Exercise-Induced Asthma

HISTORY
The patient is a 57-year-old black male who complained of chest pain and a productive cough at night and after running. The cough started about 5 months before the evaluation. The patient also noted shortness of breath when lying flat in bed. He had a minimal smoking history (3 pack-years) but had worked as a welder for 25 years. He had one brother who was diagnosed with asthma. Previous pulmonary function studies indicated moderate obstruction, but the patient reported worsening cough and breathlessness with exertion.

PULMONARY FUNCTION TESTING
Personal data
Name: M.H.
Age: 57
Height: 72 in
Weight: 190 lb
Race: Black

Baseline spirometry (3 months before exercise-induced asthma [EIA] test)
Prebronchodilator Postbronchodilator
Pred Actual %Pred Actual %Pred %Chng
FVC (L) 4.39 5.10 116 5.09 116 0
FEV1 (L) 3.46 2.79 81 3.22 93 15
FEV1 % 79 55 63
PEF (L/sec) 9.08 6.89 76 6.90 76 0

Exercise test (Flow-volume loops recorded during exercise)
Stand Walk Walk Walk Walk Walk
Speed 2.0 3.0 3.0 3.0 3.0
% Grade 0% 7% 7% 7% 6%
Time 2:00 1:00 2:00 2:00 2:00 1:00
HR 99 110 136 140 144 142
VE (L/min) 14.8 38.3 43.6 54.1 60.7 57.3

Exercise changes with spirometry
Pred %Pred Baseline 5 min Post Rx
FVC 4.39 103% 4.53 2.61 2.54
%Change –42% –7%
FEV1 3.46 74% 2.56 1.44 2.54
%Change –44% –1%
PEF 9.08 58% 5.23 3.19 5.29
%Change –39% 1%

EXERCISE AND CHALLENGE FLOW-VOLUME LOOPS

TECHNOLOGIST’S COMMENTS
All spirometric maneuvers were performed acceptably before and after exercise.

QUESTIONS

1. Interpret the following:
   • Baseline spirometry (3 months before EIA test)
   • Exercise flow-volume loops
   • Changes in spirometry after exercise
2. What is the cause of the patient’s symptoms?
3. What other tests might be indicated?
4. On the basis of these findings, what treatment might be recommended?