Interstitial and Occupational Lung Diseases 1, 2 and 3 Flashcards
What are interstitial diseases of the lung?
Any disease process affecting the lung interstitium/ parenchyma in a diffuse manner i.e. alveoli and terminal bronchi
So interstitial diseases have a restrictive or obstructive lung pattern?
Restrictive
What are the characteristic features of interstitial lung disease in terms of the lung tissue?
Chronic inflammation+/- progressive interstitial fibrosis
2 main symptoms of an interstitial lung disease?
BreathlessnessDry cough
What are the 3 main categories, in terms of time, of interstitial lung disease?
AcuteEpisodicChronic (part of systemic disease, exposure to agent, idiopathic)
What are the 4 main types of interstitial lung diseases?
ILD of known cause or associationIdiopathic interstitial pneumoniaGranulomatous ILDsOther forms of ILD
How is idiopathic interstitial pneumonia categorised?
Either idiopathic pulmonary fibrosisIdiopathic Interstitial pneumonia that isn’t IPF
What are the 6 causes of idiopathic interstitial pneumonia that are not idiopathic pulmonary fibrosis?
Desquamative interstitial pneumoniaRespiratory bronchiolitis interstitial lung diseaseAcute interstitial pneumoniaCryptogenic organising pneumoniaLymphocytic interstitial pneumoniaNon-specific interstitial pneumonia (NSIP)
What are the 2 most important granulomatous ILDs to remember?
SarcoidosisExtrinsic allergic alveolitis
What is sarcoidosis?
A granulomatous disease of unknown cause
What type of hypersensitivity reaction is sarcoidosis?
Type 4
What systems are commonly affected by sarcoidosis? (6)What systems are less commonly affected by sarcoidosis? (4)
Commonly:Lungs, lymph nodes, joints, liver, skin, eyesLess commonly:Kidneys, brain, nerves, heart
Are the granulomas in sarcoidosis caseating or non-caveating?
non-caseating(TB = caseating)
Is sarcoidosis more or less common in smokers?
Less
What are the 2 types of sarcoidosis?
AcuteChronic
What are the symptoms of acute sarcoidosis?
Erythema nodosumBilateral hilar lymphadenopathyArthritisUveitis, parotitisFever(patient will feel generally unwell)
Symptoms of chronic sarcoidosis?
Lung infiltrates (alveolitis)Skin infiltrationsPeripheral lymphadenopathyHypercalcaemiaOther organs = renal, myocardial neurological, hepatitis, splenomegaly(symptoms come on more insidiously)
Investigations for sarcoidosis? (5)
Chest x-ray (BHL)CT scan of lungs (peripheral nodular infiltrate)Tissue biopsy (e.g. transbronchial, skin, lymph node) for non-caeseating granulomaPulmonary function (restrictive lung pattern)Blood tests (ACEI as activity marker - not diagnostic test, raised calcium, raised inflammatory markers)
Treatment of acute sarcoidosis?
Self-limiting condition = usually no treatment required - steroids if vital organ affected
Treatment of chronic sarcoidosis?
Ora steroids usually neededImmunosupression e.g. aathioprine, methotrexate, anti-TNF therapy(monitor chest x-ray and pulmonary function for several years as often relapses)
What is another name for extrinsic allergic alveolitis?
Hypersensitivity pneumonitis
What type of hypersensitivity is extrinsic allergic alveolitis?
Type III hypersensitivty (predominantly - there is also a type 4 reaction)
What happens in extrinsic allergic alveolitis?
In sensitised individuals, inhalation of allergens (fungal spores, thermophilic bacteria or avian proteins) causes a hypersensitivity reactionIn the acute phase, alveoli are infiltrated with acute inflammatory cellsWith chronic exposure, granulomas form and obliterative bronchiolitis occurs
Types of extrinsic allergic alveolitis caused by exposure to protein in avian droplets?
Bird fanciers lungPigeon fanciers lung
Type of extrinsic allergic alveolitis due to exposure to aspergillus clavatus?
Malt workers lung
Type of extrinsic allergic alveolitis due to exposure to micropolyspora faeni usually seen in farmers caused by mouldy hay?
Farmers lung
Type of extrinsic allergic alveolitis typically seen in people who work with mushrooms due to exposure to thermoactinomyces vulgaris?
Mushroom workers lung
Drugs that can cause extrinsic allergic alveolitis? (3)
GoldBleomycinSulphasalazine (rheumatoid arthritis)(no cause identified in approx 30% of cases of extrinsic allergic alveolitis)
2 types of extrinsic allergic alveolitis?
AcuteChronic
Symptoms of acute extrinsic allergic alveolitis?Onset of symptoms?
CoughBreathlessnessFeverMyalgiaClassical several hours after acute exposure
Signs of acute extrinsic allergic alveolus?
+/- pyrexiaCrackles (no wheeze)Hypoxia
Appearance of a chest x-ray in a patient with acute extrinsic allergic alveolitis?
Widespread pulmonary infiltrates
Treatment of extrinsic allergic alveolitis?
OxygenSteroidAntigen avoidance
What causes chronic extrinsic allergic alveolitis?
Repeated low dose antigen exposure over time (years) leading to progressive breathlessness and a cough