Interstitial Pulmonary Diseases

بسم الله الرحمن الرحيم

IN THE NAME OF GOD THE MOST MERCIFULL

15/4/2020

Interstitial And Infiltrative Pulmonary Diseases

0BJECTIVES

In the USA,

the annual incidence is estimated to be 6.8 to 16.3 per 100,000,
a prevalence of 14.0 to 42.7 per 100,000.
U K 15% of clinical practice.

I-Diffuse parenchymal lung disease.

II-Lung diseases due to organic dusts.
III-Lung diseases due to inorganic dusts.
IV-Lung diseases due to systemic inflammatory disease.
V-Pulmonary eosinophilia and vasculitides.
VI-Rare interstitial lung diseases.


Pathology
The pathophysiologic processes are involve the interstitium, which is the microscopic space bounded by the basement membranes of epithelial and endothelial cells.
At least 180 disease entities may present as interstitial lung disease .

Etiology

In most patients, no specific cause.
Others
drugs
organic and inorganic.
The history
the occupational
medication history.

progressive fibrosis will result in

honeycombing,

increased pulmonary vascular resistance

secondary pulmonary hypertension.


Usual interstitial pneumonia pattern of idiopathicpulmonary fibrosis. Note the presence of (1) subpleural fibrosis (2) traction emphysema, (3) fibroblastic foci, and temporal heterogeneity of microscopic abnormalities at low magnification

I-Diffuse parenchymal lung disease

The diffuse parenchymal lung diseases (DPLDs) are a heterogeneous group of conditions affecting the pulmonary interstitium and/or alveolar lumen.
The presentation and natural history of these may differ widely.

they are frequently considered collectively as they share

similar symptoms,
physical signs,
pulmonary function
-radiological changes

Differntial diagnosis of interstitial lung diseases

Infection
Viral pneumonia
Pneumocystis jirovecii
Mycoplasma pneumoniae
TB
Parasites, e.g. filariasis
Fungal infection


(1)

Differntial diagnosis of interstitial lung diseases

Malignancy
Leukaemia and lymphoma
Lymphatic carcinomatosis
Multiple metastases
Bronchoalveolar carcinoma .
Pulmonary oedema Aspiration pneumonitis.
(2)

Investigation in DPL disease

General
Full blood count
• Ca2+:
• Lactate dehydrogenase:
• Serum angiotensin-converting enzyme
• ESR and CRP: non-specifically raised
• Autoimmune screen: anti-cyclic citrullinated peptide
(anti-CCP) and other autoantibodies may suggest connective
tissue disease
Radiology .
Pulmonary function .
Bronchoscopy
• Transbronchial biopsy
• Bronchial biopsy:
Video-assisted thorascopic lung biopsy (in selected cases)

Presentation of sarcoidosis

Asymptomatic: abnormal routine chest X-ray .or abnormal liver function tests
Respiratory and constitutional symptoms.
Erythema nodosum and arthralgia.
Ocular symptoms.
Skin sarcoid (including lupus pernio)
Superficial lymphadenopathy
Other






Idiopathic pulmonary fibrosis(IPF)
The most common form of the the idiopathic interstitial pneumonias (IIPs)
There is a focal damage to the alveolar epithelium consistent with an autoimmune process.
Aetiology
Remains elusive .
viruses (e.g. Epstein-Barr virus).
occupational dusts (metal or wood) .
drugs (antidepressants).
chronic gastro-oesophageal reflux.
Familial (genetic).
cigarette smoking.

Clinical features

Usually after age of 50 years.
Slowly progressive breathlessness.
A non-productive cough.
Finger clubbing.
Bi-basal fine late inspiratory crackles.
Exacerbations which are accompanied by breathlessness.
Disturbed gas exchange.
In advanced disease, central cyanosis is detectable and patients may develop features of right heart failure.


Investigation
Immunology,serology
Pulmonary function restrictive defect.
Exercise -induced arterial hypoxaemia.
Abnormal chest X-ray. A 'honeycomb' appearance .
HRCT
A lung biopsy in cases with a typical features

Lung diseases due to organic dusts

Results from :
a local immune response to animal proteins (e.g. bird fancier's lung)
fungal antigens in mouldy vegetable matter.

Hypersensitivity pneumonitis (HP) (extrinsic allergic alveolitis)

Is the most common form of lung diseases due to organic dusts.
results from the inhalation of a wide variety of organic antigens.
diffuse immune complex reaction in the walls of the alveoli and bronchioles.
Common causes include farm worker's lung and bird fancier's lung.

Examples of lung diseases caused by organic dusts

Farmer's lung
Bird fancier's lung
Inhalation ('humidifier') fever
Cheese worker's lung


Clinical feature
The acute form
within a few hours of re-exposure to the same dust,
influenza-like symptoms.
Chest auscultation reveals widespread end-inspiratory crackles .
Chronic form
low-level exposure
more often insidious
established fibrosis.

Complications

Hypoxaemia.
pulmonary hypertension.
cor pulmonale .
death.
Prognosis:
Most patients recover completely,
interstitial fibrosis

Investigations

The chest X-ray upper zone diffuse micronodular shadowing.
HRCT is more sensetive .
Pulmonary function tests show a restrictive ventilatory defect.
oxygen desaturation
type I respiratory failure.


Inhalation ('humidifier') fever

Inhalation fever shares similarities with HP.

It occurs as a result of contaminated humidifiers or air-conditioning units .

Treatment

Dust masks with appropriate filters
In acute cases prednisolone should be given for 3-4 weeks, starting with an oral dose of 40 mg per day.
Severely hypoxaemic patients may require high-concentration oxygen therapy initially.

Lung diseases due to inorganic dusts

Lung diseases caused by inorganic gases and fumes

Cause Occupation Disease

Irritant gases industrial accidents Acute lung injury,ARDS
Cadmium Welding COPD
Isocyanates Plastic Bronchial asthma Eosinophilic pneumonia

Lung diseases caused by exposure to inorganic dusts

Cause Occupation Description Coal dust Coal mining Coal worker's pneumoconiosis
Focal and interstitial fibrosis, centrilobular emphysema, progressive massive fibrosis
Silica Silicosis
Asbestos Asbestos-related disease
Iron oxide Siderosis


Industrial inorganic gases and fumes can cause
acute respiratory diseases including
pulmonary oedema
asthma.

diffuse pulmonary fibrosis (the pneumoconioses).

Silicosis

results from the inhalation of crystalline or free silica.
There is increased risk:
tuberculosis (silicotuberculosis),
lung cancer
COPD;
Asbestosis
Pulmonary complication
pulmonary fibrosis
bronchial carcinoma.
pleural disease.
diffuse interstitial fibrosis of the lungs.


Questions

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