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25 Cards in this Set
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ABPA
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Definition:
Hypersensitivity reaction to the fungus aspergillus fumigatus present in endobronchial mucus plugs. Aetiology: include associations, risk factors Asthmatics and cystic fibrosis. Pathogenesis: Allergic response triggers intense airways inflammation with eosinophils and the formation of mucous plugs. Inflammation leads to proximal bronchiectasis and fibrotic lung disease. Macroscopic Pathology: Cylindrical bronchiectasis. Microscopic Pathology: Muco-inflammatory contents with occasional fungal hyphae on special stains. Clinical Presentation: Wheeze, productive cough, dyspnoea; CXR shadows; eosinophilia. Complications: Bronchiectasis; fibrosis. Management: Steroids |
Definition:
Hypersensitivity reaction to the fungus aspergillus fumigatus present in endobronchial mucus plugs. |
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ASTHMA
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Definition:
Asthma is a chronic inflammatory disorder of the airways , resulting in paroxysmal, reversible airways narrowing, usually triggered by a stimulus. Classification: Various classification systems - clinical: mild intermittent / mild / moderate / severe persistent. - stimulus: intrinsic / extrinsic - others: occupational / drug induced / seasonal / exercise induced. Epidemiology: V. common (up to 10% population in industrialised societies). Aetiology: include associations, risk factors 1. Genetic predisposition to type 1 hypersensitivity (atopy). 2. Viral respiratory tract infections. 3. Pollution: sulphur dioxide; ozone; nitrogen dioxide. 4. Aspirin 5. Ocuupational: organic / chemical dusts. Rare: Association with systemic disorder – Churg-Strauss syndrome. Pathogenesis: 3 factors contribute to obstruction: 1. bronchial muscle constriction 2. mucosal swelling 3. increased mucous production. Extrinsic(atopic) asthma Sensitization to inhaled allergen inflammatory cells infiltrate bronchioles (mast cells) re-exposure triggers Type 1 hypersensitivity reaction (release of mediators from mast cells) bronchoconstriction; increased capillary permeability (mucosal swelling); inc. mucus production; recruited WC’s late phase of more persistent narrowing and mucosal damage. Ie: sensitized exposed acute phase (type 1 HS) late phase (established inflammation). Macroscopic Pathology: Hyperinflated lungs Mucous plugs Microscopic Pathology: Bronchioles: Thickening BM; edema, inflammatory infiltrate; hypertrophied bronchial smooth muscle. Sputum: Curschmann spirals (whorls of shed brochial epithelium in mucous plugs); eosinophils; Charcot-Leyden crystals (eosinophil membrane protein) Clinical Presentation: Recurrent episodes of SOB, wheeze, chest tightness and cough. Complications: Airleak: pneumothorax / pneumomediastinum. Collapse: mucous plugging. ABPA. Management: Medical |
Definition:
Asthma is a chronic inflammatory disorder of the airways , resulting in paroxysmal, reversible airways narrowing, usually triggered by a stimulus. |
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BRONCHIECTASIS
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Definition:
1. Permanent dilatation of bronchi and bronchioles 2. caused by destruction of the muscle and elastic tissue, 3. resulting from chronic necrotising infections. Classification: Appearance: cylindrical / saccular Epidemiology: Depends on cause. Aetiology: include associations, risk factors Congenital: Kartagener’s; cystic fibrosis; immune deficiency – Hypogammaglobulinaemia; Intralobar sequestration. Post-infectious: Necrotising pneumonia. Bronchial Obstruction: Tumour; foreign body; ABPA Chronic aspiration Collagen vascular disease. Pathogenesis: Obstruction and infection are main factors. Obstruction normal clearing mechanisms impaired pooling secretions distal to obstruction inflammation airway superimposed infection necrosis, fibrosis, dilatation of bronchial walls. Macroscopic Pathology: Usually affects lower lobes bilaterally, particularly vertically oriented airways (gravity resistance to mucous clearance); unless: due to tumour / FB – can be very localised. See bronchioles within 2-3cm of plueral surface / bigger than adjacent pulmonary arteries. Microscopic Pathology: Intense inflammatory exudate in wall of bronchi/bronchioles. Desquamation. Necrotizing ulceration. Fibrosis. Clinical Presentation: Severe persistent productive cough. Copious foul smelling sputum. Complications: Local: Acute: Pneumonia; abscess; empyema; haemoptysis (bronchial aa.) Chronic: Amyloidosis; Cor Pulmonale. Systemic: metastatic abscess; sepsis. |
Definition:
1. Permanent dilatation of bronchi and bronchioles 2. caused by destruction of the muscle and elastic tissue, 3. resulting from chronic necrotising infections. |
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Bronchopneumonia
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Definition: Bacterial Infection of the lung parenchyma characterized by patchy consolidation resulting from bronchial spread into the bronchovesicular interstitium and adjacent centrilobular alveoli.
Epidemiology: Common, age peak infants and elderly Pathogenesis: Pathogens: 1) staphylococci 2) streptococci 3) strep pneumonia 4) Hemophilus influenzae Macroscopic Pathology: Site 1) unilobar 2) Multilobar 3) Patchy with centrilobular distribution Microscopic Pathology: Consolidated area of acute suppurative inflammation Acute Inflammation 1) suppurative exudate fills the airways, peribronchial interstitium, adjacent alveoli 2) Inflammatory cell neutrophils predominate 3) Necrosis variable cause lung abscesses Organization 1) Chronic Inflammatory cells lymphocytes, macrophages, fibroblasts 2) Fibrosis interstitial-alveolar fibrosis Infant Subtype variant form of bronchopneumonia, Pathogens E. coli Group B haemolytic strep. Acute inflammation confined to the interstitium. Alveoli relatively spared-mimics interstitial pneumonia Clinical Presentation: Cough, fever, chest pain Complications: Abscess formation, empyema, suppurative pericarditis, septicaemia, distant seeding Management: Antibiotics Progress Chest X-Rays |
Definition: Bacterial Infection of the lung parenchyma characterized by patchy consolidation resulting from bronchial spread into the bronchovesicular interstitium and adjacent centrilobular alveoli.
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Goodpasture Syndrome
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Definition: - uncommon immunologic condition characterised by the simultaneous appearance of proliferative, usually rapidly progressive glomerulonephritis and a necrotizing haemorrhagic interstitial pneumonitis
Incidence & Epidemiology: - average age 26 - most cases occur in teens and twenties - M:F 7:1 Aetiology & Pathogenesis: - renal and pulmonary lesions are consequence of antibodies evoked by antigens present in glomerular and pulmonary basement membranes antibodies to alpha segment of collagen IV - trigger initiating the anti-basement membrane antibodies is still unknown - possible causative agents may be - viruses - hydrocarbon solvents - smoking (cofactor) - assoc. with HLA-DR2 subtype Macroscopic Pathology: - Lungs - are heavy, with areas of red-brown consolidation - Kidneys - may be enlarged Microscopic Pathology: - Lungs - acute focal necroses of alveolar walls - assoc. with intra-alveolar haemorrhages, fibrous thickening of the septa - hypertrophy of of lining septal cells is seen - organisation of blood in the alveolar spaces - the alveoli often contain haemosiderin stain macrophages - immunofluorescence shows linear deposits of immunoglobulins along BM - Kidneys - characteristic findings of focal proliferative glomerulonephritis - OR crescentic glomerulonephritis in rapidly progressive types - linear deposits of Ig are also seen Clinical: - respiratory symptoms begin first - principally haemoptysis - then pulmonary consolidations - then get renal manifestations - rapidly progressive renal failure - haematuria - treatment - plasma exchange Complications: - uraemia - significant pulmonary haemorrhage / consolidation -> respiratory failure - anaemia - hepatosplenomegaly - systemic hypertension Prognosis - good - has improved significantly with improved treatment |
Definition: - uncommon immunologic condition characterised by the simultaneous appearance of proliferative, usually rapidly progressive glomerulonephritis and a necrotizing haemorrhagic interstitial pneumonitis
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Lobar pneumonia
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Definition: An acute bacterial infection of the lung parenchyma affecting the majority/entire lobe characterized by confluent consolidation and resulting from centrifugal alveolar spread via the pores of Kohn and canals of Lambert
Epidemiology: Uncommon Aetiology: age peak infants and elderly, less prevalent du to Abs Pathogenesis: Pathogens: 1) Strep pneumonia 90-95% 2) Klebsiella 3) Staph Macroscopic Pathology: Site 1) unilobar 2) Multilobar 3) Patchy with centrilobular distribution Airborne spread via bronchial tree, alveolar inflammation, extensive air space spread via the pores of Kohn and canals of Lambert. Limited by pleura and fissures. Microscopic Pathology: Stages of the disease 1) Congestion-first 24 hours 2) Red hepatization exudates of neutrophils and red blood cells 3) Grey hepatization accumulation of fibrin in alveoli RBCs and neutrophils disintegrate progressive suppurative exudate 4) Resolution lung normal lung parenchyma pleura fibrosis scarring Clinical Presentation: Cough, fever, chest pain Complications: Abscess formation Staph, Klebsiella, Strep, empyema, organization lung fibrosis bacteremia Management: Antibiotics Progress Chest X-Rays Prognosis: <10% death rate death usually related to complications |
Definition: An acute bacterial infection of the lung parenchyma affecting the majority/entire lobe characterized by confluent consolidation and resulting from centrifugal alveolar spread via the pores of Kohn and canals of Lambert
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Primary Lung carcinoma
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Definition: - malignant neoplasm arising from the respiratory epithelium in the lower airways
Classification: -bronchogenic 90-95% Histologic Types - 1) Squamous cell 35% - 2) Adenocarcinoma 25% - bronchial derived - brochioalveolar - 3) Small cell 25% (oat cell, intermediate, combined) - 4) Large Cell 13% - undifferentiated, giant cell, clear cell - bronchial carcinoid 5% - other 2-5% eg mesenchymal, lymphoproliferative - Simple Classification divides into Small Cell Lung cancer and Non-Small Cell Lung Cancer - important, as SCLC is radiosensitive/chemosensitive Epidemiology: - peak incidence in 6th and 7th decades (only 2% before age 40) - 20% of all male cancers, and 10% of female cancers, - M:F ratio 2:1 (increasing frequency in females related to increased incidence of smoking) Aetiology: - 1) Smoking- average (<20/day) smokers have 10-fold increased risk, heavy (>40/day) smokers have 20-fold increased risk - 2) Industrial Hazards - Asbestos - 5 times increased risk for non-smokers, 90 times for smokers - latent period = 10 to 30 years - all carcinogens are characterised by long tumour latency period and tendency to produce squamous and large cell anaplastic tumours - 4) Genetic - occasional familial clustering - 5) Scarring- usually adenoCa Pathogenesis: carcinoma begins as in situ atypia and then progressive to a small thickening of bronchial mucosa and then a warty excrescence - following which, the tumour may then - 1) continue to grow intraluminally as a fungating mass - 2) penetrate the wall of the bronchus - infiltrating - 3) continue to grow along a broad front to produce a cauliflower like, intraparenchymal mass Macroscopic Pathology: - most lesions arise in larger bronchi, - peripheral lesions are predominantly adenoCa - tissue is usually grey-white and firm, with focal necrosis and haemorrhage in larger tumour - cavitation may occur (esp. in SCC) Microscopic Pathology: - 1) Squamous (35-50%) - most closely correlated with history of smoking (more common in men) - production of keratin and inter-cellular bridges in well-differentiated lesions - ‘field effect’ - local growth is more rapid than other types and tends to metastasise - 2) Adenocarcinoma (15-35%) - M=F - tends to produce smaller, more peripheral lesion - well-differentiated, tumour shows obvious glandular elements, others show papillary formation, while others are more solid - cuboid-columnar cells - 80% contain mucin - bronchioalveolar type characteristic lepidic growth pattern - 3) Small Cell (20-25%) - Oat cell - small distinctive cell, round or oval, with little or no discernable cytoplasm - cells frequently contain neurosecretory granules (APUD type) - thought to have endodermal rather than neural crest origin - strong association with smoking - metastasize widely and early (primary often not found) esp. brain - 4) Large Cell (10-15%) - larger, more polygonal cells and vesicular nuclei - probably represent unrecognisable poorly-differentiated SCCs and adenocarcinoma Clinical Presentation: - cough 75%, with haemoptysis in 50% - weight loss 40% - chest pain 40% - dyspnoea 20% - paraneoplastic syndrome - ADH/ACTH is usually small cell, while hypercalcaemia is usually SCC - Myasthenia Gravis, due to small cell, lambert eaton syndrome Complications: - Intra-pulmonary - obstructive emphysema atelectasis - drowned lung - distal suppuration and abscess formation - Local Extra-pulmonary - SVC obstruction - pleural or pericardial involvement - brachial plexus and sympathetic involvement (pancoast) - oesophageal obstruction and fistula formation - Distant metastases - adrenal in over half - also bone, brain (esp. small cell) and liver NB lymphangitis Management: TNM staging Prognosis: - overall 5 year survival is 10-15% poor - virtually nil survival is lesion is in a main bronchus - SCC and adenoCa tend to remain localised -> slightly better prognosis - only 20-30% have lesions deemed surgically resectable at diagnosis. This group has a 30-50% 5 year survival, excluding small cell tumours - small cell precludes surgery - untreated survival time is 6-17weeks while treated is about 1 year |
Definition: - malignant neoplasm arising from the respiratory epithelium in the lower airways
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Malignant Mesothelioma
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Definition
A malignant neoplasm of mesothelial lining, which may arise in pleura (most commonly), peritoneum or pericardium (rarely). Classification Classified according to site of origin (eg pleural or peritoneal). Also accoring to predominant cell type: epithelioid, sarcomatoid, or mixed. Epidemiology 90% have a history of asbestos exposure. Lifetime risk of up to 10% after heavy asbestos exposure, with a 25-45 year latent period. No association with smoking. NB the risk of lung carcinoma exceeds the risk of mesothelioma in asbestos workers. Peritoneal mesothelioma is associated with heavy asbestos exposure. Aetiology As discussed, the primary cause is asbestos exposure. The remaining cases are idiopathic. Pathogenesis Deletions in multiple chromosomes have been found in mesothelioma cells. P53 accumulation can be detected immunohistochemically. Some studies have demonstrated the presence of simian virus SV40 (which is a potential carcinogen) in mesothelioma, but the significance of this is controversial. Macro Extensive pleural thickening, associated with pleural effusion and direct invasion of adjacent thoracic structures. The affected lung is often encased. Micro Biphasic cell population, with epithelioid and sarcomatoid cells. Sarcomatoid cells are spindle-shaped and resemble fibrosarcoma. Epithelioid cells are cuboidal cells forming tubular or papillary structures. The gold standard is electron microscopy, which demonstrates long microvilli and abundant tonofilaments. Tissue stains are also helpful. Clinical Present with chest pain, dyspnoea and recurrent pleural effusion. Asbestosis is present in 20%. Complications Metastases are to lymph nodes, and liver / distant organs as a late complication. Local invasion of lung and chest wall is common. Management Aggressive therapy (extrapleural pneumonectomy, chemotherapy and radiotherapy) may improve prognosis in some patients. Prognosis 50% 1-year mortality. Few survive 2 year |
Definition
A malignant neoplasm of mesothelial lining, which may arise in pleura (most commonly), peritoneum or pericardium (rarely). |
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OBSTRUCTIVE PULMONARY DISEASE
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Definition: Diffuse pulmonary disease characterised by increased resistance to airflow from partial or complete obstruction of airways.
(cf: restrictive pulmonary diseases characterised by reduced pulmonary compliance and total lung capacity – from chest wall disorders or interstitial lung disease which may be acute or chronic) Classification: Emphysema; Chronic Bronchitis; Asthma; Bronchiectasis. Pathogenesis: Anatomic airway obstruction – asthma; bronchitis; bronchiectasis Loss of elastic recoil - emphysema |
Definition: Diffuse pulmonary disease characterised by increased resistance to airflow from partial or complete obstruction of airways.
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Other lung neoplasms
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Classification: carcinoid, hamartoma, metastases
Carcinoid: - slow growing neuroendocrine tumour, that may arise in the lungs from neuroepithelial bodies in the lung parenchyma Epidemiology: - 1-5% of all lung tumours - 90% of all bronchial adenomas - M:F 1:1 - majority are <40 years Pathogenesis: - arise from the neuroendocrine cells and belong to the APUDomas - amine precursor uptake and decarboxylation cells (Kulchitsky cells of the bronchial mucosa) - although multiple products may be synthesized by a single tumour, most secrete a predominant product to produce a clinical syndrome called by that name - Serotonin - 5-hydroxy tryptamine - Carcinoid Syndrome most common -there is no known relationship to cigarette smoking or other environmental factors. Occasionally associated with MEN I. Macroscopic Pathology: - polypoid tumour with a spherical or finger-like shape that commonly project into the lumen of a bronchus - usually covered by an intact mucosa - highly vascular microscopic pathology: - nests, cords and rosettes of uniform small round cells, separated by a delicate fibrous stroma - tumour cells are monotonously similar - the cytoplasmic granules are capable of reducing silver nitrate (argentaffin granules) Clinical Presentation: - intraluminal growth produces the following symptoms - cough, haemoptysis, infections, bronchiectasis, atelectasis, air trapping - Carcinoid Syndrome - in 1% of patients with carcinoid - in 20% of those with widespread mets - 5HT is degraded in the liver to functionally inactive 5-HIAA -episodic flushing, diarrhoea, bronchospasm - Other Syndromes eg cushings Management: - surgery - metastases go to liver, lymph nodes, lung and bone (osteoblastic mets) uncommon Prognosis: - overall 5-10 year survival for bronchial carcinoids is 50-90% - <10% are atypical carcinoids - showing cytological atypia, necrosis and aggressive behaviour - these have a 50% recurrence rate after 2 years Hamartoma: Definition - developmental malformation consisting of neoplastic like benign overgrowth of tissues proper to the part, appearing at birth or soon after, and generally ceasing when body growth stops Classification - Peripheral 90% - Central 10% - Single - Multiple (rare) Incidence - most common benign mass, M:F 3:1 Epidemiology - rarely seen in children - usually seen 40-60years Macroscopic Pathology - rarely >3-4cm diameter - spherical/slightly lobulated - normal surrounding lung - may have calcification (linear, speckled) - calcification increases with lesion size - cartilaginous calcification is virtually diagnostic - appearance depends on tissue composition (see below) Microscopic Pathology - may be mixture of fibrous tissue, fat, blood, vessels, lymphoid tissue, bronchial like structures and cartilag - spaces may be lined by respiratory epithelium Clinical - usually asymptomatic and detected on CxR - very slow growing - may cause airway obstruction (see below) Prognosis - good - only problems are due to localised mass effect. - no malignant potential lung metastases: -commoner than primary lung cancers 90% >50yrs more in increasing age -usually haematogenous spread but can also be direct eg mediastinal or oesophageal -primary, lymphatics eg lymphoma - origin breast 22%, renal 11% , H&N 10%, colorectal 9% -morphology patterns 1) solitary mass 25% 2) multiple nodules including miliary subtype. 3) lymphangitis carcinamatosis |
Classification: carcinoid, hamartoma, metastases
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Pneumoconioses
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Definition:
Lung disease secondary to occupational exposure to inorganic or organic dusts, or chemical fumes. Classification: Pneumoconioses are classified according to the disease-causing agent: Inorganic dust diseases include silicosis, coal-worker's pneumoconiosis and asbestosis. Organic dusts diseases include farmer's lung (mouldy hay) and asthma due to Western Red Cedar dust. Chemical fume diseases include hypersensitivity and direct toxic effects of sulphur dioxide, ammonia and benzene. Epidemiology: Occur in workers exposed to the disease-causing agent. Silicosis is the most prevalent chronic occupational disease. Asbestos-related mesothelioma can occur in family members. Aetiology: CWP is caused by coal dust. If silica is present also, the disease is worse. Silicosis is due to silica (amorphous or crystalline), with crystalline being more fibrogenic. The mixture of other minerals such as iron (haematite) is thought to be protective. Asbestos-related disease is due to asbestos fibres (a crystalline form of silica) . Asbestos may be serpentine or amphibole in fibre form, with amphibole (straight, stiff fibres) forms being more toxic. Pathogenesis: Particle size, shape and solubility is important in pathogenesis. The most dangerous particles are 1-5 microns diameter (these reach the terminal airways and alveoli). Injury is due to direct toxic effect, free radical formation, and macrophage activation with subsequent chronic inflammatory response. Smoking exacerbates the effects (partly by inhibiting mucociliary clearance). The effects of asbestos are particularly magnified by smoking - this may be partly due to adsorbtion of tobacco toxins onto asbestos fibres. Macroscopic Pathology: CWP: Disease ranges from asymptomatic anthracosis (characterised by anthracotic pigment in pulmonary lymphatics and lymph nodes) to simple CWP (coal macules 1-2mm diameter, and larger coal nodules). Upper zones more affected. Complicated CWP (progressive massive fibrosis) is characterised by black scars >2cm diameter, again in the upper zones. Silicosis: Discrete nodules in the upper zones, which tend to coalesce to hard, collagenous scars. Central cavitation may occur (NB increased incidence of TB). Fibrosis and calcification occurs in hilar & mediastinal lymph nodes. PMF also occurs. Asbestosis: Diffuse pulmonary fibrosis progresses to honeycombing, beginning in the lower zones, with a pattern similar to UIP. Pleural plaques of dense collagen +/- calcium on the parietal pleura only. Occasional pleural effusions. Microscopic Pathology: CWP: Nodules consist of carbon-laden macrophages in a delicate network of collagen. Silicosis nodules consist of a dense, lamellated collagen matrix, with birefringent silica particles within. Asbestosis is characterised by the presence of asbestos bodies, which are asbestos fibres with adsorbed brown iron-containing proteinaceous material. Fibrous tissue distorts the normal alveoli and thickens the interstitium. Clinical Presentation: The chronic pneumoconioses present with cough and progressive dyspnoea, which may lead to respiratory failure, cor pulmonale and death. The acute pneumoconioses may present with asthma, hypersensitivity pneumonitis, ARDS or pulmonary oedema. Complications: Progressive massive fibrosis may complicate CWP or silicosis. It may be progressive despite cessation of exposure. PMF typically leads to respiratory failure, pulmonary hypertension and cor pulmonale. Silicosis may be associated with an increased incidence of lung carcinoma but this is controversial. Asbestos exposure is associated with a marked increase in the incidence of lung carcinoma, especially if combined with smoking (55x). The incidence of mesothelioma is >1000x, with no smoking link. Management: Other than limitation of exposure to the offending agent, and cessation of smoking, management is largely symptomatic. Prognosis: Simple CWP is generally relatively benign. Silicosis tends to be more progressive, and although slow to kill, may cause significant morbidity. Asbestosis may also be associated with high morbidity, and with lung carcinoma or mesothelioma development, prognosis is poor. |
Definition:
Lung disease secondary to occupational exposure to inorganic or organic dusts, or chemical fumes. |
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Primary Atypical Pneumonia
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Definition: An acute infectious pneumonia due to a variety of organisms especially viruses and Mycoplasma which is characterized by patchy inflammatory changes mainly localized to the pulmonary interstitium (alveolar septum)
and lacking in alveolar exudate. Epidemiology: Mycoplasma pneumoniae (most common cause) Aetiology: Pathogenesis: Pathogens: 1) Viral: influenza A / B, RSV, adenovirus, varicella 2) Mycoplasma: Mycoplasma pneumoniae 3) Protozoal: PCP Macroscopic Pathology: All causal agents produce a similar morphological pattern Lung: Site 1) distribution variable uni/bilateral, patchy, no obvious consolidation Pleura: Usually normal effusions and pleuritis infrequent Microscopic Pathology: Changes similar to ARDS 1) alveoli normal early 2) localized to interstitium mainly 3) Mononuclear inflammatory cells 4) Alveoli variable involvement including: necrosis, viral inclusions, viral cytopathy, hyaline membranes (characteristic pink membranes lining alveoli reflect alveoli wall damage), alveolar consolidation, bacterial superinfection 5) Resolution (common) Clinical Presentation: Cough, fever, chest pain Management: Supportive therapy Bactrim PCP prophylaxis Prognosis: Depends on cause |
Definition: An acute infectious pneumonia due to a variety of organisms especially viruses and Mycoplasma which is characterized by patchy inflammatory changes mainly localized to the pulmonary interstitium (alveolar septum)
and lacking in alveolar exudate. |
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Pulmonary Infections
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Definition: Bacterial Infection of the lung parenchyma resulting in pulmonary consolidation (exudative solidification)
Classification: There is anatomical overlap: 1) lobar pneumonia 2) Bronchopneumonia 3) Interstitial pneumonia Epidemiology: Different populations are susceptible to various infections. Examples hospital acquired pneumonia, alcoholics, immune compromised etc Aetiology: include associations, risk factors pulmonary infections occur when lung or systemic defences are impaired. Pulmonary defences include nasal, tracheobronchial and alveolar mechanism to filtrate, neutralize and clear inhaled organisms and particles. Pathogenesis: Cough refelex, mucociliary clearance, decrease in alveolar macrophage activity, edema, secretions and congestion and defects in innate or specific immunity. |
Definition: Bacterial Infection of the lung parenchyma resulting in pulmonary consolidation (exudative solidification)
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Sarcoidosis
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Definition
Idiopathic systemic disease characterised by noncaseating granulomas in many tissues and organs. Classification Type I: hilar / mediastinal lymphadenopathy only. Type II: lymphadenopathy + lung disease. Type III: lung disease only. Epidemiology Chest pathology is present in 90% of cases. More common in women than men. Rare in Asians. Aetiology / Pathogenesis Probably a disease of disordered immune regulation in genetically predisposed individuals, exposed to certain environmental agents. Immune changes: oligoclonal expansion of CD4+ T cell subsets, increased TH1 and macrophage cytokines. There is anergy to common skin test antigens, and polyclonal hypergammaglobulinaemia. Genetic predisposition: familial / racial clusters; association with HLA-A1 and B8. Environmental factors: Possibly microbes, but no evidence to date. Macro All involved tissues show noncaseating granulomas. Almost all tissues may be involved. Nodules occur in the lungs, primarily along lymphatics. Healing produces fibrosis. Lymph nodes and tonsils are commonly involved. Skin and eyes are also commonly involved. Lacrimal gland and salivary gland involvement -> Mikulicz syndrome. Spleen, liver, bone marrow, muscle, heart, kidneys, CNS and pituitary are often involved. Micro Epithelioid cells and giant cells combine to form noncaseating granulomas. Schaumann bodies (laminated concretions of calcium and protein) and asteroid bodies (stellate inclusions in giant cells) are often seen and are characteristic but not pathognomonic. Clinical May be asymptomatic, or may present with lymphadenopathy, cutaneous lesions, eye involvement, splenomegaly or respiratory impairment (most common). May be chronically progressive, or relapsing & remitting. Complications Blindness from corneal ulceration or uveitis. Respiratory failure or cor pulmonale. CNS or cardiac impairment. Management Steroids may induce remission. Prognosis 65-70% recover with minimal residual impairment. 20% have permanent loss of respiratory or eye function. 10-15% die of respiratory, cardiac or CNS disease. The best prognosis in in type I. Type III disease is unlikely to remit. |
Definition
Idiopathic systemic disease characterised by noncaseating granulomas in many tissues and organs. |
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TUBERCULOSIS
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Definition: Chronic infective disease caused by infection with mycobacterium tuberculosis
Classification: • Primary TB – infection from exogenous source in previously unexposed, unsensitised person • Secondary TB – pattern of disease in previously sensitised person. May arise from (1) reactivation of latent lesions when host resistance weakens, or (2) from exogenous reinfection because of waning protection or large inoculum of virulent bacilli. • Miliary pulmonary TB - lympho/haematogenous dissemination of primary/secondary TB • Extrapulmonary (15%): Systemic miliary TB, Isolated organ TB, TB meningitis, Lymphadenitis (scrofula), Intestinal TB Epidemiology: Affects 1.7 billion people worldwide. 9 million new cases a year. 1.7 million deaths/yr M>F. Age peak 50-60 Associations / Risk factors in developed countries: Migrants, poverty, crowding, chronic debilitating illness, diabetes, Hodgkins, chronic lung disease (esp silicosis), chronic renal failure, malnutrition, alcoholism, immunosuppression (eg HIV) Aetiology: M. tuberculosis infection. (Ingestion of M. bovis in milk causing intestinal TB now less common) Pathogenesis Usually person-to-person transmission of M. tuberculosis in airborne droplets. M. tuberculosis endocytosed by macrophages replicates within phagosome of macrophage. After 3 weeks, TH1 response mounted (Type 4 cell-mediated Immune response) stimulates macrophages to kill mycobacteria, form granulomas and caseous necrosis Macroscopic Pathology: • Primary TB – 1-1.5cm grey-white consolidation in lower part of upper lobe or upper part of lower lobe (Ghon focus), which develops caseous necrosis. Regional node involvement and caseation. Ghon complex = Ghon focus + LN. • Non progressive Primary TB - sequelae in 95%. Latent lesions. Contraction, fibrosis & calcification of Ghon complex = Ranke complex • Progressive Primary TB – rare sequelae. Lower and middle lobe consolidation, lymphadenopathy, pleural effusion, spread • Secondary TB – Simon focus = <2cm focus of circumscribed, firm, grey-white consolidation in upper lobe apex <2cm from pleura (High oxygen tension in apices promotes bacterial growth). Variable central caseation and peripheral fibrosis • If favourable, develop minor caseation, then fibrocalcific scarring (Arrested fibrocalcific TB) • Progressive Secondary TB – in elderly and immunosuppressed. Includes • Cavitary Fibrocaseous TB (Localised cavitary destructive lesions) – apical cavity formed by erosion into airway, yellow-green caseous materal, fibrous wall. May erode blood vessels. • Other patterns of Progressive Pulmonary TB: • Endobronchial, endotracheal and laryngeal tuberculosis • Miliary TB – • Pulmonary - microscopic or small visible <2mm scattered yellow-white foci of consolidation • Extrapulmonary – kidney, adrenal, spleen, LN, Bmarrow, meninges, prostate, seminal vesicles, fallopian tubes • Tuberculous bronchopneumonia “galloping consumption” – in susceptible individuals. extensive diffuse consolidation. Well-defined tubercles don’t form. • Pleural involvement – serous effusions, empyema, obliterative fibrous pleuritis. Empyema – caseous necrosis, fibrosis and calcification. Microscopic Pathology: In immunocompetent: After 3 weeks, granulomatous inflammatory reaction forming caseating and non-caseating tubercles. Pattern: 1. Central caseous necrosis (combination of coagulative and liquefactive necrosis). 2. Epitheloid cells + Langhans giant cells. 3. Peripheral rim of lymphocytes & fibroblasts In immunocompromised: Characteristic granulomas do not form Clinical Presentation: May be asymptomatic Primary infections - 5% have clinically significant disease fever, pleural effusion Secondary infections – insidious onset Fever, commonly low grade and remittent. Night sweats. Sputum mucoid becoming purulent. Haemoptysis in 50% Pleuritic pain. Complications: Bronchopleural fistula, empyema Fibrosing mediastinitis Endobronchial dissemination from cavitation to other segments Cavity colonisation with aspergillus (aspergilloma) or bacteria Systemic miliary TB Management: Antibiotics RIPE (rifampicin, isoniazid, pyrazinamide, ethambutol). Previously plombage with plastic packs, Lucite balls, polythene spheres, oleothorax Prognosis: Cure or arrest of active disease is usual, unless severe immunocompromised |
Definition: Chronic infective disease caused by infection with mycobacterium tuberculosis
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Wegener Granulomatosis
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Definition:
- rare form of necrotising vasculitis characterized by the triad of upper respiratory tract, pulmonary and renal involvement Epidemiology: - M>F - peak incidence in the 5th decade Aetiology & Pathogenesis: - thought to represent some form of hypersensitivity possibly to an inhaled infectious agent or other environmental factor - dramatic response to cyclophosphamide suggests an immunologic mechanism - C-ANCA is found in 93% of patients with active generalised disease Macroscopic Pathology: - the vasculitis affects small arteries and veins and may be seen in vitually any organ of the body - Classical Feaures are: - acute necrotising granulomas of the upper and lower respiratory tract - nose, ears, sinuses, throat and lung - focal necrotising vasculitis, most prominent in the lungs and upper airways - affecting small to medium-sized vessels - granulomas may undergo progressive fibrosis and cavitation - renal disease is in the form of focal or diffuse necrotising glomerulonephritis Microscopic Pathology: - areas of focal acute necrosis are seen throughout the respiratory tract - In addition, focal granulomas are seen scattered throughout the lung parenchyma - these lesions show central necrosis surrounded by: - lymphocytes, plasma cells, macrophages and a variable number of giant cells - there is also a necrotising or granulomatous vasculitis - may be associated with or clearly separated from vessel walls - these areas are surrounded by a zone of fibroblastic proliferation containing: - giant cells and leukocytic infiltrate - may resemble a tubercle - lesions may eventually undergo progressive fibrosis and organisation - the renal lesions are of two types - focal necrotising glomerulonephritis - a more diffuse crescentic form of glomerulonephritis Clinical: - persistent pneumonitis - chronic sinusitis - evidence of renal disease - Limited Form of W.G. - some patients do not manifest the renal component - disease is restricted to the respiratory tract Prognosis: - untreated course is malignant and 80% die within one year - with treatment, up to 90% respond, with only occasional relapses. - C-ANCA is a good activity marker |
Definition:
- rare form of necrotising vasculitis characterized by the triad of upper respiratory tract, pulmonary and renal involvement |
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IDIOPATHIC INTERSTITIAL PNEUMONIAS – Classification
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• Acute (days to weeks): Acute Interstitial Pneumonia
• Sub-acute (<3/12): 1. Desquamative interstitial pneumonia 2. Cryptogenic organising pneumonia • Chronic (>3/12): 1. Usual interstitial pneumonia 2. Nonspecific interstitial pneumonia 3. Lymphoid interstitial pneumonia 4. Respiratory bronchiolitis associated interstitial lung disease |
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* IDIOPATHIC PULMONARY FIBROSIS (IPF) = USUAL INTERSTITIAL PNEUMONIA (UIP)
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Definition: chronic interstitial pneumonia of unknown cause characterised by histopathologic pattern of usual interstitial pneumonia
Classification: Epidemiology: 50-70 yo. M>F. Commonest idiopathic interstitial pneumonia Aetiology: Unknown causative agent. Majority are smokers but role not clarified (Drugs eg. Bleomycin, cyclophosphamide and busulfan and Scleroderma can produce similar pattern) Pathogenesis: “Repeated cycles” of acute lung injury (alveolitis) by some unidentified agent. “Wound healing” at these sites gives rise to exuberant fibroblastic proliferation, giving rise to “fibroblastic foci” Macroscopic Pathology: Pleural surfaces cobblestoned due to retraction of scars along interlobular septa. Firm, rubbery white areas of fibrosis seen on cut surface with lower lobe predominance, in subpleural distribution and along interlobular septa Microscopic Pathology: Patchy interstitial fibrosis, varying in intensity and with time (Temporal and spatial heterogeneity). Both early (fibroblastic proliferations) and late lesions (more collagenous, less cellular) coexist. Smooth muscle hyperplasia. Honeycomb fibrosis = dense fibrosis causing collapse of alveolar walls and formation of cystic spaces Clinical Presentation: Chronic insidious, gradually increasing dyspnea on exertion and dry cough. Hypoxemia, cyanosis and clubbing late. Complications: • Respiratory failure, Pulmonary hypertension & Cor pulmonale, • 10-15% Increased incidence of lung cancer, predominantly lower lobes • opportunistic infection • rapid deterioration Management: Lung transplant only definitive therapy. Steroids, interferon, azathioprine Prognosis: Unpredictable progression. Gradual or rapid deterioration. Mean survival 3 years or less. |
Definition: chronic interstitial pneumonia of unknown cause characterised by histopathologic pattern of usual interstitial pneumonia
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* NONSPECIFIC INTERSTITIAL PNEUMONIA (NSIP)
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Definition: Interstitial lung disease of unknown aetiology which on lung biopsy shows no diagnostic features of other well-characterized interstitial diseases.
Classification: Two histologic patterns: 1. Cellular pattern 2. Fibrosing pattern Epidemiology: 46-55 yo. Those with cellular pattern younger than those with fibrosing pattern. F>M. 2nd most common after IPF Aetiology: Unknown Pathogenesis: Macroscopic Pathology: Bilateral basal & symmetrical, subpleural. Honeycombing and consolidation infrequent Microscopic Pathology: 1. Cellular pattern – chronic interstitial inflammation containing lymphocytes, few plasma cells 2. Fibrosing pattern – diffuse or patchy interstiial fibrosis with temporal homogeneity No fibroblastic foci Clinical Presentation: Chronic Dyspnoea and cough for several months Management: Prognosis: much better prognosis than IPF. Cellular pattern better outcome |
Definition: Interstitial lung disease of unknown aetiology which on lung biopsy shows no diagnostic features of other well-characterized interstitial diseases.
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LYMPHOID INTERSTITIAL PNEUMONIA (LIP)
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Definition: Rare interstitial pneumonia characterised by interstitial lymphocytic infiltrate
Epidemiology: F>M. 40-50yo. Very rare. Rarest of the idiopathic interstitial pneumonias Aetiology/ Associations: collagen vascular diseases, Sjogrens, immunodeficiency, rarely idiopathic Pathogenesis: Macroscopic Pathology: subpleural and peribronchovascular nodules and septal lines. Perivascular cysts occasionally Microscopic Pathology: diffuse lymphocyte interstitial infiltrate, predominantly alveolar septal distribution Clinical Presentation: Chronic slow onset dyspnoea, cough, fever, weight loss, arthralgia. Signs/symptoms of underlying disease Management: steroids Prognosis: rarely progresses to fibrosis |
Definition: Rare interstitial pneumonia characterised by interstitial lymphocytic infiltrate
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* CRYPTOGENIC ORGANIZING PNEUMONIA = BRONCHIOLITIS OBLITERANS ORGANIZING PNEUMONIA (BOOP)
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Definition: clinicopathologic syndrome of unknown aetiology characterised histologically by polypoid plugs of connective tissue within small airways
Epidemiology: middle aged females. Mean age 55 Aetiology / Associations: Idiopathic type most common - Unknown aetiology (Same pattern seen as a response to infections or inflammatory injury of lungs eg. Viral/bacterial pneumonia, inhaled toxins, drugs, collagen vascular disease, graft versus host disease in bone marrow transplant patients, bronchial obstruction – not called COP) Macroscopic Pathology: (1) Diffuse centrilobular nodules – consolidation. Patchy peribronchial or peripheral in lower zones Or (2) Focal mass-like consolidation. Microscopic Pathology: 1. Early phase: localised lesion centering on a bronchiole. Lymphocytes and plasma cells in fibrous tuft in airway. Temporal homogeneity. Mild chronic inflammatory infiltrate 2. Late phase : branching polypoid plugs of fibrous connective tissue within alveolar ducts and alveoli, and often bronchioles. Underlying lung architecture normal. Interstitial fibrosis Clinical Presentation: Subacute productive cough, dyspnoea, weight loss, fever, myalgia. Pneumonia unresponsive to antibiotics. Management: Oral steroids for 6 months or longer Prognosis: some recover spontaneously but most require steroids for complete recovery. Relapse may occur. (When associated with underlying condition, prognosis same as for underlying disorder). |
Definition: clinicopathologic syndrome of unknown aetiology characterised histologically by polypoid plugs of connective tissue within small airways
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SMOKING-RELATED INTERSTITIAL DISEASES
A. DESQUAMATIVE INTERSTITIAL PNEUMONIA (DIP) |
Definition: form of interstitial pneumonitis occuring in smokers characterised by accumulation of pigmented macrophages in alveoli
Epidemiology: 30-40 yo. M>F 2:1 Aetiology/ Associations / Risk factors: Virtually all patients are smokers Macroscopic Pathology: lower zone & peripheral predominance Microscopic Pathology: accumulation of macrophages with abundant cytoplasm containing dusty brown pigment (smokers macrophages) in alveoli. Thickening of alveolar septa by sparse infiltrate of lymphocytes. Spatial homogeneity. Chronic inflammatory infiltrate. Minimal fibrosis. Honeycombing uncommon Clinical Presentation: Subacute insidious slow onset dyspnoea, dry cough, clubbing Management: Steroids (excellent response). Smoking cessation Prognosis: Good. Non progressive in vast majority. 100% survival Definition: Clinical manifestation of interstitial lung disease associated with pathologic lesion of respiratory bronchiolitis Classification: Epidemiology: 30-40 yo >30 pack years of smoking. M>F 2:1 Aetiology: Associations / Risk factors Pathogenesis: Macroscopic Pathology: centrilobular emphysema, centrilobular nodules. Upper lobe predominance Microscopic Pathology: bronchiolocentric accumulation of alveolar macrophages with pigment. Mild patchy submucosal and peribronchiolar infiltrate of lymphocytes and histiocytes. Mild peribronchiolar fibrosis. Clinical Presentation: chronic mild cough, dyspnoea Management: Smoking cessation Prognosis: smoking cessation usually results in improvement * HYPERSENSITIVITY PNEUMONITIS = EXTRINSIC ALLERGIC ALVEOLITIS Definition: spectrum of immunologically mediated, predominantly interstitial, lung disorders caused by prolonged exposure to inhaled organic dusts acting as antigens. ?Characterised by mononuclear interstitial pneumonitis progressing to fibrosis. Classification: Acute EAA – heavy acute exposure Subacute EAA – less intense but continuous exposure Chronic EAA – prolonged exposure, presenting months to years later Epidemiology: Aetiology/ Associations / Risk factors: Organic dust containing antigens eg. Spores of thermophilic bacteria, fungi, animal proteins, bacterial products Pathogenesis: Type III (immune complex) hypersensitivity and Type IV (delayed type) hypersensitivity Macroscopic Pathology: 1. Acute EAA – consolidation early +/- lymphadenopathy 2. Subacute-Chronic EAA - firm lung, distorted lung architecture, honeycombing Microscopic Pathology: In subacute and chronic forms disease centred on bronchioles Interstitial pneumonitis Noncaseating granulomas Intralveolar infiltrates seen in 50%. Interstitial fibrosis and obliterative bronchiolitis in late stages. Clinical Presentation: Acute attacks 4-6 hours following inhalation of antigenic dust – fever, dyspnoea, cough, leukocytosis Chronic form – progressive respiratory failure, dyspnoea, cyanosis, restrictive lung pattern Complications: Management: Prognosis: can progress to serious chronic fibrotic lung disease without removal of the environmental agent |
Definition: form of interstitial pneumonitis occuring in smokers characterised by accumulation of pigmented macrophages in alveoli
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SMOKING-RELATED INTERSTITIAL DISEASES
B. RESPIRATORY BRONCHIOLITIS-ASSOCIATED INTERSTITIAL LUNG DISEASE (RB-ILD) |
Definition: Clinical manifestation of interstitial lung disease associated with pathologic lesion of respiratory bronchiolitis
Classification: Epidemiology: 30-40 yo >30 pack years of smoking. M>F 2:1 Aetiology: Associations / Risk factors Pathogenesis: Macroscopic Pathology: centrilobular emphysema, centrilobular nodules. Upper lobe predominance Microscopic Pathology: bronchiolocentric accumulation of alveolar macrophages with pigment. Mild patchy submucosal and peribronchiolar infiltrate of lymphocytes and histiocytes. Mild peribronchiolar fibrosis. Clinical Presentation: chronic mild cough, dyspnoea Management: Smoking cessation Prognosis: smoking cessation usually results in improvement |
Definition: Clinical manifestation of interstitial lung disease associated with pathologic lesion of respiratory bronchiolitis
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ACUTE INTERSTITIAL PNEUMONIA
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Definition: clinicopathologic syndrome of unknown aetiology demonstrating widespread acute lung injury with rapidly progressive clinical course, resembling ARDS
Epidemiology: wide age range. mean age 50 years. M=F Aetiology / Pathogenesis : Unknown Macroscopic Pathology: Acute phase - Identical appearance to ARDS. Heavy, firm, red, boggy lungs. Diffuse consolidation Late phase – fibrosis, architectural distortion, cysts, traction bronchiectasis Microscopic Pathology: Identical appearance to ARDS. 1. Exudative phase - Congestion, interstitial and intra-alveolar oedema, inflammation and fibrin deposition. Temporal homogeneity. Alveolar walls lined with waxy hyaline membranes. 2. Organizing phase – organizing fibrin, loose organising fibrosis in alveolar lumens Clinical Presentation: Acute respiratory failure often following an illness of less than 3 weeks’ duration resembling URTI Complications: chronic interstitial disease Management: Lung transplant only definitive therapy Prognosis: Mortality rate 50%, most deaths in 1-2 months. Survivors may develop recurrences and chronic interstitial disease. |
Definition: clinicopathologic syndrome of unknown aetiology demonstrating widespread acute lung injury with rapidly progressive clinical course, resembling ARDS
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PULMONARY INVOLVEMENT IN COLLAGEN VASCULAR DISEASES
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Definition: pulmonary involvement during the course of a collagen vascular disease
Classification: by patterns: NSIP pattern, UIP pattern, vascular sclerosis, organizing pneumonia, bronchiolitis Epidemiology: as for underlying diseases 1. Scleroderma – M<F 1:3. 50-60 yo. Lungs involved in >50% 2. SLE – M<F 1:10. 20-40 yo. 3. RA – M<F 1:4. 20-50 yo but M>>F develop rheumatoid lung Aetiology / Associations: collagen vascular diseases including SLE, RA, scleroderma, dermatomyositis/polymyositis, mixed connective tissue disease Pathogenesis: Macroscopic Pathology / Microscopic Pathology: 1. Scleroderma – Bilateral lower lobe fibrosis, peripheral. NSIP more than UIP pattern. Honeycombing. Alveolar changes ? aspiration related. Variable fibrous thickening of small pulmonary vessels 2. SLE - Pleural disease, pleuritis in 45% Lupus pneumonitis in 10% - patchy bilateral alveolar consolidation, oedema, haemorrhage Chronic interstitial fibrosis in 3% - bilateral lower lobes, peripheral 3. RA 1. Chronic pleuritis. Pleural effusions in 3%, usually unilateral. Bilateral pleural thickening 2. DIP pattern and fibrosis – bilateral basal, peripheral 3. Intrapulmonary rheumatoid nodules – rare only in advanced RA. 0.3-7cm well circumsribed nodules +/- cavitation. Usually multiple, often peripheral Micro: (1) central fibrinoid necrosis, surrounded by (2) peripheral epitheloid histiocytes, lymphocytes, (3) fibrosis 4. Pulmonary hypertension – due to pulmonary arteritis affecting small and medium sized arteries. Micro: fibroelastoid intimal proliferation 5. Caplan syndrome = coexistence of RA and a pneumoconiosis leading to development of distinctive nodular pulmonary lesions 0.5-5cm. Mainly peripheral upper lobes. Micro similar to rheumatoid nodules Clinical Presentation: Complications: Management: Prognosis: |
Definition: pulmonary involvement during the course of a collagen vascular disease
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