Interstitial Lung Disease

Cough DDx

E:
cough variant asthma:
-post nasal drip
-GERD

post-viral cough:
-pertussis
-COPD
-ACE inhibitors

acute cough
u3 weeks
clinical
viral URI dx
r/o pneumonia

persistent cough
3-8 weeks

chronic cough
8+ weeks

no red flags:
r/o TB
r/o cancer

Dyspnea DDx

acute
pneumonia
COPD exacerbation
asthma
pneumothorax
PE
cardiac dx
pleural effusion
diffuse alveolar hemorrhage
etc.

chronic
COPD
interstitial lung dx (ILD)
pulmonary HTN
pulmonary alveolar proteinosis

Interstitial Lung Disease (ILD)

PP: injury to lung parenchyma→inflammatory response→persistent alveolitis→irreversible fibrosis→decreased gas exchange

E: idiopathic
mx
environmental/occupation exposure
viral
bx
fungal
primary pulmonary dxs
systemic dxs

CM: progressive dyspnea
non-productive cough
exercise→hypoxemia

PE: tachypnea
small lung volumes (shallow)
bibasilar late inspiratory crackles

DX: lung volume→decreased
diffusion capacity (DLCO)→decreased
6-minute walk distance→decreased

CXR
patchy distribution
ground glass/reitculonodular changes

CT
reticulation
architectural distortion
honeycombing

differentiation
hx
bronchoalveolar lavage (BAL)
transbronchial biopsy
surgical lung biopsy (open/VATS)

ILD Etiology (Full)

mx
amiodarone
nitrofurantoin
sulfas
bleomycin
cyclophosphamide
methotrexate
nitrosoureas
gold salts
penicillamine
phenytoin

environmental/occupation exposure
asbestos
silica
hard metals
beryollium
thermophyllic actinomyces
avian antigens
aspergillus species
gases
fumes
chlorine
isocyanates
paraquat
sulfur dioxide
ionizing radiation
injection mx→talc

fungal
cocciodioides immitis
blastomyces dermatidis
histoplasma capsulatum

bx
mycobacteria

viral
disseminated pneumocystis jirovecii

primary pulmonary dxs
cryptogenic organizing pneumonia (COP)
acute interstitial pneumonia (AIP)
desquamative interstitial pneumonia (DIP)
nonspecific interstitial pneumonia (NSIP)
pulmonary alveolar proteinosis

systemic dxs
acute respiratory distress syndrome (ARDS)
amyloidosis
ankylosing spondylitis
dermatomyositis
polymyositis
RA
systemic sclerosis/scleroderma
systematic lupus erythematosus
chronic eosinophilic pneumonia (CEP)
goodpasture sx
idiopathic pulmonary hemosiderosis
inflammatory bowel dx
langerhans cells histiocytosis/eosinophilic granuloma
lymphangitic spread of cancer/lymphangitic carcinomatosis
lymphangioleiomyomatosis
PE
pulmonary venous HTN
chronic sarcoidosis
granulmatosis polyangiitis (formerly wegener granulomatosis)

Usual Interstitial Pneumonia (UIP)

E: 55-60 y/o
male

CM: clubbing (25-50%)
inspiratory crackles

PE: diffuse+fine+late inspiratory crackles

DX:
PFT
restrictive ventilatory defect
reduced diffusing capacity
restrictive physiology

CXR→progressive fibrotic changes x years

ANA+RF→positive (25%)

HRCT
diffuse+patchy fibrosis
pleural honeycombing

TX:
NP: lung transplantation

MX: nitedanib
pirfenidone
no corticosteroids
no antifibrotic agents
no immunomodulator/immunosupressant agents

P: always progressive
median survival rate→3 years

Respiratory Bronchiolitis-Associated Interstitial Lung Disease (RB-ILD)

RF: heavy smokers

E: 40-45 y/o

CM: clubbing (25-50%)

PE: diffuse+fine+late inspiratory crackles

DX:
PFT
restrictive ventilatory defect
reduced diffusing capacity

ANA+RF→positive (25%)

TX:
NP: stop smoking (essential)
lung transplantation

MX: corticosteroids
prednisone x 2+months trial
nintedanib
pirfenidone
no antifibrotic agents
no immunomodulator/immunosupressant agents

P: spontaneous remission→20%
medial survival rate→10+ years

Acute Interstitial Pneumonia (AIP)/Hamman-Rich Syndrome

E: young
wide age range

CM: acute onset→respiratory failure
prodrome→viral syndrome (50%)
similar to idiopathic ARDS

TX:
NP: mechanical ventilation (critical)
lung transplantation

MX: corticosteroids
prednisone x 2+months trial
nintedanib
pirfenidone
no antifibrotic agents
no immunomodulator/immunosupressant agents

C: lung fxn normal
or
lung fxn permanent impairment

P: 2-month mortality rate→50-90%
pt survival→not progressive

Nonspecific Interstitial Pneumonia (NSIP)

E: 45-55 y/o
female

CM: cough/dyspnea x months (not years)
similar sx to UIP→clubbing (25-50%)

TX:
NP: stop smoking (essential)
lung transplantation

MX: corticosteroids
prednisone x 2+months trial
nintedanib
pirfenidone
no antifibrotic agents
no immunomodulator/immunosupressant agents

P: depends of extent of fibrosis
median survival rate→10+ years

Cryptogenic Organizing Pneumonia (COP)
Formerly Bronchiolitis Obliterans Organizing Pneumonia (BOOP)

E: 50-60 y/o
wide variation

CM: abrupt onset
weeks-months→flu-like illness
dyspnea
dry/non-productive cough
fatigue
fever
weight loss

DX:
PFT
restriction
concomitant obstruction (25%)

TX:
NP: stop smoking (essential)
lung transplantation

MX: corticosteroids
prednisone x 2+months trial
nintedanib
pirfenidone
no antifibrotic agents
no immunomodulator/immunosupressant agents

C: relapses common

P: tx response→good long-term prognosis

Restrictive Physiology On PFTs