Restrictive Pulmonary Disorders
Objectives - Identify restrictive disease facts and principles across pleural, alveolar, interstitial, neuromuscular, thoracic, and extrathoracic causes.
Restrictive Lung Disease Overview
Restrictive lung disease is a group of respiratory diseases that restrict lung expansion, causing decreased lung volume, increased work of breathing, and inadequate ventilation and/or oxygenation.
The source uses PAINT for restrictive categories:
| Letter | Category | Examples |
|---|---|---|
| P | Pleural | Pleural effusions, empyema, pneumothorax |
| A | Alveolar | Edema, hemorrhage |
| I | Interstitial | IPF, pneumonitis |
| N | Neuromuscular | Myasthenia gravis, ALS, Guillain-Barre |
| T | Thoracic/extrathoracic | Obesity, kyphoscoliosis, ascites |
Restrictive Disease Diagnosis
| Test or Measure | Restrictive Pattern |
|---|---|
| Spirometry | Measures flows and volumes |
| Lung volumes | Primary PFT test to diagnose restriction; measures RV/FRC and TLC |
| Diffusion | Measures how well oxygen moves across the alveolar-capillary membrane |
| Airway resistance | Normal |
| Compliance | Normal or low |
Pleural Diseases
Pleural diseases in the source include:
- Pleural effusion: fluid
- Pneumothorax: air
- Hemothorax: blood
- Bronchopleural fistula: BPF
Pleural Effusion
Pleural effusion is any abnormal, excessive amount of fluid in the pleural space.
| Type | Mechanism | Causes | Pleural Fluid |
|---|---|---|---|
| Transudative effusion | Hydrostatic pressure | CHF, liver failure or cirrhosis, nephrotic syndrome | Decreased proteins |
| Exudative effusion | Inflammatory process | Pneumonia, cancer, TB, PE, viral infections | Increased proteins |
Symptoms include sharp chest pain worse with cough or deep breaths, cough, tachypnea, and shortness of breath.
Diagnosis can include:
- Physical exam
- Diminished breath sounds
- Dull percussion
- Asymmetrical chest expansion
- Tracheal deviation away from the affected lung
- Chest x-ray showing blunting of the costophrenic angle
- CT
- Ultrasound
Treatment includes thoracentesis to remove fluid and treatment of the underlying cause. Recurring pleural effusions may be treated with a pleural catheter, pleurodesis using chemicals or talc in the pleural space, or surgical removal of pleura.
Pneumothorax
Pneumothorax occurs when rupture of the lung or airway and visceral pleura allows air into the pleural space.
| Type | Key Points |
|---|---|
| Primary spontaneous pneumothorax | Occurs without underlying lung disease; late teens to early twenties; tall, thin, male pattern |
| Secondary spontaneous pneumothorax | Occurs with underlying lung disease such as COPD, especially emphysema, asthma, cystic fibrosis, or interstitial lung disease |
| Open pneumothorax | Traumatic, open chest wall injury, "sucking chest wound," caused by penetrating injury such as stab wound, gunshot, or impalement |
| Tension pneumothorax | Air enters pleural space and has no vent to the atmosphere; most dangerous during positive pressure ventilation |
In a closed pneumothorax, the chest wall is intact. A patient breathing spontaneously can have equilibration of pressures across the collapsed lung. The patient has symptoms but it is not usually life-threatening.
Pneumothorax Signs and Symptoms
Signs and symptoms are relative to size and type:
- Dyspnea
- Cyanosis
- Restlessness and agitation
- Chest pain
- Tachypnea
- Tachycardia initially, but bradycardia may occur as the air leak worsens
- Hypertension initially, but hypotension may occur as the air leak worsens
Treatment options include observation, needle aspiration, and a small pigtail catheter.
Diagnosis includes patient history and physical exam, chest x-ray, breath sounds, and digital percussion.
Tension Pneumothorax
In tension pneumothorax, mediastinal shift can quickly lead to cardiovascular collapse. The vena cava and right heart cannot accept venous return. No venous return means no cardiac output, and no cardiac output means death.
Signs and symptoms include:
- Tracheal deviation away from the affected side
- Decreased breath sounds on the affected side
- Hypertympanic percussion note over the affected side
- Jugular venous distension
- Unequal chest expansion
- Pulsus paradoxus, a larger-than-normal drop in systolic blood pressure during inhalation
- Subcutaneous emphysema
- Difficulty ventilating the patient with high airway pressures
Hemothorax
Hemothorax is associated with traumatic injuries and thoracic surgery. The lung collapses to some degree depending on the amount of blood.
The source notes there is less risk of mediastinal shift because the amount of blood needed to cause a shift would result in life-threatening blood volume loss.
Pneumothorax and hemothorax treatment can include:
- Oxygen
- Observation
- Percutaneous needle aspiration for air only
- Chest tube for air or fluid
Bronchopleural Fistula
Bronchopleural fistula is a pneumothorax involving a large airway such as a mainstem, lobar, or segmental airway. It causes a large air leak.
Source points include:
- Common after lung resections
- May require multiple chest tubes
- Monitor air leak on the chest drainage device
- Air leak may be continuous on a ventilator, occur during inspiration on a ventilator, during expiration, or during forced expiration/cough
- Closely monitor ventilator values including tidal volume, airway pressure, and PEEP
Interstitial Lung Disease
Interstitial lung disease is a broad category of more than 200 diseases affecting the lung parenchyma, characterized by fibrosis or inflammation.
| Term | Meaning |
|---|---|
| Interstitium | Area between the capillaries and alveoli; not primarily a disease of the airways or alveoli |
| Lung parenchyma | Portion of the lung involved in gas transfer: alveoli, alveolar ducts, and respiratory bronchioles |
| Granuloma | Collection of macrophages that forms when the immune system attempts to wall off foreign substances it cannot eliminate |
Disease progression varies, but the common link is inflammation:
- Bronchiolitis: inflammation of the bronchioles
- Alveolitis: inflammation of the alveoli
- Vasculitis: inflammation of pulmonary capillaries
The lung is affected through damage, alveolar inflammation, and scarring or fibrosis that begins in the interstitium.
Interstitial Lung Disease With Known Cause
| Category | Examples From Source |
|---|---|
| Tobacco exposure | Respiratory bronchiolitis ILD, desquamative interstitial pneumonia, pulmonary Langerhans cell histiocytosis |
| Hypersensitivity pneumonitis | Cell-mediated immune reaction to inhaled antigens from bacteria, fungi, humidification systems, indoor hot tubs, or animal proteins |
| Drug-related | Antiarrhythmics such as amiodarone and tocainide; illicit drugs such as heroin, methadone, and talc; chemotherapy agents such as bleomycin, mitomycin, and methotrexate |
| Radiation-related | Radiation therapy |
| Occupational | Asbestosis, silicosis, coal workers pneumoconiosis |
| Systemic disease | Sarcoidosis, connective tissue disease, lymphangioleiomyomatosis |
Tobacco-related ILDs differ by where cells collect:
- RB-ILD: macrophages collect in the bronchioles.
- DIP: macrophages collect in the alveoli.
- PLCH: macrophages, fibroblasts, and eosinophils collect around small airways.
Sarcoidosis
Sarcoidosis is an idiopathic multisystem disorder in which inflammatory cells collect in granulomas.
It most commonly affects the lungs and lymph nodes, but can also affect the eyes, skin, heart, and other organs. The source identifies it as the most common ILD in the U.S.
There is no cure. Most patients do well with no treatment or modest treatment. In some cases it goes away on its own, but it may last for years and cause organ damage.
Symptoms include:
- Fatigue
- Swollen mediastinal lymph nodes
- Weight loss
- Pain and swelling in joints such as the ankles
- Persistent dry cough
- Shortness of breath
- Wheezing
- Chest pain
- Pulmonary nodules on chest x-ray
Interstitial Lung Disease of Unknown Cause
Unknown-cause ILDs listed in the source:
- Idiopathic pulmonary fibrosis (IPF)
- Nonspecific interstitial pneumonia (NSIP)
- Cryptogenic organizing pneumonia (COP)
- Lymphocytic interstitial pneumonia (LIP)
Interstitial Lung Disease Signs, Diagnosis, and Treatment
| Category | Findings |
|---|---|
| Signs and symptoms | Dyspnea on exertion, nonproductive cough, productive cough not common, fine inspiratory crackles, wheezing not common, hemoptysis, pneumothorax |
| Pulmonary function | Restrictive pattern on FVC and plethysmography, decreased DLCO, decreased lung compliance |
| ABG | Normal or decreased PaO2 |
| Exercise testing | 6-minute walk and oxygen titration |
| Imaging | X-ray with reduced lung volumes and bilateral reticular or reticulonodular opacities; high-resolution CT; air bronchograms |
| Procedures | Bronchoscopy, bronchoalveolar lavage, biopsy, surgical lung biopsy |
| Treatment | Oxygen therapy, vaccinations, avoiding infection, pneumococcal vaccine, influenza vaccine, hand hygiene, pulmonary rehab and exercise, transplant |
Neuromuscular Disorders
The source lists myasthenia gravis, Guillain-Barre syndrome, phrenic nerve damage, spinal cord trauma, and stroke.
Myasthenia Gravis
Myasthenia gravis is an incurable neuromuscular autoimmune disease causing muscle weakness. Symptoms can include double or blurred vision, drooping eyelids, difficulty speaking and swallowing, and limb weakness.
It affects most of the body, spreading from eyes and face to other areas over weeks, months, or years. One in 5 patients have only eye muscle involvement. It can be controlled with treatment. Severe cases can lead to respiratory failure but do not significantly affect life expectancy.
Cause: thymus gland abnormalities release antibodies that block or destroy nicotinic acetylcholine receptors at the nerve-muscle junction.
Symptoms include:
- Ocular and facial weakness
- Ptosis
- Dysphagia
- Hoarseness
- Diplopia
- Difficulty walking
- Myasthenic crisis with life-threatening respiratory muscle weakness and acute respiratory failure
Diagnosis includes history and physical, acetylcholine receptor antibodies, CT or MRI to evaluate the thymus, and the Tensilon test. Edrophonium chloride blocks the enzyme that breaks down acetylcholine, causing sudden temporary improvement in muscle strength when positive.
Monitoring includes:
- Vital capacity less than 20 mL/kg or 30% of baseline
- Max inspiratory pressure less than -30 cmH2O
- Max expiratory pressure less than +40 cmH2O
Treatment includes thymectomy, anticholinesterases such as pyridostigmine or Mestinon, IV immune globulin, corticosteroids, immunosuppressants such as methotrexate, plasmapheresis, and mechanical ventilation.
Guillain-Barre Syndrome
Guillain-Barre syndrome is also called acute demyelinating polyneuropathy. It is a rare inflammatory disorder in which the immune system attacks the protective myelin sheath of peripheral nerves, preventing nerves from sending signals to muscles.
The exact cause is unknown, but it is often preceded by respiratory or GI infection 1-4 weeks before symptoms. Most cases are mild. Extreme cases cause breathing difficulty and require ventilation. Recovery may take several weeks to more than a year, and most patients make a total recovery even from severe cases.
Symptoms include:
- Paresthesia or pins-and-needles sensations in fingers, toes, ankles, or wrists
- Weakness in the legs spreading to the upper body
- Unsteady walking
- Difficult eye or facial movements, including speaking, chewing, or swallowing
- Severe pain and cramps
- Tachycardia
- Difficulty breathing
- Respiratory failure in about 20% of patients
Diagnosis includes history and physical, spinal tap showing elevated protein without elevated white cells, electromyography, and nerve conduction studies.
Monitoring uses the same respiratory muscle thresholds:
- Vital capacity less than 20 mL/kg or 30% of baseline
- Max inspiratory pressure less than -30 cmH2O
- Max expiratory pressure less than +40 cmH2O
Treatment includes IV immune globulin, plasmapheresis, and mechanical ventilation.
Phrenic Nerve Damage
Causes include:
- High cervical spine injury causing total diaphragmatic paralysis
- Cardiac surgery causing unilateral diaphragmatic paralysis
Symptoms may be absent. Athletes, musicians, and others who use their lungs more fully may notice decreased ventilatory capacity.
Diagnosis includes reduced lung volumes, reduced vital capacity, reduced total lung capacity, even lower values when supine, chest x-ray, and fluoroscopic sniff test. During sniff testing, paradoxical movement means the affected side moves upward during vigorous inspiration.
Treatment listed in the source is surgical plication of the affected side.
Stroke
Stroke is an acute interruption in blood flow to an area of the brain.
| Type | Source Definition |
|---|---|
| Ischemic stroke | Abrupt blockage of arteries leading to the brain by a clot |
| Hemorrhagic stroke | Bleeding into brain tissue when a blood vessel bursts |
| Transient ischemic attack | Listed as TIA |
Sudden signs and symptoms include:
- Numbness or weakness of face, arm, or leg, especially on one side
- Confusion or trouble speaking or understanding speech
- Trouble seeing in one or both eyes
- Trouble walking, dizziness, loss of balance, or loss of coordination
- Severe headache with no known cause
Respiratory complications include central or obstructive sleep apnea, venous thromboembolisms, swallowing abnormalities, aspiration, and pneumonia.
Diagnosis includes history and physical, labs, CT scan, MRI, carotid ultrasound, and echocardiography.
Treatment includes thrombolytic therapy using tissue plasminogen activator, surgery, endovascular procedures, physical therapy, and occupational therapy.
Chest Wall or Thoracic Diseases
Kyphosis is an AP curvature of the spine. Scoliosis is a lateral curvature of the spine. Kyphoscoliosis combines kyphosis and scoliosis.
Flail chest occurs when multiple adjacent ribs are fractured in two or more places, causing a portion of the thoracic cage to become free-floating.
High-Yield Review
| Topic | High-yield point |
|---|---|
| Restriction | Decreased lung volume with increased work of breathing |
| Pleural effusion | Fluid in pleural space; transudative has decreased proteins, exudative has increased proteins |
| Tension pneumothorax | Mediastinal shift can cause cardiovascular collapse |
| BPF | Large airway pneumothorax with large air leak |
| ILD | Broad category affecting lung parenchyma with fibrosis and/or inflammation |
| Myasthenia gravis | Autoimmune neuromuscular weakness; crisis can cause acute respiratory failure |
| Guillain-Barre | Immune attack on peripheral nerve myelin; can cause respiratory failure |
| Phrenic nerve damage | Causes reduced lung volumes and paradoxical sniff-test movement |