pregnancy

• Pyelonephritis is the #1 misdiagnosis of appendicitis in pregnancy because urinary frequency is often present in normal pregnancy, and appendicitis can cause pyuria

• Pregnant patients have the same rates of cystitis and asymptomatic bacteriuria as non‐pregnant patients, but have higher rates of progression to pyelonephritis – which is why the 2 former need to be treated with antibiotics

• Antibiotic management of asymptomatic bacteriuria and cystitis in pregnancy:
  • First‐line treatment is nitrofurantoin (even though there is a theoretical risk of haemolytic anemia of the fetus in G6PD mothers) or Celphalosporins (eg, Cephalexin, even though it does not cover enterococci).
  • SMX‐TMP may be used in 2nd trimester (TMP is a folic acid antagonist and therefore contraindicated in the 1st trimester, and SMX may persist in fetal circulation after birth and lead to kernicterus if given shortly before delivery, so is not recommended in 3rd trimester); β‐lactams (including penicillin and amoxicillin) are safe but have high rates of resistance to E.coli.
  • Length of treatment is a minimum of 3 days (EMC experts recommend 7 days)
• Indications for admission to hospital: all pregnant women with pyelonephritis (needing IV cephalosporin or ampicillin‐gentamicin) and women in their 3rd trimester with cystitis (because of risk of pre‐term labor)

• All pregnant women need follow‐up urine cultures 1‐2wks following diagnosis to ensure effective treatment (⅓ have recurrence); complications of UTIs in pregnancy: pre‐term labour, low birth weight and sepsis

Septic abortion

• Classic case
  • Young woman with an unwanted pregnancy having an illegal abortion (in a country where abortions are illegal) or missed abortion not adequately followed and treated leading to retained products with infection.
• Clinical presentation
  • Pregnant patient in 1st trimester presenting with abdominal pain, vaginal bleeding and discharge, and fever, especially if there is a history of miscarriage or missed abortion
• Treatment
  • Antibiotics and urgent surgical (not medical) evacuation (i.e. dilatation and curettage)

For more on emergencies in pregnancy on EM Cases:
Episode 23: Vaginal Bleeding in Early Pregnancy
Best Case Ever 9 Vaginal Bleeding in Early Pregnancy
Best Case Ever 68 Ectopic Pregnancy Pitfalls in Diagnosis
CritCases 9 Pre-Eclampsia and Preterm Labor – Time Sensitive Management
Rapid Reviews Videos on First Trimester Bleeding and Ectopic Pregnancy:
First Trimester Bleeding P1
First Trimester Bleeding P 2: Ectopic Pregnancy

Dr. Helman, Dr. Lee and Dr. Shelton have no conflicts of interest to declare.

Key References

Vanden hoek TL, Morrison LJ, Shuster M, et al. Part 12: cardiac arrest in special situations: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2010;122(18 Suppl 3):S829-61.

Patel C et al. Pulmonary Embolism in Pregnancy. The Lancet , Volume 375 , Issue 9728 , 1778.

Delzell JE. Urinary Tract Infections during Pregnancy. Am Fam Physician. 2000 Feb 1;61(3):713-720.

Chan WS, Lee A, Spencer FA, et al. Predicting deep venous thrombosis in pregnancy: out in “LEFt” field?. Ann Intern Med. 2009;151(2):85-92.