CARDIO - RESTRICTIVE LUNG DISEASE

Restrictive lung diseases are characterized by the following:

• Reduced lung volumes either because of an alteration in lung parenchyma or because of a disease of the pleura

• Chest wall

• Neuromuscular apparatus

Restrictive disease are associated with:

• A decreased TLC (Total lung capacity)

• Measures of expiratory airflow are preserved

• Airway resistance is normal

• Forced expiratory volume in 1 second (FEV1) /forced vital capacity (FVC) ratio is increased

Obstructive lung diseases, such as asthma and chronic obstructive pulmonary disease (COPD), show a ???

normal or increased total lung capacity (TLC)

Obstructive lung diseases are characterized by the following:

• An obstruction in the air passages

• With obstruction defined by exhalation that is slower and shallower than in someone without the disease

Obstruction can occur when:

• Inflammation and swelling cause the airways to become narrowed or blocked, making it difficult to expel air from the lungs

• It results in an abnormally high volume of air being left in the lungs (increased residual volume)

• Increased residual volume leads to both the trapping of air and hyperinflation of the lungs—changes that contribute to a worsening of respiratory symptoms

Lung diseases that are categorized as being obstructive:

• Chronic obstructive pulmonary disease (COPD)

• Chronic bronchitis

• Asthma

• Bronchiectasis

• Bronchiolitis

• Cystic fibrosis

Intrinsic restrictive disorders are those that occur due to ___?

restriction in the lungs (often a “stiffening”)

Intrinsic restrictive disorders are those that occur due to restriction in the lungs (often a “stiffening”) and include:

• Pneumonia

• Pneumoconioses - industrial lung disease

• Adult respiratory distress syndrome (ARDS)

• Eosinophilic pneumonia

• Tuberculosis

• Sarcoidosis - accumulation of particles

• Interstitial lung diseases due to a known cause (such as pulmonary fibrosis) and idiopathic pulmonary fibrosis

• Lobectomy - isang part lang ng lungs ang inooperahan

• Pneumonectomy - buong lungs tinanggal

Restrictive Lung Diseases (EXTRINSIC)

• Outside of the lungs that restricts the expansion of the lungs

Extrinsic restrictive disorders refer to those that originate outside of the lungs. These include impairment caused by the following:

• Scoliosis

• Obesity

• Obesity hypoventilation syndrome

• Pleural effusion

• Malignant tumors

• Ascites - abdominal swelling caused by cirrhosis or liver cancer

• Pleurisy

• Rib fractures

Restrictive Lung Diseases (NEUROLOGICAL)

caused by disorders of the central nervous system that prevent the lungs from working properly.

Most common causes in RLD (neurological)

• Paralysis of the diaphragm

• Guillain-Barre syndrome

• Myasthenia gravis

• Muscular dystrophy

• Amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease)

The many disorders that cause reduction or restriction of lung volumes may be divided into two groups based on anatomical structures

1. intrinsic lung diseases or diseases of the lung parenchyma

2. extrinsic disorders or extrapulmonary diseases

Pathology for Intrinsic Lung Diseases

• Pathology is the study of diseases – what causes them, how they develop, what they do to the body, and what they look like under a microscope.

• Cause inflammation or scarring of the lung tissue (interstitial lung disease) or result in filling of the air spaces with exudate and debris (pneumonitis)

(INTRINSIC) These diseases can be characterized according to etiological factors which are the following:

• Idiopathic fibrotic diseases

• Connective-tissue diseases

• Drug-induced lung diseases

• Environmental exposures (inorganic and organic dusts)

• Primary diseases of the lungs (including sarcoidosis)

Pathology for extrinsic disorders or extrapulmonary diseases

The chest wall, pleura, and respiratory muscles are the components of the respiratory pump, and they need to function normally for effective ventilation

(EXTRINSIC) Diseases of these structures result in the following:

• Lung restriction

• Impaired ventilatory function

• Respiratory failure (eg, nonmuscular diseases of the chest wall, neuromuscular disorders)

This mnemonic has been used to divide the causes of restrictive lung disease into:

P - Pleural

A - Alveolar

I - Interstitial

N - Neuromuscular

T - Thoracic cage abnormalities

The maximum volume of air forcibly exhaling from the point of maximal inhalation

FVC or FORCED VITAL CAPACITY

during FVC maneuver

FEV1 or FORCED EXPIRATORY VOLUME IN 1 SECOND

Expressed as percentage

FEV1/FVC or RATIO OF FEV1 AND FVC

OBSTRUCTIVE DISORDERS

decrease in both FEV1 and FEV1/FVC ratio

RESTRICTIVE DISORDERS

normal FEV1/FVC ratio

PATHOPHYSIOLOGY

the study of how disease affects the way the body normally works. It focuses more on the process and function – how the disease changes things inside the body.

Functional reserve capacity (FRC)

• the volume of air in the lungs when the respiratory muscles are fully relaxed and no airflow is present

• determined by the balance of the inward and elastic recoil of the lungs and the outward elastic recoil of the chest wall

Restrictive lung diseases are characterized by

reduction in FRC and other lung volumes because of pathology in the lungs, pleura, or structures of the thoracic cage (MOST IMPORTANT)

Etiology

means the cause of a disease.

Collagen-vascular diseases are potential cause of restrictive lung disease which includes the following:

• Scleroderma

• Polymyositis

• Dermatomyositis

• Systemic lupus erythematosus

• Rheumatoid arthritis

• Ankylosing spondylitis

Instrinsic lung disease cause either

• ↑ inflammation and/or scarring of lung tissue (interstital lung disease)

• ↓ fill the air spaces with exudate and debris (pneumonitis)

Etiology of extrinsic disorders

• Nonmuscular diseases of the chest wall, in which kyphosis can be idiopathic or secondary, may cause restrictive lung disease

• The most common cause of secondary kyphoscoliosis is neuromuscular disease

• Neuromuscular diseases manifest as respiratory muscle weakness and are due to myopathy or myositis, quadriplegia, or phrenic neuropathy from infectious or metabolic causes

Acute disorders

last days to weeks and include acute interstitial pneumonitis, eosinophilic pneumonia, and diffuse alveolar hemorrhage

Subacute disorders

• lasting weeks to months include sarcoidosis, drug-induced interstitial lung disease, alveolar hemorrhage syndrome, cryptogenic organizing pneumonia (COP), and connective-tissue diseases

• Chronic cases lasting months to years include idiopathic pulmonary fibrosis (IPF), sarcoidosis, and pulmonary langerhans cell histiocytosis

Smoking history

Pulmonary langerhans cell histiocytosis, desquamative interstitial pneumonitis, IPF, and respiratory bronchiolitis occur with increased frequency among persons who smoke or those who previously smoked

Prior medication use

A detailed history of previously use medications is needed to exclude the possibility of drug-induced lung disease

Occupation history

Seek a strict chronological listing of the patient’s lifelong employment, including specific duties and known exposure

Environmental exposure

A review of the domestic and work environment of the patient and spouse is invaluable

Symptoms of intrinsic diseases

• Progressive exertional dyspnea is the predominant symptom

• Dry cough is common and may be disturbing sign

• Hemoptysis or grossly bloody sputum occurs in patients with diffuse alveolar hemorrhage syndromes and vasculitis

• Wheezing is an uncommon manifestation but can occur in patients with an airway-centered process

Symptoms of extrinsic diseases

• Nonmuscular diseases of the chest wall affect patients with kyphoscoliosis.

• Patients younger than 35 years tend to be asymptomatic, whereas middle-aged patients develop dyspnea, decreased exercise tolerance, and respiratory infections.

• The cause of respiratory failure is often multifactorial and is secondary to spinal deformity, muscle weakness, disordered ventilatory control, sleep-disordered breathing, and airway disease

• Patients develop dyspnea upon exertion, followed by dyspnea at rest, and their condition ultimately advances to respiratory failure

Velcro crackles

are common in most patients with interstitial lung disorders.

Inspiratory squeaks or scattered, late, inspiratory high-pitched rhonchi

are frequently heard in patients with bronchiolitis.

Cyanosis

at rest is uncommon in persons with interstitial lung diseases, and this is usually a late manifestation of advanced disease.

Digital clubbing

is common in those with IPF and is rare in others (eg, those with sarcoidosis or hypersensitivity pneumonitis)

Erythema nodosum

suggest sarcoidosis

Maculopapular rash

can occur in those with connective-tissue diseases or drug-induced lung diseases.

Raynaud phenomenon

present in patients with connective-tissue diseases, and telangiectasia is present in those with scleroderma.

Peripheral lymphadenopathy, salivary gland enlargement, and hepatosplenomegaly

signs of systemic sarcoidosis

Uveitis

observed in sarcoidosis and ankylosing spondylitis

Palpable purpura

signifying a leukocytoclastic vasculitis.

hematuria and anasarca

renal involvement

Cor pulmonale

occurs in late stages of pulmonary fibrosis or advanced kyphoscoliosis

Extrinsic disorders

• Severe kyphoscoliosis and massive obesity - easily recognizable

• Pleural disorders - decreased tactile fremitus, dullness on percussion, decreased breath sound intensity

• Neuromuscular diseases - accessory muscle usage, rapid shallow breathing, paradoxical breathing, systemic involvement

Differential Diagnosis

• Acute respiratory distress syndrome

• Asbestosis

• Bronchitis

• Chronic obstructive pulmonary disease (COPD)

• Coal worker’s pneumoconiosis

• Emphysema

• Eosinophilic pneumonia

• Hypersensitivity pneumonitis

• Idiopathic pulmonary fibrosis

• Interstitial (nonidiopathic) pulmonary fibrosis

• Lung transplantation

• Lymphocytic interstitial pneumonia

• Obesity

• Pulmonary eosinophilia

Intrinsic lung diseases

• Routine laboratory evaluations often fail to reveal positive findings.

• The decision to perform additional tests should be directed by the findings of the clinical assessment.

Extrinsic disorders

An elevated creatine kinase level may indicate myositis, which may cause muscle weakness with resultant restrictive lung disease

Chest Radiography for Intrinsic Lung Disorder

• Diagnosis of interstitial lung disorder → often based on abnormal chest radiograph findings (can be normal in ~10% of patients)

• Most common abnormality → reticular pattern

• Other patterns → nodular, reticulonodular, mixed patterns (e.g., alveolar filling with ground-glass appearance, increased interstitial markings)

Tests for Extrinsic Disorders

Chest radiographs → show nonmuscular chest wall diseases and deformities of spinal column and ribs

Other Tests – Pulmonary Function Testing

• Complete lung function testing → spirometry, lung volume, diffusing capacity, ABG measurements

• All restrictive disorders → ↓ TLC, ↓ FRC, ↓ RV

• Restrictive pattern → ↓ FEV1 and ↓ FVC with normal or ↑ FEV1/FVC ratio

• Definitive diagnosis of restriction → decreased TLC

Obstructive and Restrictive Lung Patterns

FORCED VITAL CAPACITY (FVC)

Obstructive pattern: Decreased or normal

Restrictive pattern: Decreased

Obstructive and Restrictive Lung Patterns

FORCED EXPIRATORY VOLUME IN ONE SECOND (FEV1)

Obstructive pattern: Decreased

Restrictive pattern: Decreased or normal

Obstructive and Restrictive Lung Patterns

FEV1/FVC Ratio

Obstructive pattern: Decreased

Restrictive pattern: Normal or increased

Obstructive and Restrictive Lung Patterns

Total lung capacity (TLC)

Obstructive pattern: Normal or increased

Restrictive pattern: Decreased

Tests for Extrinsic Lung Disorders

• Severe kyphoscoliosis → produces restrictive pattern

• TLC → markedly reduced; RV relatively preserved

• Vital capacity → reduced

• RV/TLC ratio → elevated

• Maximal inspiratory & expiratory pressures → modestly ↓ in mild disease, severely ↓ in advanced disease

• Hypoxemia → due to V/Q mismatch from atelectasis and shunt

• Neuromuscular diseases → maximal inspiratory & expiratory mouth pressures vary (normal → severely reduced)

• Maximal inspiratory pressure < 30 cm H₂O → ventilatory failure likely

• Chronic muscular diseases → ↓ vital capacity, ↓ FRC, preserved RV, moderately ↓ TLC

Medical Care

• Treatment → depends on specific diagnosis (based on clinical evaluation, imaging, and lung biopsy)

• Ancillary therapy → supplemental oxygen (relieves exercise-induced hypoxemia, improves performance)

Three drugs given that mainstay the therapy for many of the interstitial lung diseases:

• Corticosteroids - are the first line therapy but are associated with myriad adverse effects

• Immunosuppressive agents

• Cytotoxic agents

Cytotoxic therapy

may be considered for patients who do not respond to steroids, experience adverse effects, or have contraindications to high-dose corticosteroid therapy.

Treatment of Extrinsic Lung Disorders

• Neuromuscular diseases → preventive therapies (reduce impaired secretion clearance, prevent & promptly treat respiratory infections)

• Respiratory failure or severe gas exchange abnormalities during sleep → noninvasive positive-pressure ventilation (nasal/oronasal mask)

• Failure of noninvasive devices → permanent tracheotomy + ventilator assistance (portable ventilator)