Resp interstitial Flashcards
Indications for corticosteroid treatment for sarcoidosis are:
parenchymal lung disease,
uveitis,
hypercalcaemia and
neurological or cardiac involvement
Compliance define
is defined as the volume change produced by a change in the distending pressure:
ΔV/ ΔP
Define elastic recoil
lung’s tendency to collapse and push the air back out
What happens during inhalation
diaphragm & intercostal muscles contract to pull the ribs up and out and expand the chest cavity. = vacuum that pulls the lungs open to allow air in
Decreased compliance and increased recoil of lung indicates
Restrictive
diffuse parenchymal lung diseases or DPLDs (interstitial lung diseases), the lung tissue itself is damaged. = fibrotic, rigid lung with reduced compliance and increased recoil
-doesnt allow air to enter during inhalation, thereby reducing lung volumes.
FVC define
air exhaled forcefully after taking a deep breath.
What is residual volume or RV? How is it measured?
air left in the lungs after exhaling as hard as possible
plethysmography
Define total lung capacity or TLC
FVC + RV
FRC define
volume of air that remains in the lungs after normal expiration.
FRC= RV + expiratory reserve,
Define PFT’s for restrictive lung d’s (5)
- Decrease FVC
- Decrease RV
- Reduction TLC, (FVC+RV)
4.Decrease FRC
5.Decrease in FEV1, - FEV1/FVC ratio= same or increased (increased elastic recoil)
Name the Diffuse parenchymal lung diseases or DPLDs (interstitial lung diseases)
- Granulomatous diseases,(sarcoidosis,hypersensitivity pneumonitis)
- Occupational exposures, (asbestosis, silicosis, berylliosis, and coal workers’ pneumoconiosis;
- miscellaneous diseases( RA, GPA, Goodpasture syndrome, pulmonary Langerhans cell histiocytosis,)
4.unknown cause-idiopathic pulmonary fibrosis.
Explain type 4 hypersensitive reaction in granuloma development
Type 4 hypersensitive rnx
1. antigen picked up APC, (dendritic cell or an alveolar macrophage)
2. APC then presents the antigen to a CD4+ T-helper cells, APC secrete **IL-12 **of a cause CD4+ receptor of Th cell, causing it to differentiate Th1 cell.
3. Th1 cells to start secreting IL-2, =T cells in the area proliferate,+ interferon gamma, which activates phagocytes like macrophages.
4. The activated macrophages, now called epithelioid macrophages surround the antigen, =a ball-like nodule called a granuloma, which is meant to “wall off” the antigen and prevent it from spreading.
5. when several activated macrophages fuse together. = , and have multiple nuclei, which are arranged peripherally in the shape of a horseshoe.
Why does Sarcoidosis have raised Ca2+
macrophages inside the granulomas cause an increased conversion of vitamin D to its active form (1,25-dihydroxycholecalciferol)
Sarcoidosis presentation to
- eye
-Hrt
-Joint
- Uveitis
- Dilatative or restrictive
- RA
Sarcoidosis presentation to
-liver
Sarcoidosis presentation in the liver
hepatomegaly, abdominal pain, cirrhosis or cholestatic liver disease with jaundice.
Signs of neurosarcoidosis
Bell’s palsy
What do find on BAL in sarcoid?
elevated CD4+/CD8+
Poor prognosis Sarcoidosis (5)
- insidious onset, symptoms > 6 months
- absence of erythema nodosum
- extrapulmonary manifestations: e.g. lupus pernio, splenomegaly
- CXR: stage III-IV features
- black African or African–Caribbean ethnicity
Stages of Sarcoidosis (0-4)
- stage 0 = normal
- stage 1 = bilateral hilar lymphadenopathy (BHL)
- stage 2 = BHL + interstitial infiltrates
- stage 3 = diffuse interstitial infiltrates only
- stage 4 = diffuse fibrosis
What is the role of ACE levels in Sarcoidosis?
ACE levels have a sensitivity of 60% & specificity of 70%. Thus not reliable in the diagnosis of sarcoidosis although they may have a role in monitoring disease activity.
Extrinsic allergic alveolitis/ Hypersensitivity pneumonitis
Is what type of hypersensitivity?
caused by immune-complex mediated tissue damage (type III hypersensitivity immune complex mediated) although delayed hypersensitivity (type IV) is also thought to play a role
Examples Extrinsic allergic alveolitis (4)
- bird fanciers’ lung: bird droppings
- Farmers lung: spores of Saccharopolyspora rectivirgula from wet hay (formerly Micropolyspora faeni)
- Malt workers’ lung: Aspergillus clavatus
- Mushroom workers’ lung: thermophilic actinomycetes*
Explain type III hypersensitivity immune complex mediated reaction in Examples Extrinsic allergic alveolitis
- Antigen is picked up by dendritic cells or alveolar macrophages which take it to the nearest lymph node, where they present it to Th1 cells.
- Th1 cells then activate B cells to produce IgG antibodies that go into the bloodstream,
- IgG antibodies meet the antigens= immune complexes.
