Matthew McCabe Flashcards
What is the other name for alveolar cells?
Pneumocytes
Describe type I pneumocytes
‘Wallpaper’ of the alveoli. Simple Squamous Epithelial cells- make up ~90% of the surface area with minimal thickness. Maximises gas diffusion
Describe type II pneumocytes
‘Clara cells’. Polygonal in shape, have microvilli on surface and excrete pulmonary surfactant
What are ‘Dust cells’?
Free floating alveolar macrophages. Phagocytose any particles which have not been trapped by mucous
What are the two gross stages of ILS?
1) Alveolitis- acute inflammatory stage
2) Fibrosis- chronic fibrotic stage
What are the different types of ILS we need to know?
1) Fibrosing Alveolitis= Idiopathic Pulmonary Fibrosis= Interstitial Pneumonia
2) Sarcoidosis
3) Extrinsic Allergic Alveolitis
4) Pneumoconiosis
Then ILS assocaited with Connective Tissue diseases
What are the key PATHOLOGY points of Fibrosing alveolitis/ Idiopathic Pulmonary Fibrosis
Idiopathic
Characterised by sub pleural & basal fibrosis
Causes ‘dilated air spaces with surrounding fibrosis’
LATE STAGE histology shows ‘Honeycombing’ of lung. Microscopically we see ‘punched out lesions’
What are the key CLINICAL points of Fibrosing alveolitis/ Idiopathic Pulmonary Fibrosis
FINE END INSPIRATORY CRACKLES Arthralgia weight loss/ fatigue exertional dyspnoea Ground glass appearance ON X RAY IN EARLY STAGES
What tests do we use to investigate IPF?
1) Spirometry, Chest X-ray, Full blood works, CT chest,
If these dont work then try:
2) Bronchial alveolar lavage or trans bronchial biopsy
DTPA can be used to show disease activity once diagnosis is made
What is the management plan of IPF?
No cure. treat symptoms with:
Oxygen, Pulmonary Rehab & Opiates
Consider Lung Transplant
What inflammatory cells are present in the different stages of ILS?
if we carry out a bronchial-alveolar lavage:
Alveolitis stage= lymphocytes= good prognosis
Fibrosis stage= neutrophils/ eosinophils = poor prognosis
What are the Buzzwords for a Sarcoidosis Presentation?
20-40 yo Afro Caribbean women Hilar Lymphadenopathy Erythema Nodusum Dry cough/ breathless/ chest pain Splenomegaly Keratoconjuctivitis Sicca Hypercalcaemia / Hyperuricaemia +/- renal stones Phalangeal cysts
What is the pathophysiology of Sarcoidosis?
A granulomatas disease which causes the formation of non-caseating granulomas throughout many parts of the body.
α 1 hydroxylase enzyme is found in sarcoidosis granules. This means that the calcidiol is converted to calcitriol in sarcoidosis granules- causing osteoclast activation- hence the phalyngeal cysts & hypercalcaemia
What tests do we use for Sarcoidosis?
Blood for Hypercalcaemia Slit lamp for occular involvement Chest X ray & spirometry (will show restrictive pattern) X ray of hands for phalyngeal cysts Ultrasound to show splenomegaly
What is Sarcoidosis treatment?
1) Prednisolone (40-60mg for first 6 weeks, then taper down over 1 year)
2) Immunosuppressants (methotrexate, ciclosporin, cyclophosphamide)
3) Infliximab
4) Lung Transplant in unretractable cases
What is the other name for Extrinsic Allergic Alveolitis
Hypersensitivity Pneumonitis
What is the generalised mechanism of the umbrella terms Extrinsic Allergic Alveolitis/ Hypersensitivity Pneumonitis?
EAA/ HP are conditions in which sensitised individuals undergo pulmonary hypersensitivity reactions to seemingly ‘normal’ inhaled allergens.
What are the two stages of Extrinsic Allergic Alveolitis/ Hypersensitivity Pneumonitis?
In the acute phase, the alveoli are infiltrated with acute inflammatory cells.
With chronic exposure to the allergen(s) there is granuloma formation and IRREVERSIBLE obliterative bronchiolitis (the complete blockage of small airways)
What types of hypersensitivity reactions are responsible for Extrinsic Allergic Alveolitis/ Hypersensitivity Pneumonitis?
Types II & III
What are the 4 types of Extrinsic Allergic Alveolitis/ Hypersensitivity Pneumonitis and their respective allergens?
- Thermophilic bacteria – Farmers lung.
- Avian proteins – Bird fanciers lung
- Aspergillus Clavatus =Malt workers lung
- Thermoactinomyces Sacchari = Sugar worker’s lung
What are the Acute vs Chronic Symptoms & tests for EAA/ HP?
Acute= Fevers, rigors, dyspnoea, DRY COUGH. Chest X ray shows UPPER ZONE consolidation & restrictive spirometry during periods of exposure
Chronic= weight loss, Exertional dyspnoea. Chest X ray shows UPPER ZONE fibrosis & permanent restrictive spirometry
Treatment of EAA/ HP
Avoid allergen. In chronic cases prednisolone & O2 may be required
What does the umbrella term Pneumoconiosis represent?
Pneumoconiosis is the name given to a set of occupational lung diseases which is caused by dust being inhaled into the lungs over a prolonged period of time (>15 years).
What is the pathophysiology of Pneumoconiosis?
Dust particles are inhaled and digested by dust cells. Upon breakdown, macrophages release inflammatory enzymes and IL-1 which active fibroblasts which increase collagen deposition- thus causing fibrosis.
What are the different types of Pneumoconiosis and what dust particles are responsible for each type?
1) Coal worker’s Lung- caused by carbon dust
2) Asbestosis — asbestos fibres
3) Silicosis (potter’s rot) -crystalline silica dust
What are the buzzwords for Coal workers lung?
Asymptomatic chronic bronchitis
CXR will show MULTIPLE SMALL ROUND OPACITIES (1-10mm) IN UPPER ZONES OF THE LUNGS ( be aware rheumatoid conditions can present with nodules so history is key here)
What is the most fatal complication of ANY untreated Pneumoconiosis?
Progressive Massive Fibrosis (most commonly seen in cases of coal workers lung). Fibrosis of entire lung- fibrotic masses arising in upper zone & up to 10cm diameter
What are the buzzword X ray findings for silicosis?
CXR SHOWS EGG SHELL CALCIFICATION OF HILAR LYMPH NODES AND DIFFUSE NODULES IN UPPER ZONES IN LUNGS
How many types of Asbestos fibres are there and how dangerous is each type?
1) White fibres- least fibrogenic
2) Brown fibres- very rare and have intermediate fibrogenicity
3) Blue fibres- most fibrogenic
What are the 2 key clinical features of asbestosis?
Pleural plaques
Fine end respiratory crackles
What is mesothelioma?
Cancer of the mesothelial cells lining either the visceral pleura or the visceral pertioneum of other organs (rare) 99% of cases will have asbestos in the history. Mesothelioma can occur up to 45yrs after exposure.
How do we diagnose mesothelioma?
1) CXR/ CT shows pleural thickening &/or effusions
2) If Pleural fluid is aspirated- Blood will be present
3) Pleural biopsy is gold standard
Management for Mesothelioma?
Can use chemo but realistically. Compensation & a coffin.
What is the other name given to Interstitial Lung Disease?
Diffuse Parenchymal Lung Disease
