Clinical Review

Safe, efficient management of acute asthma

OBG Manag. 2006 April;18(4):30-44

References

1. Cydulka RK, Emerman CL, Schreiber D, Molander KH, Woodruff PG, Camargo CA, Jr. Acute asthma among pregnant women presenting to the emergency department. Am J Respir Crit Care Med. 1999;160:887-892.

2. Otsuka H, Narushima M, Suzuki H. Assessment of inhaled corticosteroid therapy for asthma treatment during pregnancy. Allergology Int. 2005;54:381-386.

3. Gluck JC, Gluck PA. The effects of pregnancy on asthma: a prospective study. Ann Allergy. 1976;37:164-168.

4. Schatz M, Harden K, Forsythe A, et al. The course of asthma during pregnancy, post partum, and with successive pregnancies: a prospective analysis. J Allergy Clin Immunol. 1988;81:509-517.

5. Mabie WC, Barton JR, Wasserstrum N, et al. Clinical observations on asthma in pregnancy. J Matern Fetal Med. 1992;1:45-50.

6. Beck SA. Asthma in the female: hormonal effect and pregnancy. Allergy Asthma Proc. 2001;22:1-4.

7. Lehrer S, Stone J, Lapinski R, et al. Association between pregnancy-induced hypertension and asthma during pregnancy. Am J Obstet Gynecol. 1993;168:1463-1466.

8. Alexander S, Dodds L, Armson BA. Perinatal outcomes in women with asthma during pregnancy. Obstet Gynecol. 1998;92:435-440.

9. Schatz M, Dombrowski M, Wise R, et al, for the Maternal-Fetal Medicine Units Network, The National Institute of Child Health and Development; The National Heart, Lung and Blood Institute. The relationship of asthma medication use to perinatal outcomes. J Allergy Clin Immunol. 2004;113:1040-1045.

10. Ericson A, Kallen B. Use of drugs during pregnancy-unique Swedish registration method that can be improved. Swedish Medical Products Agency. 1999;1:8-11.

11. Dombrowski MP, Schatz M, Wise R, et al, for the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network and the National Heart, Lung and Blood Institute. Asthma during pregnancy. Obstet Gynecol. 2004;103:5-12.

12. Kallen B, Rydhstroem H, Aberg A. Asthma during pregnancy: a population based study. Eur J Epidemiol. 2000;16:167-171.

13. Stenius-Aarniala B, Piirila P, Teramo K. Asthma and pregnancy: a prospective study of 198 pregnancies. Thorax. 1988;43:12-18.

14. Metzger WJ, Turner E, Patterson R. The safety of immunotherapy during pregnancy. J Allergy Clin Immunol. 1978;61:268-272.

15. National Heart, Lung, and Blood Institute; National Asthma Education and Prevention Program Asthma and Pregnancy Working Group. NAEPP expert panel report. Managing asthma during pregnancy: recommendations for pharmacologic treatment-2004 update [published correction appears in J Allergy Clin Immunol. 2005;115:477]. J Allergy Clin Immunol. 2005;115:34-46.

16. American College of Obstetricians and Gynecologists (ACOG) and The American College of Allergy, Asthma and Immunology (ACAAI). Position statement: The use of newer asthma and allergy medications during pregnancy. Ann Allergy Asthma Immunol. 2000;84:475-480.

17. Gluck JC, Gluck PA. Asthma controller therapy during pregnancy. Am J Obstet Gynecol. 2005;192:369-380.

Both authors receive grant/research support from Astra Zeneca. In addition, Dr. Joan Gluck receives grant/research support from Sepracor.

It is unclear whether fetal complications associated with oral steroids are a direct result of the drugs or if increased use of oral steroids is just a marker for more severe underlying asthma or exacerbation of asthma. Nevertheless, women who require oral corticosteroids should be educated about the signs and symptoms of threatened preterm delivery.

TABLE 2

Some asthma “controller” medications are safer than others

TYPE OF DRUG	MEDICATIONS
PREGNANCY CATEGORY B
Inhaled corticosteroid	Budesonide
Mast cell stabilizer	Cromolyn
Mast cell stabilizer	Nedocromil
Leukotriene modifier	Montelukast
Leukotriene modifier	Zafirlukast
PREGNANCY CATEGORY C
Inhaled corticosteroids	Beclomethasone
	Fluticasone
	Flunisolide
	Triamcinolone
Leukotriene modifier	Zileuton
Methylxanthine	Theophylline
Long-acting beta-agonist	Formoterol
Long-acting beta-agonist	Salmeterol
SOURCE: Reprinted from Gluck JC, Gluck PA. Asthma controller therapy during pregnancy. Am J Obstet Gynecol. 2005;192:369-380, © 2005 with permission from Elsevier. ¹⁷

Fetal surveillance and monitoring

Fetal distress can be caused by acute or chronic maternal hypoxia from severe chronic asthma or acute exacerbations. IUGR may also be related to hypoxia, or it may be a direct result of treatment with oral steroids.¹³

Surveillance with nonstress testing and serial ultrasound, as well as fetal monitoring, may be necessary to check for IUGR, especially in women with severe asthma, because any hypoxemia can affect the fetus. During a severe asthma attack, continuous fetal monitoring (depending on gestational age) may be necessary.

How to control asthma

“Controller” and “reliever” drugs

Daily “controller” drugs are needed to manage inflammation in the lung; they include inhaled corticosteroids and leukotriene inhibitors.

“Reliever” medications such as beta-adrenergic inhalers act rapidly to calm exacerbations, and should be kept readily available.

Individualize allergen avoidance

Environmental allergens or lung irritants can exacerbate asthma. As many as 85% of patients with asthma also have allergies to 1 or more substances such as animals, pollens, molds, and dust mites, which can worsen symptoms. Lung irritants such as smoke, chemical fumes, and environmental pollutants can also be problematic. Finally, some drugs such as aspirin and beta-blockers can trigger acute symptoms.

An important part of treatment for these patients is identification and avoidance of asthma and allergy triggers.

Strategies include keeping pets out of the bedroom, sealing old pillows and mattresses in special encasings, removing drapes, using special filter vacuum bags while cleaning, closing the windows between 5 AM and 10 AM when pollen is highest, and limiting exposure to smoke.

Preconception immunotherapy may help

Immunotherapy is a cornerstone of maintenance therapy for asthma that cannot be controlled via avoidance strategies or medication. Identification of allergy triggers requires skin testing (scratch, patch, or intradermal). Starting with minute amounts of allergen extracts, regular injections with increasing doses are given to stimulate a protective, specific immune response.

Because it takes several months for the treatments to take full effect, and because there is a greater risk of adverse reactions with increasing doses, this therapy should not be initiated during pregnancy. However, it can be carefully continued during pregnancy in women who are already benefiting from it and not experiencing adverse reactions.

If a woman is in the “build-up” phase of immunotherapy when she conceives, continue treatment without increasing the allergen dose.¹⁴

Treatment recommendations

Treatment guidelines generally categorize asthma according to severity (TABLE 3).¹⁵ While these guidelines assist in decision-making, each patient should receive an individualized treatment plan. Severity of the disease is based on clinical signs and symptoms as well as pulmonary function, as measured by FEV1 (forced expiratory volume in the first second of a pulmonary function test). This classification system is helpful in deciding how well asthma is controlled and also in following response to treatment.

Choice of the appropriate medications to control asthma during pregnancy is critical for the best maternal and fetal outcomes (TABLE 3).

No daily medication is needed in women with mild asthma.

Women with mild asthma whose day-time symptoms occur less than daily and whose nighttime symptoms occur less than weekly, often have fewer symptoms during pregnancy.

The tipping point. If the patient is using an entire canister of short-acting inhaled beta-agonist in a month, her disease control is inadequate. This is the point at which therapy should be increased to include long-term control medications, such as daily inhaled corticosteroids or leukotriene inhibitors (TABLE 3).

The most severe asthma, characterized by frequent daytime and nighttime symptoms, is more likely to become exacerbated during pregnancy. These women require careful monitoring to ensure that their medications are prescribed at adequate levels.

TABLE 3

How to determine severity—and treat accordingly

SEVERITY	SYMPTOMS		PEAK FLOW (OR FEV1)	TREATMENT
SEVERITY	DAY	NIGHT	PEAK FLOW (OR FEV1)	TREATMENT
Mild Intermittent	≤2/week	≤2/month	≥80%	No daily medication needed.
				ACUTE SYMPTOMS Beta-2 adrenergic inhaler
				IF EXACERBATION IS UNABATED Systemic corticosteroids
Mild Persistent	>2/week	>2/month	≥80%	MAINTENANCE Low-dose inhaled corticosteroid
				ALTERNATIVE MAINTENANCE Cromolyn,
				Leukotriene receptor antagonist, or
				Theophylline (5–12 μg/mL serum level).
				ACUTE SYMPTOMS Beta-2 adrenergic inhaler
				IF NOT IMPROVED Systemic corticosteroids
Moderate Persistent	Daily	>1/week	>60% to <80%	Low-dose inhaled corticosteroid and
				Long-acting inhaled beta-2 agonist or
				Medium-dose inhaled corticosteroid.
				ALTERNATIVE TREATMENT
				Low-dose inhaled corticosteroid and
				Theophylline or leukotriene antagonist
Severe Persistent	Continual	Frequent	<60%	High-dose inhaled corticosteroid and
				Long-acting inhaled beta-2 agonist.
				ACUTE SYMPTOMS
				Beta-2 adrenergic inhaler (short acting) and
				Systemic corticosteroids (2 mg/kg/day, not to exceed 60 mg/day).
FEV1=forced expiratory volume in the first second of pulmonary function test.
SOURCE: Modified from National Heart, Lung, and Blood Institute¹⁵