Interstitial Lung diseases &

Idiopathic Pulmonary fibrosis

By

Majid Nawaz

&

Tehsina Nawaz

Bannu Medical College Bannu.

Scenario A 19 years old boy presents

with the complaint of

productive cough, on

examination there are few

inspiratory crackles over the

upper zones of both lungs.

Cardiovascular and

abdominal examination is normal…. His chest x ray z shown,,,, ,,he does not smoke…sputum microbiology report shows scanty pseudomonas …. He also gives the history of repeated chest infection and there is no family history of chest infection.

Interstitial lung diseases

A variety of acute & chronic lung diseases with variable degrees of pulmonary inflammation &

fibrosis – ILDs“Interstitial” is misnomer – involves cellular & interstitial components of alveolar wall extending into alveolar space – Diffuse Parenchymal Lung Disease

classification

Idiopathic pulmonary fibrosis a specific form of chronic, progressive fibrosing interstitial pneumonia of unknown cause, primarily occurring in older

adults, limited to the lungs, and associated with the histopathologic and/or radiologic pattern of usual interstitial

pneumonia (UIP)According to American Thoracic

Society out Of the 7 listed

idiopathic interstitial pneumonias Idiopathic pulmonary fibrosis

is the most common disease

Why is it bad?

• a poor prognosis, • upto date, no proven effective therapies are

available for the treatment beyond lung transplantation

• 60% of patients with idiopathic pulmonary fibrosis die from their idiopathic pulmonary fibrosis,

• mean survival of 2-5 years from the time of diagnosis

• Death rates increase with increasing age, and are consistently higher in men than women .

pathogenesis The previous theory generalized inflammation progressed to widespread

parenchymal fibrosis. However, anti-inflammatory agents and immune modulators failed in modifying the natural course of the disease

The current theory unknown endogenous or environmental stimuli disrupt the

homeostasis of alveolar epithelial cells, resulting in diffuse epithelial cell activation and aberrant epithelial cell repair.

Causes

The etiology of idiopathic pulmonary fibrosis remains undefined; however, in the current hypothesis , exposure to following inciting agent in a susceptible host may lead to the initial alveolar epithelial damage

• smoke, • environmental pollutants, • environmental dust, • viral infections, • gastroesophageal reflux disease, • chronic aspirationContributors• Prostaglandin E2 deficiency• Genetic basis • Caveolin-1 deficiency

clinical presentationHistory It is critical to obtain a complete history, including medication

history, social history, occupational history, exposure history, and review of systems, to ensure other causes of interstitial lung disease are excluded.

• exertional dyspnea .

• nonproductive cough .

• obstructive sleep apnea

• Associated systemic symptoms can occur but are not common. E.g

• weight loss,• fatigue, • arthralgias, • low-grade fevers,• myalgias.

Physical examination

• fine bibasilar inspiratory crackles (Velcro crackles).

• Digital clubbing.

• Extrapulmonary

involvement does not

occur with idiopathic

pulmonary fibrosis .

Pulmonary hypertension is a common co morbidity in patients with idiopathic pulmonary fibrosis

American Thoracic Society – Diagnostic Criteria

• According to them, in immunocompetent adult, the presence of all of the major diagnostic criteria as well as at least 3 -4 minor criteria increases the likelihood of correct diagnosis of IPF.

Major Criteria

1. Exclusion of other known causes of ILD such as certain drug toxicities, environmental exposures & connective tissue disorders

2. Abnormal pulmonary function studies that include restriction(reduced VC, increased FEV1/FVC ratio ) and impaired gas exchange

3. Bibasilar reticular abnormalities with minimal ground glass opacities on HRCT scans

4. Transbronchial lung biopsy or BAL showing no features to support alternative diagnosis

Minor Criteria

1. Age > 50 yr

2. Insidious onset of otherwise unexplained dyspnea on exertion

3. Duration of illness > or equal to 3 months

4. Bibasilar, inspiratory crackles ( dry / velcro type in quality )

Differential Diagnosis

1. Restrictive Lung Disease

2. Nonidiopathic Pulmonary Fibrosis

3. Sarcoidosis

4. Tobacco Worker's Lung

5. Pulmonary edema ( Cardiogenic, High-Altitude, Neurogenic)

6. Drug-Induced Pulmonary Toxicity

7. Pneumococcal Infections

8. Pneumonia, (Aspiration ,Bacterial , Fungal ,Viral)

Laboratory Studies

Results from routine laboratory studies are nonspecific for the diagnosis of idiopathic pulmonary fibrosis; however, some Routine lab Investigations are to rule out other causes of parenchymal diseases

1. Elevated ESR, hypergammaglobinemia may be foun

2. Positive anti nuclear antibodies / RA Factor occur in 10 -20 % of cases, usually in low titres.

Imaging StudiesChest radiography The chest radiograph lacks diagnostic specificity for

idiopathic pulmonary fibrosis.

The typical findings are

1. peripheral reticular opacities (netlike linear and curvilinear densities) predominantly at the lung bases .

2. Honeycombing (coarse reticular pattern)

3. lower lobe volume loss can also be seen

bilateral lower lobe reticular opacities (red circles).

High-resolution computed tomography

HRCT findings are significantly more sensitive and specific for the diagnosis of idiopathic pulmonary fibrosis . The typical findings are

1. Bilateral basal and subpleural reticulation .

2. Traction bronchiectasis .

3. Basal honeycombing with minmal ground glass opacities.

GGO – may be present but less extensive than reticular abnormalityLobar volume loss – if advanced

honeycombing

Traction bronchiectasis

reticular opacities (red circle) distributed in both lung bases and the minimal ground-glass opacities (blue circle).

Other tests

Pulmonary function testing

Vital capacity, functional residual capacity, total lung capacity, and forced vital

capacity (FVC) all are reduced.

Decreased diffusion capacity of carbon monoxide

(DLCO).

a decline in DLCO greater than 15% over 1 year is also associated with increased mortality.

6-Minute walk testing

used in the in clinical assessment of patients with idiopathic pulmonary fibrosis .

Desaturation below the threshold of 88% during the 6MWT has been associated with an increased mortality.

Heart rate recovery (HRR)

specifically the failure of the heart rate to decline at 1 or 2 minutes postexercise, is associated with increased mortality

Bronchoalveolar lavage BAL is not required for the diagnosis of idiopathic

pulmonary fibrosis; however, BAL fluid analysis can be useful to exclude other alternative diagnoses .

Increased numbers of neutrophils in BAL fluid are found in 70-90% of all patients with idiopathic pulmonary fibrosis,

Transthoracic echocardiography • Transthoracic echocardiography is an excellent modality

to detect pulmonary hypertension.

Surgical lung biopsy• A surgical lung biopsy specimen can be obtained through

either an open lung biopsy or video-assisted thoracoscopic surgery (VATS). VATS is preferred because it is associated with less morbidity and a shorter hospital stay compared with open lung biopsy.

In patients with UIP pattern on HRCT a surgical lung biopsy is not needed for the diagnosis of idiopathic pulmonary fibrosis. However, in patients with possible UIP pattern or inconsistent with UIP pattern on HRCT, a surgical lung biopsy is needed for the diagnosis of idiopathic pulmonary fibrosis

Bronchoscopy

Bronchoscopy with BAL and/or transbronchial biopsy is not required for the diagnosis of idiopathic pulmonary fibrosis. However, it can be used to ensure that alternative

diagnoses are excluded.

Approach to the Diagnosis of Approach to the Diagnosis of IPFIPF

Clinical• History• Physical• Laboratory• PFTs

Primary care physicians

Pulmonologists Radiologists Pathologists

Multidisciplinary

Radiology

• Chest X-ray• HRCT

Pathology

• Surgical lung biopsy

treatment

Medical CareThe goal of is the assessment and treatment of comorbid medical conditions. Common comorbid medical conditions e,g chronic obstructive pulmonary disease, obstructive sleep apnea, gastroesophageal reflux disease, and coronary artery disease. Therefore, if any of these comorbid illnesses are present, they should

be managed according to current practice guidelines.

Patients with hypoxemia oxygen saturation < 88%) at rest or with exercise should be prescribed

oxygen therapy to maintain a saturation of at least 90% at

rest, with sleep, and with exertion.

 

Vaccination against influenza and pneumococcal infection should be encouraged in all patients with idiopathic

pulmonary fibrosis.

Sufficient clinical evidence is lacking to show that any treatment definitely improves survival / quality of life

Conventional treatment options:

1.Corticosteroids

2.Immunosupressants/cytotoxic agents

3.Antifibrotic agents

in alone or combination

Surgical Care

Cadaveric Lung transplantation for idiopathic pulmonary fibrosis has been shows a survival benefit over medical therapy

Guidelines for listing a patient for lung transplantation evaluation include

1. diffusion capacity of carbon monoxide less than 39%

2. 10% or greater decrement in forced vital capacity during 6 months of follow-up,

3. decrease in pulse oximetry below 88% during a 6-minute walk test (6MWT),

4. honeycombing on high-resolution computed tomography (HRCT) imaging (fibrosis score >2

ComplicationsThe following are complications that can be seen in

patients with idiopathic pulmonary fibrosis:

 

1. Pulmonary hypertension

2. Acute exacerbation of pulmonary fibrosis

3. Respiratory infection

4. Acute coronary syndrome

5. Thromboembolic disease

6. Adverse medication effects

7. Lung cancer

Consultations

• A suspected patient should be referred to a pulmonologist for further evaluation and management.

• A diagnosed patient should be referred for lung transplantation evaluation .

Diet• Any patient who is overweight should be encouraged to

meet with a nutritionist and make dietary changes to achieve ideal body weight.

• Maintaining adequate nutritional intake is important for quality of life in patients with idiopathic pulmonary fibrosis

Activity

• Regular activity improves walk distance and symptoms or quality of life.

• Therefore, patients should be encouraged to participate in regular exercise to maintain a maximal

degree of musculoskeletal conditioning.