Agency for Toxic Substances and Disease Registry
Case Studies in Environmental Medicine (CSEM) 

Environmental Triggers of Asthma
Case Study and Pretest

Instructions

Case Study

A 12-year-old girl arrives at your office with her mother for an evaluation of the child’s cough. The mother reports that the child has a nocturnal nonproductive cough 2 to 3 times per month for the past 3 months associated with increasing episodes of shortness of breath that resolve spontaneously. During soccer games, the girl has recurrent episodes of cough and wheezing, which are only relieved when she uses a friend’s albuterol inhaler.

Past medical history reveals that the patient has had recurrent upper respiratory infections and had bronchitis 2 years ago. The patient has had no hospitalizations or emergency department visits. Current medications include diphenhydramine for her intermittent runny nose and an occasional puff from her friend’s albuterol inhaler during soccer games.

Family history reveals that the girl lives with her mother, father, and older sister in a house on the outskirts of the community. The father had a history of seasonal hay fever as a child. Both parents are indoor and outdoor smokers. The mother reports that her husband has had some difficulties with episodic cough and shortness of breath, but has not seen a physician.

A review of systems reveals that the patient has numerous episodes of sneezing, itchy eyes, and clear discharge from the nose. You ask the mother to leave the examination room. This allows you to ask the patient confidentially if she has been smoking or is around friends who smoke. The patient states that neither she nor any of her friends smoke cigarettes or any other inhaled substances, such as marijuana. In addition, the patient has not reached menarche and she denies sexual activity. The patient has met developmental milestones and followed a 50th-percentile growth curve. She is a 7th grader doing well academically, with no school absences.

Physical examination reveals a young girl, who sits quietly and comfortably, in no apparent distress. Her vital signs are as follows: temperature 98.6ºF (37.0ºC), respiratory rate 17, heart rate 82, blood pressure 118/75 mmHg. No dyspnea or stridor is evident. Her skin color is normal, without cyanosis. Examination of the nares reveals boggy, red turbinates with moderate congestion, but no sinus tenderness or flaring. The tympanic membranes are mobile and without erythema or air/fluid levels. Inspection of the chest does not show accessory muscle use or intercostal, suprasternal, or supraclavicular retractions. The antero-posterior diameter does not seem to be increased. Pulmonary auscultation reveals inspiratory and expiratory wheezing scattered throughout both lung fields. Her peak expiratory flow rate (PEFR) reading is 285 liters per minute (L/min). You explain to the patient and her mother that her predicted normal should be 360 L/min (give or take 20%), which is the predicted normal PEFR for her age and build. The rest of the physical examination is unremarkable. The fingers are not clubbed, nor are the nail beds cyanotic.

Your primary working diagnosis for this patient is asthma.

Initial Check Questions

1. List the primary and differential diagnosis for wheezing in this patient.
2. What are some risk factors for asthma in this patient and her family?
3. What further questions might you ask about other environmental triggers of asthma in this household?
4. What tests would you order to confirm or rule out your primary diagnosis?

Initial Check Answers

1. The differential diagnosis for wheezing in this patient includes bronchial asthma (primary diagnosis), exercise induced asthma, wheezing solely associated with respiratory infections, foreign body aspiration, and wheezing associated with gastroesophageal reflux. Less likely diagnoses include cystic fibrosis, immunodeficiency states, congenital abnormalities, and vocal cord dysfunction.

   The information for this answer comes from section “Differential Diagnosis of Asthma”.

2. This family has a history of atopy. Both parents are smokers. The patient has a history of recurrent upper respiratory infections and bronchitis, as well as a suspicion of allergic rhinitis.

   The information for this answer comes from section “Differential Diagnosis of Asthma”.

3. Ask the parent and patient about possible exposures and events that worsen the wheezing. This information should include exacerbation due to upper respiratory illness, seasonal variation in symptoms, relationship of symptoms to specific exposures, and exacerbation with exposure to nonspecific triggers such as cigarette or woodstove smoke or household cleaning products. The home environment should be reviewed, with a focus on the patient’s environment, particularly within his or her bedroom, the presence of furry pets and carpeting, condition of home heating and cooling system, past water damage or leakage, and smoking within the home. The environment outside the home should also be reviewed, including a potential relationship of symptoms and school and recreational activities.

   The information for this answer comes from section “Environmental Triggers of Asthma”.

4. If there is any question about the diagnosis, consider referral to a pulmonologist or allergy/asthma specialist. In the pulmonologist’s office, the measurement of forced expiratory volume in 1 second (FEV1) before and after short-acting bronchodilator therapy can be used to demonstrate reversible airway obstruction. This should be done by spirometry (for children who are able to cooperate), preferably using American Thoracic Society guidelines. (ATS 1995) Simple peak expiratory flow monitoring in the general practitioner’s office can be used, although variability in peak expiratory flow limits its application in screening for asthma. Chest radiographs should be performed for individuals with systemic symptoms such as fever and signs suggestive of a localized lung abnormality. A total immunoglobulin E (IgE) level, an eosinophil count, and a differential count for eosinophils on nasal or sputum secretions may also provide useful information.

   The information for this answer comes from section “Clinical Assessment”.