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What is the asthma popluation?
- 300 million worldwide
- 22 million Americans
- (6 million children)
- (1.8 million ER visits)
- 30.5 million prescriptions/5.9 billion cost
- 5000 deaths / year
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How far above the clavicles do the lungs extend?
1-2 cm
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What enters the lungs at the hilum?
- Mainstem bronchi
- Blood vessels
- Lymphatic vessels
- Nerves
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What is the size of the average trachea?
- 2.0 - 2.5 cm in diameter
- 10 - 12 cm long
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Describe the movement action of bronchi during the respiratory cycle.
- Relax during inspiration (bronchodilation)
- Tighten during expiration (bronchoconstriction)
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Describe the Gas Conduction Path
- Trachea
- Mainstem bronchi
- Subsegment bronchi
- Bronchioles (no cartilage)
- Terminal bronchiole
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Describe the Gas Exchange Path
- Respiratory bronchioles
- Alveolar ducts
- Alveolar sacs
- Alveoli (majority of gas exhange)
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What are the 3 tissue layers of the airways?
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Desribe the mucosa
- Epithelial lining
- Main cells: pseudostrtified ciliated columnar epithelium
- Beneath epithelium, Basal cells (cilia and goblet)
- Goblet cells - secrete mucous
- Cilia cells - clear and defend airways
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Describe the submucosa
- Contains:
- Bronchial glands (major source of tract secretions)
- more glands = more secretion production
Mast cells (secrete mediators: histamine & leukotrienes)
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How do histamines work?
- Constricts smooth muscles (bronchospams, dyspnea)
- Inflames airways (inc blood vessel permeability)
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How do Leukotrienes work?
- Bronchoconstrictor
- Cause inflammation by attracting / activating eosinophils
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Describe the adventitia
- Connective tissue that surrounds the airways
- Contains blood vessels, nerves, lymph vessels and adipose tissue
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What are the 3 changes during an asthma attack?
- Bronchial smooth muscle constriction
- Mucosal inflammation
- Hypersecretion of mucous
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Describe the physiology of an asthma attack.
- 1. Smooth muscles hypertrophy (up to 3 times)
- 2. Goblet cells increase (more mucous)
- 3. Bronchial glands enlarge (excessive mucous)
- 4. Mucosa infiltrated with eosinophils, lmphocytes and mast cells (becomes inflamed)
- 5. Cilia damaged
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Describe Airway Thickening or Airway Remodeling
Permanent scar tissue due to poorly managed, recurrent asthmatic episodes. This tissue replaces normal airway tissue and may not respond to treament, and leads to loss of lung function.
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Acute vs Chronic Asthma
days and weeks vs. years
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Define Status Asthmaticus
A severe asthma attack that does not respond to conventional therapy.
Severe hypoxemia requiring hospitialization.
Inc risk for poorly treated asthma or previous experience of status astmaticus.
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S/S of Status Asthmaticus
- 1. Extreme dyspnea
- 2. Little to no breath sounds
- 3. Lactic acidosis
- 4. Restlessness, anxiety
- 5. No cough or wheeze
- 6. Inability to speak
- 7. Cyanosis
- 8. Sweating
- 9. Accessory muscles use
- 10. Pulsus paradoxus ( Change in HR/BP during RR)
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EIA: suspicions, methods, diagnosis and tx
- 1. In all patients with asthma
- 2. Mouth breathing, unfiltered particles
- 3. Inc HR>80% Max, look for 15% drop in FEV1
- 4. SABA 15-20 minutes before exercise
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Nocturnal Asthma
- MOST DEATHS
- Makes more difficult to control daytime asthma
- Unknown reasons why worse at night
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Contributing factors to nocturnal asthma
- 1. Increase mucus or sinusitius
- 2. Increased exposure to allergens
- 3. Cooling of airway
- 4. Lying in a reclined position
- 5. Reflux
- 6. Late phase allergen response
- 7. Circadian rhythm of hormone secretion (epinephrine, cortisol and melatonin)
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Difficult-to-treat asthma
Does not respond to corticosteroids
- Patient commonalities:
- poor tx compliance
- psychological / psychiatric disorders
- genetics
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Smoking results on asthma
- more difficult to control
- inc exacerbations
- inc hospitalization
- more rapid dec in lung function
- inc risk of death
- dec respond to corticosteroids
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3 types of asthma triggers
- Irritants: perfumes, cleaning products, smoke
- Allergens: dander, mites, pollen, dust
- Physical: viruses, exercise, weather, emotions
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Medical conditions contributing to asthma attacks
- Reflux
- Sinusitis
- Rhinits
- Sensitivity to beta blockers
- Aspirin and other non-steroidal anti-inflammatories
- Sulfite food preservatives
- Stress / depression
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Home triggers
- Smoke
- Dust / dust mites
- Animal dander
- Molds (Altemaria, Cladosporium and Aspergillus)
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Outdoor Allergen Triggers
- Most difficult to avoid
- Trees in Spring (pollens released between 12-6pm)
- Grasses in Summer (pollens released 7:30-eod)
- Weeds in Fall (pollens released sunrise-9am)
- All plants release on warm sunny days, no cool rainy
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Pollen counts
- Rise in the atmosphere as the day warms
- Falls as air cools after sunset
- Most reaches ground between 8-10 pm
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Food allergens most common source (hint: proteins)
- Peanuts
- Fish (fresh and saltwater)
- Shellfish
- Eggs
- Wheat
- Cow's milk
- Tree nuts (walnut, cashew, hazelnut, almonds, Brazil)
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Lesser known food allergens
- Spinach and beets
- Melons (watermelon, honeydew, pumpkin, squash)
- Onions, garlic, asparagus
- Broccoli, cabbage or cauliflower
- Tomatoes, potatoes or bell peppers
- Cherries, peaches or plums
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Food additive triggers
Monosodium glutamate (MSG) - preservative
Tratrazine (yellow dye #5, FD&C yellow, #5) - found in many foods, meds (cold and flu) and vitamines
Sulfites - in processed foods (dried fruit, potatoes), salad bars, shrimp, guacamole, wine, beer. DYSPNEA most common reaction. Life threatening.
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Drug / chemical triggers
- Aspirin and NSAIDS sensitivity (28% adult, 5% kids)
- Non-selective beta-blockers
- Contraceptives
- Omega 3 oils
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Aspirin challenge test
- High risk of fatal consequences
- Be prepared to perform CPR
- Test only when asthma in remission, FEV1>70 or personal best
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Non selective beta blocker drugs
- 1. Propranolol (Inderal)
- 2. Metoprolol (Lopressor)
- 3. Nadolol (Corgard)
- 4. Carvedilol (Coreg)
- 5. Timolol maleate (Timoptic)
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Non selectivce beta blocker drug uses
- 1. Glaucoma
- 2. High BP
- 3. Anxiety
- 4. Angina and heart attacks
- 5. Irregular heart rhythm
- 6. Thyroid problems
- 7. Migraines
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Infection triggers
- Viruses (RSV, Rhonovirus, Influenza)
- Bacteria (Mycoplasma, Chlamydia)
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Occupational asthma triggers
- Over 250 substances
- Gets better after away from work for a few days
- Workplace didn't cause, just makes asthma worse
- Latency period of a few months to years from exposure
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Occupational asthma triggers
- Latex - liquid from rubber tree
- Industrial irritants
- Physical conditions (temp / humidity)
- Formaldehyde and volatile organic compouds
- (new linoleum floor, synthetic carpet, furniture)
- Metals (platinum, chromium, nickel sulfate)
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Co-morbidity Factors
- 1. Rhinitis / sinusitis
- 2. GERD
- 3. Pregnancy
- 4. Obesity
- 5. VCD
- 6. Surgery
- 7. OSA
- 8. Stress
- 9. Depression
- 10. Allergic bronchopulmonary aspergillosis
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TX of rhinitis and sinusitis
Rhinitis: Intranasal corticosteroids, anti-histamines
Sinusitius: antibiotics surgery
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TX of GERD
- 1. No food < 3 hrs before bed
- 2. Small meals
- 3. Avoid fried foods, caffeine, alcohol
- 4. Elevate HOB
- 5. OTC drugs: Zantac, Tagament, Prilosec, Pepcid
- 6. Pres drugs: Nexium, Prevacid
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BMI Index
weight in kg / height in m2
- underweight: <18.5
- normal 18.5 - 24.9
- overweight 25.0 - 29.9
- obesity 30.0 - 39.9
- extreme obesity >40.0
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Surgery considerations
- Anesthesia may depress respiratory function
- Perform PFT before surgery
- Short course of oral corticosteroids prior to surgery
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OSA and asthma
- OSA and asthma, CPAP improves PF
- only asthma, CPAP disrupts sleep
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Allergic Bronchopulmonary Aspergillosis ABPA
Suspects / Symptoms
Suspect in asthma pt with pulmonary infiltrates or are corticosteroid dependant
Doesn't damage lung tissue, grows in mucus causing inflammation
- Sputum w brown plugs
- Mobile pneumonia on xray
- Eosinophils in sputum and blood
- Elevated serum IgE
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ABPA tx
- Oral Prednisone
- Itaconazole (oral antifungal)
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