Restrictive and Obstructive lung diseases Flashcards
What are the intrinsic restrictive lung diseases?
1. Pneumoconiosis A. Asbestosis 2. Radiation Fibrosis 3. RA 4. ARDS/IRDS 5. Hypersensitivity Pneumonitis 6. Pulmonary Fibrosis A. Sarcoidosis B. Idiopathic C. Eosinophilic Pneumonia 7. Drugs A. Methotrexate B. Amiodarone C. Bleomycin
What are the extrinsic restrictive lung diseases?
- Asthma
- Dz restricting lower thorax/abd volume
A. Obesity
B. Diaphragmatic hernia
C. Ascites - Chest wall deformities
A. Pectus Excavatum
B. Kyphosis
What are examples of obstructive lung diseases?
Asthma Bronchiectasis Bronchitis Chronic obstructive pulmonary disease (COPD) Cystic Fibrosis Bronchiolitis
What is the FEV1/FVC ratio in obstructive lung diseases?
FEV1/FVC ratio < 0.7
Inability to exhale 70% of their breath within one second
Define asthma
Chronic inflammatory disorder of the airways
What are the characteristics of asthma?
Variable and recurring sx’s
Airflow obstruction
Hyperactive (hyper-responsive) airways
What is the epidemiology of asthma?
- Diagnosed by age 7 in 75% of cases
- Childhood asthma: males > females
- By age 40: female adults > male adults
- Blacks > whites
- Death rates highest among black males ages 15-24 yr
What is the pathophys of asthma?
Inflammatory cell infiltration with eosinophils, neutrophils, and T lymphocytes
Plugging of small airways with thick mucus
Collagen deposits beneath basement membrane
Hypertrophy of bronchial smooth muscle
Airway edema
Mast cell activation
What happens to the sensitivity/reactivity in asthma?
Leads to airway hyper-responsiveness (hyperactivity) and ↓ airflow
What are the exacerbating factors for asthma?
- Atopy: atopic dermatitis, excema
- Obesity
- Exercise
- URI
- Gastroesophageal reflux disease (GERD): may have silent reflux, not responding to asthma tx, may respond to proton pump inhibitor and asthma meds
- Changes in weather
- Stress
What common allergens are asst. with asthma?
- Environmental causes
A. Dust mites
B. Animal dander
C. Pollen
What are the sxs of asthma?
- Episodic dyspnea
- Chest tightness
- Persistent cough (↑ am & hs)
- Wheezing
- Increased nasal secretions
- Nasal polyps
- Eczema
What dx studies are used to diagnose asthma?
- Symptomatic adults and children > 5yo
A. Spirometry- useful to distinguish asthma from COPD
-Measurement of FEV in one sec (FEV1) and FVC
B. PFT’s
-↓ FEV1, normal FVC, decreased FEV1/FVC ratio
C. Peak Expiratory Flow Meter (PEF)
When do PFTs improve in asthma pts?
- after trial of bronchodilator
A. Significant reversibility
≥ 12% and 200 ml in FEV1 OR
≥ 15% and 200 ml in FVC after inhaling short acting bronchodilator
What Peak expiratory flow results indicate poorly controlled asthma?
- Comparison with one’s own baseline is most effective at predicting exacerbations
A. 20% change in PEF values from morning to afternoon or from day to day indicates poorly controlled asthma
What are the risk factors for asthma?
- Personal Hx of atopic diseases
- FH of atopy and/or asthma
- Smoking
A. Active or 2nd-hand smoke - Occupational exposure
- Home heating system
What is a positive methacholine challenge (bronchoprovocation testing) test? When is it indicated?
- Useful when asthma is suspected but PFT’s are non-diagnostic
- Positive test
≥ 20% fall in FEV1 at exposure to concentration of 8 mg/ml or less
What are the steps in methacholine challenge test
1.) Perform PFT
2.) Inhale nebulized methacholine
3.) Repeat PFT
4.) Repeat using increasing doses until reaction
20% decrease in FEV1= bronchospasm
5.) Inhale nebulized albuterol to reverse effect
When is methacholine challenge contraindicated?
- FEV1 < 65% of predicted
- MI or CVA w/in last 3 mos.
- Known aortic or cerebral aneurysm
- Uncontrolled HTN SBP>200 or DBP>100
- Pregnancy/nursing mothers
When are ABGs indicated in asthma?
- Typically done if patient in distress
- Normal early in asthma exacerbation
- During severe exacerbations, patients may retain CO2 Respiratory Acidosis
What are the signs of impending respiratory failure?
- Change in level of consciousness
- Cyanosis
- Pulsus paradoxus > 10 mm Hg
A. Abnormally large decrease in systolic BP and pulse wave amplitude during inspiration
B. Normal fall in pressure is less than 10 mmHg - O2 saturation < 90%
- pCO2 > 45 mmHg
What factors impact the decision to hospitalize an asthma pt?
- Duration & severity of sx’s
- Severity of airway obstruction
- Course & severity of prior exacerbations
- Medication use at time of exacerbation
- Access to medical care
- Adequacy of social support
When is a cxr indicated for asthma?
Indicated when ruling out pneumonia or pneumothorax
When is skin testing indicated in asthma pts?
Identifies allergens that may be triggers for asthma