Transcript Viral and Bacterial Pneumonia in the Pediatric Patient

When Athletes Can’t Breathe:
Exercise-Induced Asthma/Bronchospasm
Mark A. Brown, M.D.
Professor of Pediatrics
Director, University of Arizona Pediatric
Pulmonary Center
[email protected]
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If from running, gymnastic exercises, or
any other work, the breathing becomes
difficult, it is called “Asthma”. The
symptoms of its approach are heaviness of
the chest…, difficulty of breathing in
running or on a steep road.
Areteaus, The Cappadocian, First Century AD
Definitions
• EIB - Symptoms of chest tightness,
shortness of breath, cough and/or wheezing
following vigorous exercise
• EIA - chest tightness, shortness of breath,
cough and/or wheezing - triggered by
exercise in a patient with asthma (known or
unknown)
Prevalence
• EIB
– 14% of collegiate cross country runners (Thole,
et al. Med & Sci in Sports & Exer 2001;
33:1641-1646.)
– 50% of elite summer athletes had positive
screening test (Holzer, et al. J Allergy Clin
Immunol 2002; 101:374-380.)
Prevalence
EIB affects approximately:
• 90% of asthmatics
• 35-40% of those with allergic rhinitis
• 12-15% of the general population
• 3-25% of athletes (higher percentages in younger
age groups)
Olympians and Asthma
• 212% increase in βagonist use from 1984 to
1996
• 151% increase in βagonist use from 1996 to
2000
• 66% of athletes using βagonists in 2004 were
also using inhaled
corticosteroid
Fitch, KD. Clin Rev Allergy Immunol 31:259, 2006
Carlsen KH et al. Allergy 63:387, 2008
% Baseline
Typical EIB Time Course
Exercise
Time (min)
% Baseline
Typical EIA Time Course
Exercise
Time (min)
% Baseline
EIB Refractory period
Exercise
Time (min)
Physical Factors
• Exercise: type, intensity, duration
• Bronchial hyper-responsiveness (BHR)
• Environmental factors
– Direct: temperature, humidity
– Indirect (through increase in BHR): air
pollution, viral infections, allergen exposure
High Asthmagenic Activities
• High Minute Ventilation • Activities associated with
Activities
cool, dry conditions
–
–
–
–
–
Long-distance running
Cycling
Basketball
Soccer
Rugby
–
–
–
–
Ice hockey
Speed skating
Cross country skiing
Scuba diving
Low Asthmagenic Activities
• Low minute ventilation
activities
–
–
–
–
–
–
–
–
–
–
Football
Baseball
Downhill skiing
Karate
Wrestling
Boxing
Sprinting
Gymnastics
Racquet sports
Golf
• Activities associated with
warm, humid conditions
–
–
–
–
Swimming
Diving
Water polo
Water skiing
Proposed Stimuli
• Respiratory (airway) heat loss
• Increased airway fluid osmolality
• Rapid airway cooling and rewarming
Respiratory Heat Loss
• Degree of bronchoconstriction is
proportional to respiratory heat exchange
• Sufficient respiratory heat exchange induces
bronchoconstriction in the absence of
exercise
» Deal, et al. J Appl Physiol 1979; 46:467-475
Respiratory Heat Loss
• Direct airway temperature measurements
confirm fall with exercise/hyperventilation
» McFadden, et al. J Appl Physiol 1985; 58:564-570.
» McFadden, et al. J Appl Physiol 1985; 76:1007-1010.
• Bronchoconstriction induced following
inhalation of hot dry air
» Anderson, et al. Eur J Respir Dis 1985; 67:20-30.
Increased Airway Fluid Osmolality
• Bronchoconstriction induced following
inhalation of hot dry air
» Anderson, et al. Eur J Respir Dis 1985; 67:20-30.
• Level of minute ventilation necessary to
induce bronchoconstriction same regardless
of air temperature (humidity constant)
» Eschenbacher & Shepherd. Am Rev Respir Dis 1985;
131:894-901.
Increased Airway Fluid Osmolality
• Osmolality of nasal secretions increases in
response to cold dry air
» Togias, et al. Am Rev Respir Dis 1988; 137:625-629.
• Osmolality of tracheal lining fluid is
increased in tracheostomy patients
» Potter, et al. Am Rev Respir Dis 1967; 96:83-87.
• Osmolality of tracheal lining fluid is
increased in dog trachea exposed to air
» Boucher, et al. J Appl Physiol 1981; 50:613-620.
Proposed Mechanisms
• Neuropeptide release
• Mediator release
• Vascular engorgement
Neuropeptide Release
• Hypertonic saline induces changes of
neurogenic inflammation
» Umeno, et al. J Clin Invest 1990; 85:1905-1908.
• Little evidence to support sympathetic/vagal
mechanisms
Mediator Release
• Supported by studies of
– Direct measurement of mediators released into
lung fluid following hypertonic,
hyperventilation and exercise stimuli;
– Effects of specific mediator antagonists or
synthesis inhibitors on induced
bronchoconstriction
Mediator Release
•
•
•
•
•
Histamine
Prostaglandins
ECP
PAF
Bradykinin
• Leukotrienes
• Neutrophil
chemotactic activity
(IL-8, LTB4)
• Substance P/NEP
Diagnosis
• History alone is an unreliable indicator of EIB.
– 45.8% of adolescents who screened negative by history
had EIB (Bukolic RE. J Peds 2002; 141:306-308.)
– Poor correlation between reported symptoms and
exercise challenge in collegiate cross-country
runners/elite athletes (Thole, et al. Med & Sci in Sports
& Exer 2001; 33:1641-1646. Rundell, et al. Med & Sci
in Sports & Exer 2001; 33:208-213. Rundell, et al.
Med & Sci in Sports & Exer 2000; 32:309-316.)
Diagnosis
•
Diagnosis confirmed by >15-20% fall in
PEFR or FEV1 after
– formal exercise challenge test taking into
account the type of exercise, temperature and
relative humidity (confirmed by a positive test,
but not excluded by a negative test);
– formal eucapnic hyperventilation challenge as
an alternative (more sensitive; negative test
usually excludes EIA).
Exercise Challenge
• Baseline spirometry or
PEFR
• Exercise Challenge
– Exercise to 80% calculated
maximal heart rate or O2
consumption of 30-35
ml/min/kg for 6-10 min
– FEV1 or PEFR every 3-5
min after exercise for 20-30
min
Eucapnic Hyperventilation
• Subject breathes 5% CO2/21% O2/74% N2 at 30 x FEV1 for 6
minutes
• Spirometry measured before and at regular intervals afterward
• At least comparable to, perhaps more sensitive than
methacholine challenge
% Baseline
Exercise/Eucapnic
Hyperventilation Response
Exercise/EH
Time (min)
Inhaled Mannitol
• Inhalation of powdered mannitol increases
lung lining fluid osmolality, perhaps
mimicking changes associated with
exercise.
• Compared to eucapnic hyperventilation,
mannitol challenge was 96% sensitive and
92% specific for EIB. (Holzer, et al. Am J
Respir Crit Care Med 2003; 167:534-537.)
Differential Diagnosis
•
•
•
•
Poorly controlled asthma
Poor conditioning
Vocal cord dysfunction
Cardiac disease
Vocal Cord Dysfunction
Exercise-associated respiratory symptoms
Symptoms DURING exercise
Undiagnosed or poorly
controlled asthma
Further history, exam,
spirometry
Classification of severity, selection
of appropriate therapy, patient
education
Follow-up 6-8 weeks
Symptoms FOLLOWING exercise
Presumptive diagnosis of EIB
Further history, exam,
spirometry
Prophylaxis with -agonist
Optimal Response
Suboptimal Response
Exercise/EH Challenge
Normal
Abnormal
Reconsider Dx,
Reassess
Escalate therapy
Prevention
• Careful sport selection
– Low minute ventilation/warm humid conditions
• Simple Measures
• Prophylactic pharmacologic therapy
– -agonists
– Inhaled anti-inflammatories: Cromolyn, Nedocromil,
steroids
– LABA
– LTRA
• Induction of refractory period
Simple Preventive Measures
• Improve physical conditioning
• Exercise in warm humidified environment
• In cold weather cover mouth/nose with
scarf or mask
• Gradually decrease intensity of exercise at
end of work-out
• Avoid aeroallergens, pollutants
Therapeutic Sequence
•
•
•
•
•
Simple Measures
-agonists
Inhaled corticosteroids
Inhaled long-acting -agonists
Ipratropium or leukotriene receptor
antagonists
Medications approved by both
the NCAA and USOC
Medication
Albuterol*
Terbutaline*
Salmeterol*
Cromolyn
Nedocromil
Effectiveness
High
High
High
Moderate
Moderate
*Approval by the USOC is dependent on a previous notification and independent
assessment by the Olympic Medical Commission. NCAA and USOC allow agonists by inhalation only.
Medications approved by both
the NCAA and USOC
Medication
Triamcinolone*
Fluticasone*
Budesonide*
Flunisolide*
Theophylline, SR
Ipratropium
Effectiveness
Very
Very
Very
Very
Moderate
Possible
*Approval by the USOC is dependent on a previous notification
and independent assessment by the Olympic Medical Commission.
Alternative Medicine Approaches
• Omega-3 fatty acid supplementation
» Mickleborough, et al. Am J Respir Crit Care Med
2003; 168:1181-1189.
• Buteyko Breathing Technique - relaxation?
» Bowler, et al. Med J Australia. 1998; 169:575-578.
» Cooper, et al. Thorax 2003; 58:674-679
May there never develop in me
the notion that my education is
complete, but give me the strength
and leisure and zeal continually to
enlarge my knowledge.
Maimonides