Asthma in pregnancy
Jump to navigation
Jump to search
|
Asthma Microchapters |
|
Diagnosis |
|---|
|
Other Diagnostic Studies |
|
Treatment |
|
Case Studies |
|
Asthma in pregnancy On the Web |
|
American Roentgen Ray Society Images of Asthma in pregnancy |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Varun Kumar, M.B.B.S. [2]; Lakshmi Gopalakrishnan, M.B.B.S. [3]
Overview
Asthma is one of the most common pulmonary conditions occurring during pregnancy[1] with a prevalence rate of 3.7% to 8.4% in United States during the period 1997-2001[2].
Pathophysiology
- During pregnancy, due to high levels of progesterone, minute ventilatory rate is increased causing compensated respiratory alkalosis.[3]
- The arterial blood gases may reveal a higher pO2 and lower pCO2 with mild alkalotic pH. Normal pCO2 during pregnancy is suggestive of impending respiratory failure.
- Asthma is characterized by broncho-constriction or inflammation of airways with production of thick mucoid secretions. In a small prospective study involving 16 asthmatic pregnant women, hyper-reactivity was seen to be lower as evidenced by a reduction in minimum medication requirements.[4]
Natural History, Complications and Prognosis
Severe or poorly controlled asthma cause maternal hypoxia, hypercapnia and respiratory alkalosis which may impair fetal oxygenation and uteroplacental blood flow. Asthma during pregnancy may have negative impact on both mother and the child especially in severe or poorly controlled cases.
Complications include:
- Complications during labor[5]
- Congenital anomalies
- Complications of corticosteroid use[6]
- Cesarean delivery[5]
- Hyperemesis
- Hypertensive conditions[7][5]
- Low birth weight infants[5][8]
- Neonatal hypoglycemia
- Neonatal mortality
- Neonatal seizures
- Preterm labor and premature delivery[5][8]
- Preeclampsia[9]
- Respiratory failure
- Uterine hemorrhage
Diagnosis
History and Symptoms
- The majority of patients have personal or family history of other atopic diseases.
- The clinical presentation of asthma in pregnancy varies with individuals both spontaneously and with therapy.
- In some cases, asthma is characterized by chronic respiratory impairment and others experience episodic attacks secondary to a number of triggering events including upper respiratory tract infection, stress, cold air, exercise, exposure to allergen (such as pets, dust, mites, pollen) or air pollutants (such as smoke or traffic fumes).
- The cardinal symptoms of asthma include:
- Loud expiratory wheeze
- Nocturnal cough
- Dyspnea
- Chest tightness
- Stridor in the absence of a wheeze may be confused with a COPD-type of disease and hence it is difficult to diagnose asthma based upon the history alone.[10][11][12]
Physical Examination
Appearance of the Patient
Vitals
- Tachypnea
- Tachycardia
- Pulsus paradoxus
- Fever in presence of respiratory infection
Respiratory Examination
Inspection
- Retraction of accessory muscles of respiration such as sternocleidomastoid, abdominal and pectoralis muscles with each breath
Percussion
- Hyper-resonant in all lung fields.
Auscultation
- Long, high-pitched expiratory wheeze
- Rhonchi
- Bronchovesicular breath sounds
- Silent chest among patients in distress is a sign of severe and complicated asthma
Cardiovascular Examination
- Jugular venous distension secondary to increased intrathoracic pressure in presence of pneumothorax
- Tachycardia
Extremities
Laboratory Findings
- Blood tests: Leukocytosis may be noted as a physiologic response to pregnancy or corticosteroid therapy
- Arterial blood gases: Low pCO2 and elevated pO2 may be noted initially secondary to hyperventilation resulting in respiratory alkalosis. Elevated pCO2 may be noted in patients with severe asthma with impending respiratory failure.
Compensated respiratory alkalosis is the physiologic change noted in pregnancy secondary to hyperventilation due to high levels of progesterone. Asthma causes overlapping of respiratory acidosis over physiologic respiratory alkalosis and hence a modest elevation in pCO2 may be noted.
Other Diagnostic Studies
Pulmonary Function Testing
- In normal pregnancy, FEV1, vital capacity, total lung capacity, FEV1/FVC remains unchanged while functional residual capacity, residual volume decreases with increase in tidal volume. FEV1 may decrease when pregnant women lie in supine position.
- Pregnant women with acute asthma should rest in seated position rather than lying down.[13]
- As with non-pregnant asthmatics, pregnant asthmatics have reduced FEV1 and increased residual volume, functional residual capacity, and total lung capacity which can be reversed with bronchodilators.
Methacholine Challenge Test
- Methacholine challenge test is usually not recommended in pregnancy as it can have teratogenic effects[14] (Pregnancy Category C).
Treatment[15]
- Monitor asthma control during all prenatal visits.
- Asthmatic symptoms worsen in about a third during pregnancy and improve in a third; hence, medications should be adjusted accordingly.
- Patients should rest in seated position rather than lying down[13]
- Oxygen supplementation should be provided to maintain pO2 over 70mm Hg[16]
- Regular monitoring and maintenance of lung function to ensure adequate oxygen supply to the fetus.
- It is safer to treat asthma with medications than to have poorly-controlled asthma.
Treatment of Chronic Asthma in Pregnancy
- Albuterol is the preferred short-acting β2-agonist (SABA)
- Inhaled corticosteroid such as budesonide alone or in combination with a long acting beta agonist such as salmeterol are recommended for the initial management of moderate persistent asthma.
- Montelukast or zafirlukast can be considered as an alternative therapy.
Treatment of Acute Exacerbation of Asthma in Pregnancy
- Oral or intravenous glucocorticoids is recommended for acute exacerbation of asthma similar to non-pregnant asthmatics[17].
- Use of methylxanthines is not recommended in emergency setting as they do not provide additional benefit when compared to beta adrenergics and IV glucocorticoids.[18]
- Magnesium sulfate which is usually given during hypertensive conditions in pregnancy or preterm labor also have a beneficial effect on asthma by relaxing airway muscles[19].
- Use of epinephrine should be avoided in pregnancy as it can lead to congenital malformations, fetal tachycardia, and vasoconstriction of the uteroplacental circulation.[20]
Peripartum Management
- Peripartum pain control can be managed with butorphanol or fentanyl. Morphine and meperidine should be avoided as they can induce release of histamine and possibly cause bronchoconstriction.
- Epidural anesthesia is preferred for pain control during labor in the gestational asthmatics. In case general anesthesia is required, ketamine and halogenated anesthetics are preferred as they have bronchodilatory effects.
- Use of oxytocin is recommended in induction of labor and control of postpartum hemorrhage.[21]
- Use of prostaglandin E1 and E2 analogs are shown to be safe in pregnancy[22]. However, prostaglandin F2 alpha analogs should be avoided as they can induce bronchospasm.[23] Ergot derivatives have similar property and therefore should also be avoided.
References
- ↑ Rey E, Boulet LP (2007). "Asthma in pregnancy". BMJ. 334 (7593): 582–5. doi:10.1136/bmj.39112.717674.BE. PMC 1828355. PMID 17363831.
- ↑ Kwon HL, Belanger K, Bracken MB (2003). "Asthma prevalence among pregnant and childbearing-aged women in the United States: estimates from national health surveys". Ann Epidemiol. 13 (5): 317–24. PMID 12821270.
- ↑ Wise RA, Polito AJ, Krishnan V (2006). "Respiratory physiologic changes in pregnancy". Immunol Allergy Clin North Am. 26 (1): 1–12. doi:10.1016/j.iac.2005.10.004. PMID 16443140.
- ↑ Juniper EF, Daniel EE, Roberts RS, Kline PA, Hargreave FE, Newhouse MT (1989). "Improvement in airway responsiveness and asthma severity during pregnancy. A prospective study". Am Rev Respir Dis. 140 (4): 924–31. PMID 2679270.
- ↑ 5.0 5.1 5.2 5.3 5.4 Liu S, Wen SW, Demissie K, Marcoux S, Kramer MS (2001). "Maternal asthma and pregnancy outcomes: a retrospective cohort study". Am J Obstet Gynecol. 184 (2): 90–6. doi:10.1067/mob.2001.108073. PMID 11174486.
- ↑ Perlow JH, Montgomery D, Morgan MA, Towers CV, Porto M (1992). "Severity of asthma and perinatal outcome". Am J Obstet Gynecol. 167 (4 Pt 1): 963–7. PMID 1415433.
- ↑ Lehrer S, Stone J, Lapinski R, Lockwood CJ, Schachter BS, Berkowitz R; et al. (1993). "Association between pregnancy-induced hypertension and asthma during pregnancy". Am J Obstet Gynecol. 168 (5): 1463–6. PMID 8498428.
- ↑ 8.0 8.1 Breton MC, Beauchesne MF, Lemière C, Rey E, Forget A, Blais L (2009). "Risk of perinatal mortality associated with asthma during pregnancy". Thorax. 64 (2): 101–6. doi:10.1136/thx.2008.102970. PMID 19008298.
- ↑ Triche EW, Saftlas AF, Belanger K, Leaderer BP, Bracken MB (2004). "Association of asthma diagnosis, severity, symptoms, and treatment with risk of preeclampsia". Obstet Gynecol. 104 (3): 585–93. doi:10.1097/01.AOG.0000136481.05983.91. PMID 15339773.
- ↑ Pratter MR, Hingston DM, Irwin RS (1983) Diagnosis of bronchial asthma by clinical evaluation. An unreliable method. Chest 84 (1):42-7. PMID: 6861547
- ↑ Irwin RS, Curley FJ, French CL (1990) Chronic cough. The spectrum and frequency of causes, key components of the diagnostic evaluation, and outcome of specific therapy. Am Rev Respir Dis 141 (3):640-7. PMID: 2178528
- ↑ Pratter MR, Curley FJ, Dubois J, Irwin RS (1989) Cause and evaluation of chronic dyspnea in a pulmonary disease clinic. Arch Intern Med 149 (10):2277-82. PMID: 2802893
- ↑ 13.0 13.1 Nørregaard O, Schultz P, Ostergaard A, Dahl R (1989). "Lung function and postural changes during pregnancy". Respir Med. 83 (6): 467–70. PMID 2623214.
- ↑ FDA
- ↑ National Asthma Education and Prevention Program (2007). "Expert Panel Report 3 (EPR-3): Guidelines for the Diagnosis and Management of Asthma-Summary Report 2007". J Allergy Clin Immunol. 120 (5 Suppl): S94–138. doi:10.1016/j.jaci.2007.09.043. PMID 17983880.
- ↑ http://www.nhlbi.nih.gov/health/prof/lung/asthma/astpreg.txt
- ↑ Schatz, M, Wise, RA. Acute asthma in pregnancy. In: Acute Asthma: Assessment and Management, Corbridge T, et al (Eds), McGraw-Hill, New York 2000.
- ↑ Wendel PJ, Ramin SM, Barnett-Hamm C, Rowe TF, Cunningham FG (1996). "Asthma treatment in pregnancy: a randomized controlled study". Am J Obstet Gynecol. 175 (1): 150–4. PMID 8694041.
- ↑ Schatz, M, Wise, RA. Acute asthma in pregnancy. In: Acute Asthma: Assessment and Management, Corbridge T, et al (Eds), McGraw-Hill, New York 2000.
- ↑ National Heart, Lung, and Blood Institute. National Asthma Education and Prevention Program Asthma and Pregnancy Working Group (2005). "NAEPP expert panel report. Managing asthma during pregnancy: recommendations for pharmacologic treatment-2004 update". J Allergy Clin Immunol. 115 (1): 34–46. doi:10.1016/j.jaci.2004.10.023. PMID 15637545.
- ↑ Minerbi-Codish I, Fraser D, Avnun L, Glezerman M, Heimer D (1998). "Influence of asthma in pregnancy on labor and the newborn". Respiration. 65 (2): 130–5. PMID 9580925.
- ↑ Towers CV, Briggs GG, Rojas JA (2004). "The use of prostaglandin E2 in pregnant patients with asthma". Am J Obstet Gynecol. 190 (6): 1777–80, discussion 1780. doi:10.1016/j.ajog.2004.02.056. PMID 15284797.
- ↑ Arakawa H, Lötvall J, Kawikova I, Löfdahl CG, Skoogh BE (1993). "Leukotriene D4- and prostaglandin F2 alpha-induced airflow obstruction and airway plasma exudation in guinea-pig: role of thromboxane and its receptor". Br J Pharmacol. 110 (1): 127–32. PMC 2176029. PMID 8220872.