Asthma

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Contents

Introduction

Bronchial asthma is episodic reversible airways obstruction. Still an important cause of death in the UK, commonly in a fashion which later analysis indicates could theoretically have been interrupted. Please see cardiac asthma if referring to similar symptoms owing to left ventricular failure.

Aetiology

Asthma involves inflammation in the small airways. Failures in the regulation of the innate and adaptive immune response is believed to be central. There are several subtypes but allergic asthma which explains 50% of presentations is driven by the type 2 helper T cell (Th2). Activation of Th2 produces cytokines such as interleukin-4, interleukin-5 and interleukin-13 controlled by trans-acting T-cell-specific transcription factor GATA-3.

Precipitants

  • Pollen
  • Animal dander
  • Many other allergens
  • Irritant gases/toxins
  • Histamine release by any means
  • Drugs

Associations


Clinical features

Signs

  • Wheezing
  • Cough
  • Dysponea

Investigation

  • Peak Expiratory Flow Rate (PEFR)
  • Reversibility testing
Info bulb.pngReversibility testing in Asthma conflates two elements, and thus using the term without qualification tends to confuse either speaker or listener. Airway obstruction may be reversible acutely by beta-agonist inhalation, and asthma is reversible by oral steroid administration (Prednisolone 30-40mg/day)over a period of several days.

Management

See British Thoracic Society guidelines

Drug therapy

The various inhaled therapies are available in assorted combination inhalers, and in far too many incompatible devices.

Non-drug therapy

External Links