Diffuse Parenchymal Lung Diseases

When does radiation pneumonitis occur?

1-6 months after radiation complete. Can be severe with progression of days to weeks leading to respiratory failure (helpful to differentiate from malignancy which is not as quick)

Name 3 ways RA can present in the lung?

1. Acute interstitial pneumonia 2. Nodules 3. Pleural effusion 4. Bronchiectasis

What usually causes a hypersensitivity pneumonitis?

1. Antigens from decaying organic matter (mold etc.) 2. Mycobacteria (hot tubs) 3. Animal proteins (bird feces and dander) 4. Inorganic low molecular weight chemicals (pesticides, machine lubricants)

What does imaging show in RB-ILD?

1. CXR: usually shows bronchial wall thickening and alveolar infiltrates in basilar and central distribution but can be normal. 2. HRCT: centrilobular nodules with scattered ground glass attenuation

What interstitial lung diseases are associated with smoking?

1. Pulmonary Langerhans cell histiocytosis 2. Respiratroy bronchioloitis-associated ILD 3. Desquamative interstitial pneumonia 4. possibly IPF

How do you treat Pulmonary Langerhans cell histiocytosis?

1. STOP smoking Disease may stabilize after stopping but most gradually progress. 2. IF the patient has the related systemic Langerhans cell histiocytosis then treat with chemotherapy (2CdA (cladribine)).

What percent of DPLD patients have normal CXR's

20%

What percentage of patients undergoing radiation therapy get radiation pneumonitis

7-20%

Describe ground glass infiltrates.

Alveolar attenuation but can still see lung architecture.

What is the radiographic appearance of radiation pneumonitis

Alveolar opacification with occassional air bronchograms. May develop nonanatomic edge at border of radiation port.

11 drugs that can cause an acute episode of DPLD (cellular infiltrate +/- eosinophilia)

Amiodarone Azathioprine Bleomycin Carbamazepine Ethambutol Fluoxetine GM-CSF Imatinib INH Sulfonamides Trazadone

7 drugs that cause a chronic DPLD from cumulative effect leading to cellular injury. (interstitial infiltrate)

Ampho B Amiodarone Bleomycin Cyclophosphamide Methadone Methotrexate Nitrofurantoin

How are connective tissue DPLD's treatments adjusted?

Based on serial radiologic, clinical and PFT's.

Does hypersensitivity pneumonitis cause a cell mediated reaction or antibody?

Cell mediated. Can form granulomas.

What is the typical radiology findings for DPLD caused by cellular injury related to chronic drug therapy (i.e. methotrexate, amiodarone)

Chronic interstitial changes.

How do you treat radiation pneumonitis?

Corticosteroids - 80% response rate. 1-1.5mg/kg of prednisone for several weeks followed by taper over weeks to months.

How do you treat DPLD secondary to systemic sclerosis?

Cyclophosphamide corticosteroids have no proven benefit.

What is DIP?

Desquamative Interstitial Pneumonia - similar to RB-ILD. These are overlapping disorders.

What is radiation fibrosis?

Distinct from radiation pneumonitis. Occurs 6-24 months after radiation. Fibrosis which is irreversible.

What are the 3 most common causes of DPLD?

Drugs Connective Tissue Diseases Environmental exposures

Name a DPLD that may present similar to ARDS

Eosinophilic pneumonia

What are symptoms of radiation pneumonitis?

Fever, weight loss, dry cough, dyspnea

What are the classic CT findings in hypersensitivity pneumonitis?

Ground glass opacities and centrilobular nodules in the mid and upper lungs. The centrilobular opacities are thought to represent a cellular infiltrate leading to bronchiolitis which may lead to air trapping.

What are previous names of pulmonary Langerhans cell histiocytosis

Histiocytosis X Eosinophilic granuloma

Most drug induced DPLD's cause disease by what type of mechanism?

Hypersensitivity reaction - may have peripheral eosinophilia

Name 2 DPLD's that are often in the lower lobes.

IPF Asbestosis.

Name 3 DPLD's that involve the peripheral airways

IPF chronic eosinophilic pneumonia crytopogenic organizing pneumonia

Is idiopathic pulmonary fibrosis (IPF) more common in young or old patients.

Increases with age.

What does the histopathology show in chronic hypersensitivity pneumonitis?

It can difficult to distinguish between IPF. 2/3 of surgical biopsies from multiple lobse show specific features for hypersensitivity pneumonitis 1/3 show usual interstitial pneumonia

What information does a lung biopsy give you in DPLD's?

It gives a distinct histolopathogic pattern but these patterns often have multiple potential underlying causes. Need clinical, radiologic and historical data in addition to histopathology to pinpoint diagnosis.

What is Usual intersititial pneumonia?

It is a histologic description of lung disease. Seen in IPF, connective tissue associated lung DPLD, radiation -induced lung disease and occassioanly hypersensitivity pneumonitis.

What might lab tests show in hypersensitivity pneumonitis?

Leukocytosis Elevated inflammatory markers IgG specific serum precipitins (false negatives and false positives are a problem)

What is the significance of precipitating antibodies in a patient with suspected hypersensitivity pneumonitis?

Most people in an exposed population will develop antibodies but only a minority develop clinical signs of the disorder. A positive test is supportive only.

Is hypersensitivity pneumonitis IgE mediated?

No

Can radiation pneumonitis occur outside the radiation field?

Occassionally and can even involve opposite lung.

Name 2 DPLD's that have cystic airspaces.

Pulmonary Langerhans cell histiocytosis Lymphangioleiomyomatosis IPF can look cystic at areas of honeycombing

Name 2 DPLD's that often involve the central lungs

Pulmonary alveolar proteinosis Sarcoidosis

Name 3 connective tissue diseases that interstitial lung disease may be the presenting symptom?

RA Dermatomyositis Polymyositis

How do you treat RB-ILD and DIP?

STOP smoking andavoid all passive exposure to smoke. Patients usually improve. Steroids for severe disease but questionable efficacy.

How do you treat RA lung disease

Same way you treat RA. Although methotrexate can cause DPLD.

Interstitial lung disease and erythema nodosum

Sarcoidosis

Small nodular pattern distributed centrally along the pulmonary vascular bundles.

Sarcoidosis

What DPLD's can be diagnosed by bronchoscopy?

Sarcoidosis Eosinophilic pneumonia's Will not help in disease's that require a histopathologic pattern.

Name 2 DPLD's that are often in upper lobes.

Sarcoidosis Hypersensitivity pneumonitis

What do PFT's show in Pulmonary Langerhans cell histiocytosis?

Severe: obstructive pattern with low DLCO Mild: restricitve, obstructive or normal

What do PFT's show in hypersenitivity pneumonitis?

They show a reduced DLCO and can show either an obstructive or restrictive pattern.

How are connective tissue disease DPLD's treated?

Treated with medications targeted at underlying disease.

Pleural effusions are rare in DPLD's. True or False.

True. Should think of CHF or CA etc..

DPLD's that may present with acute worsening due to alveolar hemorrhage? List 3.

Wegener's Churg-Strauss Microscopic polyangiitis

What DPLD often causes a "map-like appearance of normal lung with sharp borders to diseased lung?

hypersensitivity pneumonitis

What causes acute eosinophilic pneumonia?

idiopathic, but may be due to inhaled toxins Smoking has been linked to this disorder in Japanese and militart recruits.

What is a rare cystic lung disease which occurs exclusively in women?

lymphangioleiomyomatosis

Which lung disease occurs exclusively in women?

lymphangioleiomyomatosis.

What is the histopathologic finding in DPLD of systemic sclerosis?

nonspecific interstitial penumonitis note: 75% of patients with systemic sclerosis have some evidence of lung disease on HRCT.

What do PFT's look like in RB-ILD?

obstrucitve or mixed obstructive/restrictive

What is respiratory bronchiolitis-associated interstitial lung disease (RB-ILD)?

occurs in current or former smokers bronchiolitis that occurs in most smokers and is occassionally severe enough to cause symptoms

How do patient's with RB-ILD present?

persistent cough and dyspnea

What is a good resource for looking at drug induced DPLD?

pneumotox.com

What does the histopathology show in acute hypersensitivity pneumonitis?

poorly formed granulomas bronchiolitis lymphoplasmacytic interstitial infiltrates

What is typical radiology findings for DPLD caused by a hypersensitivity reaction to drugs?

reticular lines with scattered ground glass attenuation progressing to consolidation.

How is acute eosinophilic pneumonia treated?

steroids - good response

What are the imaging findings in Pulmonary Langerhans cell histiocytosis?

thin walled cysts in upper and middle lung-fields (virtually pathognomonic)

Lymphangioleiomyomatosis is associated with what genetic disease?

tuberous sclerosis (15%)

Typical patient with Pulmonary Langerhans cell histiocytosis?

young active smoker (<40 years old) Subacute progressive cough and dyspnea 25% have pneumothorax