What is Asthma?

Study Notes

Asthma is a chronic inflammatory disease of the airways characterized by hyperresponsiveness, mucosal edema, and mucus production.
Approximately 26 million people in the United States have asthma.
In Egypt, the incidence rate of asthma is approximately 6.7% among the general population.
Asthma impacts both men and women, with a higher prevalence observed in females.
The risk of asthma tends to increase with age.
Asthma is the most common chronic disease in childhood.

Asthma is a chronic inflammatory disorder of the airways involving many cells and cellular elements, including mast cells, eosinophils, T lymphocytes, macrophages, neutrophils, and epithelial cells.
Inflammation in asthma causes recurrent episodes of wheezing, breathlessness, chest tightness, and coughing.
Airflow obstruction in asthma results from contraction of the airway smooth muscle and swelling of the airway wall due to smooth muscle hypertrophy and hyperplasia, inflammatory cell infiltration and edema, goblet cell and mucous gland hyperplasia with mucous hypersecretion, protein deposition including collagen, epithelial desquamation, and near fatal asthma (NFA).

NFA is described as acute asthma associated with a respiratory arrest or arterial carbon dioxide level greater than 50mmHg, with or without altered conscious state.
Two distinctive phenotypes of NFA have been identified: eosinophilic inflammation associated with gradual deterioration over days-weeks, and neutrophilic inflammation with rapid onset and response to therapy.

End of the bed test: inability to speak in full sentences, use of accessory muscles or tracheal tugging, cyanosis, and sweating.
Clinical signs: pulsus paradoxus (>15mmHg decreased with inspiration), quiet chest on auscultation, confusion or decreased level of consciousness, hypotension or bradycardia.
Objective measurements: FEV1.

A 25-year-old lady, Miss Poor Compliance, is rushed into the Emergency Department with severe asthma, having been given 3x 5mg salbutamol nebs and 0.5mg of adrenaline IM prehospital.
She is sitting forward in the tripod position, using her accessory muscles to breathe, and is tachypneic, agitated, and unable to talk.
Vital signs: pulse 143, BP 138/95, RR 42, Sp02 91% on neb, GCS 14/15.