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This Month's Feature Review:
Allergies and Dysfunctional Breathing
Summary of salient points in article:
" Hyperventilation Syndrome is very common in the general population and might aggravate symptoms in about one third of asthmatics.
" Asthma and Hyperventilation often co-exist.
" There is a big overlap between Hyperventilation and Panic Disorder.
" Allergic patients (patients with hay fever and asthma) seems to be more prone to hyperventilation than the general population
" Hyperventilation can masquerade as anaphylaxis.
" Exercise-induced Asthma can be mistaken for Exercise-induced Hyperventilation.
" Hyperventilation Syndrome can be effectively treated with a course of physiotherapy treatment, including education, relaxation and breathing control.
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Prevalence of dysfunctional breathing in patients treated for asthma in primary care: cross sectional survey
Mike Thomas, GP et al, Leicester, UK
Objectives: To estimate the prevalence of dysfunctional breathing in adults with asthma treated in the community.
Design: Postal questionnaire survey using Nijmegen questionnaire (assess 16 symptoms associated with abnormal breathing on a five point scale. A total symptom score of >23 has been reported as showing a sensitivity of 91% and specificity of 95% as a screening instrument in patients with diagnosed hyperventilation syndrome).
Setting: ?One general practice with 7033 patients.
Participants: All adult patients aged 17-65 with diagnosed asthma who were receiving treatment.
Main outcome measure: Score of? >23 on Nijmegen questionnaire.
Results: 227/307 patients returned completed questionnaires; 219 (71.3%) questionnaires were suitable for analysis. 63 participants scored .23. Those scoring >23 were more likely to be female than male (46/132 (35%) vs. 17/87 (20%), p=0.016 and were younger (mean SD) age 44.8 (14.7) vs. 49.0 (13.8, P=0.05). Patients at different treatment steps of the British Thoracic Society asthma guideline were affected equally.
Conclusions: About a third of women and a fifth of men had scores suggestive of dysfunctional breathing. Although further studies are needed to confirm the validity of this screening tool and these findings, these findings suggest scope for the therapeutic intervention and may explain the anecdotal success of the Buteyko method of treating asthma.
Reference: BMJ 2001; 322:1098-1100 (5 May)
Self-reported hay fever and panic attacks in the community
Renee D Goodwin, PhD, Division of Epidemiology, Columbia University, New York
Objective: The objective of this study was to determine the relationship between self-reported hay fever and common mental disorders among adults in the general population.
Methods: Data was drawn from the Midlife Development in the US survey, a representative household survey of the adult US population (25 to 74 years old; n=3032). Multivariate logistic regression analyses were used to determine the relationship between self-reported hay fever and current major depression, panic attacks, generalised anxiety disorders, and alcohol/substance use disorders.
Results: Self-reported hay fever was associated with significantly increased odds of panic attack (odds ratio = 1.8 [1.2, 2.6]), which persisted after adjusting for differences in socio-demographic characteristics and co morbid mental disorders. Self-reported hay fever was not associated with significantly increased likelihood of major depression, generalised anxiety, or alcohol/substance use disorders.
Conclusions: Consistent with previous findings, these data show a relationship between self-reported hay fever and increased likelihood of panic attacks among young adults in the general population. The mechanism of the observed association remains unknown. Future work that examines the relationship between panic attacks and hay fever, as well as other mental disorders using both self-report and objective measurement of allergic response in prospective, longitudinal, epidemiologic data may be useful in improving our understanding of this observed link.
Reference: Annals of Allergy, Asthma, & Immunol 2002; 88:556-559
Exercise-induced hyperventilation: a psuedoasthma syndrome
Abdel-Hai Hammo, MD et al, Univ. of Iowa, Iowa, USA
Background: Exercise-induced asthma (EIA) is common and generally responds well to an inhaled Beta-2-agonist (ventolin).
Objective: We examined the physiologic changes in airflow and gas exchange that occurred during standardised treadmill exercise in patients previously diagnosed with exercise-induced asthma whose histories appeared atypical or where conventional treatment, including an inhaled beta-2-agonist, was ineffective.
Methods: During a 1-year period 32 patients, aged 8 to 18, met these criteria. All had previously been diagnosed as having exercise-induced asthma. Exercise consisted of treadmill running at a time when the patients had received no beta-2-agonist, cromolyn, or nedocromil for at least 4 hours. Spirometry was done before and at 2, 5, 10, and 15 minutes after exercise; oxygen saturation was monitored by pulse oximetry; and end-tidal carbon dioxide was monitored with nasal canula.
Results: Despite the previous diagnoses of EIA, 11 patients who described chest tightness during exercise had decreased FEV1 less than 15% with all but one of those less than 10% (mean decrease 5.6%) but demonstrated demonstrated decreases in end-tidal CO2 greater than in all of the other 21 patients (mean 23.2 versus 9.8%, P<0.01). Only 4 patients had unequivocal evidence of bronchospasm with cough and wheezing accompanying chest tightness in association with decrease in FEV1 from 18 to 22%. Seventeen patients had neither their symptoms reproduced nor physiologic abnormalities.
Conclusions: These data show that chest discomfort perceived as dyspnoea (shortness of breath) during vigorous exercise may be associated with reduced carbon dioxide (hypocapnia) from hyperventilation without bronchospasm in children and adolescents previously misdiagnosed and treated as having exercise-induced asthma.
Reference: Ann Allergy Asthma Immunol 1999; 82:574-578
Carbon dioxide hypersensitivity, hyperventilation, and panic disorder
Pappa LA et al, Dept Psychiatry, Columbia University, New York
Objective: The purpose of the article is to offer comprehensive, databased explanation of the relationship between hyperventilation and panic disorder linking CO2 hypersensitivity, cognitive/behavioural factors, and the respiratory effects of antipanic pharmacological and psychological treatments.
Methods: The authors conducted a computerised search of MEDLINE for relevant articles.
Results: Some panic patients have a chronic, subtle respiratory disturbance. Acute hyperventilation is neither necessary nor sufficient for panic to occur. Respiratory abnormalities in panic patients may adaptively aim at coping with a hypersensitive CO2 chemoreceptor system. Some pharmacological agents also stimulate the respiratory system, causing hyperventilation. Triggering this hypersensitive respiratory control mechanism may incite panic. Antipanic medications may reset the receptor threshold. Misattribution and catastrophic interpretation of somatic symptoms or the sense of loss of control may contribute to panic symptoms. Behavioural interventions such as desensitisation or breathing retraining may block the full-blown attack. Cognitive strategies through cognitive control of respiration may supplement and accentuate these interventions.
Conclusions: Panic disorder may be due to inherently unstable autonomic nervous system, coupled with cognitive distress.
Reference: Am J Psychiatry 1993 Aug; 150(8): 49-57
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