Non-neoplastic lung pathology Flashcards
(37 cards)
Define asthma
Paroxysmal contraction of airways resulting in decreased airflow due to reversible airway obstruction over a period of time.
Extrinsic – Children predominate – Exposure to external agent eg pollen, chemicals (occupational), drugs Aspergillus etc
Intrinsic – Adults predominate – Causes include exercise, infection, stress et
What is the histopathology behind asthma?
- Shedding of bronchial epithelial cells (? due to specific failure of intercellular adhesion mechanisms)
- Thickening of epithelial basement membrane.
- Eosinophils and by products of their degranulation (Charcot-Leyden crystals) - seen in allergic disease and parasitic infections
. •Increased bronchial gland mass with increased mucusCurschmann’s spirals •Increased smooth muscle
•Inflammation of bronchial mucosa: T-lymphocytes, eosinophils, +/- neutrophils.
What cells get involved in causing bronchoconstriction in Asthma?
Th2 cells - recognise IgE and allergen which causes release granule causing histamine and leukotriene release which causes bronchoconstriction
What is status asthmaticus(acute severe asthma )
- asthma attack that doesn’t improve with traditional treatments, such as inhaled bronchodilators
- Hyperinflation (NOT emphysema)
- Petechial haemorrhages
- Mucoid plugging of large and small airways
- Atelectasis (resorption collapse distal to mucoid impaction in segmental bronchi)
COPD consists of chronic bronchitis and emphysema. What is the difference between these?
Chronic Bronchitis:
Essentially a clinical diagnosis - ’A persistent cough with sputum production for at least 3 months over the past 2 consecutive years
• May be prone to recurrent infections • ‘Blue bloater’ • Increased mass of bronchial mucus glands (Reid index >0.4)
Causes: •Tobacco smoking •Atmospheric pollution
Emphysema
Essentially a pathological/morpholo gical diagnosis • Pink Puffer clinically • Loss of alveolar walls and dilatation of air spaces clinically
What is the pathophysiology behind chronic bronchitis
Pathological changes in large airways:
- Increase in submucosal gland mass (Reid index >0.4) - thickness of mucus gland/thickness of bronchus wall
- Increase in numbers of goblet cells
- Increase in smooth muscle
- Chronic inflammatory cell infiltrate of lamina propria
- High secretion of sputum
- Blue bloaters due to obstructed airflow - V/Q mismatch = respiratory acidosis, Type 2 resp failure
What is the pathophysiology behind emphysema
Abnormal permanent enlargement of air spaces distal to the terminal bronchiole, accompanied by destruction of their walls without obvious fibrosis’
- Neutrophil release protease which destroy the wall and macrophage destroy the elastin.
Alveoli do not contract as well to breathe out - air space trapping - harder to breathe out - pink puffers - harder to get air out and they have to use external muscles
What is the most common type of emphysema morphology type?
Which one is associated with alpha 1 antitrypsin deficiency?
Centrilobular- 75% cases caused generally by cigarette smoking
– Panacinar (panlobular) – associated with α 1- antitrypsin deficiency
– Paraseptal (distal acinar)-cause unclear-may be a cause of spontaneous pneumothorax
– Irregular emphysema -associated with scarringclinically not significan
What type of emphysema does this person have?
Centrilobular emphysema - affects proximal central bronchioles
Complications:
- Cor Pulmonale - RHF(right ventricle enlargement)
- Respiratory Failure
- Polycythaemia
- Lung cancer-double the incidence in male bronchitics.
- Pneumothorax- Ruptured bullae can occur if there is coexistent emphysema
Interstitial Pulmonary Fibrosis
‘A condition characterized by progressive interstitial scarring leading to respiratory incapacity, and effacement of the lung architecture, which in extreme case may result in a ‘honeycomb’ pattern’
What is honeycomb lung
Honeycomb Lung
- ‘Cysts’ several mm to >1 cm diameter, in background of dense fibrous scarring • Most prominent in subpleural parenchyma at lung bases
- Represents the end stage of pulmonary fibrosis derived from a number of causes
How is Interstitial Fibrosing Alveolitis subclassified?
Idiopathic (Cryptogenic [CFA])
- Diagnosis by exclusion
- Incidence 3-5/100,000 •
Secondary including
– Connective tissue diseases – Dust and smoke inhalation – Asbestos – EAA, sarcoidosis – Shock lung, radiation – Drugs
Interstitial pulmonary fibrosis Morphological Patterns
What are the different types
NUDA
AIP (Acute interstitial pneumonia) • UIP (Usual interstitial pneumonia) • DIP (Desquamate interstitial pneumonia) • NSIP (Non-specific interstitial pneumonia) • GIP, LIP probably not as important
Why does insterisial fibrosis need to be classified?
Due to prognosis - UIP high mortality and treatment is rubbish
UIP - BAD TO GIVE STEROIDS!
NSIP - improves with steroids
What does this person have?
Acute Interstitial Pneumonia
Very rare but severe
First described by Hamman and Rich • Well individuals • Signs of URTI • Progressive rapid respiratory failure • High mortality
Essentially signs of diffuse alveolar damage • Necrosis of alveolar lining cells with exudate. • Hyaline membranes are frequently seen • Later organisation by fibrosis occurs. • High Mortality
Usual Interstitial Pneumonia
Insidious onset of dyspnoea, in adults 40-70 years
- Progressive downhill course, median survival 4-5 years
- Seen with CFA(cryptogenic fibrosing alveolitis) but may also be associated with collagen-vascular diseases, especially rheumatoid arthritis and scleroderma
- Pathology – spacial and temporal heterogeneity, non-uniform inflammatory and fibrosing process; fibroblastic foci; honeycomb change
What type of interntial pneumonia does this person have?
Who is more likely to get it?
What is the pathology seen?
Does it respond to steroids?
Desquamative Interstitial Pneumonia
• Uncommon; occurs in middle-aged smokers • Dyspnoea and cough • Usually responds to steroid treatment; relatively good prognosis • Now believed to be related to respiratory bronchiolitis. • Pathology – increased numbers of macrophages in alveolar spaces, uniform interstitial fibrosis
Non-specific Interstitial Pneumonia
What is the treatment?
What are the symptoms
What does it show on micropscopy?
- Dyspnoea and cough in middle-aged adults - diagnoses by ruling out
- Underlying connective tissue disease in some patients
- Steroid-responsive in most patients
- Microscopy – uniform interstitial inflammatory and fibrosing process,
Hypersensitivity pneumonitis aka Extrinsic Allergic Alveolitis.
What are names of some the hypersensitivities?
How would they present acutely and chronically?
Farmer Lung, Bagassosis, Bathtub Refinisher’s Lung, Bird Breeder Disease, Cheese Worker’s Lung, Enzyme detergent sensitivity, Epoxy resin lung, farmer lung, lab tech lung, maltworker lung, malt bark stripper disease, mushroom picker disease, mushroom worker lung
Acute: Follows exposure to large amounts of
antigen; sudden onset of dyspnoea, fever, chills;
symptoms subside following cessation of
exposure, reappear on re-exposure.
•Chronic: Results from prolonged exposure to small amounts of antigen; insidious onset of dyspnoea, dry cough, fatigue; reticulonodular infiltrates on CXR; can progress to irreversible lung damage if exposure persists.
How does Extrinsic Allergic Alveolitis present radiologically and histologically?
Radiologically
–Lower lobe ground glass and fine nodular densities
characteristic
•Histologically
–Variable lymphoplasmacellular infiltrate centred on
small airways and alveolar ducts
–Small non
-necrotising loose granulomas
–Foamy macrophages
–BOOP like pattern seen in 50% cases.
The most prevalent chronic occupational disease worldwide is?
Why does it happen
What does it do in the lung
Silicosis
People breathe in silicon dioxide due to sand, quartz and granite having it. Airborne silica found in sandblasting, rock drilling, roof bolting, foundry work, stone cutting, drilling, quarrying, tunelling
Collagenous noduleswithin the lungs and in mediastinal lymph nodes
- Irreversible
- Low mortality but if severe tends to cause respiratory incapacity
Often long latency between exposure and development of silicosis
- However, many cases are asymptomatic
- Pathology is that of well defined nodular opacities in the upper and posterior lung zones
- Lung nodules may coalesce to form confluent complicated nodules.
