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)
*associated with ship building, roofing, plumbing
*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
*classically affects the LOWER lobes and presents as “Ivory white,” calcified, supradiaphragmatic and pleural plaques
silicosis - overview
*immune reaction to inhalation of silica dust (engulfed by alveolar macrophages and not cleared)
*“eggshell” calcification of hilar lymph nodes on CXR
*associated with sandblasting, quarry workers, construction sites, mines, foundries
*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 in 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
*small, rounded nodular opacities seen on imaging
hypersensitivity pneumonitis - overview
*aka “extrinsic allergic alveolitis”
*immune sensitivity to inhaled ORGANIC antigen/protein (mixed type III/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
hypersensitivity pneumonitis - pathology
*acute/subacute: POORLY FORMED interstitial GRANULOMAS and marked LYMPHOCYTIC INFLAMMATION (distinguished by the presence of granulomas and exposure history)
*chronic: dense fibrotic changes
hypersensitivity pneumonitis - examples
*Farmer’s lung
*Pigeon-breeder’s lung
*Suberosis
*Maple bark stripper’s disease
*Trombone lung
*Hot-tub lung
*Bagassosis
granulomatous inflammation in interstitial lung disease
*mutinucleated giant cells
*granulomas, sometimes very prominent
*usually NON-NECROTIZING in noninfectious causes
*lymphocytic infiltration is variable
*typical ddx: infection (TB and other mycobacteria), Hypersensitivity Pneumonitis, Sarcoidosis, drug-induced
Usual Interstitial Pneumonia (UIP)
*term used to describe the injury pattern seen on CT scan and biopsy that can come from more than one disease
*typical diagnosis: Idiopathic Pulmonary Fibrosis
*pattern:
-basilar and subpleural fibrosis
-fibroblastic foci on biopsy
-honeycombing
-temporal heterogeneity (patchy and varied)
-lymphocytic interstitial inflammation
Idiopathic Pulmonary Fibrosis - characteristic pattern of findings
UIP (Usual Interstitial Pneumonia)
Nonspecific Interstitial Pneumonia (NSIP)
*term used to describe the injury pattern seen on CT scan and biopsy that can come from more than one disease:
*typical diagnoses: autoimmune diseases (Lupus, Rheumatoid Arthritis, drug-induced)
PATTERN:
*lymphocytic interstitial inflammation WITHOUT GRANULOMAS and without honeycombing
*subpleural sparing
Organizing Pneumonia
*term used to describe the injury pattern seen on CT scan and biopsy that can come from more than one disease
*typical diagnoses: post-infectious; cryptogenic (COP)
*a very common reaction to injury
*a cause of recurrent pneumonia despite appropriate antibiotics
*treatment: corticosteroids
PATTERN:
*plugs of collagen matrix and some fibroblasts in bronchioles
*“migratory infiltrates” on CXR
*no fibrosis or honeycombing
*lung architecture is preserved
Desquamative Interstitial Pneumonia (DIP)
*term used to describe the injury pattern seen on CT scan and biopsy that can come from more than one disease
*typical dx: Respiratory Failure in a SMOKER
*treatment: smoking cessation
PATTERN:
*accumulation of PIGMENTED ALVEOLAR MACROPHAGES completely filling the airspaces
Eosinophilic Pneumonia
*term used to describe the injury pattern seen on CT scan and biopsy that can come from more than one disease
*typical dx: many causes (smoking, vaping, drug induced, idiopathic); Loeffler syndrome (transient and due to parasitic infection)
*treatment: corticosteroids
PATTERN:
*eosinophils and macrophages fill airspaces
*eosinophilic microabscesses may be present
