Restrictive lung disease

Restrictive Lung Disease Microchapters
Overview
Classification Acute respiratory distress syndrome Hypersensitivity pneumonitis Occupational lung diseases Pleural Effusion Interstitial lung disease Sarcoidosis Neuromuscular diseases Scoliosis Muscular dystrophy Amyotropic lateral sclerosis (ALS) Myasthenia gravis
Spirometry Findings in Various Lung Conditions
Approach to Lung Disorders
Differentiating Restrictive Lung Disease from other Diseases

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aditya Ganti M.B.B.S. [2], Akshun Kalia M.B.B.S.[3], Usama Talib, BSc, MD [4], Cafer Zorkun, M.D., Ph.D. [5]

Overview

Restrictive lung disease (RLD) is a group of diseases characterized by an inability to attain complete expansion of the lungs. This may result from an abnormality in the parenchyma of the lungs or an abnormality outside the lung parenchyma (such as fluid accumulation or musculoskeletal abnormalities) hindering normal lung expansion and thus ability to ventilate normally. Restrictive lung diseases presents with a restrictive pattern on pulmonary function test and includes a decrease in total lung capacity (TLC), residual volume (RV), forced vital capacity (FVC), forced expiatory volume (FEV1), and a normal to increased FEV1/FVC ratio. Unlike obstructive lung disease (characterized by air trapping within the lungs), restrictive lung diseases result in decreased lung volumes and a lower than normal amount of air within the lungs. RLDs include acute respiratory distress syndrome, hypersensitivity pneumonitis, occupational lung diseases, pleural effusion, interstitial lung disease, sarcoidosis, and neuromuscular diseases such as scoliosis, muscular dystrophy, amyotropic lateral sclerosis (ALS), and myasthenia gravis.

Classification

Various diseases that present with a restrictive pattern on pulmonary function tests include:

• Acute respiratory distress syndrome
• Hypersensitivity pneumonitis
• Occupational lung diseases
• Pleural Effusion
• Interstitial lung disease
• Sarcoidosis
• Neuromuscular diseases
  • Scoliosis
  • Muscular dystrophy
  • Amyotropic lateral sclerosis (ALS)
  • Myasthenia gravis

Spirometry Findings in Various Lung Conditions

Spirometry can help distinguish restrictive lung disease from obstructive lung diseases. On spirometry the findings include:

Approach to Lung Disorders

Spirometry

Low FEV1/FVC ratio

Normal to high FEV1/FVC ratio

Obstructive Lung Disease

Restrictive Lung Disease

Bronchodilator therapy

DLCO

Increased FEV1

No change in FEV1

Normal DLCO

Decreased DLCO

Asthma

COPD

Chest wall disorders

Interstitial Lung Disease

Differentiating Restrictive Lung Disease from other Diseases

Restrictive lung disease must be differentiated from other diseases that cause dyspnea, cough, hemoptysis, and fever such as ARDS, hypersensitivity pneumonitis, pneumoconiosis, sarcoidosis, pleural effusion, interstitial lung disease (ILD), lymphocytic interstitial pneumonia, obesity, pulmonary eosinophilia, and neuromuscular disorders.

Disease		Clinical manifestations											Diagnosis
		History	Symptoms				Physical exam						Lab findings	PFT	Imaging		Gold standard
		History/Exposure	Dyspnea	Cough	Hemoptysis	Fever	Cyanosis	Clubbing	JVD	Peripheral edema	Auscultation	Other prominent findings		DLCO	CXR	CT
Acute Respiratory Distress Syndrome (ARDS)		Trauma Sepsis Drug overdose Massive transfusion Acute pancreatitis Aspiration pneumonia	+	+/–	–	–	+/–	–	+/–	–	Coarse breath sounds Rhonchi Decreased breath sounds	Initially respiratory alkalosis transforming to respiratory acidosis	PaO2 / FiO2 <300 BNP level of less than 100 pg/mL Leukopenia Leukocytosis Thrombocytopenia	↓	Bilateral pulmonary infiltrates: Initially patchy peripheral Later diffuse bilateral Ground glass appearance Frank alveolar infiltrate	Bronchial dilatation within areas of ground-glass opacification	PaO2 / FiO2 <300
Hypersensitivity Pneumonitis		History of allergen exposure	+	+	–	+	–	+	–	–	Diffuse fine bibasilar crackles	Constitutional symptoms: Weight loss Anorexia Muscle weakness	Neutrophilia Elevated ESR Elevated CRP Elevated immunoglobulin No peripheral blood eosinophilia	↓	Poorly defined micronodular or diffuse interstitial pattern In chronic form: Fibrosis Loss of lung volume Coarse linear opacities	Ground–glass opacities Diffusely increased radiodensities Diffuse micronodules Focal air trapping Mosaic perfusion Occasionaly thin-walled cysts Mild fibrotic changes	Clinical diagnosis
Pneumoconiosis	Silicosis	Occupational history Sandblasting Bystanders Quartzite miller Tunnel workers Silica flour workers Workers in the scouring powder industry	+	+	+/–	–	+	+	+	–	Hyperresonant Fine crackles Rhonchi Bronchial breath sounds Expiratory wheezing Increased tactile fremitus. Loud P2	Increased susceptiblity to tuberculosis.	Respiratory acidosis Abnormal sputum Anemia Neutrophilia Elevated ESR Elevated CRP Elevated immunoglobulin	↓	Small round opacities Symmetrically distributed Upper–zone predominance Diffuse interstitial pattern of fibrosis without the typical nodular opacities in chronic case	Nodular changes in lung parenchyma Progressive massive fibrosis Bullae, emphysema Pleural, mediastinal, and hilar changes	Lung biopsy
	Asbestosis	Shipyard workers Pipe fitting Insulators	+	+	+/–	–	+	+	+	–		Lung cancer Mesothelioma		↓	Predilection to lower lobes Fine and coarse linear, peripheral, reticular opacities	Subpleural linear opacities seen parallel to the pleura Basilar lung fibrosis Peribronchiolar, intralobular, and interlobular septal fibrosis Honeycombing Pleural plaques
	Berylliosis	Electronic manufactures	+	+	+/–	–	+	+	+	–		–		↓	Hilar adenopathy Increased interstitial markings.	Ground glass opacification Parenchymal nodules Septal lines
	Byssinosis	Cotton wool workers	+	+	+/–	–	+	+	+	–		Increased susceptibility to Actinomyces and Aspergillus infection.		↓	Diffuse air-space consolidation	Pulmonary fibrosis with honeycombing Peri-bronchovascular distribution of nodules Ground-glass attenuations
Disease		Clinical manifestations											Diagnosis
		History	Symptoms				Physical exam						Lab findings	PFT	Imaging		Gold standard
		History/Exposure	Dyspnea	Cough	Hemoptysis	Fever	Cyanosis	Clubbing	JVD	Peripheral edema	Auscultation	Other prominent findings		DLCO	CXR	CT
Sarcoidosis (stage 2–5)		African American Autoimmune	+	+	+	+	–	–	–	–	Usually normal Occasional crackles	Dermatologic manifestations Ocular involvement Osseous involvement Heart failure from cardiomyopathy Lymphocytic meningitis Cranial nerve palsies	Hypercalcemia or hypercalciuria  Elevated 1, 25–dihydroxyvitamin D levels Elevated angiotensin–converting enzyme (ACE)	↓	Bilateral hilar lymphadenopathy	High–resolution CT (HRCT): Active alveolitis Fibrosis	Biopsy
Pleural Effusion		Transudate CHF Cirrhosis Exudate Parapneumonic causes  Malignancy	+	+	+/–	+/–	+/–	+/–	+/–	+/–	Decreased tactile fremitus  Diminished or inaudible breath sounds Pleural friction rub	Peripheral edema, distended neck veins, and S3 gallop suggests congestive heart failure Edema may also be a manifestation of nephrotic syndrome, pericardial disease, or when combined with yellow nailbeds, the yellow nail syndrome. Cutaneous changes and ascites suggest liver disease. Lymphadenopathy or a palpable mass suggests malignancy.	Thoracentesis  Exudate Transudate LDH, glucose, cytology Other specific labs of underlying etiology	NL	Supine: Blunting of the costophrenic angle Homogenous increase in density spread over the lower lung fields Lateral decubitus: Free flowing effusion as layers	Thickened pleura Mild effusions can aslo be detected	Thoracocentesis
Interstitial lung disease		Connective–tissue disorder Pneumoconiosis	++	+	+	–	+/–	+/–	+/–	+/–	End–inspiratory fine crackles Wheezing	Increased A-a gradient Normal pCO2	Depending on the underlying cause: Elevated ESR Serologic testing for ANA, RF, ANCA, and ASCA may be positive	↓	Reticular and/or nodular opacities Honeycomb appearance (late finding)	Bilateral reticular and nodular interstitial infiltrates	Video–assisted thoracoscopic lung biopsy
Lymphocytic Interstitial Pneumonia		Autoimmune Lymphoproliferative disorders	+	+	+	+	–	+	–	–	Wheezing Rales	Increased A–a gradient Normal PCO2	Polyclonal hypergammaglobulinemia Increased LDH	NL	Bibasilar interstitial or micronodular infiltrates	Determines the degree of fibrosis Cysts (characterstic)	Open lung biopsy
Obesity		Diabetes mellitus	+	+	–	–	–	–	–	+	Wheezing	–	Increased hematocrit	NL	X ray findings are often limited due to body habitus	CT findings are variable and depends upon severity of obesity	Clinical
Pulmonary Eosinophilia		Infections Parasitic Fungal Mycobacterial	+	+	+	+	+	–	+	+	Wheezing Rales	Increased A–a gradient	Leukocytosis with eosinophilia (> 250/µL)	↓	Interstitial or diffuse nodular densities	Determines extent and distribution of the disease Interstitial infiltrates Cysts and nodules	Biopsy of lesion (skin or lung)
Disease		Clinical manifestations											Diagnosis
		History	Symptoms				Physical exam						Lab findings	PFT	Imaging		Gold standard
		History/Exposure	Dyspnea	Cough	Hemoptysis	Fever	Cyanosis	Clubbing	JVD	Peripheral edema	Auscultation	Other prominent findings		DLCO	CXR	CT
Neuromuscular diseases	Scoliosis	Postural abnormality	+	–	–	–	–	–	–	–	Decreased breath sounds	In severe scoliosis, the rib cage may press against the lungs making it more difficult to breathe.	F/O genetic conditions Marfan's syndrome Edward's syndrome Total lymphocyte count (should be >1500/μL) Nutritional status must be assessed	NL	Accurate depiction of the true magnitude of the spinal deformity can be assessed by supine anteroposterior (AP) and lateral spinal radiographs	N/A	Clinical Radiographs
	Muscular dystrophy	Proximal muscle weakness	+	–	–	–	–	–	–	–	Decreased breath sounds	Rash	Elevated CPK and aldolase +ANA +Anti–Jo abs Elevated ESR, CRP and RF	NL	N/A	N/A	Muscle biopsy
	ALS	Muscle weakness Neurological deficit	+	–	–	–	–	–	–	–	Decreased breath sounds	Symptoms begin with limb involvement due to muscle weakness and atrophy.  Cognitive or behavioral dysfunction Sensory nerves and the autonomic nervous system are generally unaffected	N/A	NL	Not significant	Not significant	Clinical diagnosis Nerve conduction studies and needle electromyography (EMG)
	Myasthenia gravis	Difficulty in: Getting up from chair Combing Swallowing	+	–	–	+	–	–	–	–	Decreased breath sounds	Extraocular, bulbar, or proximal limb muscles. Breathing is rapid and shallow Respiratory muscle weakness may lead to acute respiratory failure and require immediate intubation	Anti–acetylcholine receptor (AChR) antibody (Ab) test positive	NL	Thymoma as an anterior mediastinal mass	Thymoma as an anterior mediastinal mass	Electromyography

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