Restrictive Lung Diseases

Physiology
	⁃	Opposing forces:
	⁃	Lungs kept open by chest wall.
	⁃	Ribs kept curved by lungs.
	⁃	Restriction Causes:
	⁃	Extrinsic: Pleura, chest wall, or muscles. 
	⁃	Intrinsic: Lung parenchyma
	⁃	Can have hypercapnia and hypoxia

Extrinsic
	⁃	Hypoxia is caused by ATX and shunt. Normal folks sats go up with exercise. In restriction it goes down due to progressive V/Q mismatch. ILD patients also have early desaturation with sleep. 
	⁃	In chest wall diseases FRC is decreased more than expected compared to TLC and RV.
	⁃	In weakness, tidal volumes going to look normal unless very, very severe.  However, during max effort, TLC will be decreased, FRC will be normal, ERV decreased, and RV increased.

Intrinsic
	⁃	Inflammation/Scarring (ILD) vs Air Space Filling (pneumonitis)
	⁃	CHF and PNA is restrictive due to air space filling.

ILD
	⁃	IPF accounts for almost half of all ILD
	⁃	IPF is increasing in all Western nations
	⁃	Affects all sections of the parenchyma so all share similar clinical, radiographic, physiologic, or pathologic manifestations
	⁃	Characteristics
	⁃	dyspnea (starts first upon exertion	
	⁃	restrictive PFTs
	⁃	excessive elastic recoil
	⁃	hypoxia 
	⁃	due to V/Q mismatch
	⁃	destruction of capillary beds
	⁃	hypoxia is worse with exercise due to increased perfusion which makes V/Q worse
	⁃	typically with increased WOB and shallow tidal volumes
	⁃	frequently useful to divide between with-granuloma and without-granuloma
	⁃	granuloma (nodular on HRCT)
	⁃	insult -> t cells -> CD4 -> Th1 and Th2 -> granuloma -> resolution vs scarring
	⁃	eosinophilic lung syndromes
	⁃	sarcoid
	⁃	langerhans cell granulomatosis
	⁃	granulomatous vasculitides
	⁃	hypersensitivity pneumonitis
	⁃	beryllium
	⁃	silica
	⁃	mycobacteria and fungi
	⁃	Imaging
	⁃	HRCT often more important than lung biopsy
	⁃	Reticular (interstitial) vs nodular (granulomatous)
	⁃	Interstitial ground glass = alveolitis
	⁃	Where predominant
	⁃	radiologist can make dx 60-80% of the time
	⁃	Lung biopsy
	⁃	transbronchial bx makes dx 40-80% of the time - especially for granulomas
	⁃	VATS needs 2 different lobs and honeycombing should be avoided
	⁃	BAL helpful
	⁃	pulmonary alveolar proteinosis - surfactant on stain
	⁃	infections and malignancy
	⁃	PIE (pulmonary interstitial eosinophils)
	⁃	Non Medication Treatment
	⁃	Permanent removal of offending agents if possible
	⁃	Early diagnosis and aggressive suppression of acute and chronic inflammatory processes
	⁃	Aggressive treatment of hypoxia
	⁃	Medication Treatments
	⁃	Steroids (especially for alveolitis)
	⁃	cyclophosphamide and azathioprine

Sarcoidosis
	⁃	classic granulomatous ILD
	⁃	can involve any organ
	⁃	if you find it in any organ, it’ll be in the lung 90% of the time even with normal CXR
	⁃	typically dx of radiography and symptoms
	⁃	radiographic staging is not progression ( stage 1 to 2, etc)
	⁃	self limited vs not self limited
	⁃	self limited: (stage 1 film)
	⁃	bilateral hilar nodes and enlarged paratracheal nodes
	⁃	not self limited 
	⁃	(stage 2) hilar adenopathy with diffuse parenchymal changes
	⁃	(stage 3) diffuse infiltrates without adenopathy
	⁃	(stage 4) burned out with fibrosis and cystic disease
	⁃	Often will see nodules in perivascular distribution. Thus transbronchial bx is very high yield. 
	⁃	Pathology is non-caveating granuloma with histiocytes, lymphocytes and giant cells
	⁃	Diagnosis of exclusion
	⁃	ACE levels aren’t very helpful. Many people with sarcoid have negative ACE. If elevated, its a marker of disease and response to therapy.
	⁃	Who to Treat?
	⁃	self limit - about 3/4 will remit over 2 years
	⁃	Only 5-15% progress to fibrosis and respiratory failure
	⁃	Treat with symptoms or progressive disease
	⁃	20% in lung volumes
	⁃	Disease in CNS, heart, etc.
	⁃	Drugs
	⁃	Steroids
	⁃	MTX, azathioprine, hydroxychloroquine (skin more than lung)
	⁃	Remicade (anti TNF alpha)
	⁃	Should be considered in severe or other organ system disease
	⁃	common drug side effect is TB reactivation because of granuloma distraction

IPF
	⁃	Typically over age 50
	⁃	Progressive exertion dyspnea and non-productive cough
	⁃	50% clubbing, 90-100% crackles
	⁃	Often will be worked up for CHF first
	⁃	median survival 4-6 years (unchanged in 15 years)
	⁃	HRCT with honeycombing but still diagnosis of exclusion
	⁃	Atypical, surgical bx should be obtained
	⁃	Prevalence increases with age
	⁃	Males 2-4: Females 1
	⁃	Pathology is UIP
	⁃	Hold up to light. honeycombed areas will show up when held up to room light.
	⁃	Normal adjacent lung tissue. Different temporal.
	⁃	Contrast with NSIP which is homogenous and all got hit together.
	⁃	pathologists often disagree in both NSIP and UIP although mild improvement with 2 lobes
	⁃	Radiographical
	⁃	irregular reticular abnormalities
	⁃	sub pleural, posterior, and lower lobe predominance
	⁃	sub pleural honecombing
	⁃	min ground-glass
	⁃	late traction bronchiectasis
	⁃	mild LAD
	⁃	Consider alternative:
	⁃	pleural effusion
	⁃	pleural thickening
	⁃	moderate ground glass
	⁃	large LAD
	⁃	central lobular nodules and cysts
	⁃	Consider prone scan for early disease

Pneumoconioses
	⁃	Can be example of crossover between fibrosis and granulomatous ILD.
	⁃	Non-fibrogenic are less likely to cause problems.
	⁃	All have associations with smoking and COPD.
	⁃	Increased risk of developing RA and 2-3X greater risk adenocarcinoma.
	⁃	fibrosis
	⁃	asbestosis
	⁃	multinodular or reticular
	⁃	pleural plaques are “tattoo” of asbestosis (50%)
	⁃	benign asbestosis pleural effusions
	⁃	path: asbestos bodies
	⁃	risk of adenocarcinoma and mesotheloma
	⁃	silicosis
	⁃	ceramics 
	⁃	upper lobe nodules and progress to massive fibrosis
	⁃	coal workers pneumoconiosis
	⁃	hard metal pneumoconiosis
	⁃	non-fibrosis
	⁃	aluminosis
	⁃	anthracosis
	⁃	siderosis (iron)
	⁃	stannosis (tin)
	⁃	talcosis
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