Senin, 20 Februari 2012

All About Asthma - Introduction and Info on Asthma

Introduction

Asthma affects more than 5 million people in the United Kingdom and for the majority it is a disease that can be well managed with readily available current therapies. Sadly, in the region of 1,500 patients continue to die from their asthma every year. As well as those patients that suffer a fatal asthma attack (FA), there is a cohort of patients that have suffered from a near fatal asthma attack and are subsequently at higher risk of morbidity and mortality. near fatal asthma attack is defined by the British Thoracic Society (BTS) as an asthma attack associated with a raised PaCO2 and/or requiring mechanical ventilation with raised inflation pressures.Patients with fatal asthma have been hypothesised as representing two distinct subgroups according to the onset of symptoms prior to death. One of the scientist examined the autopsy findings of 37 subjects aged 2 to 34 years dying from asthma and classified them as slow onset (Type 1) (n=21) or rapid onset (Type 2) (n=16). Subjects did not differ by age, race, sex, obesity or use of corticosteroids. Type 1 mortalities were hospitalised more and made more emergency room visits in the year prior to death than type 2 mortalities. Slow onset patients had a predominance of eosinophils and basement membrane thickening along with higher health care utilisation.

Incidence and prevalence of fatal and near fatal asthma

Specific data on FA and near fatal asthma attack in the UK are hampered by the lack of a fatal asthma registry. Two studies have attempted to circumvent this problem in different fashions. Harrison et attempted to analyse all asthma deaths in the Eastern region between 2001 and 2003 by means of a confidential enquiry and compared it with previous Norwich and East Anglian data. Between 1998 and 2003 there was a downward trend in the asthma mortality rate. Misclassification on the death certificate was common. Only 57 of 95 notified deaths (60%) were confirmed as asthma deaths. 311 asthma deaths were studied between 1998 and 2003. In 2001-3 the male: female ratio was 3:2. 53% of patients had severe asthma and 21% moderately severe disease. In 19 cases (33%) at least one significant co-morbid disease was present. Monthly death rates peaked in August, with a smaller peak in April, suggesting a seasonal allergic cause. In 11 cases (20%), mostly males aged under 20, the final attack was sudden and 10/11 occurred between April and August. Therefore in 80% of deaths the final attack was not sudden, and may have been preventable. In 81% of cases there was significant behavioural and/or psychosocial factors such as poor compliance (61%), smoking (46%), denial (37%), depression (20%) and alcohol abuse (20%). The overall medical care was appropriate in only 33% of cases, leading the authors to conclude that 'at-risk' registers in primary care may improve recognition and management of 'at-risk' patients. Watson et analysed data from the CHKS database, which provides data on 70% of inpatient coverage in the UK. Between 2000-2005 the mortality rate was 1063 patients from 250,043 asthma admissions. December and January had the peak number of deaths post asthma admission, which were nearly all in adults. Women and those over 45 years had the highest rate of death. These 2 studies demonstrate that in the UK there is a peak in asthma deaths in young people (aged up to 44 years) in July and August and in December and January in older people.

Risk factors associated with fatal and near fatal asthma

A systematic review of the risk factors associated with near fatal asthma attack and FA has been performed by Alvarez et. Increased use of beta-agonists, oral steroids, theophylline and a history of hospital and/or ICU admissions and mechanical ventilation due to asthma were predictors of near fatal asthma attack and FA. The use of inhaled corticosteroids (ICS) demonstrated a trend toward a protective effect against FA. Poor compliance with prescribed medication is a key issue; approximately 60% of patients that die from asthma demonstrate evidence of poor compliance to medication, in particular to ICS. Severe asthma and FA may also be associated with fungal sensitization. Many airborne fungi are involved including species of Alternaria, Aspergillus, Cladosporium and Penicillium, and exposure may be indoors, outdoors or both. Prevention of fatal and near fatal asthma What can be done to prevent FA and near fatal asthma attack attacks? The majority of severe asthma attacks develop relatively slowly with more than 80% developing over greater than 48 hours. There are many similarities between patients with FA, near fatal asthma attack and control patients with asthma that are admitted to hospital, indicating that better management of high risk patients including early intervention has the capacity to prevent asthma deaths. Improving patient compliance is of key importance in preventing FA and near fatal asthma attack, but this is never easy in clinical practice. Effective measures to improve compliance include patient-directed consultations and addressing patients' fears of ICS side effects. It is critical that patients do not use long acting bronchodilators (LABA) in the absence of ICS; pragmatically this is best achieved, in those patients who need both drugs, by prescribing combination ICS/LABA inhalers, thus guaranteeing ICS delivery to the patient.

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