Brittle asthma

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Brittle asthma
Asthma (lungs)
PreventionAllergen avoidance and self-management approach

Brittle asthma is a type of asthma distinguishable from other forms by recurrent, severe attacks.[1][2][3] There are two subtypes divided by symptoms: Type 1 and Type 2,[4] depending on the stability of the patient's maximum speed of expiration, or peak expiratory flow rate (PEFR). Type 1 is characterized by a maintained wide PEF variability despite considerable medical therapy including a dose of inhaled steroids, and Type 2 is characterized by sudden acute attacks occurring in less than three hours without an obvious trigger on a background of well controlled asthma.[5]

Brittle asthma is one of the "unstable" subtypes of "difficult asthma", a term used to characterize the less than 5% of asthma cases that do not respond to maximal inhaled treatment, including high doses of corticosteroids combined with additional therapies such as long-acting beta-2 agonists.[6][7]

Diagnosis

Types

The 2005

dyspnea), wheezing, and chest tightness.[9] Individuals with type 1 suffer chronic attacks in spite of ongoing medical therapy, while those with type 2 experience sudden, acute and even potentially life-threatening attacks even though otherwise their asthma seems well managed.[10]

When first defined by Margaret Turner-Warwick in 1977, the term brittle asthma was used specifically to describe type 1, but as studies into the phenotype were conducted the second type was also distinguished.[11]

Treatment

In addition to any issues of

long acting beta-adrenoceptor agonist,[12] whilst type 2 needs allergen avoidance and self-management approaches.[13] Since catastrophic attacks are unpredictable in type 2, patients may display identification of the issue, such as a MedicAlert bracelet, and carry an epinephrine autoinjector.[8]

Epidemiology

The condition is rare. 1999's Difficult Asthma estimates a prevalence of approximately 0.05% brittle asthma sufferers among the asthmatic population.[14] Though found in all ages, it is most commonly found in individuals between the ages of 18 and 55; it is present in both sexes, though type 1 has been diagnosed in three times as many women as men.[14] Hospitalization is more frequent for type 1 than type 2.[14]

References

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  8. ^ a b Warrell, 1347.
  9. ^ Saunders (2005). "Asthma". In Homer A. Boushey Jr., M.D.; David B. Corry, M.D.; John V. Fahy, M.D.; Esteban G. Burchard, M.D.; Prescott G. Woodruff, M.D.; et al. (eds.). Mason: Murray & Nadel's Textbook of Respiratory Medicine (4th ed.). Elsevier.
  10. ^ Holgate et al., 292.
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  14. ^ a b c Holgate et al., 293.