216 SECTION 3 • MEDICAL PROBLEMS IN THE ATHLETE
DIAGNOSIS
- The diagnosis of EIB is often based on history and
self-reported symptoms. Numerous studies have
demonstrated that this approach is unreliable
(Tikkanen and Peltonen, 1999; Rice et al, 1985; Thole
et al, 2001). Tikkanen et al found that only 61% of
athletes with a positive field exercise challenge had
reported symptoms, while 45% of athletes with a neg-
ative field test did report symptoms (Rice et al, 1985).
More reliable diagnosis is based on pulmonary func-
tion testing after a thorough history and physical
examination has ruled out any other explanation of the
symptoms.
•Office spirometry should be done at rest to rule out
underlying chronic asthma in anyone suspected of
having EIB. A normal resting test with suspicion of
EIB warrants a bronchoprovocation test. Many physi-
cians will give a trial of a prophylactic bronchodilator
if classic history and mild symptoms exist. - Options for confirming EIB include direct and indi-
rect challenge tests. - Direct challenge testing involves administration of
increasing doses of a pharmacologic agent, such as
methacholine, to cause bronchoconstriction. These
tests are highly sensitive, but have a poor specificity for
EIB(Anderson, 1997).
INDIRECT CHALLENGE TESTS
EXERCISECHALLENGETEST
- Performed either in a laboratory or in the field, this
test seeks to simulate the athlete’s sport in order to
provoke EIB. Formal pulmonary function tests are
done with FEV 1 being the index most often measured
in the lab versus peak expiratory flow rate(PEFR) in
the field. Solitary EIB will have a preexercise baseline
FEV 1 or PEFR between 80 and 100% of normal pre-
dicted values. The exercise is most commonly free or
treadmill running for 5 to 8 min at a high intensity
(≥85–90% maximum predicted heart rate). FEV 1 or
PEFR is measured at 1-, 3-, 5-, 10-, and 15-min inter-
vals. Positive test =a fall in FEV 1 or PEFR of 15%.
Mild EIB =15 to 25% drop, moderate EIB =25 to
40% drop, and severe EIB =more than a 40% drop
(Smith and MacKnight, 1998). - Field testing offers the advantage of more closely
mimicking actual sport, but can be difficult to control
environmental factors as well as hard to control/monitor
rate of exertion (Eliasson et al, 1992). - Laboratory testing is more costly and eliminates pos-
sible contributing environmental triggers. Offers
advantage of controlled cardiovascular workload and
ability to monitor pulmonary and cardiovascular func-
tion during exercise (Rundell et al, 2000).- Other indirect challenge tests include the eucapnic
voluntary hyperventilation (EVH) challenge test, the
hyperosmolar saline challenge test, and the mannitol
challenge test. These tests offer promise in difficult to
diagnose and elite athletes, but are not readily avail-
able other than at research centers (Holzer, Brukner,
Douglass, 2002). - Pharmacologic treatments(Also see asthma section
above): A variety of agents are available to treat EIB.
Treatment should be tailored to the individual athlete
and his or her sport.
BETA-AGONISTS
•First-line therapy is usually with an inhaled short-
acting beta-agonist, such as albuterol, 2–4 puffs
taken 15 to 30 min prior to activity. Albuterol’s onset
of action is ≤5 min and duration of effect is ~2–6 h.
It is 90% effective (Lemanske and Henke, 1989). All
athletes with EIB should carry a short-acting beta-
agonist inhaler with them during exercise to relieve
acute exacerbations that occur despite prophylaxis.
The long acting beta-agonist, salmeterol, lasts 12 h
and should be considered in athletes involved in
endurance/all day events as well as in children where
activity is unpredictable. It needs to be taken at least
1 h before exercise, but preferably more than 4 h
before activity (Tan and Spector, 1998). Usual dura-
tion of action is 12 h, but with regular bid use, effect
can wane after 9 h (Nelson et al, 1998). This effect
can be counteracted if combined with an inhaled
steroid.MAST-CELLSTABILIZERS- Cromolyn sodium blocks late phase EIB while
nedocromil sodium blocks immediate and late phase
EIB. Both should be administered as 2–4 puffs 20 min
prior to exercise. The duration of action is ~2 h. They
are ~70–85% effective (Smith and LaBotz, 1998). Not
to be used to treat acute symptoms, but useful for
repeated bouts of exercise as they have minimal/no
side effects. Combining with beta-agonists does not
appear to be better than beta-agonist alone (Smith and
LaBotz, 1998). - Inhaled corticosteroids:Steroids are not effective
when used as prophylaxis prior to exercise. Studies
show decreased airway responsiveness to exercise
after 4 weeks of inhaled corticosteroids (Henriksen
and Dahl, 1983; Waalkans et al, 1993). Based on the
potential for side effects, corticosteroids should be
reserved for those patients refractory to beta-agonists
or mast-cell stabilizers. This lack of response should
also prompt reevaluation for chronic asthma.