Asthma (STUDENT)

Asthma Overview

Introduction

  • Updated clinical guidelines for asthma are developed and disseminated regularly by:

    • National Asthma Education and Prevention Program (NAEPP) through the report titled "Expert Panel Report 3, Guidelines for the Diagnosis and Management of Asthma—Full Report."

    • Global Initiative for Asthma (GINA).

National Asthma Education and Prevention Program (NAEPP)

  • The first evidence-based asthma guidelines were published in 1991 by NAEPP, coordinated by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health.

NAEPP Guidelines Structure

  • The NAEPP guidelines focus on four key components:

    • Assessment and monitoring of asthma

    • Patient education

    • Control of factors contributing to asthma severity

    • Pharmacological treatments

Global Initiative for Asthma (GINA)

  • Launched in 1993, GINA collaborates with:

    • National Heart, Lung, and Blood Institute (NHLBI)

    • World Health Organization (WHO)

  • Specific goals of GINA include:

    • Increase awareness of asthma and its public health consequences.

    • Identify the reasons for the rising prevalence of asthma.

    • Promote studies on the association between asthma and the environment.

    • Reduce asthma morbidity and mortality.

    • Improve asthma management and therapy accessibility.

Evidence-Based Management Program

  • GINA uses evidence-based guidelines from NAEPP and resources from global asthma experts, providing a user-friendly program for asthma management.

Anatomic Alterations of the Lungs

  • Asthma results in several anatomic changes in the lungs including:

    • Smooth muscle constriction of bronchial airways (bronchospasm)

    • Excessive production of thick, whitish bronchial secretions

    • Mucous plugging

    • Hyperinflation of alveoli (air trapping)

    • Atelectasis in severe cases caused by mucous plugging

    • Bronchial wall inflammation and potential fibrosis due to remodeling

Histopathological Findings

  • Increased eosinophils and Charcot-Leyden crystals (stained purplish-red) may be observed under high magnification.

Etiology and Epidemiology

  • Prevalence Data (CDC/NCHS):

    • Approximately 20.3 million adults (8.0%) and 4.7 million children (6.5%) have asthma in the United States.

    • Roughly 1 in 10 children and 1 in 12 adults have asthma.

    • Total estimated patients in the US: 24.9 million.

    • Globally, WHO estimates that about 262 million people have asthma.

Risk Factors

Host Factors

  • Factors contributing to asthma:

    • Genetics: Role in the production of IgE antibodies,
      airway hyperresponsiveness, inflammatory mediators, T-helper cells.

    • Obesity: Increased prevalence and difficulty in management among obese patients due to comorbidities and reduced lung function.

    • Sex: Higher prevalence in boys before the age of 14 (peaking around ages 5-7). In adulthood, asthma is more common in females.

Environmental Factors

  • Includes:

    • Allergens

    • Pollutants: Indoor and outdoor

    • Infections

    • Occupational sensitizers

    • Tobacco smoke

    • Diet

Other Risk Factors

  • Additional triggers include:

    • Drugs

    • Food additives and preservatives

    • Exercise-induced bronchoconstriction

    • Gastroesophageal reflux

    • Sleep-related (nocturnal asthma)

    • Emotional stress

    • Perimenstrual asthma (catamenial asthma)

    • Allergic bronchopulmonary aspergillosis

Diagnosis of Asthma

  • The following indicators increase suspicion for asthma:

    • Wheezing, along with:

    • Cough

    • Recurrent wheeze

    • Recurrent difficulty in breathing

    • Recurrent chest tightness