Respiratory ILD Flashcards
define ILD/ DPLD
group of lung diseases affecting the interstitium (alveolar epithelium, pulmonary capillary endothelium, basement membrane, perivascular and perilymphatic tissue). ILDs interfere with gas transfer. They cause a restrictive pattern. Symptoms: breathlessness, dry cough. ILD can be acute/ episodic/ chronic (chronic can be part of systemic disease/ due to chronic exposure to an agent/ idiopathic)
What are the 4 main categories of ILD?
- ILD of known cause e.g.drugs/ collagen vascular disease
- Idiopathic Interstitial Pneumonia (IIP)
- Granulomatous ILDs e.g. sarcoidosis, EAA
- Other forms of ILD e.g. LAM
What are the 8 types of Idiopathic interstitial pneumonia?
- Idiopathic pulmonary fibrosis
- Desquamative interstitial pneumonia
- Acute interstitial pneumonia
- non-specific interstitial pneumonia
- Lymphocytic interstitial pneumonia
- Cryptogenic organising pneumonia
- IIP other than IPF
Collagen Vascular disease
A group of disease which affect the connective tissue (can cause ILD of known origin)
Idiopathic pulmonary fibrosis
a chronic and ultimately fatal disease characterised by a progressive worsening dyspnea. Poor prognosis.
Desquamative interstitial pneumonia
Form of IPF featuring elevated levels of macrophages. Name is derived from former belief that these macrophages were pneumocytes (alveolar cells) that had been desquamated. This disease is associated with people who have smoking history.
Respiratory bronchiolitis interstitial lung disease
Associated with smoking.
This is a histological finding, not a pathological description. Appearance is similar to that of desquamative interstitial pneumonia
Acute interstitial pneumonia
Rare, severe, usually affects otherwise health individuals. No known cause or cure, often characterised as an ILD, but is also a form of ARDS
Cryptogenic organising pneumonia (AKA bronchiolitis obliterans organising pneumonia (BOOP))
inflammation of the bronchioles and surrounding tissue of the lugs. Often a complication of existing inflammatory disease e.g. rheumatoid arthritis. “Organising” refers to unresolved pneumonia (the alveolar exudate persists and eventually undergoes fibrosis). That phase of resolution/ remodelling following bacterial infections is commonly referred to as organising pneumonia.
Non-specific interstitial pneumonia (NSIP)
2 different disease patterns with different prognoses: cellular, and fibrosing. Cellular pattern has chronic inflammation and minimal fibrosis. Fibrosing pattern has interstitial fibrosis with various inflammation levels. Both patterns are uniform and lack the prominent fibroblastic foci that are found in other types of IIP.
Lymphocytic interstitial pneumonia
A syndrome secondary to autoimmune and other lymphoproliferative disorders
Sarcoidosis
Disease involving abnormal collections of inflammatory cells that form lumps known as granulomas. Granulomas are non-caseating - unknown aetiology (but probably infective agent in susceptible individual, imbalance of immune system with type 4 hypersensitivity). LESS common in smokers. There is genetic pre-disposition for sarcoidosis.
LAM (Lymphangioleiomyomatosis)
Rare, progressive and systemic disease that results in cystic lung destruction. Mostly affects women of child-bearing age. Lung destruction is consequence of diffuse infiltrationof neoplastic smooth muscle-like cells, which invade all lung structures including lymphatics, airway walls, blood vessels, and interstitial spaces. Consequences of obstruction of vessels and airways include chylous fluid accumulations, haemoptysis, airflow obstruction, pneumothorax.
Clinical features of acute sarcoidosis
-erythema nodosum
-bilateral hilar lymphadenopathy
-arthritis
-uveitis
-parotitis
-fever
The disease often settles in a couple of months without treatment
Clinical features of chronic sarcoidosis
- lung infiltrates (alveolitis)
- skin infiltrations
- peripheral lymphadenopathy
- hypercalcaemia
- other organs: renal, myocardial, neurological, hepatitis, splenomegaly
Key difference between TB and sarcoidosis? (Both are granulomatous).
TB is infective, unlike sarcoidosis
Differential Diagnosis of Sarcoidosis
- TB: but TB is infective
- Carcinoma: lung cancer often spreads to lymph nodes, giving high calcium and enlarger hilar
- fungal infection?
- Do a blood test (ACE levels raised in granulomatous diseases), check CRP, plasma viscosity, raised calcium
Treatment of acute sarcoidosis
no treatment
steroids if vital organ affected
Treatment of chronic sarcoidosis
oral steroids usually needed, immunosuppression
Extrinsic Allergic Alveolitis (EAA) AKA hypersensitivity pneumonitis
inflammation of the alveoli casued by type 3 hypersensitivity reaction to allergen (inhaled dusts)
caused by thermophilic actinomycetes e.g. farmer’s lung, avian antigens (bird fancier’s lung), drugs
No cause identified in 30% cases. Can be acute or chronic
Clinical features and treatment of acute EAA
cough, breathless, fever, myalgia, symptoms occur hours after exposure, crackles (no wheeze), hypoxia, CXR shows widespread pulmonary infiltrates
Treatment: oxygen, steroid, antigen avoidance
Clinical features and Treatment of Chronic EAA
may be crackles, clubbing is unusual (unlike other types of pulmonary fibrosis), CXR shows pulmonary fibrosis (mostly in upper zones), PFTs are restrictive.
Diagnosis: history, preciptins (IgG to specific antien(s)), lung biopsy if in doubt
Treatment: remove antigen exposure, oral steroids if breathless or low gas transfer
Idiopathic pulmonary fibrosis
most important of all the ILDs. More common in smokers and in men
Aetiology unknown: could be imbalance of fibrotic repair system/ related to gastric reflux
It is NOT an inflammatory disease.
Secondary causes could be: rheumatoid/ SLE/ systemic sclerosis/ asbestos/ drugs
Doesn’t respond to anti-inflammatories (since it’s not an inflammatory disease)
Clinical features of IPF
progressive breathlessness, dry cough, clubbing, bilateral fine inspiratory crackles, restrictive pattern, reduced lung volumes, low gas transfer
CXR shows bilateral infiltrates
CT shows reticulonodular fibrotic shadowing, worse at lung bases and periphery, traction bronchiectasis (subtype of bronchiectasis in which there is irreversible dilation of bronchi and bronchioles in areas of pulmonary fibrosis or distorted lung parenchyma), honey-combing cystic changes. Lung biopsy not necessary if CT diagnostic
