Interstitial lung diseases Flashcards
what is the lung interstitium
Lung interstitium is the region of the alveolar wall exclusive of and separating the basement membranes of alveolar epithelial and pulmonary capillary endothelial cells.
what is interstitial lung disease categorized by
- a group of pulmonary disorders (>200) characterized by a similar pathology with an insidious and progressive presentation of :
- damaged alveoli and surrounding tissue
- dyspnea on exertion
- dry cough
- late inspiratory rales
- CXR with septal thickening and reticulonodular changes
what structures are affected by ILD
a collection of support tissues within the lung that includes:
* alveolar epithelium
* pulm capillary endothelium
* alveolar basement membrane
* perivascular tissues
* perilymphatic tissues
(Layman’s Terms: the tissue and space around the air sacs of the lungs)
what is the frequency of ILDs in the following diagnoses:
- idiopathic pulmonary fibrosis
- occupational and environmental
- sarcoidosis
- drug and radiation
- idiopathic pulmonary fibrosis - 55%
- occupational and environmental - 26%
- sarcoidosis - 10%
- drug and radiation - 1%
what is the pathophysiology of ILD
injury to the alveolar epithelial or capillary endothelial cells (alveolitis) leads to progressive, irreversible scarring and stiffness of lung parenchyma
this results in poor O2 exchange
what is included in lung parenchyma
bronchioles, alveoli and capillaries
what is the mechanism of ILD
repetitive and/or excessive injury followed by dysregulation of tissue repair
what can cause dysregualtion of tissue repair
genetic predisposition
autoimune d/o
superimposed diseases
what are the two histopathological categories of ILD
granulomatous lung disease
inflammation/fibrosis
what occurs during granulomatous lung disease
accumulation of T lymphocytes, macrophages, and epithelioid cells¹ organized into discrete structures (granulomas) within in the lung parenchyma
granulomas then become fibrotic
what occurs during inflammation/fibrosis of the lung
repetitive injury results in chronic inflammation leading to fibrotic alveoli
what are possible eitologies of ILD
medication related
environmental
infectious
primary pulm disorders
systemic disroders
what is the onset time line of the majority of ILD
chronic - months to years
what is the MC age of presentation in ILD
20-40
what about a patients social history would increase risk of ILD
smoking
occupational or environmental exposure
if a patients ILD is onset days-weeks what is likely the etiology
- allergy
- acute interstitial pneumonia
- hypersensitivity penumonitis
what are symptoms associated with ILD
fatigue
weight loss
worsening dyspnea (MC)
nonproductive cough (MC)
when would you see extrapulmonary symptoms in ILD
only if it is associated with a connective tissue disorder
what physical exam findings are associated with ILD
- cachexia
- tachypnea
- late inspiratory rales (often heard first bibasilar in posterior axillary line, less common in granulomatous)
- rhonchi (aka sonorus rhonchus)
what does late ILD present as on PE
- digital clubbing
- pulm HTN
also this:
what would a CXR show in ILD
bibasilar reticular and/or reticulonodular pattern with honeycombing in late stage
honeycombing indicates poor prognosis
what is the preferred imaging for ILD
HRCT (she said we dont really need to know what it shows for this_)
what would you order to workup ILD
- PFTs includeing:
- spirometry
- DLco
- pulse ox
- 6MWT
- ABG
- EKG
how do ILDs resent on spirometry
most are restrictive but if sarcoidosis or hypersensitivity then will be obstructive.
also shows obstructive if mixed w COPD
what DLco is common in ILD
< 80% DLco is common in ILD but not specific
how does pulse ox and ABG ususally present in ILD
normal until late disease
what would a 6MWT show in ILD
desaturation <88% during 6 minute walk test (6MWT) is associated with increased mortality
what would you see in a ILD pt on EKG
normal unless pulm HTN:
pulm HTN: right axis deviation, evidence of right ventricular hypertrophy or right atrial enlargement
what additional specialty workup can be done in ILD
- bronchoalveolar lavage
- lung biopsy
(these arent done often)
what is a bronchoalveolar lavage and how does it present in ILD
- obtains samples of cells and pulmonary fluid for assessment of cell count, cultures and cytologic analysis
- BAL in ILD is usually nonspecific²
when is a lung biopsy used in ILD workup and what would you evaluate in the biopsy?
- last resort to confirm/stage disease
- the histopathologic pattern is evaluated in combination with the clinical information to determine the diagnosis
what is the managment goals for an asymptomatic ILD patient
reduce risk factors (smoking cessation, remove offending agent)
what is the managment goals for symptomatic ILD patients
- remove offending agent (if known)
- manage hypoxemia (oxygen)
- suppression of inflammatory process (steroids)
- improve quality of life (pulmonary rehab)
- manage complications (pulmonary hypertension and cor pulmonale¹)
what is the term used to describe RV enlargement, dysfunction and subsequent failure
cor pulmonale
when is supplemental oxygen indicated in ILD and what is the treatment goal
- indicated at <88% O2 (at rest or with exertion)
- goal - 90-92%
what pharmacotherapy is suggested to decerase inflammation in ILD
glucocorticoids (prednisone) for 4-12 weeks and then if patient is stable, they can be tapered down over another 4-12 weeks
if there is no improvement in inflammation with glucocorticoids, what other pharmacotherapy is initiated for ILD
immunosuppressent will be added to steroid. such as:
- cyclophosphamide
- azathioprine
- mycophenolate mofetil
what is included in pulmonary rehabilitation in ILD treatment
we learned this already but just in case!
how often should ILD patients follow up
every 3-6 months
during visits they should:
- reassess symptoms, PFTs
- monitor for comorbid conditions
what is patient education that should be given about ILD
- fibrosis is irreversible
- compliance is vital to slow progression
what is the pathophysiology theory about idiopathic pulmonary fibrosis
- An epithelial-fibroblastic disease, in which endogenous or environmental stimuli disrupt the homeostasis of alveolar epithelial cells leading to abnormal epithelial cell repair and fibrosis
- Excessive production and dysregulation of myofibroblasts
what are clinical findings of idiopathic pulmonary fibrosis
gradual onset of exertional dyspnea with nonproductive cough
what is the MC onset and demographic for idiopathic pulmonary fibrosis
MC onset 55-60y/o with slight male predominance
what PE findings are in idiopathic pulmonary fibrosis
fine inspiratory rales/crackles with or without digital clubbing
what is found on PFT studies for Idiopathic pulmonary fibrosis
- restrictive PFT pattern
- reduced DLco
- hypoxemia worsened with exercise
what radiologic findings are seen in idiopathic pulmonary fibrosis
HRCT scan typically shows:
* bibasilar, reticular opacities
* traction bronchiectasis
* honeycombing
what must you do to observe histology of idiopathic pulmonary fibrosis
open or VATS biopsy to obtain histology results
what does histology show in idiopathic pulmonary fibrosis
alternating areas of healthy lung, interstitial inflammation, fibrosis, and honeycomb change
fibrosis will predominate over inflammation
how do you manage idiopathic pulmonary fibrosis
- glucocorticoids NOT recommended
- antifibrotics - nintedanib or pirfenidone
- refer for lung transplant!!
- encourage patients to apply for clinical trials!
what type of drug is nintedanib
tyrosine kinase inhibitor
what type of drug is pirfenidone
anti-inflammatory agent, antifibrotic agent
what do antifibrotics (nintedanib and pirfenidone) do to treat idiopathic pulmonary fibrosis
do not reverse fibrosis but can prevent further scarring!
what are the risks and CI of antifibrotics
high risk of drug induced liver injury and CI in liver disease
must monitor LFTs prior to therapy and then Q monthly for 6 months then Q 3 months
what may be associated with acute exacerbations of idiopathic pulmonary fibrosis
COVID-19 mRNA vaccine
what is the new class of agent being studied that has both antifibtoric and immunomodulatory effects
phosphodiesterase 4B inhibitors
what is sarcoidosis
an inflammatory disease, of unknown etiology¹, characterized by the presence of noncaseating² (non-necrotizing) granulomas involving two or more organ systems
what is the MC organs effected in sarcoidosis
- lungs including mediastinal lymph nodes (MC)
- skin and eyes
who is sarcoidosis MC in
African american women and Northern Europeans
age onset 20-60 (seriously, come on. )
how does sarcoidosis tend to present in african american females? how is it different from presentation in NE descent?
AA women - acute, severe disease
NE - mild, chronic disease
what are presentation findings in sarcoidosis
- dyspnea and cough x 2-4 weeks
- ROS with fever, fatigue, night sweats and weight loss.
- lung exam normal
when in sarcoidosis would you see wheezing on lung exam?
only if there is endobronchial involvement or traction bronchiectasis due to scarring
what are the findings of the skin in sarcoidosis
- erythema nodosum (LE panniculitis)
- lupus pernio (vesicular rash on cheeks/nose)
- maculopapular lesions (MC chronic form of disease)
what all should be done during an eye PE for sarcoidosis
PE should include visual acuity, tonometry, slit lamp, and fundoscopic testing
what ocular findings present in sarcoidosis
- anterior or posterior granulomatous uveitis
- conjunctival lesions and scleral plaques
- may lead to blindness if untreated
how does anterior ganulomatous uveitis present
insidious onset, +/-pain, slight photophobia, blurred vision
how does posterior ganulomatous uveitis
painless, floaters, loss of visual field, scotomas, decreased vision
when is topical opthalmic steroids contraindicated?
when dendritic lesions are found in the eye. this indicates herpes and can make it worse
what initial labs should be ordered in a patient with sarcoidosis
what lab findings present in sarcoidosis
- hypercalcemia (5%) or hypercalciuria (20%)
- elevated ESR
- Elevated ACE levels (40-80%)
what causes hypercalcemia or hypercalciuria in sarcoidosis patients
Granulomas produce 1,25 dihydroxyvitamin D which increases intestinal absorption of Ca - ultimately results in a suppressed PTH
what causes elevated ACE levels in sarcoidosis patients
- Pulmonary granulomas secrete ACE
- Consider: ACEI use will produce low ACE level in the presence of sarcoidosis
what do PFT sudies show in sarcoidisis
- DLco (most sensitive) reduced diffusing capacity (<80%)
- spirometry - nonspecific (can be restrictive, obstructive or normal)
- 6MWT - depends on severity of disease ( diminished distance and exercise induced hypoxemia. )
what does a CXR show in sarcoidosis (consider each stage)
what does an HRCT scan show in sarcoidosis
- adenopathy >2cm in the short axis
- infiltrates that are patchy or confluent
what would a biopsy show in sarcoidosis
noncaseating granulomas
what would bronchoalveolar lavage show in sarcoidosis
- increased lymphocytes
- high CD4/CD8 cell ratio
what would you use to assess for caridac involvement in sarcoidosis? how common is cardiac involvement
found in 5% of patients
use EKG, 24hr holter monitor, and/or echo
DDX for pulmonary sarcoidosis
what are indications for treatment for sarcoidosis
basically anything
what is the treatment for advanced pulmonary fibrosis secondary to sarcoidosis
lung transplant is their only hope:/
what is the prognosis for sarcoidosis
- Spontaneous remission within 2-5 years occurs in most patients
- A chronic sarcoid disease state, leads to worse outcomes
how often should patients with sarcoidosis follow up
yearly!
PFTS, Chemistry panel, CXR, EKG
what are additional historical questions that may be asked when assessing occupational/environmental lung disease
what would uncomplicated vs complicated Occupational/Environmental Lung Disease look like on PFT?
uncomplicated - restrictive pattern with decreased DLco
complicated - obstructive pattern with deceased DLco
what is pneumoconiosis and what are the 3 types
A chronic fibrotic lung disease caused by the inhalation of inorganic dusts
1. coal minors lung
2. silicosis
3. asbestosis
what is the treatment for pneumoconiosis
supportive for all three types
what is the presentation for pneumoconiosis
Presentation ranges from asymptomatic disorders with diffuse nodular opacities on CXR to severe, symptomatic, life-shortening disorders
what is the pathophysiology of coal workers pneumoconiosis
Pathophysiology - alveolar macrophages ingest inhaled coal dust leading to the formation of “coal macules”, usually 2–5 mm in diameter
what is the clinical presentation of simple coal workers pneumoconiosis
Simple: asymptomatic, minimal changes on PFT, small (<1 cm) rounded opacities on CXR
what is the clinical presentation of complicated coal workers pneumoconiosis
Complicated: symptomatic, diminished lung function on PFT, nodules ≥1 cm in diameter generally confined to the upper half of the lungs
what type of occupation would expose someone to silica
Rock mining, coal mining (via rock dust), quarrying, stone cutting, tunneling, masonry, sandblasting, pottery
what is silicosis
Silicosis is a fibronodular lung disease caused by inhalation of dust containing crystalline silica
what is the pathophysiology of silicosis
Pathophysiology - alveolar macrophages ingest the particles inducing an inflammatory response resulting in cell damage and fibroblast release leading to fibrosis
what is the clinical presentation of acute silicosis
- occurs in heavily exposed environments
- few weeks to years after exposure
- cough, SOB, pleuritic pain, weight loss, fatigue
what is the clinical presentation for chronic silicosis
hat does the PE for silicosis show
rales
what does imaging CXR show for simple silicosis
Simple Silicosis - multiple small (< 10 mm) nodules that are scattered diffusely throughout the lungs but may be more prominent in the upper lung fields.
what does imaging CXR show for complicated silicosis
Complicated Silicosis bilateral upper lobe masses, which are formed by the coalescence of nodules
what foes a CT show in silicosis
small nodules are seen coalesced into larger masses
what does silicosis increase the risk of
- TB due to alveolar macrophage dysfunction
- all patients should have yearly tuberculin skin test and screening CXR
what is asbestos
A group of minerals that are shaped like long, thin fibers and used in insulation for pipe, cements, textile, spackling on walls, patching, gaskets, sheet material, ceiling tiles in homes or schools
what is asbestosis
A nodular interstitial fibrosis occurring in workers exposed to asbestos fibers over many years
what is the pathophysiology of asbestosis
asbestos fibers are inhaled and completely or partially ingested by macrophages depending on the size of the fiber resulting in an inflammatory response, fibroblast proliferation and chronic scarring
when do symptoms appear for asbestos and what are they
- after 20 years of latency
- Dyspnea on exertion (MC symptom and progressive over time)
what will the physical exam present as in asbestosis
- bibasilar, fine end-inspiratory crackles
- clubbing (<1/2 of patients)
what does CXR show in asbestosis
- linear (reticular) opacities (often seen first)
- multinodular parenchymal opacities of various size and shape
- pleural plaques
- honeycomb changes in advanced cases
what parts of the lungs are most affected in asbestosis? what parts are generally spared?
Visceral pleura may be fibrotic and associated with parietal pleural plaques, while the central portions of the lung are relatively spared
why should you order a HRCT when suspecting asbestosis
up to 30% of asbestos exposed patients have normal CXR and abnormal CT
what is used in asbestosis suspicion if HRCT is not diagnostic? what will it show?
Bronchoalveolar Lavage (BAL)
will show asbestos bodies even in patients who are asymptomatic
what does a lung autopsy show in patients with asbestosis
small, stiff lungs with fibrosis in the subpleural regions of the lower lobes
what is additional management of asbestosis
Smoking cessation is important due to increased risk of lung carcinoma, especially mesothelioma
what is hypersensitivity pneumonitis
aka: extrinsic inflammatory alveolitis
A nonatopic, nonasthmatic inflammatory pulmonary disease resulting from exposure to inhaled organic antigens leading to an acute illness
what is the pathophysiology of hypersensitivity pneumonotis
immune-mediated disorders characterized by diffuse inflammation of interstitial lung, terminal bronchioles, and alveol
this is overwhelming but may be good to look at
what is the clinical presentation of acute hypersensitivity pneumonitis
- flu like illness (fever, chills, malaise, cough, chest tightness, dyspnea, HA)
- onset within hours following exposure
- gradual improvement 12 hours - several days after removal of exposure
what does CXR show in acute hypersensitivity pneumonitis
a poorly defined micronodular or diffuse interstitial pattern
what is the clinical presentation of subacte/chronic hypersensitivity pneumonitis
- Insidious onset of productive cough, dyspnea, fatigue, anorexia, and weight loss
- onset over weeks to months
- progresses to persistent cough and dyspnea
what are the CXR findings for subacute/chronic hypersensitivity pneumonitis
progressive fibrotic changes with loss of lung volume and coarse linear opacities are common
why is prompt diagnosis important in hypersensitivity pneumonitis
- Symptoms can be reversible if the offending antigen is detected and removed early in the course of illness
- Continued exposure may lead to progressive disease
what is the management for hypersensitivity pneumonitis
- Treatment consists of identification and avoidance of offending agent
- Oral corticosteroids can be useful, especially in severe or protracted cases
what is radiation lung injury
The lung is an exquisitely radiosensitive organ that can be damaged by external beam radiation therapy.
what are the factors that determine the degree of pulmonary injury in radiation lung injuries
- Volume of lung irradiated
- Dose and rate of exposure
- Other potentiating factors such as concurrent chemotherapy, previous radiation therapy in the same area, and simultaneous withdrawal of corticosteroid therapy
radiation therapies of which cancers are MC in radiation lung injuries
- breast cancer (10%)
- lung cancer (5–15%)
- lymphoma (5–35%)
what is the pathogenesis of radiation lung injury
unknown
possibly a hypersensitivity reaction
what are the two phases of the pulmonary response to radiation
- an acute phase (radiation pneumonitis)
- chronic phase (pulmonary radiation fibrosis)
what is the onset of radiation lung therapy
Onset: 2-3 months (range 1-12 months) after completion of radiation therapy
what is the clinical presentation of radiation lung disease
- insidious onset of dyspnea, intractable dry cough, chest fullness or pain, weakness, and fever
- In severe disease, respiratory distress and cyanosis occur that are characteristic of ARDS
- Inspiratory rales may be heard in the involved area
what is found on CXR for radiation lung injury
- alveolar or nodular opacities limited to the irradiated area
- Air bronchograms are often observed
what is the treatment for radiation pneumonitis
Treatment is supportive; steroids may be given
what is pulmonary radiation fibrosis
- Most common in patients who receive a full course of radiation therapy for cancer of the lung or breast
- May occur with or without prior hx of radiation pneumonitis
what is the clinical presentation of pulmonary radiation fibrosis
most patients are asymptomatic, although slowly progressive dyspnea may occur
what is found on imaging for pulmonary radiation fibrosis
- obliteration of normal lung markings
- dense interstitial and pleural fibrosis
- reduced lung volumes
- tenting of the diaphragm
- sharp delineation of the irradiated area
what is the treatment for pulmonary radiation fibrosis
- No specific therapy is proven effective
- Corticosteroids have no value
what are connective tissue diseases
- autoimmune disorders of unknown etiology that lead to inflammation and damage to the connective tissues:
- skin, fat, muscle, joints, tendons, ligaments, bone, cartilage, and even the eye, blood, and blood vessels
what are the MC CTDs associated with ILD
- Progressive Systemic Sclerosis
- Rheumatoid Arthritis
- Systemic Lupus Erythematosus
- Sjögren Syndrome
- Polymyositis and Dermatomyositis
what are clinical findings suggestive of CTDs
musculoskeletal pain, weakness, fatigue, fever, joint pain or swelling, photosensitivity, Raynaud’s phenomenon, pleuritis, dry eyes, dry mouth
what usually precedes, the pulmonary symptoms or the CTD symptoms?
Pulmonary symptoms occasionally precede the more typical systemic manifestations of CTD’s by months or years
How many drugs today are known to cause drug induced ILD
- > 350 drugs
- known to cause lung disease
how does the onset vary with drug induced ILD
- abrupt and fulminant (days-wks) OR insidious (wks - months)
- The drug may have been taken for several years before a reaction develops
- Symptoms may begin weeks to years after the drug has been discontinued
what are the MC symptoms in drug induced ILD
- exertional dyspnea
- nonproductive cough
what are some common drugs that cause drug induced ILD
what is the treatment of drug induced ILD
Treatment - discontinuation of any possible offending drug and supportive care
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