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what are the physical, chemical, humoral and cellular defences of the innate immunity of respiratory tract?
- phsical: nasal turbinates, hair, mucociliary escalator
- chemical: defensins, surfactant
- humoral: complement
- cellular: neutrophila, macrophage, eosinophils, mast cells
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which Ab is predominantly secreted in the PROXIMAL airway?
IgA
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which T cell subset is predominant in the PROXIMAL airway?
CD4
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which Ab is predominantly secreted in the DISTAL airway?
IgG
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give an example of a PRIMARY immunodeficiency
x-linked agammaglobulinaemia
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give an example of a SECONDARY immunodeficiency
related to underlying disease e.g. HIV or postBM transplant
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what is the commonest innate immunodeficiency of the lung? and how does it cause immunodeficiency?
cigarette smoking: paralyses mucociliary escalator
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why do ex-smokers initially suffer increased cough?
no mucociliary escalator
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what is primary ciliary dyskinesia? what are consequences? (2)
- rare genetic condition affecting ciliary function
- leading to reps infection and INFERTILITY
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how do patients with Ab deficiency present?
infection of sino-pulmonary tract (strep pneum, h.infl)
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is 2ry Ab deficiency common or rare?
common
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what can cause secondary Ab defiency?
- IgG loss: kidneys (nephrotic syndrome), gut (protein losing gut enteropathy, skin (massive burns)
- IgG impaired production: systemic illness malabsorption, sepsis
- IgG suppression of production: BM failure e.g. in leukaemia
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give an example of primary Ab deficiency?
x-linked agammaglobulinaemia
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what is the commonest severe antibody deficiency in adults?
common variable immunodeficiency
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in adults what is the commonest cause of cellular immunodeficiency?
secondary to HIV get low CD4 levels - permit opportunistic infection with fungi PCP or CMV
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what is type1 hypersensitivity reaction and give an e.g.?
IgE mediated, allergic diseases, atopy..
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what is type2 hypersensitivity reaction and give an e.g.?
direct antibody mediated eg Goodpasture's syndrome, M.Gravis (antiAChR Ab)
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what is type3 hypersensitivity reaction and give an e.g.?
immune complex mediated e.g. hypersensitivity pneumonitis, EAA - get an Ab against an inhaled substance, SLE
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what is type4 hypersensitivity? e.g.?
- cell mediated, delayed type
- sarcoidosis, TB, asbestos
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what are the 2 Inx for allergy?
- 1. skin prick test: allergen introduced and reaction (wheal and flare) inspected after 15 mins. NB if already taking anti-histamines this test wouldn't work
- 2. Antigen specific IgE test by ELISA (still called RAST radioallergosorbant)
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what is the action of the Th2 cytokine IL-5?
eosinophilia
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which Th2 cytokines provoke mucus hypersecretion and SM contraction and more Ab prod?
IL4, IL13
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what component of BM are Goodpastures Ab directed to?
collagen IV
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give 2 symptoms of Goodpastures
- renal failure
- pulmonary haemorrhage - smokers
-
what is farmer's lung?
- hypersensitivity pneumonitis. type 3 hypersensitivity (immune complex)
- inhale Ag e.g. mouldy hay - develop IgG Ab
- on re-exposure the formation of Ag-Ab complexes leads to acute pneumonitis:
- cough, fever, SOB
- illness subsides over DAYS if antigen is removed
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what is the lab test for farmer's lung
measure precipitating antibodies against antigens e.g. mould
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give 2 examples of small vessel vasculitis
- Churg Strauss disease
- Wegener's granulomatosis
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give 2 examples of medium vessel vasculitis
Kawasaki, polyarteritis nodosa
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give 2 examples of large vessel vasculitis
giant cell arteritis (aka temporal arteritis), Takayasu's arteritis
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what are the general Ix done in systemic vasculitis?
- urinalysis - protein/blood
- urea & creatinine - renal failure
- U&Es
- CRP/ESR - monitor response to Rx
- Blood cultures - exclude endocarditis
- cryoglobulings - Ig precipitated by cold - deposit in fingers - vasculitis
- Transfer factor - increased in pulmonary haemorrhage (NB decreased in COPD)
- autoimmune serology: antiBM, pANCA
- lung and renal imaging
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what situation may transfer factor be increased in?
pulmonary haemorrhage
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what does pANCA mean? and which antibodies and diseases is it assoc. with?
- peripheral antineutrophil cytoplasmic antibody
- antibodies: MPO (myeloperoxidase)
- disease: microscopic polyangiitis, Churg Strauss syndrome, PSC
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what does cANCA mean? which antibodies and disease is it assoc. with?
- cytoplasmic antineutrophil cytomasmic antibodies
- antibodies: PR3 (proteinase 3)
- disease: Wegener's granulomatosis (90% sensitivity)
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if ANA is positive, what will the lab go on to test?
- dsDNA: lupus
- AB against ENA (extractable nuclear antigens) e.g. Ro=lupus/Sjorens; La=lupus; Sm=lupus, RNP=mixed CT diseaes; Scl70=systemic sclerosis; Jo1=polymyositis
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what is Churg Strauss also known as? and what is it linked to? which Ab?
- eosinophilic vasculitis
- linked to atopy and asthma
- pANCA/MPO positive
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where do you get symptoms in Churg Strauss?
- lower and upper resp tract
- sinusitis
- lung
- peripheral neuropathy: inflam of epineural vessels - leading to mononeuritis multiplex
- skin: rash
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what is the difference between cause and symptoms Goodpastures and Wegeners granulomatosis?
- Goodpastures syndrome: type2 hypersensitivity, direct Ab mediated, Ab against type4collagen of BM of lung and glomerular. get renal failure and pulmonary haemorrhage due to capillarities
- Wegeners granulomatosis: necrotising small vessel vasculitis. affects upper and lower resp tract, skin and kidneys.
- nasal inflam - collapsed nasal bridge
- sinus involvement - perforate palate or orbital plate
- lung - cavitiating lesions on CXR so confuse with TB and lung cancer
- 90% cANCA/PR3+
-
what is the difference between empyema and abscess?
- empyema: collection of pus in a PRE-EXISTING anatomical cavity eg pleural cavity
- abscess: collection of pus in a NEWLY FORMED cavity
-
give 3 examples of inorganic pneumoconiosis?
- coal dust: anthracosis
- asbestosis
- silica: silicosis
-
what can inorganic pneumoconiosis present as?
- often clinically insig
- or direct interstitial fibrosis and bad resp compromise
-
what is pathology of inorganic pneumoconiosis?
inflam in interstitial, pleural effusions and fibrotic nodules
-
what is the syndrome when inorganic pneumoconiosis are assoc. with RA?
Caplan's syndrome
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name 2 types of organic pneumoconiosis and their causative agent and general pathology?
- farmers' lung: actinomycetes in mouldy hay (fungal derived bacteria)
- bird fanciers' lung: animal proteins from faeces (birds)
- aka EAA/hypersensitivity pneumonitis
- sensitisation to organic inhaled allergen
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what is the initial and later type of hypersens in organic pneumoconiosis?
- initial: type 3 immune complexes
- later: type 4 cell mediated response with granulomatous inflame
-
what 2 values are raised in sarcoidosis?
-
what is different to the granulomatous inflam in sarcoidosis compared to e.g. TB/wegeners?
- no necrosis in sarcoid
- just very round giant cells with epithelia cells around them
-
what is honeycomb lung? and what is it a feature of?
- idiopathic pulmonary fibrosis
- it is interstitial fibrosis leading to cystic air spaces
-
name 3 complications of interstitial lung diseases:
- resp failure type 1 (as restrictive)
- pulm hypertension
- cor pulmonale
-
which cells in the alveoli make surfactant?
type 2 pneumocytes
-
what are the complications of COPD?
- pneumonia (as inc mucus)
- pulm htn
- cor pulmonale
- respiratory failure type 2 (as obstructive)
- polycythaemia due to hypoxia
- pneumothorax: if the cystic spaces in the lung rupture then air into pleural space
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how does the TLC differ in COPD from interstitial lung disease?
- COPD: TLC increased due to inc RV as there is inc airway resistance from obstruction
- interstitial lung disease: TLC decreased due to decreased lung COMPLIANCE
- NB diffusion capacity is reduced in both
-
what is the definition of chronic bronchitis? (6marks)
- clinical definition
- chronic sputum
- chronic cough
- on most days for 3 months a year
- for 2 consecutive years
- when not due to a specific disease e.g. TB
-
what is the definition of emphysema? 5 marks
- pathological definition
- abnormal permanent increase in the size of air spaces
- beyond terminal bronchiole
- with destruction of their walls
- but WITHOUT fibrosis
-
what is emphysema an imbalance of?
protease and antiprotease
-
what is the most common protease inhib?
alpha 1 antitrypsin
-
what 2 things do neutrophils release?
- protease
- oxygen free radicals
-
what 2 things inhibit alpha 1 antitrypsin?
- oxygen free rads (made by neutrophils)
- oxidants from cigarette smoke
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what is the 2 main classification of emphysema, association, where located?
- Centriacinar: cigarette smoke, upper zones, increased protease 2ry to airway inflame
- Panacinar: alpha 1 antitrypsin deficiency, lower zones, decreased anti protease activity
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what is the inheritance of alpha 1 antitrypsin and clinical sign?
- auto RECESSIVE
- Pi = protease inhibitor
- PiZZ (homozygous): emphysema before 40yo
- heterozygous: emphysema IF SMOKE
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what is the most common type of asthma?
atopic asthma
-
what is the difference between atopic and non-atopic asthma? (mechanism, triggers, age, sex, FH, tests)
- atopic (extrinsic): type1 hypersen, triggers are dust, pollen, animal dander, food, childhood, m>f, FH of atopy, skin prick test +ve wheal and flare to identify allergen
- non atopic (intrinsic): hyperactivity of airways, triggers: cold, stress, exercise, aspirin, viral, f>m, adult onset, no FH, skin prick test -ve
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which drug can cause drug induced asthma?
aspirin
-
what are the features of drug induced asthma?
nasal polyps, urticaria
-
how many phases contribute to the pathogenesis of asthma - airway obstruction?
- acute response(immediate): smooth muscle spasm, mucosal oedema
- late phase(12-24hrs): epithelial damage, inflame, mucus exudation
- chronic phase(with repitition): mucus gland hyperplasia, SM hypertrophy, bronchial BM thickening
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