INTERSTITIAL & INFILTRATIVE PULMONARY DISEASES

Dr.Bilal Natiq Nuaman,MD C.A.B.M.,F.I.B.M.S.,D.I.M.

2016-20171

Diffuse parenchymal lung disease (Interstitial lung disease) • The diffuse parenchymal lung diseases (DPLDs)

are a heterogeneous group of conditions affecting the pulmonary parenchyma (interstitium)and/or alveolar lumen, which are frequently considered collectively as they share a sufficient number of clinical physiological and radiographic similarities.

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Drugs causing interstitial lung disease

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Idiopathic pulmonary fibrosis• Idiopathic pulmonary fibrosis (IPF) is defined as

a progressive fibrosing interstitial pneumonia of unknown cause, occurring in adults.

Clinical features • IPF usually presents in the older adult and is

uncommon before the age of 50 years. • more typically presents with progressive

breathlessness and a non-productive cough. Clinical findings include finger clubbing and the presence of bi-basal

fine late inspiratory crackles.8

InvestigationsEstablished IPF will be apparent on chest X-ray

as bilateral lower lobe and subpleural reticular shadowing.

HRCT typically demonstrates a patchy, predominantly peripheral, subpleural and basal reticular pattern and, in more advanced disease, the presence of honeycombing cysts and traction bronchiectasis.

Pulmonary function tests classically show a restrictive defect with Reduced lung volumes and gas transfer.

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prognosis In advanced disease, central cyanosis is

detectable and patients may develop features of right heart failure.

A median survival is 3 years . • Various autoimmune diseases are associated

with IPF (SLE,RA). IPF is associated with an increased risk of

carcinoma of the lung.

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ManagementTreatment is difficult.

Oxygen may help breathlessness but opiates may be required to relieve severe dyspnea.

Where appropriate, lung transplantation should be considered.

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Sarcoidosis is a multi system disorder, characterized by noncaseating epithelioid granulomas. The etiology is unknown, although atypical mycobacteria, viruses and genetic factors have been proposed. Sarcoidosis is less common in smokers. sparing Arab and Chinese populations.

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Clinical features Any organ may be affected but 90% of cases affect the lungs. Otherwise, lymph glands, liver, spleen, skin, eyes, parotid glands and phalangeal bones are the most frequently involved sites. bilateral hilar lymphadenopathy( BHL) may be detected in an otherwise asymptomatic individual undergoing CXR. Löfgren’s syndrome – erythema nodosum, peripheral arthropathy, uveitis, bilateral hilar lymphadenopathy (BHL), lethargy and occasionally fever – commonly presents in the third or fourth decade. Pulmonary disease may present insidiously with cough, exertional breathlessness and radiographic infiltrates.

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The most common cause for bilateral hilar enlargement in an asymptomatic person (incidental radiologic finding) is sarcoidosis.

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Investigations ● FBC: demonstrates lymphopenia. ● LFTs: may be mildly deranged. ●Ca2+: may be elevated. ● Serum ACE: may provide a nonspecific marker of disease

activity. ●Chest x-ray : bilateral hilar lymphadenopathy and/or

parenchymal infiltrates. ●HRCT: characteristic appearances include reticulonodular opaci-

ties. ●Pulmonary function test : restrictive pattern (normal FEV1/FVC) ● Bronchoscopy: may demonstrate a ‘cobblestone’ appearance of

the mucosa, and bronchial and transbronchial biopsies usually show noncaseating granulomas.

The occurrence of erythema nodosum in patients in the second to third decades with BHL on CXR is often sufficient for a confident diagnosis.

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Management The majority of patients enjoy spontaneous remission. Patients who present with acute illness and erythema nodosum may require NSAIDs and, if systemically unwell, a short course of corticosteroids. Systemic corticosteroids are also indicated in the presence of hypercalcaemia, pulmonary function impairment and renal impairment. Uveitis responds to topical steroids. In patients with severe disease, both methotrexate and azathioprine have been used successfully and selected patients with severe disease may be referred for single lung transplantation.

OCCUPATIONAL LUNG DISEASE Exposure to dusts, gases, vapors and fumes at work

can Cause several different types of lung disease:

• Acute bronchitis and even pulmonary edema from irritants such as sulphur dioxide, chlorine or ammonia.

• Occupational asthma-this is now the Commonest industrial lung disease in the developed world

• Occupational pneumonia. • Hypersensitivity pneumonitis. • Pulmonary fibrosis due to mineral dust. • Bronchial carcinoma and mesothelioma due to

industrial agents( e.g. Asbestos, silicosis). 21

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Occupational pneumonia• Welders appear to be at increased risk of

pneumonia. • Farm, and abattoir workers may be exposed to

Coxiella burnetii, the causative agent of Q fever (Atypical pneumonia+hepatitis+endocarditis).

• Birds (parrots) infected with Chlamydia psittaci can cause psittacosis in humans.

• Sewage workers, farmers, animal handlers and veterinarians run an Increased risk of contracting leptospirosis (pneumonia+hepatitis+renal failure).

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Hypersensitivity pneumonitisHypersensitivity pneumonitis (HP; also called extrinsic allergic alveolitis) results from the inhalation of a wide variety of organic antigens, which give rise to a diffuse immune complex reaction in the alveoli and

bronchioles. Common causes include farmer’s lung and bird

fancier’s lung.

Cigarette smokers have a lower risk of developing the disease due to decreased antibody reaction to the antigen.

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Clinical featuresTypically fever, malaise, cough and shortness of

breath come on several hours after exposure to the causative antigen. Thus, a farmer forking hay in the morning may notice symptoms during the late afternoon and evening with resolution by the following morning.

On examination, the patient may have a fever, tachypnoea, and coarse end inspiratory crackles and wheezes throughout the chest.

Continued exposure leads to a chronic illness characterized by severe weight loss, effort dyspnea and cough as well as the features of idiopathic pulmonary fibrosis .

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ManagementIf practical, the patient should cease exposure to

the inciting agent. Dust masks with appropriate filters may minimize

exposure . In acute cases, prednisolone should be given for 3–4

weeks, starting with an oral dose of 40 mg per day. Severely hypoxemic patients may require high concentration oxygen therapy initially.

Most patients recover completely but, if unchecked, fibrosis may progress to cause severe respiratory disability, hypoxemia, pulmonary hypertension, corpulmonale and eventually death.

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Pneumoconiosis

This means a permanent alteration of lung structure due to the inhalation of (inorganic) mineral dust, excluding bronchitis and emphysema.

Pneumoconiosis is a general term used to describe lung fibrosis resulting from inhalation of dusts such as coal, silica and asbestos.

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Coal worker’s pneumoconiosis (CWP): Prolonged inhalation of coal dust overwhelms alveolar macrophages, leading to a fibrotic reaction. Simple coal worker’s pneumoconiosis (SCWP) refers to the appearance of small radiographic nodules in an other wise well individual. Progressive massive fibrosis (PMF) refers to the formation of conglomerate masses (mainly in the upper lobes), which may cavitate, associated with cough, sputum and breathlessness. PMF may progress after coal dust exposure ceases and, in extreme cases, causes respiratory failure.

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Silicosis: This occurs in stonemasons who inhale crystalline silica, usually as quartz dust. Classic silicosis develops slowly after years of asymptomatic exposure. Radiological features are similar to those of Coal worker’s pneumoconiosis (CWP), with multiple 3–5mm nodular opacities, in the mid and upper zones. As the disease progresses, Progressive massive fibrosis (PMF) may develop. Enlargement of the hilar glands with an ‘eggshell’ calcification is uncommon and non specific. Fibrosis progresses even when exposure ceases. Individuals with silicosis are at increased risk of TB, lung cancer and COPD.

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Industries and occupations at risk for silicosis are: ➤ tunnel mining ➤ underground excavation ➤ quarrying: sandstone, granite, sand ➤ stone work: granite sheds, monumental masonry, tombstones ➤ ceramic industry: manufacture of pottery, stone- ware, bricks for ovens ➤ sandblasting

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Asbestosis Asbestosis is a pneumoconiosis in which diffuse parenchymal lung fibrosis develops as a result of heavy prolonged exposure to asbestos. The lag interval between exposure and the onset of disease is typically 30–40 years, the clinical features are similar to those of idiopathic pulmonary fibrosis, with cough, progressive dyspnoea, bibasal crackles, clubbing (in advanced disease) and a restrictive ventilatory defect (reduced lung volumes) with impaired gas diffusion (reduced transfer factor for carbon monoxide). Chest X-ray shows bilateral, predominantly basal reticulonodular shadowing.

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In contrast to silicosis, asbestosis does not predispose to tuberculosis. However, it is associated with a high risk of bronchial cancer, pleural and peritoneal mesothelioma, and gastrointestinal cancers.

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Mesothelioma Mesothelioma is a malignant tumor of the pleura, in which there is an identifiable history of asbestos exposure(20-40 years) in at least 90% of cases. It usually presents with pain, dyspnoea, weight loss and lethargy, and features of a pleural effusion .

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CHARACTERISTIC CXR PATTERNS FOR INTERSTITIAL LUNG DISEASE · UPPER LOBE PREDOMINANCE—sarcoidosis, hypersensitivity pneumonitis, pneumoconiosis, silicosis, ankylosing spondylitis, TB

· LOWER LOBE PREDOMINANCE—idiopathic pulmonary fibrosis, asbestosis, rheumatoid arthritis, scleroderma.

· BILATERAL HILAR/MEDIASTINAL ADENOPATHY WITH INTERSTITIAL INFILTRATES—sarcoidosis, TB, fungal, lymphoma.

· EGGSHELL CALCIFICATION OF HILAR/MEDIASTINAL LYMPH NODES—silicosis (other pneumoconiosis), TB, fungal.

· CALCIFIED PLEURAL PLAQUES—asbestos

• PLEURAL EFFUSIONS WITH INTERSTITIAL INFILTRATES—HF, lymphangitic carcinomatosis, rheumatoid arthritis, SLE

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Pulmonary hypertension

In normal lungs, the pulmonary arterial pressure is about 20/8mmHg and the mean pulmonary artery pressure is 12–15mmHg. Pulmonary hypertension is defined as a mean pulmonary artery pressure of >25 mmHg at rest. It may occur as a result of hypoxemia and chronic lung disease, when it is often referred to as cor pulmonale, but in some cases there is no demonstrable cause, which is termed idiopathic pulmonary hypertension. Presentation is with exertional dyspnea and syncope. Primary pulmonary hypertension (PPH) is a rare but important disease that predominantly affects women, aged 20–30 yrs.

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Causes of Secondary Pulmonary Hypertension Cardiac Disease Eisenmenger syndrome Left-sided heart failure

Parenchymal Lung Disease Chronic obstructive pulmonary disease Interstitial lung disease

Vascular Impairment Chronic Pulmonary thromboembolic disease Sickle cell disease

Infections HIV Schistosomiasis

Miscellaneous Obstructive sleep apnea Collagen vascular diseases (through either direct vascular effect or interstitial changes in the parenchyma)

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Electogardiograpgy Eighty per cent of patients with pulmonary hypertension have an abnormal electrocardiogram: Right axis deviation, ‘P pulmonale’, Dominant R in right precordial leads, Right bundle branch block)

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Chest radiography ■ Shows enlarged pulmonary arteries with rapid tapering of vessels toward the periphery of the lungs (a “pruned tree” appearance) (Fig. 22-8) ■ May also see right-heart enlargement ■ For secondary pulmonary hypertension caused by parenchymal lung disease, look for hyperinflation and bullous disease (suggestive of COPD) or increased interstitial markings (suggestive of interstitial lung disease)

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Management includes diuretics, oxygen, anticoagulation and vaccination against infection. Specific treatments include sildenafil (viagra) and the oral endothelin receptor antagonist bosentan; these can dramatically improve exercise performance symptoms and prognosis in selected cases. Pulmonary thrombo-endarterectomy should be contemplated in patients with chronic proximal pulmonary thromboembolism . Heart–lung transplantation may be considered in selected patients.

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Cor Pulmonale

Cor pulmonale, often referred to as pulmonary heart disease, can be defined as altered RV structure and/or function in the context of chronic lung disease and is triggered by the onset of pulmonary hypertension.

Cor pulmonale is the third most common cardiac disorder after the age of 50. Pulmonary embolism is the most common cause of acute cor pulmonale.

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causes of cor pulmonale Respiratory disorders': · Obstructive: - COPD. -Chronic persistent asthma. · Restrictive: -Intrinsic - interstitial fibrosis, lung resection. - Extrinsic - obesity, muscle weakness, kyphoscoliosis. Pulmonary vascular disorders: · Pulmonary emboli. · Adult respiratory distress syndrome. · Primary pulmonary hypertension. · Vasculitis of the small pulmonary arteries.

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The most common cause of right HF is not pulmonary parenchymal or vascular disease but left HF. Therefore, it is important to evaluate the patient for LV systolic and diastolic dysfunction. Orthopnea and PND are rarely symptoms of isolated right HF and usually point toward concurrent left heart dysfunction. The increase in intensity of the holosystolic murmur of tricuspid regurgitation with inspiration (“Carvallo’s sign”) may be lost eventually as RV failure worsens.

BNP levels are elevated in patients with cor pulmonale secondary to RV myocardial stretch

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TREATMENT The treatment of cor pulmonale is directed at the underlying cause while at the same time reversing hypoxemia, improving RV contractility, decreasing pulmonary artery vascular resistance, and improving pulmonary hypertension. ●Continuous positive airway pressure (CPAP) is used in patients with

obstructive sleep apnea.

● Phlebotomy is reserved as adjunctive therapy in polycythemia patients (hematocrit, 55%) who have acute decompensation of cor pulmonale or remain polycythemic despite long-term oxygen therapy.

●Acute pulmonary exacerbating conditions should be treated.

● Long-term oxygen supplementation has improved survival in hypoxemic patients with COPD.

●RV volume overload should be treated with diuretics (e.g., furosemide); however, overdiuresis can reduce RV filling and decrease cardiac output.

●Theophylline and sympathomimetic amines may improve diaphragmatic excursion, myocardial contraction, and pulmonary artery vasodilation.

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the possible causes of collapse: Malignancy (cachexia, clubbing. nicotine staining, lymphadenopathy) Tuberculosis (apical signs, lymphadenopathy) Hilar lymphadenopathy, i.e. sarcoidosis (erythema nodosum) Mucus plugs(features of asthma ,COPD, or bronchiectasis) Foreign body

Atelectasis Atelectasis is the collapse of lung volume resulting in reduced or absent gas exchange. It may affect part or all of a lung. It is usually not bilateral. It is a condition where the alveoli are deflated down to little or no volume, as distinct from pulmonary consolidation, in which they are filled with liquid.

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CLINICAL PRESENTATION AND PHYSICAL FINDINGS

• Cough, dyspnea • Trachea deviated towards lesion • Diminished chest expansion • Dull chest percussion ●Decreased vocal fremitus and vocal resonance • Decreased or absent breath sounds

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Respiratory causes of clubbing Interstitial lung disease Carcinoma of the lung Mesothelioma Bronchiectasis Cystic fibrosis Lung abscess Empyema long standing TB

Thank You

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