Obstructive lung disease Flashcards
What is Asthma?
- Chronic inflammation of the airways. • Intermittent airflow obstruction.
- Bronchial Hypersensitivity
Clinical signs and symptoms for asthma and COPD
AIRFLOW OBSTRUCTION • Shortness of breath. (Dyspnea) • Cough • Chest tightness • Wheezing • Tachycardia • Tachypnoea
Prevention is better than cure
- Test to ensure asthma diagnosis
- Full medical history check
- Spirometry (Peak flow)
- Allergy testing
- X-ray to rule out other diseases • Blood tests
- Severity of asthma is variable • Need action plan.
- Avoid triggers if possible.
- Treat attack early.
- Take medication as prescribed.
Acute asthma attack
- Allergens (pollen, dust mites, fur, food)
- Airborne Irritants (smoke, chemicals, pollution) • Medication (aspirin, ibuprofen)
- Emotional triggers (stress, laughing)
- Respiratory infections
- Change in environment (hot/cold, wet/dry)
- Exercise
Medications for asthma
- Two categories of medications to manage asthma
- Preventers - which are usually corticosteroids to reduce airway inflammation
- Relievers – fast acting bronchodilators
- Usually inhaled from a puffer
- Tablets and injections can be used in more severe cases
Imaging for asthma
- Plain Chest X-Ray. (1st modality utilised in most cases)
- CT. Usually Hi-Resolution CT Chest (HRCT) if required.
- NM not utilised clinically. Poor specificity.
- MRI not used due to low hydrogen concentration in lungs. Artefacts created by air-tissue interfaces.
- US not used due reflection of soundwaves from air.
CXR for asthma
• CXR features
– Normal in 3⁄4 of patients
– Pulmonary hyperinflation
– Bronchial wall thickening Pulmonary oedema (acute asthma)
• Complications
– Atelectasis/collapse (mucous plugging)
– Pneumonia
– Eosinophilic lung disease
CT chest basics
- Number 1 imaging modality for many chest pathologies
- Can be performed with or without iodine based IV contrast
- Contrast used for pathologies that have vascular influence
- Non contrast scans used to examine chronic lung pathology
- Images viewed using 2 different window settings
- Mediastinal windows demonstrate heart, blood vessels along with other soft tissue masses
- Lung Windows focus on the Lung tissue only
- Images are often reformatted into different planes
- Computer processes from the one set of data
CT for asthma
- Not commonly required
- Usually performed as HRCT Chest
- Technique can vary
- Contrast not usually needed
- Usually performed in complex cases where more than one disease process may be present
What is COPD?
• COPD – Chronic Obstructive Pulmonary Disease
• COPD can be divided into two clinical phenotypes:
1. Pulmonary emphysema = abnormal, pathological, permanent enlargement of distal (distal to terminal bronchioles) airspaces + wall destruction without fibrosis
2. Chronic bronchitis = defined clinically as a cough productive of sputum occurring on most days in 3 consecutive months over 2 consecutive years with enlargement of mucosal glands & inflammatory infiltration
COPD involves:
Pulmonary emphysema, chronic bronchitis and chronic asthma
COPD clinical diagnosis
Diagnostic criteria (GOLD 2009): • Dyspnea
– Progressive, usually worse with exercise, persistent, described as increased effort to breathe
• Chronic cough
– May be intermittent, may be nonproductive
• Chronic sputum production – Any pattern
• History of exposure to risk factors
– Tobacco smoke, occupational dust, chemicals, fumes or smoke from cooking or heating fuels
Chronic bronchitis (blue bloaters)
- Patients may be obese
- Frequent cough and expectoration due to irritation by mucous
- Dyspnea; use of accessory muscles of respiration common
- Coarse rhonchi and wheezing on auscultation
- Patients may have signs of right heart failure
- Cyanotic (lips & nail bed); mismatched V:Q defect leading to hypoxemia
- Productive cough for 3 months for 2 successive years where other chronic causes have been excluded
- Chronic inflammation of bronchi.
- Bronchial narrowing.
- Increased mucous production.
- Hypertrophy mucous glands.
- Increased number of goblet cells.
- Fibrosis & smooth muscle hypertrophy.
Emphysema (pink puffers)
- Patients may be very thin with a barrel chest
- Loss of skeletal muscle and subcutaneous fat
- Patients typically have little or no cough or expectoration
- Dyspnea; breathing may be assisted by pursed lips and use of accessory respiratory muscles (tripod sitting position)
- The chest may be hyper-resonant, and wheezing may be heard on auscultation
- Non-cyanotic; matched V:Q defect no hypoxemia
- Abnormal enlargement of distal airspaces (distal to terminal bronchioles)
- Wall distention & destruction with minimal or absent fibrosis.
- Loss of alveolar capillaries.
- Loss of elasticity in connective tissue.
- Air becomes trapped in alveoli.
Pulmonary emphysema classifications
- Centrilobular / Centriacinar (smoking / upper zones)
- Panlobular / Panacinar (genetic disorder - alpha-1 antitrypsin deficiency / lower zones)
- Paraseptal / Distalacinar (rarest associated with bullae formation & spontaneous pneumothorax)
Progressive disease
- Decreased size & number of pulmonary vessels & branches
- Distorted vessels (stretched, straightened, curved) with increased branching angles
- Avascular regions
