Ves Dimov, M.D.
Allergy and Immunology
Cleveland Clinic Florida
Westin Florida, United States of America
Asthma Phenotypes: A Practical Approach to Diagnosis and Treatment
This is a free full text editorial by Richard Lockey, a Past President of the World Allergy Organization, who teaches that “Asthma is the most treatable of all chronic diseases known to mankind.” Yet, outcome data from throughout the world indicate that the diagnosis and treatment of asthma are not optimal and need improvement. Why? Here are 4 reasons:
- Asthma is not thought of as a complex, heterogeneous disease or syndrome that consists of different phenotypes and endotypes.
- Asthma is variable, particularly in its severity, and is influenced by known, unknown, avoidable, and unavoidable environmental factors.
- Treatment usually requires complex inhalational devices that are difficult to understand and use, and with which adherence is suboptimal.
- Assessment of asthma is primarily based on symptoms, and, at times, all symptoms are due to asthma, but many times some or all symptoms are due to unrecognized and untreated comorbid or coexisting conditions.
Allergists/immunologists are well suited to provide the type of comprehensive care required to optimize asthma outcomes.
Source: Lockey RF. Asthma phenotypes: an approach to the diagnosis and treatment of asthma. JACI: In Practice 2014; 2(6): 682-685. (doi:http://dx.doi.org/10.1016/j.jaip.2014.09.008)
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Image Source: Flow Chart; Open Clipart, open access; free to use
Elderly patients with asthma have greater involvement of small and large airways than nonelderly patients
This study from Japan aimed to clarify the pathophysiologic characteristics among 45 elderly patients with asthma (older than 65 years).
Elderly patients with asthma had lower values for FEV1, mid-forced expiratory flow (percentage predicted), and ratio of FEV1 to FVC than nonelderly patients with asthma. In CT chest measurements, elderly patients with asthma had greater airway wall thickening and air trapping.
Impulse oscillation measurements indicated that elderly patients with asthma showed greater resistance at 5 Hz (used as an index of total airway resistance), greater decrease in resistance from 5 to 20 Hz, a higher ratio of decrease in resistance from 5 to 20 Hz to resistance at 5 Hz, higher integrated area between 5 Hz and frequency of resonance, greater frequency of resonance, and lower reactance at a frequency of 5 Hz (potential markers of small airway disease).
Total serum IgE levels and positive rates of specific IgE antibodies against several allergens were significantly lower.
Based on spirometric, CT, and impulse oscillation analyses, elderly patients with asthma have greater involvement of small and large airways than nonelderly patients with asthma.
Source: Inoue H, Niimi A, Takeda T, Matsumoto H, Ito I et al. Pathophysiological characteristics of asthma in the elderly: a comprehensive study. Annals of Allergy, Asthma & Immunology 2014; 13(5): 527-533. (doi:http://dx.doi.org/10.1016/j.anai.2014.08.002)
Lung Sound Analysis Predicts Airway Inflammation in Patients with Asymptomatic Asthma
The expiratory-inspiratory ratios of sound power in the low-frequency range (E-I LF) from 36 patients with asymptomatic asthma were compared with those of 14 healthy controls.
The mean E-I LF was higher in the patients with asthma and with increased sputum eosinophils than in those patients without increased sputum eosinophils (0.45 vs 0.20) or in the healthy controls (0.25). Sputum eosinophil ratio and exhaled nitric oxide were independently correlated with E-I LF.
For the prediction of increased sputum eosinophils and increased fractional exhaled nitric oxide levels, the E-I LF thresholds of 0.29 and 0.30 showed sensitivities of 0.80 and 0.74 and specificities of 0.83 and 0.77, respectively.
Lung sound analysis (LSA) could predict airway inflammation of patients with asymptomatic asthma.
Source: Shimoda T, Nagasaka Y, Obase Y, Kishikawa R, and Iwanaga T. Prediction of airway inflammation in patients with asymptomatic asthma by using lung sound analysis. JACI: In Practice 2014; published online ahead of print, 4 October.