0071643192.pdf

ASTHMA

Reactive airway disease consists of three classical components: Airway inflam-

mation, bronchial hyperresponsiveness, and reversible airflow obstruction.

Asthma is more prevalent in blacks than whites, and, in childhood, asthma is

more prevalent in boys than girls.

CAUSES

Common triggersinclude respiratory infections, environmental allergens/

irritants, weather changes, and exercise. Rarer causes include aspirin or

NSAID hypersensitivity, β-blocker use, and emotional stressors.

Risk factors for death include:

■ Previous ICU admission/intubation

■ More than two hospitalizations or three ED visits in the past year

■ Use of corticosteroids or >2 canisters of β 2 agonist MDIs per month

■ Difficulty perceiving presence or severity of airflow obstruction

■ Low socioeconomic status

■ Illicit drug use

■ Serious comorbidities

SYMPTOMS/EXAM

■ Dyspnea, wheezing, coughing, chest tightness

■ Fever and purulent sputum usually represent a complicating process such

as pneumonia.

THORACIC AND RESPIRATORY

DISORDERS

TABLE 10.5. Etiologies of Hypercarbia

CAUSE MECHANISM DISEASESTATES

Depressed central ↓Minute ventilation Drug overdose

respiratory drive CNS lesion/infarction

Central sleep apnea

Hypothyroidism

Peripheral nerve Same as above Guillain-Barré syndrome

disorders ALS

Poliomyelitis

West Nile virus

Neuromuscular Same as above Myasthenia gravis, botulism

junction disorders

Muscle disorders Same as above Muscular dystrophy

Glycogen storage disease

Lung disorders ↓Alveolar ventilation due COPD

to obstructive lung disease Asthma

Cystic fibrosis

Chest wall disorders Chest wall mechanics are Kyphoscoliosis

altered, leading to ↓alveolar Massive obesity

ventilation.

Death due to asthma is rising.