Asma

ASMA
Description
Chronic, reversible inflammatory airway disease:
* Exacerbations characterized by reversible bronchoconstriction, airway hyper-responsiveness, and airway edema.
* Four major classifications of asthma severity used primarily to initiate therapy (1,2):
* Intermittent (symptoms < = 2 d/wk, night-time awakenings < = 2 ×/mo, short-acting β-agonist use < = 2d/wk, no interference with normal activity, and normal FEV1 between exacerbations with FEV1 (predicted) >80% and FEV1/FVC >85%)
* Mild persistent (symptoms >2 d/wk but not daily, night-time awakenings 1–4 ×/mo, short-acting β-agonist use >2 d/wk but not daily, minor limitations in normal activity, and FEV1 (predicted) >80% and FEV1/FVC >80%)
* Moderate persistent(daily symptoms, night-time awakenings 3-4 ×/mo or >= 1 ×/wk but not nightly, depending on age, daily use of short-acting β-agonist, some limitation in normal activity, and FEV1 [predicted] 60–80% and FEV1/FVC 75–80%)
* Severe persistent (symptoms throughout the day, night-time awakenings > 1 ×/wk, short-acting β-agonist use several times a day, extremely limited normal activity, andFEV1 [predicted] <60% and FEV1/FVC < 75%)
Epidemiology
Prevalence
* Children more commonly than adults
* One of the most common chronic diseases of childhood, affecting 6 million children
* In children, more common in boys than girls; in adults, more common in women than men
* Prevalencia en México 10%
Pregnancy Considerations
* In the US, 3.7–8.4% of pregnant women areaffected. Asthma is potentially the most common serious medical problem to complicate pregnancy.
* Prevalence of asthma in seniors (>65) is 5.3%
Risk Factors
* Host factors: Genetic predisposition, gender, race, body mass index (BMI) (obesity has been associated with higher asthma rates)
* Environmental exposures: Viral infections, airborne allergens, tobacco smoke, etc.
*Patients with food allergies and asthma are at increased risk for fatal anaphylaxis from those foods.
Genetics
* Inheritable component with complex genetics
* Active area of research: Treatments may be directed to specific genotypes.
General Prevention
* Eliminate or modify exposure to asthma triggers.
* Consider allergen immunotherapy when indicated
* Treat comorbidities such asallergic rhinitis.
* Annual influenza vaccine (inactivated influenza vaccine) is recommended for all patients over age 6 months (4).
* Patients at risk for anaphylaxis should carry an EpiPen.
Pathophysiology
* Inflammatory cell infiltration, sub-basement fibrosis, mucus hypersecretion, epithelial injury, smooth muscle hypertrophy, angiogenesis
* Remodeling of airways may occur(1).
Etiology
Host and environmental factors
Commonly Associated Conditions
* Atopy: Eczema, allergic conjunctivitis, allergic rhinitis
* Obesity
* Sinusitis
* Gastroesophageal reflux disease (GERD)
* Obstructive sleep apnea (OSA)
* Allergic bronchopulmonary aspergillosis (rare)
* Stress/depression
Diagnosis
It is important to classify asthma severity.
History
*Symptoms of recurrent episodes of airway obstruction or airway hyper-responsiveness may include:
* Cough (particularly if worse at night)
* Wheeze
* Chest tightness
* Difficulty breathing
* Symptoms are typically precipitated or worsened by exercise, viral infections, irritants such as allergens, changes in weather, stress or strong emotions, and/or menstrualcycles.
* Airflow obstruction is at least partially reversible.
* Alternative diagnoses are excluded.
* No es raro que la única manifestación sea la tos escasamente productiva.
* Síndrome de Samter triada característica: hipersensibilidad a la aspirina, rinosinusitis polipoidea crónica y asma bronquial.
Physical Exam
* May be normal
* Focus on:
* General appearance:...