Restrictive Lung Disease
Adult-Gerontology Acute Care Practice Guidelines
Definition
A.A reduction in the total lung capacity secondary to a decrease in lung elasticity or disease of the chest wall, pleura, or neuromuscular etiology. Disorders can be classified as intrinsic or extrinsic.
Incidence
A.The incidence is highly variable and dependent on the etiology of restriction.
B.The incidence of some disorders is not well known.
C.Interstitial lung diseases (ILDs), although rare, are a cause of restrictive lung disease affecting approximately 500,000 individuals each year and resulting in 40,000 deaths.
D.Nonidiopathic and idiopathic pulmonary fibrosis (type of ILD) are a common cause of restrictive lung disease.
E.Approximately 30 cases per 100,000 of restrictive lung disease are due to idiopathic pulmonary fibrosis.
F.The prevalence of disease increases with age.
G.Frequency of occurrence is typically higher in men.
Pathogenesis
A.An exogenous or endogenous stimulus causes repetitive injury to the lung parenchyma, leading to epithelial and endothelial damage. Activation of local and systemic factors (e.g., fibroblasts, growth factors, clotting, factors, cytokines) occurs.
B.A provisional matrix is formed. There is a dysregulation of the intricate network and lack of matrix degradation, leading to aberrant wound healing and progressive lung remodeling, ultimately causing pulmonary fibrosis.
Predisposing Factors
A.Predisposing factors depend on the etiology of the restrictive lung disease.
B.Risk factors include:
1.Obesity.
2.Kyphoscoliosis.
3.Myasthenia gravis.
4.Chronic pleural disease (e.g., trapped lung).
5.Autoimmune disease (e.g., scleroderma, systemic lupus erythematosus).
6.Occupational exposures.
7.Medications such as amiodarone, bleomycin, and methotrexate.
8.Idiopathic lung disease such as pulmonary fibrosis, more common in the elderly and men.
9.Sarcoidosis.
Subjective Data
A.Common complaints/symptoms.
1.Symptoms and complaints may vary depending on the underlying cause of the restrictive lung disease.
2.Dyspnea (see Figure 2.1): Most common complaint. It can be present with exercise or at rest as the disease progresses.
3.Possible chronic cough (see Figure 2.3), wheezing (see Figure 2.2), or chest discomfort.
4.Possible hemoptysis.
5.Fatigue.
B.Common/typical scenario.
1.Duration of illness (e.g., acute onset, chronic).
C.Family and social history.
1.Smoking history.
2.Occupational history or exposures.
3.Family history of fibrotic lung disease.
D.Review of symptoms.
1.Neurologic—any confusion, fatigue, muscle weakness.
2.Respiratory—shortness of breath at rest, upon exertion, or that is progressive; dry cough; bloody sputum; pain on inspiration; recent or frequent colds.
3.Use of medications such as nitrofurantoin, amiodarone, or others that have the potential to cause lung disease.
Physical Examination
A.Dyspnea, which may be more evident with activity.
B.Tachypnea.
C.Cyanosis or oxygen desaturation with activity.
D.Possible bibasilar inspiratory crackles, scattered inspiratory rhonchi, or wheezing.
E.Digital clubbing.
F.Obese.
G.Other disease-specific signs and symptoms (e.g., rash, Raynaud’s, muscle weakness), depending on the underlying etiology.
Diagnostic Tests
A.Laboratory studies.
1.Usually nonspecific.
2.Serologic testing. This may be appropriate in patients suspected of having an underlying disorder causing restrictive disease such as rheumatoid arthritis.
B.Chest x-ray.
1.Typically nonspecific findings, which may vary with the type of restrictive disease.
2.Possible evidence of increased interstitial markings, bibasilar reticular pattern, or a nodular pattern.
3.Honeycombing, which is typically noted as a late or advanced finding.
4.If an extrinsic factor is suspected, then imaging may reveal a trapped lung, pleural effusion, etc.
C.Chest CT
1.More sensitive and better assessment of the extent of disease compared to a chest x-ray.
2.May reveal findings characteristic of specific restrictive diseases. Some restrictive diseases such as idiopathic pulmonary fibrosis can be diagnosed solely with a chest CT.
3.If an extrinsic factor is suspected, then imaging may reveal a trapped lung, pleural effusion, etc.
D.Pulmonary Function Testing
1.Valuable for assessing the response to therapy and monitoring disease progression.
2.Does not diagnosis a specific disease.
3.Characteristic findings include a reduced total lung capacity (TLC), functional residual capacity (FRC), and residual volume (RV).
4.The forced expiratory volume in one second (FEV1) and forced vital capacity ratio is usually normal or increased.
5.The diffusing capacity of carbon monoxide is reduced in patients with an intrinsic etiology of restrictive disease. If the diffusing capacity is normal, then the etiology of restrictive disease is an extrinsic factor such as neuromuscular disease.
E.Arterial blood gas
1.May be normal or indicate hypoxemia and a respiratory alkalosis.
2.May reveal an increased alveolar-arterial gradient.
F.Bronchoscopy and/or lung biopsy
1.Beneficial for identifying diseases associated with intrinsic factors or the lung parenchyma.
2.A bronchoalveolar lavage (BAL) may be useful in narrowing the differential diagnoses.
a.The clinical usefulness of the BAL has not been well established.
3.A lung biopsy can confirm the diagnosis, evaluate disease activity, and exclude other diagnoses.
a.Open thoracotomy
b.Video-assisted thoracoscopic lung biopsy
c.Transbronchial lung biopsy via bronchoscopy
G.Additional imaging or testing may be warranted to assess for complications resulting from restrictive diseases such as an echocardiogram to evaluate for pulmonary hypertension or right-sided heart failure.
Evaluation and Management Plan
A.Treatment may vary depending on the underlying etiology for restrictive disease.
B.Intrinsic etiologies are defined as diseases of the lung parenchyma. Extrinsic etiologies are extra-pulmonary causes including neuromuscular disorders, the chest wall, etc.
C.Patients should receive smoking cessation counseling.
D.Avoidance of environmental and/or occupational exposures.
E.Medications suspected of causing restrictive disease should be stopped immediately.
F.Supplemental oxygen therapy should be administered for all patients with oxygen saturations less than 88% on room air at rest or upon exertion.
G.Pulmonary rehabilitation or regular activity/exercise should be encouraged because it has been shown to improve endurance and quality of life.
H.Patients should receive vaccinations for influenza and pneumococcal.
I.Treatment regimens for intrinsic causes usually includes:
1.Corticosteroid therapy
a.Use of corticosteroids is generally accepted; however, timing, dosing, and continuation versus discontinuation of treatment is highly variable and dependent on the intrinsic cause for restrictive disease as well as patient responsiveness.
b.The long-term effects of corticosteroid therapy must be considered.
c.Pulse high dose corticosteroids are typically used for acute exacerbations.
2.Immunosuppressive agents (e.g. cyclosporine, azathioprine) may be used in certain diagnoses. These medications should not be routinely or empirically used without a definitive diagnosis.
3.If worsening respiratory symptoms, patients may require invasive mechanical ventilation.
4.Patients with refractory disease to treatment and progressive worsening, may be a candidate for lung transplantation and should be referred to lung transplant specialist and center.
J.Treatment for extrinsic causes include:
1.Weight loss counseling and plan for obese patients
2.Non-invasive positive pressure ventilation for patients who have impaired gas exchange
3.Identification of the extrinsic disorder and treatment accordingly.
4.For patients with a trapped lung, chronic effusion, or empyema, a decortication may be required.
Follow Up
A.Follow-up is variable and dependent on the patient’s symptoms and medical management. It should be individualized.
B.Post-hospital discharge, patients will follow-up with their provider in one week.
Consultation/Referral
A.Patients with restrictive lung disease should be referred to a pulmonologist for diagnosis and management.
B.Patients with an extrinsic etiology for restrictive disease such as myasthenia gravis should be referred to a neurologist or the appropriate consultant for the disorder.
Individual/Special/Geriatric Considerations
A.To adequately assess responsiveness to immunosuppressive medications, the provider should note it may not be evident until eight to twelve weeks after therapy initiation.
B.Patients with parenchymal restrictive disease (e.g. idiopathic or non-idiopathic pulmonary fibrosis) receiving treatment with high dose steroids should receive prophylactic treatment for pneumocystis jiroveci pneumonia (PJP).
C.Patients with progressive disease are typically discharged on home oxygen therapy. Increased oxygen requirements may be necessary to maintain a goal saturation greater than 88%. The patient and family is instructed that oxygen therapy may be tailored to maintain oxygen saturations at rest and with exertion. If the patient is requiring increased oxygen therapy from baseline, then an immediate follow-up appointment with their pulmonologist or hospital admission may be warranted.