Hypersensitivity pneumonitis Flashcards
Antigens causing hypersensitivity pneumonitis
Farmers lung - saccharopolyposa reotivirgida
Saw mill workers lung
Bird fanciers lung - avian protein
Mushroom workers lung - themophilic actinomyecetes
Humidifier lung
Cheese washer
Suberosis
malt - aspergillus clavatus
HS pneumonitis presentation
Cough + SOB
Fever, weight loss
Can -> preogressive fibrosis
More in upper lobes
Lung sounds HS pneumonitis
Lung sounds - inspiratory squawk in upper zones
or crackles middle zones
What can meausre in brid fanciers lung
IgG antibodies
Treatment o HS pneumonitis
REMOVE antigen exposure
IMmunosupress- steroids, mycophenolate, cyclophosphamide
Chronic treatment for chronic fibrosing lung progressive diseases
Nintedanib
Dexamethasone and antiIL6 drugs
HS pneumonitis on CT
Ground glass
Small centrilobular nodules
Air trapping + AW limitation = AW mosaicism
Middle zones
Type of hypersensitivity reaction -> pneumonitis
Immune complex mediated tissue damage - type III
delayed IV - CHRNOCI
pROTEINS IN BIRD FANCIERS LUNG
avian proteins
What causes farmers lung
spores of Saccharopolyspora rectivirgula (formerly Micropolyspora faeni)
Symptoms in relation to symptoms exposure
Acute - 4-8 hrs after exposure
Subside in 24-48 hours
Chronic after long term low exposure
Acute HS pneumonitis vs chronic
Cough (productive or non-productive)
Dyspnoea
Fever
Malaise
Chest tightness
Acute type 1 respiratory failure may develop in severe cases
Chronic - insidious
Insidious cough/dyspnoea symptoms
Weight loss
Clubbing (50% of cases)
More widespread fibrotic changes mimicking idiopathic pulmonary fibrosis
What hear on auscultation in HS pneumonitis
Bilateral midzone inspiratory crepitations
Investigations HS p
FBC
ABG- esp if T1RF
Serum participant antibodies
CXR, HRCT
lung function - FVC + FEV1 , DLCO
Acute= restrictive, chronic = obstructive
Broncheolar lavage - BAL - fluid for antigens
What seen in BAL HS pneumonitis
Leucocytosis
Complications pneumonitis chronic
Chronic oxygen requirement
Widespread fibrosis may result in chronic hypoxaemia requiring long-term oxygen therapy at home
Decreased lung function will lead to a reduced ability to carry out physical activities and activities of daily living
What is allergic bronchopulmonary aspergillosis
When asperillus fumigatus colonises resp tract with compromised immunity eg atopy,asthma, CF causing AW ostruction, inflmaation, mucoid impaction -> bronchiectasis, fibrosis, AW compromise
What investigation can help with ABPA
Skin test for allergic reaction to aspergillus fumigatus
IgG and IgE againtst
Eosiniphilia
