Restrictive Lung Disease Flashcards
restrictive lung disease - summary
*these patients cannot FILL the lungs sufficiently (contrast to obstructive lung disease, where patients cannot sufficiently get air out of the lungs)
*any disease with a DECREASED TOTAL LUNG CAPACITY (TLC) is a restrictive lung disease
*when severe, restrictive lung diseases can lead to respiratory failure (can be due to accumulation of CO2 or decrease in blood oxygen)
restrictive lung disease - spirometry tracing
*air is exhaled normally
*the FEV1/FVC ratio is greater than LLN (there is no obstruction)
*flow-volume loop appears normal shape
why is the TLC decreased in restrictive lung disease
can be the result of either:
1. a decrease in lung compliance
2. a decrease in the force generated by the respiratory muscles
causes of restrictive lung disease with NORMAL lungs
- neuromuscular disorders (ALS, myasthenia gravis, phrenic nerve injury, acute or chronic inflammatory demyelinating polyneuropathy)
- skeletal disorders (scoliosis, kyphosis, spinal compression fractures)
- severe obesity
findings of neuromuscular disorders associated with restrictive lung disease with normal lungs
*history: weakness of skeletal muscle, bulbar weakness, major thoracic or abdominal surgery (CABG, ex-lap)
*PE: decreased muscle tone or stigmata of NM dysfunction
*test results: AChR antibody (myasthenia gravis); abnormal sniff test (phrenic nerve injury)
*management: treatment of the underlying condition
findings of skeletal disorders associated with restrictive lung disease with normal lungs
*history: congenital skeletal abnormality, trauma
*PE: scoliosis, kyphosis, pectus excavatum
*test results: imaging showing low lung volumes, skeletal abnormalities
*management: surgical correction (not done just for low lung volumes)
findings of severe obesity associated with restrictive lung disease with normal lungs
*history: exertional dyspnea, nonrestorative sleep
*PE: BMI > 40, diminished breath sounds
*test results: imaging showing low lung volumes; serum bicarbonate > 30
*management: medical and surgical weight loss options; treatment of sleep disorders
interstitial lung disease
*a heterogeneous collection of individual diseases that share similar clinical, radiographic, physiologic, or pathologic features and affect the pulmonary interstitium
*types of restrictive lung disease in which the lungs are abnormal
*DLCO (diffusing capacity) is also abnormal
*note - these can also affect the airways
pneumoconioses
*a group of diseases associated with inhalation of non-organic fibers or dusts
*a type of interstitial lung disease that causes restrictive lung disease
*inhaled particle size is important - 1 to 5 micrometers can be deposited in the terminal respiratory unit (smaller than this - exhaled; larger - impact on airway mucus and expelled)
*examples: asbestos, silicosis, and coal workers’ lung
*treatment: PREVENTING INHALATION
asbestos-related pneumoconiosis
*asbestos is a crystalline fiber with flame-retardant properties (previously used in insulation, vehicle brakes, etc)
*multiple manifestations in the body, with long latency (eosinophilic pleural effusion, pleural plaques of calcium, etc)
*ASBESTOSIS: fibrosis of the lung associated with asbestos fibers; progressive fibrous change (can see honeycombing)
-asbestos bodies are the hallmark of asbestos exposure
-need fibrosis + asbestos bodies to confirm asbestosis
silicosis - overview
*interstitial lung disease (pneumoconiosis) associated with silica
*immune reaction to inhalation of silica dust (engulfed by alveolar macrophages and not cleared)
*associated with sandblasting, quarry workers, construction sites
*strong UPPER-LOBE predilection
*synergistic risk for tuberculosis infection
silicosis - phases
*acute: could be asymptomatic, or could present with fevers, cough, bilateral imaging opacities/nodules
*chronic: “eggshell” calcifications on upper nodules, conglomerate nodules +/- cavitation, progressive fibrotic damage to lung
Coal Workers’ pneumoconiosis - overview
*caused by inhalation of coal dust and ash
*lung nodules form and coalesce, in some cases leading to PROGRESSIVE MASSIVE FIBROSIS (PMF)
*affects upper lobes mainly
hypersensitivity pneumonitis - overview
*aka “extrinsic allergic alveolitis”
*immune sensitivity to inhaled ORGANIC antigen/protein (type III or IV hypersensitivity)
*inhalation amount can be large or small
*two types: fibrotic and non-fibrotic
*treatment: avoiding repeat exposure; for severe sx, corticosteroids
hypersensitivity pneumonitis - clinical presentations
*acute: cough, fever, dyspnea, bilateral centrilobular nodules plus ground glass opacities
*subacute: acute sx plus weight loss and fatigue
*chronic: irreversible fibrotic change begins, can be disabling
