PPT 16: Asthma Flashcards
Exam 3
Airway diameter (resistance) is determined by what 3 things?
- Contraction and relaxation of smooth muscles
- ANS input
- Greatest resistance is in medium bronchi
What is the patho behind asthma?
Airway inflammation Mucosal thickening, plugs
Contraction of airway smooth muscle
What are the suspected reasons behind increased asthma prevalence?
- Infant second-hand smoke
- Worsening air quality
- Hygiene hypothesis
What are the symptoms of asthma?
- Wheezing, breathlessness, chest tightness, coughing
- ↑ at night, early morning
What are the measurements for asthma testing?
FEV1
PEF
What is PEF testing?
- Peak expiratory flow
- Maximum flow of forced expiration
What is FEV1 testing?
- Bronchial hyperreactivity testing
- Fall in forced expiratory volume in 1 second provoked by inhaling increasing concentrations of histamine or methacholine
What are the treatment modalities for asthma?
Contraction of smooth muscle
- Beta adrenergic agonists
Edema and cellular infiltration
- Anti-inflammatory agents
Extrinsic or atopic asthma is also known as _______
Type 1 Hypersensitivity Reactions
What are the mediators responsible for in the early asthma reaction?
- Diffuse throughout airway wall
- Cause muscular contraction and vascular leakage
- Immediate bronchoconstriction
What are the 3 mediators in the early asthma response?
Histamine, PGs, and leukotrienes
What are the mediators responsible for in the late asthma reaction?
Occurs 2-8 hours after immediate effects
- Sustained bronchoconstriction
- Cellular infiltration
- Mucous hypersecretion
The early asthma reaction is mediated by ____ cells, while the late reaction is mediated by ______
early: mast cells
late: WBCs
What kind of cells is mucus produced by?
Produced by goblet and epithelial cells
Mucus is composed of?
- 95% water
- 5% glycoproteins
Mucus is has increased ____ in asthma
viscosity
What is the role of mucus?
Defense against irritants and microorganisms
Describe the type 1 hypersensitivity reaction in detail
1st exposure:
1. dendritic cell on mucosa processes allergen, then turns into an antigen presenting cell → MHCII receptor presented on antigen presenting cell surface to activate immune response → migrates to regional lymph node and presents to T cell
2. T cell releases IL4 → activates B cells → B cells turn into plasma cells (antibody producing factories) and produce IgE or the B cells turn into B memory cells
- Dupixent (monocloncal antibody) - blocks IL4
3. IgE binds to surface of mast cells → sensitization of mast cells and basophils
2nd exposure: allergic reaction
1. Allergen binds to IgE antibodies on mast cells → Degranulation
2. Histamines and leukotrienes are released
3. Allergy symptoms
The difference between a type 1 hypersensitivity reaction in allergies and asthmatics is that asthma has less _______
histamine - more leukotriene and PG
Differentiate between PANS and SANS airway control
PANS - vagus nerve, contracts bronchiolar SM (M3)
SANS - relaxes bronchiolar SM (B2), circulating catecholamines
Asthma attack causes (7)
- Allergens
- Respiratory infections (viral or bacterial)
- Irritants
- Certain medications
- Exercise
- GERD
- Anxiety/Stress
Croup is also known as _____
Acute laryngotracheobronchitis
What is the age range for croup?
6 months to 5 years
What is the main symptom of croup?
Causes seal-like barking cough
In severe cases, croup can be treated with ______
nebulized epinephrine
COPD includes what 2 things?
chronic bronchitis and emphysema
Define chronic bronchitis
- Hypersecretion of mucus and chronic productive cough that lasts for at least 3 months of the year and for at least 2 consecutive years
- Inspired irritants increase mucus production and the size and number of mucous glands
- The mucus is thicker than normal
Define emphysema
- Abnormal permanent enlargement of the gas-exchange airways accompanied by destruction of alveolar walls without obvious fibrosis
- Loss of elastic recoil
What are the two treatment categories for asthma?
- Short-term relievers (bronchodilators)
- Long-term controllers (anti-inflammatory and leukotriene antagonists)
What are the effects of B2 agonists on obstructive airway diseases?
- Relax airway smooth muscle
- Inhibit some of substances from mast cells
- Inhibit microvascular leakage
- Increase mucociliary transport
The toxic effect of sympathomimetics is ______
skeletal muscle tremor
What are the 2 drugs that are non-selective sympathomimetics used to treat asthma? What is an adverse effect?
Epinephrine and isoproterenol - arrythmogenic
What are the 3 B2 selective sympathomimetics used to treat asthma?
Terbutaline, formoterol, salmeterol, albuterol
Only 10-20% of aerosol drugs are delivered to the lungs due to _____
Particle size
Pattern of breathing
Geometry of airways
What are the proposed MOA of methylxanthines on asthma?
- Inhibits phosphodiesterase
- Inhibits adenosine receptors
- Anti-inflammatory action
What are the examples of methylxanthines?
Theophylline and caffeine
Why is theophilline given in tea form?
too strong in pure form - toxic effects (N/V, arrythmias), narrow TI, positive chronotrope and inotrope
How are muscarinic antagonists useful in treating airway obstructive disorders? What are the drugs?
- Effective bronchodilators - Block contraction of airway smooth muscle, mucus secretion
- Parasympathetic blockade
Drugs: - Parenteral atropine
- Inhaled ipratropium bromide, tiotripium (COPD)
What are the positive effects of chronic corticosteroid use?
- Reduce bronchial activity
- Increase airway caliber
- Reduce frequency of asthmatic exacerbations
- Improve quality of life
What are the negative effects of chronic corticosteroid use?
- Increase in osteoporosis
- Slow the rate of growth in children
- Oropharyngeal candidiasis
What are the corticosteroids used as long-term controllers in obstructive airway diseases?
Prednisone, Fluticasone
What is the MOA of Leukotriene Pathway Inhibitors?
- Inhibit 5-lipoxygenase - Zileuton
- Inhibit receptor binding – Montelukast
Leukotriene Pathway Inhibitors improve ______ induced asthma
aspirin
______ is a monoclonal antibody drug that targets ___ on Mast Cells
Omalizumab, IgE
What are the 3 classes of short-term relievers in obstructive airway diseases?
- B2 agonists
- Methylxanthines
- M3 antagonists
What are the 3 classes of long-term relievers in obstructive airway diseases?
- Corticosteroids
- Leukotriene Pathway Inhibitors
- Monoclonal antibodies
What drugs are used for COPD, but not asthma?
SAMA and LAMA - muscarinic antagonists
- atropine, ipratropium bromide, tiotropium (longest acting)
COPD is _____ responsive to corticosteroids than asthma
less
What drugs are used in asthma but not COPD?
- Leukotriene receptor antagonists (Montelukast)
and LOX inhibitor (Zileuton) - Mast cell stabilizer/ monoclonal antibodies (Omalizumab)
What is the treatment standard for COPD?
LABA and LAMA
What are the meds given for asthma progression?
Mild - SABA
Moderate - ICS or LTRA
- ICS for relief
Severe - oral corticosteroids, anti-IgE antibody
