Pulmonary Pathophysiology: Restrictive Lung Dysfunction Flashcards
Define restrictive lung dysfunction (RLD)
- Abnormal reduction in pulmonary ventilation caused by restricted expansion of the chest wall or the lungs
- Decreased volume of air or gas moving in & out of the lungs
Pathophysiology of RLD is related to what 3 factors
- Decreased compliance of both the lung & the chest wall
- Decreased lung volumes & capacities
- Increased work of breathing
What are some causes of increased work of breathing
- Increased airway resistance
- Increased flow rates
- Decreased lung or chest wall compliance
Greater ___________ pressure is required to achieve a normal TV in RLD
- Transpulonary
6 classic signs of RLD
- Tachypnea (increased RR)
- Hypoxemia (low blood O2 concentration)
- Decreased breath sounds with dry inspiratory crackles
- Decrease in lung volumes & capacities
- Decreased diffusing capacity of lung for carbon monoxide (DLCO)
- Cor pulmonale (R sided HF): due to pulmonary HTN or hypoxia
What are the 3 hallmark signs of RLD
- Dyspnea
- Irritating, dry, & nonproductive cough
- Wasted, emaciated appearance as the disease progresses
If etiological factors of RLD are permanent or progressive, then treatment consists of supportive measures:
- Supplemental O2 to support the PaO2
- Antibiotic therapy to fight 2ndy pulmonary infection
- Measures to promote adequate ventilation & prevent the accumulation of pulmonary secretions
- Good nutritional support
If etiological factors are reversible, treatment is _____________ and ____________
- Corrective and supportive
What does diffusing capacity of the lung for carbon monoxide (DLCO) measures
- Measures how well the lungs transfer O2 from the air into the blood
- Normal: 75-140% predicted
- Mildly Reduced= 60-75% predicted
- Severely Reduced= <40% predicted
Describe what low and high DLCO indicates are may be seen in
- Low DLCO means the lungs aren’t getting O2 from the air to the blood efficiently
- Low DLCO with restrictive pathology may indicate interstitial lung disease (ILD)
- Reduced DLCO with obstructive pathology could suggest emphysema
- High DLCO may be seen in asthma or obesity
Define atelectasis
- Incomplete expansion
- Clinical manifestation of several lung & chest disorders
- Region of lung parenchyma is collapsed & non-aerated
What are the 5 types of atectasis
- Resorptive/obstructive: most common, often caused by an obstruction
- Passive: loss of volume in lungs caused by pneumothorax or diaphragmatic dysfunction; lack of deep breathing, under general anesthesia
- Adhesive: surfactant deficiency (greater tendency for alveoli to collapse)
- Compressive: caused by space occupying lesion, pleural effusion/tumor, or empyema
- Cicatrization: volume loss caused by decreased pulmonary compliance bc of fibrosis
Define pneumonia
- Inflammatory process of the lung parenchyma
- Usually begins with an infection in the lower respiratory tract
Causative agents of pneumonia
- Bacteria
- Viruses
- Fungi
- Mycoplasmas
Symptoms of a bacterial pneumonia
- High fever
- Chills
- Dyspnea
- Tachypnea
- Productive cough
- Pleuritic pain
Symptoms of a viral pneumonia
- Moderate fever
- Dyspnea
- Tachypnea
- Non-productive cough
- Myalgias (pain in muscle/muscle group)
What is adult respiratory distress syndrome (ARDS)/acute lung injury
- Widespread inflammatory condition affecting pulmonary tissue
- Leads to increased pulmonary vascular permeability/lung weight and loss of aerated tissue
- All pts develop some muscle wasting/weakness that continues past 1yr post discharge
Pulmonary triggers of ARDS
- Pneumonia
- Inhalation injury
- Aspiration of gastric contents
- Chest trauma/pulmonary contusion
- Near drowning
Extrapulmonary triggers of ARDS
- Sepsis
- Major trauma
- Burns
- Pancreatitis
- Fat embolism
- Hypovolemia
- Transfusion related acute lung injury (TRALI)
- Cardiopulmonary bypass
- Drug induced
Symptoms of ARDS
- Appear acutely ill
- Dyspneic at rest & with any activity
- Breathing pattern fast & labored
- Cyanotic
- May have impaired mental status, restlessness, HA, & increased anxiety
Causes of ARDS
- Hyaline membrane damage
- Ruptured alveolar walls
- Intra-alveolar edema
What is interstitial lung disease
- A group of lung disorders that cause problems with diffusion of O2 into the blood stream as a result of progressive scarring & fibrosis of the lung tissue
Common causes of interstitial lung disease (ILD)
- Exposures in the environment
- Autoimmune disease
- Medication effects
- Genetics
- Idiopathic or unknown reasons
Describe idiopathic pulmonary fibrosis (IPF)
- Most common idiopathic interstitial pneumonia
- Worst prognosis of the ILDs
- Bc of poor diffusion capacity individuals with ILD often require supplemental O2 as the disease progresses & especially with exercise
Symptoms of pulmonary fibrosis
- SOB that gets worst over time
- Dry cough that doesn’t improve
- Achy joints & muscles
- Feeling tired or weak
- Losing weight slowly & without trying
Describe idiopathic pulmonary fibrosis (IPF)
- Progressive, irreversible, & usually lethal lung disease
- Progressive worsening of dyspnea & lung function
- Most important environmental risk factors: cigarette smoking, exposure to metal & wood dust
What is sarcoidosis
- Idiopathic granulomatous inflammatory disorder that affects many organ systems (lungs, heart, skin, CNS, & eyes)
- Lungs are most involved organ
- Typically affects young adults
What are the 3 distinct features of sarcoidosis
- Alveolitis
- Formation of well-defined round or oval granulomas
- Pulmonary fibrosis
Fibrotic lung disease that affects the smaller airways; Produces restrictive and obstructive lung dysfunction describes
- Bronchiolitis obliterans
Bronchiolitis obliterans is characterized by
- Necrosis of the respiratory epithelium in the affected bronchioles
Causes/association of Bronchiolitis obliterans in children versus adults
- Pediatrics: often caused by viral infection
- Adults: associated with toxic fume inhalation or by viral, bacterial, or mycobacterial infectious agents, particularly M. pneumonia
What are the 7 ways RA can affect the lungs
- Pleural involvement
- Pneumonitis
- Interstitial fibrosis
- Development of pulmonary nodules
- Pulmonary vasculitis
- Obliterative bronchiolitis (OB)
- Increased incidence of bronchogenic CA
Characterized by various antigen–antibody reactions; May involve the skin, joints, kidneys, lung, nervous tissue, and heart describes
- Systemic lupus erythematosus (SLE)