Asthma I Intro Flashcards
components of asthma (3)
Asthma is a chronic condition
• It is characterized by paroxysmal (sudden) or recurring respiratory symptoms
• It is associated with chronic inflammation
• It is associated with airway hyperresponsiveness that is normally reversible
asthma
what are the paroxysmal (sudden) or
persistent symptoms? (5)
- Dyspnea (shortness of breath)
- Chest tightness
- Wheezing
- Sputum production
- Cough
asthma
Epidemiology
most children are diagnosed by the age _____
But most have symptoms by the age _____
5
2
This chronic disease persists in 30-40% of cases
• Between 30-70% of patients will markedly improve or be symptom-free by adulthood
• <20% develop severe disease
asthma
Prevalence refers to all individuals affected by a disease at a particular moment in time
girls vs boys
In children <12, incidence greater in boys than girls (2:1)
In adolescence, this reverses (greater among females)
asthma
mortality
which groups have higher rates of death?
what causes death the most?
Rates of death are higher older aged-groups
• E.g. higher rate of death in women >65
• But…this may be over-reported, as many patients may have co- morbid COPD or heart failure
It is estimated that ~80% of asthma-related deaths could be prevented with proper asthma education
• Most asthma-related deaths occur outside the hospital setting
• Few have asthma action plans
• Inadequate treatment is a risk factor
asthma
Morbidity refers to the rates of disease in a population or the condition of suffering from a disease or medical condition
Poor asthma control may lead to? (5)
which group has higher hospitalization rates
Poor asthma control may lead to the following: • Unscheduled physician visits • Hospitalizations • Missed days from work or school • Limitation of daily activities • Psychological impact
- Children with asthma are more likely to exhibit anxious and
depressive symptoms - Stigma with use of medications
Children from low socioeconomic groups had 56% higher hospitalization rates than those from high SES groups
asthma
morbidity - impaired quality of life
what is the measure of the global of
overall assessment of an individual’s well-being?
what 3 domains are affected with uncontrolled asthma?
Health-related quality of life (HRQOL)
The three core HRQOL domains normally assessed are the patient’s physical,
psychological, and social domains (many QOL tools available)
Physical: Restriction in walking upstairs, playing sports & exercise
Psychological: Fear of lack of control and anxiety about an asthma attack. Caregivers of children with asthma have higher rates of emotional stress, etc.
Social: Family life disrupted (e.g., night disturbances, visits to health services)
asthma
economic costs
what are direct costs vs indirect costs?
Direct costs are associated with treatment, care, and rehab, including:
• Medications, physician visits, hospital care, research
Indirect costs are associated with lost economic output (productivity costs), injury-related disability, and death, including:
• Sick time, inability to perform housekeeping, time spent travelling and waiting for medical care
Natural History of Asthma: describes the course of asthma in a particular individual
what 3 things interact?
- varies substantially among individuals, unpredictable
- persistent asthma results from a complex interaction
between the immune system of a genetically predisposed individual and the environment
Natural History of Asthma
3 steps
- • Genetic disposition
• Environmental exposure - • TH2 cell response
3.• Chronic inflammation
• Airway remodeling
• Airway hyperresponsiveness
Natural History of Asthma
Infants
• Chronic Persistent Asthma presents
during the first five years
• Most infants with episodes of wheezing with URT infection do not develop asthma, RSV infection the lower respiratory tract is associated with a three to four times greater risk of wheezing in school age children.
• Environmental allergen exposure - not exposing to env and hygiene issues
Natural History of Asthma
Children & Adolescence
Children with episodic asthma generally
have excellent outcomes in adult life (resolution or intermittent)
- spectrum of wheezing severity in childhood tends to remain constant into adulthood
- most children with only infrequent wheezing during childhood had remission of wheezing after puberty
- Presence of allergy, identified by sensitization and high levels of IgE, is also associated with persistent asthma in adolescence and into adulthood
Respiratory Syncytial Virus Infection (RSV)
what are symptoms?
which group gets it most?
• It is the most common cause of bronchiolitis and pneumonia in children < than 1 year of age
Symptoms of RSV infection usually include
• Runny nose
• Decrease in appetite
• Coughing
• Sneezing
• Fever
• Wheezing
• Most RSV infections go away on their own in a week or two.
• There is no specific treatment for RSV infection
Hygiene Hypothesis
- immune system of a newborn is skewed toward T-Helper 2 cytokine generation
- Following birth, environmental stimuli such as infections will activate T-Helper 1 responses and bring the relationship between these T-Helper cells back to balance
- Not exposing the child to the hygiene and environmental issues is thought to set the stage for the promotion of IgE antibodies to key environmental
allergens and thus increase the risk of asthma
factors favoring TH1 phenotype leading to protective immunity
- rural env
- TB, measles, hep A infection
- older siblings
- early exposure to daycare
factors favoring TH2 phenotype leading to allergic diseases including asthma
- widespread use of antibiotics
- western lifestyle and diet
- sensitization to house dust mites, cockroaches
- urban env
Asthma in adulthood
May persist from childhood
• May relapse from childhood
• May develop as true adult-onset asthma from:
Medications like beta-blockers
Smoking various substances
Hormone Replacement Therapy / sex influence
Occupational exposures
10-15% of adult-onset asthma is due to this , or existing asthma
may be exacerbated by work-related exposures
• Will be discussed in later lectures
ashtma pathophys
Airway inflammation and changes in airway structure
inheritable component, but it is not simple
• Multiple genes may be involved in the pathogenesis of asthma, and these genes may vary based on the patient’s ethnic group
FYI
Focus of research as been:
• Production of allergen-specific IgE antibodies (atopy)
• expression of airway hyperresponsiveness
• generation of inflammatory mediators (e.g., cytokines, chemokines, and growth factors)
• Genetic profiles may help to determine a patient who will respond to a specific treatment
ashtma pathophys
- chronic inflamm
- Affects the entire airway
- Is persistent (background) even though symptoms may be episodic
- immune cells including: mast cells, eosinophils, and T-helper 1, 2-type T cells.
- Abnormal responses to inhaled agents, specifically increased signaling between the airway epithelium and immune cells
- This increased signaling facilitates allergic sensitization and predisposes exacerbations and persistent asthma (resulting in airway remodeling)
- Thickening of the airway wall, excessive mucus production, edema due to microvascular leakage. All of which result in a reduction in airway size.
- Breakdown of airway epithelium. Which results in exposure of nerve endings making airways more sensitive / reactive
ashtma pathophys
- Airway Remodeling
see table for more
• structural changes in response to inflammation that are often irreversible
• Increased airway smooth muscle
Results from hypertrophy (increased cell size) and hyperplasia (increased number of cells)
• Subepithelial fibrosis
Results from accumulation of collagen (from fibroblasts) and proteoglycans (from myofibroblasts)
• Mucus hypersecretion
Results from an increased number of goblet cells and mucus glands
ashtma pathophys
- Airway Hyperresponsiveness
• Associated with inflammation and narrowing of airways
• When exposed to stimuli, airways
become irritable or “twitchy,” which leads to constriction
Clinical Presentation – Signs of airflow obstruction
signs are observed by others
▫ Wheezing Inspiratory and expiratory ▫ Tachypnea Increased respiration rate ▫ Decreased breath sounds ▫ Accessory muscle use Muscles of the head and neck ▫ Intercostal retractions ▫ Nasal flaring
most has no observable signs
Clinical Presentation – Sympytoms
experienced by pt
• Cough
This may be the only symptom of asthma and is caused by stimulation of nerves in the airway
• Wheeze
Whistling sounds that occur due to airway narrowing, usually heard on expiration
This occurs when airways are narrowed by ~30%
Just because there is no wheeze does not mean airways arenot narrowed
• Chest tightness
A feeling of pressure
• Dyspnea
Shortness of breath