eMedicine Specialties > Emergency Medicine > Obstetrics & Gynecology

Pregnancy, Asthma: Differential Diagnoses & Workup

Author: Markus Little, MD, Staff Physician, Department of Emergency Medicine, State University of New York Downstate Medical Center
Coauthor(s): Richard H Sinert, DO, Associate Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, Research Director, State University of New York College of Medicine; Consulting Staff, Department of Emergency Medicine, Kings County Hospital Center
Contributor Information and Disclosures

Updated: Jun 30, 2009

Differential Diagnoses

Anxiety
Pneumonia, Empyema and Abscess
Bronchitis
Pneumonia, Immunocompromised
Chronic Obstructive Pulmonary Disease and Emphysema
Pneumonia, Mycoplasma
Foreign Bodies, Trachea
Pulmonary Embolism
Neoplasms, Lung
Pneumonia, Aspiration
Pneumonia, Bacterial

Other Problems to Be Considered

Airway obstruction
Amniotic fluid embolism
Acute congestive heart failure (CHF), secondary to peripartum cardiomyopathy
Physiologic dyspnea of pregnancy

Workup

Laboratory Studies

  • Complete blood cell count (CBC) with differential  
    • This is performed to assess the degree of nonspecific inflammation and the possibility of a comorbid anemia or thrombocytopenia.
    • Leukocytosis may be the result of a physiologic response to pregnancy, steroid therapy, upper respiratory tract infections, or the stress of an asthma attack.
  • Arterial blood gas level  
    • Arterial blood gas (ABG) analysis indicates the level of oxygenation and respiratory compensation.
    • PaCO2 is generally low in early stages of exacerbation as a result of hyperventilation.
    • An increase in PaCO2 can be a sign of impending respiratory failure.
    • ABG results often show a decrease in PaO2.
    • Physiologic changes that accompany pregnancy in the pulmonary system slightly alter normal ABG values: pH 7.4-7.45, pO2 95-105 mm Hg, pCO 2 28-32, and bicarbonate 18-31 mEq/L.
  • Blood cultures must be obtained in patients in whom pneumonia is found or reasonably suggested.

Imaging Studies

  • Chest radiography
    • A normal chest radiograph in late pregnancy typically reveals an enlarged heart and some prominent lung markings from elevation of the diaphragm.
    • Chest radiography is indicated when the other coexistent conditions such as pneumonia, barotrauma, CHF, or chronic obstructive pulmonary disease are likely.
    • Chest radiographs (2 views) with a shielded maternal abdomen provides the fetus of approximately 0.00005 rad.

Other Tests

  • Pulmonary function tests  
    • Hand-held peak flow meters are available in most EDs. If the patient’s baseline is known, clinicians can use measurement to assess severity of attack and its response to medications.
    • Reversible airflow obstruction is central to the diagnosis and assessment of asthma.
    • Changes in pulmonary function during acute asthma include the following:
      • Decreased peak expiratory flow rate (PEFR) and forced expiratory volume in one second (FEV1)
      • Mild reduction in the forced vital capacity (FVC)
      • An increased residual volume (RV), functional residual capacity (FRC), and total lung capacity (TLC)
      • Normal diffusing capacity
    • Patients with asthma usually demonstrate a greater than 15% increase in FEV1, FVC, and PEFR when treated with bronchodilators.

More on Pregnancy, Asthma

Overview: Pregnancy, Asthma
Differential Diagnoses & Workup: Pregnancy, Asthma
Treatment & Medication: Pregnancy, Asthma
Follow-up: Pregnancy, Asthma
References
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References

  1. [Guideline] Reddel HK, Taylor DR, Bateman ED, et al. An official American Thoracic Society/european Respiratory Society statement: asthma control and exacerbations: standardizing endpoints for clinical asthma trials and clinical practice. Am J Respir Crit Care Med. Jul 1 2009;180(1):59-99. [Medline].

  2. [Guideline] American College of Obstetricians and Gynecologists (ACOG). Asthma in pregnancy. ACOG practice bulletin; no. 90. Washington (DC): American College of Obstetricians and Gynecologists (ACOG). Feb 2008;[Full Text].

  3. Sly RM, O'Donnell R. Stabilization of asthma mortality. Ann Allergy Asthma Immunol. Apr 1997;78(4):347-54. [Medline].

  4. Hornby PJ, Abrahams TP. Pulmonary pharmacology. Clin Obstet Gynecol. Mar 1996;39(1):17-35. [Medline].

  5. Mabie WC. Asthma in pregnancy. Clin Obstet Gynecol. Mar 1996;39(1):56-69. [Medline].

  6. Mays M, Leiner S. Asthma. A comprehensive review. J Nurse Midwifery. May-Jun 1995;40(3):256-68. [Medline].

  7. Nelson-Piercy C, Moore-Gillon J. Asthma in pregnancy. Br J Hosp Med. Feb 7-20 1996;55(3):115-7. [Medline].

  8. Rey E, Boulet LP. Asthma in pregnancy. BMJ. Mar 17 2007;334(7593):582-5. [Medline].

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Further Reading

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Keywords

asthma in pregnancy, asthma, pregnancy, asthma guidelines, asthma assessment, asthma treatment, asthma symptoms, asthma causes, respiratory disease, asthmatic, wheeze, wheezing, noisy breathing, difficulty breathing, cough, allergy, allergic disease, reactive airway disease, bronchiolitis, bronchial asthma, acute asthma, allergies, bronchial airways, bronchial airway narrowing, inflammation of the bronchi, bronchial smooth muscle contraction, dyspnea, airway narrowing, allergic asthma, idiosyncratic asthma, treating asthma in pregnancy, maternal asthma, pulmonarydisease and pregnancy

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Contributor Information and Disclosures

Author

Markus Little, MD, Staff Physician, Department of Emergency Medicine, State University of New York Downstate Medical Center
Disclosure: Nothing to disclose.

Coauthor(s)

Richard H Sinert, DO, Associate Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, Research Director, State University of New York College of Medicine; Consulting Staff, Department of Emergency Medicine, Kings County Hospital Center
Richard H Sinert, DO is a member of the following medical societies: American College of Physicians and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

Assaad J Sayah, MD, Chief, Department of Emergency Medicine, Cambridge Health Alliance
Assaad J Sayah, MD is a member of the following medical societies: National Association of EMS Physicians
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Mark Zwanger, MD, MBA, Assistant Professor, Department of Emergency Medicine, Thomas Jefferson University
Mark Zwanger, MD, MBA is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and American Medical Association
Disclosure: Medicines Company Consulting fee Consulting; Pfizer Salary Employment

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Pamela L Dyne, MD, Professor of Clinical Medicine/Emergency Medicine, David Geffen School of Medicine at UCLA; Attending Physician, Department of Emergency Medicine, Olive View-UCLA Medical Center
Pamela L Dyne, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

 
 
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