Pulmonary pathology Flashcards
What are some diseases of infancy and childhood?
Hyaline membrane disease
Bronchopulmonary dysplasia
What is hyaline membrane disease?
Due to deficiency of pulmonary surfactant.
Clinically symptoms of tachypnoea & dyspnoea develops within hours after birth followed by cyanosis.
Histologically there is diffuse alveolar damage with formation of hyaline membrane.
Treatment is with oxygen, surfactant and artificial ventilation.
If infant survives resolution follows within next few days.
What is chronic bronchitis?
A clinical term defined as cough and sputum for 3 months in 2 consecutive years. Caused by:
–chronic irritation by inhaled substances: cigarette smoking
–Microbiologic infection: H. influenza and strept. Pneumonia
What is pneumonia?
This is usually due to infection affecting lower air ways, and can be classified according to various criteria:
Clinical circumstances: Primary or Secondary
Aetiological Agent: Bacterial, Viral, Fungal, Others
Anatomical pattern: Lobar pneumonia or Bronchopneumonia
What is tidal volume?
Amount of air inhaled/exhaled during each normal/quiet respiration.
What is vital capacity?
Amount of air exhaled after maximum inspiration.
What is total lung capacity?
Vital capacity plus residual volume.
What is Forced expiratory volume in 1 Second (FEV1)?
The maximum volume of air exhaled from the lungs within the 1st second after a previous maximum inspiration. Reduced with obstructed airways, pulmonary fibrosis or oedema, or muscle weakness.
What is the Forced Expiratory Ratio (FEV1 / VC)?
Low in obstructive defects. Normal or high in restrictive defects.
What is the Transfer Factor for Carbon Monoxide (TCO)?
Air containing a known concentration
of carbon monoxide is inhaled; the breath is held for15 seconds and then exhaled. The amount of CO absorbed is a measure of pulmonary gas exchange. TCO is reduced in pulmonary fibrosis, oedema, embolism and anaemia.
What are examples of obstructive (increase in resistance to airflow) airway diseases? and restrictive diseases? (reduced lung capacity)
Obstructive: – Emphysema
– Chronic bronchitis
– Bronchiectasis
– Asthma
Restrictive: a) Acute or chronic interstitial or infiltrative lung diseases e.g. ARDS, Pneumoconiosis
b) Chest wall disorders e.g. poliomyelitis, kyphoscoliosis, severe obesity and pleural diseases.
What is emphysema?
An obstructive airway disorder. This is an anatomical term defined as permanent enlargement of airspaces distal to the terminal bronchioles together with destruction of their walls (hyperinflation if no destruction). There are at least 6 different types of emphysema.
What is bronchiectasis?
This is a chronic necrotizing infection of the bronchi and bronchioles leading to, or associated with, abnormal and permanent dilation of these airways, particularly in lower lobes.
Clinically this is manifested by cough, fever and the expectoration of copious amounts of foul-smelling purulent sputum.
What is bronchial asthma?
Is a disease characterised by hyperactive airways leading to episodic, reversible bronchoconstriction, owing to increased responsiveness of the tracheo-bronchial tree to various stimuli.
There are five major clinical categories of asthma:
1. Atopic 2. Non-atopic 3. Aspirin induced 4. Occupational 5. Allergic bronchopulmonary aspergillosis.
What is atopic asthma?
Most common type, begins in childhood.
Triggered by a variety of environmental agents including dust, pollens, food and animal dander.
Often a family history of atopy.
Mediated by type 1 hypersensitivity reaction.
Release of histamine and other chemical mediators leads to
– Bronchoconstriction – causing wheezing, tachypnoea and dyspnoea.
– Increased vascular permeability - oedema – mucus hypersecretion
Serum lgE levels are usually raised.
Grossly the lungs are overdistended; bronchi and bronchioles are occluded by mucus plugs.
Skin test with offending antigen results in an immediate wheal and flare reaction.
