Restrictive lung disease - Sarcoidosis Flashcards
What is sarcoidosis?
This is a multisystem granulomatous (type IV hypersensitivity reaction) disorder of unknown aetiology. It most commonly involves the mediastinal lymph nodes and lungs.
What is a granuloma?
A mass or nodule composed of chronically inflamed tissue formed by the response of the mononuclear phagocyte system to an insoluble or slowly soluble antigen or irritant.
If the foreign substance is inert, the phagocytes turn over slowly; if the substance is toxic or reproducing, the cells turn over faster, producing a granuloma.
A granuloma is characterized by epithelioid multinucleate giant cells, as seen in tuberculosis.
What age range does sarcoidosis normally affect?
20-40 years
Which sex does sarcoidosis normally effect more?
Women
What type of granulomas are produced in sarcoidosis?
Non-caseating granulomas
What are the pulmonary features of sarcoidosis?
- Dry cough
- Progressive dyspnoea
- Decreased exercise tolerance
- Chest pain
What are non-pulmonary signs of sarcoidosis?
- Fatigue and weight loss
- Lymphadenopathy
- Hepatomegaly/Splenomegaly
- Uveitis/conjunctivits/Keratoconjunctivits sicca
- Glaucoma
- Terminal phalangeal bone cyst
- Lacrimal and parotid gland enlargement
- Bell’s palsy/Neuropathy
- Meningitis
- SOL
- Erythema nodosum
- Subcut nodules
- Cardiomyopathy
- Arrythmias
- Hypercalcaemia/hyperuricaemia
- Pituitary dysfunction
How does acute sarcoidosis commonly present?
Erythema nodosum +/- polyarthalgia
What are causes of bilateral hilar lymphadenopathy?
- Sarcoidosis
- Infection - TB, mycoplasma
- Malignancy
- Organic dust disease
- Extrinsic allergic alveolitis
- Histiocytosis
What is pulmonary infiltration with normal lung function suggestive of?
Sarcoidosis
What is the following?
Erythema nodosum
Eruption of red, tender nodules and plaques, predominantly over the lower extremities, especially the extensor surfaces. It is a form of panniculitis.
What is the mechanism behind the development of the following?
Erythema nodosum
Immune complexes form after exposure to an antigen and are deposited in venules around areas of subcutaneous fat and connective tissue. The subsequent inflammation causes the lesions.
What tests would you consider doing if you suspected sarcoidosis?
- Bedside - ECG, PFTs, eye exam
- Bloods - FBC, U+E’s, LFTs, serum ACE, Ca2+
- Imaging - CXR
- Specific - Tuberculin skin test, Bronchoscopy, 24 hr urine calcium, BA lavage, biopsy
Why would you perform an FBC when investigating sarcoidosis?
May be a mild normochromic, normocytic anaemia plus raised ESR.
What might you see on CXR in someone with sarcoidosis?
- Bilateral hilar lymphadenopathy
- Parenchymal lung disease
- Pulmonary fibrosis
What stage of sarcoidosis is the following CXR?
Stage 1 - BHL
What stage of sarcoidosis is the following?
Stage II - BHL + peripheral infiltrates
What stage of sarcoidosis is the following CXR?
Stage III - Peripheral infiltrates only
What stage of sarcoidosis is the following CXR?
Stage IV - end stage pulmonary fibrosis
What are the histological features of sarcoidosis?
Discrete non-caseating epithelioid and giant cell granulomas which coalesce to form larger nodules.
These nodules are predominantly found in relation to bronchovascular bundles, septae and the pleura.
