Robbin 15 and 16 Flashcards
_ is a defective development of both lungs resulting in decreased wt, vol, and acini for body wt and gestational age. It is caused by _
pulmonary hypoplasia, caused by anything that compress the lungs or impede normal lung expansion in utero such as congenital diaphragmatic hernia and oligohydramnios.
Foregut cysts are abnormal detachments of primitive foregut and most often located in _
hilum and middle mediastinum
The walls of bronchogenic cyst contains _
bronchial glands, cartilage and smooth muscle, usually present due to compression of nearly structures or found incidentally.
what is pulmonary sequestration?
discrete area of lung tissue that 1) lacks any connection to airway system and 2) has an abnormal blood supply arising from the aorta or its branches.
extralobar and intralobar sequestration differ by their presentation how?
Extralobar external to the lung and come to attention in infants as a mass lesion. Intralobar occur within lung and present in older kids often due to recurrent localized infection or bronchiectasis.
Atelectasis differs in infants vs adults how?
Infants = incomplete expansion Adults = collapse of previously inflated lung creating areas of airless parenchyma
Adult or acquired atelectasis produces a well _ regions but poorly _, predisposing for infection.
well perfused. poorly ventilated
Adult or acquired atelectasis comes in what three flavors?
- Resorption atelectasis
- Compression atelectasis
- Contraction atelectasis.
_ atelectasis is a consequence of complete obstruction without impairment of blood flow
Resorption
In resorption atelectasis, decreased lung volume results in a mediastinal shift to which side?
affected side
What are some causes of resorption atelectasis?
mucous plug associated with asthma, bronchitis, aspiration pneumonia, foreign body etc.
_ is consequence of partially or totally filled pleura with exudate (CHF), tumor, air (pneumothorax), blood (hemothorax), when air pressure threatens the function of lungs and great vessels (tension peumothorax), or with an extra-pulmonary mass compressing lung parenchyma
Compression atelectasis
In compression atelectasis, compression pushes lung and results in a mediastinal shift to which side?
away from the affected side
what is contraction atelectasis?
Fibrotic changes prevent expansion, resulting in reduced lung volume and ventilation. This is the only irreversible atelectasis.
_ is the accumulation of fluid in alveolar space due to either 1) increased capillary hydrostatic pressure, 2) decreased capillary oncotic pressure or 3) an increased vascular permeability
Pulmonary edema
1 is due to increased hydrostatic pressure and most commonly associated with 2 sided congest heart failure.
- Hemodynamic pulmonary edema.
2. Left
In _ pulmonary edema basal regions develop edema first (dependent edema) b/c pressure is great in dependent areas, and alveolar macrophages have hemosiderin in them called siderophages or heart failure cells. As this progresses fibrosis and thickening of the affected areas results in a gross brown and firm appearance called brown induration
hemodynamic
_ is a type of edema that is dependent on an increased capillary permeability
microvascular injury pulmonary edema.
Microvascular injury pulmonary edema is most commonly associated with _
pneumonia. but can also be caused by inhaled gases (O2, smoke) liquid aspiration (near-drowning) or trauma
In microvascular injury pulmonary edema, edema begins in 1 and then moves into 2
- vascular ednothelium
2. alveoli
_ can result from the extreme case of microvascular injury pulmonary edema
acute respiratory distress syndrome
What are some morphological findings of acute respiratory distress syndrome?
acute gross = heavy, firm, red, and boggy lungs
Acute histo: interstitial and interalveolar edema, inflammation (neutrophils), hyaline membrane = fibrin rich edema with cytoplasmic/lipid remnants
_ is a manifestation of severe acute lung injury characterized by abrupt onset of significant hypoxemia and bilateral pulmonary infiltrates in the absence of cardiac failure
Acute respiratory distress syndrome
In the pathogenesis of ARDS, list the chain of events from initiation to resolution
- Endothelial activation: injury sensed by resident alveolar macrophages which secretes mediators such as TNF. these mediators can directly injury endothelial cells or activate endothelial cells to express increased levels of adhesion molecules procoagulant proteins and chemokines
- Adhesion and extravasation of neutrophils: neutrophils adhere to activated endothelium and migrate into interstitium and alveoli and release inflammatory mediators including ROS, and cytokines. Macrophages migration inhibitory factor (MIF) also helps to sustain ongoing inflammation –> increased recruitment and adhesion of leukocytes, causing more endothelial injury, local thrombosis
- Accumulation of intraalveolar fluid and formation of hyaline membranes. damage to type II alveolar cells –> surfactant abnormalities –> compromise gas exchange. Ultimately the debris of dead cells forms hyaline membranes
- Resolution of injury is impeded in ALI/ARDs due to epithelial necrosis and inflammatory damage that impairs ability of remaining cells to assist with edema resorption. If inflammatory stimulus is lessened, macrophage remove intraalveolar debris and release fibrogenic cytokines such as TGFb and PDGF which stimulate fibroblast and collagen deposition leading to fibrosis of alveolar walls. Bronchiolar stem cells proliferate to replace pneumocytes.
what are some causes of ARDS?
- infection (pneumonia, sepsis (typically gram negative sepsis)
- aspiration
- acute pancreatitis
- trauma with shock
- amniotic fluid embolism
- uremia
How to patients with ARDS present clinically?
- Profound dyspnea and tachypnea
- cyanosis and hypoxemia, respiratory failure and appearance of diffuse bilateral infiltrates on Xray.
How is ARDS treated?
- respiratory support and treat underlying cause
- mechanical ventilation with low tidal volume
- PEEP (positive end-expiratory pressure) to prevent airway collapse at end expiration, recruits collapsed alveoli. together increases FRC and decrease shunting
_ is widespread acute lung injury associated with rapidly progressive clinical course. Usually occurs age 59. Patients presents with acute respiratory failure often following an illness of less than 3 wks duration that resembles an URI
Acute interstitial pneumonia
_ lung disease are characterized by an increase in resistance to airflow due to partial or complete obstruction at any level from the trachea and larger bronchi to the terminal and respiratory bronchioles.
Obstructive
FEV1/FVC ratio less _ generally indicates airway obstruction
0.7
_ is characterized by reduced expansion of lung parenchyma and decreased total lung capacity
restrictive disease
In restrictive lung disease FEV1/FVC ratio is _
normal
Restrictive lung disease occur in what two broad conditions?
- chest wall disorders ( severe obesity, pleural disease, kyphoscoliosis, and neuromuscular disease such as poliomyelitis
- chronic interstitial and infiltrative disease such as pneumoconioses and interstitial fibrosis.
Emphysema, chronic bronchitis, asthma and bronchiectasis are all what kind of lung disease?
Obstructive Lung disease
What two lung diseases are often grouped as COPD?
emphysema and chronic bronchitis, because most patients have features of both since major trigger is smoking
_ is characterized by irreversible enlargement of the airspaces distal to the terminal bronchiole, accompanied by destruction of their walls without obvious fibrosis leading to increased work to breathe
Emphysema
Emphysema is classified into what four types?
- centriacinar (most common, 95%)
- panacinar
- paraseptal
- irregular
1 and 2 causes clinically significant airflow obstruction
In centriacinar emphysema, which part of the respiratory bronchioles are affected?
central or proximal parts of the acini. distal alveoli are spared. Lesion are more severe in upper lobes, particularly in the apical segments. Normal and emphymatous airspaces coexist within the same acinus and lobule
In this form of emphysema, the acini are uniformly enlarged from the level of respiratory bronchiole to the terminal blind alveoli. Associated with a1-antitripsin deficiency
panacinar (panlobular) emphysema. The entire acinus is affected, not the entire lung. Affects lower lobes, esp bases.
in distal acinar (paraseptal) emphysema which parts of the acini are spared and which parts are affected?
central and proximal parts are spared and distal alveoli are affected. Forms along the pleura and lobule margins adjacent to fibrosis or scarring. may form cyst like structure associated with penumothorax in young adults
this form of emphysema is asymptomatic, clinically insignificant, almost always found on autopsy and irregular pattern of alveolar enlargement always is associated with scarring.
Irregular emphysema
How does emphysema appear grossly on morphology?
Large, voluminous lungs with hyperinflation (well developed pan- and centri) and bullae/blebs associated (distal acinar emphysema)
How does emphysema appear microscopically?
Abnormally large alveoli separated by thin septa, large alveoli from trapped air.
- pores of Kohn are so large that septae seem to float in alveoli
- blood vessels are compressed by emphysematous alveoli
Explain the pathogenesis of development of emphysema
Smoking and other noxious particles cause lung damage and inflammation. Factors include:
- inflammatory mediators and leukocytes (Leukotriene B4, IL8, TNF etc) –> epithelial damage and structural change
- protease- antiprotease imbalance. relative deficiency of protective antiprotease which in some are genetic in basis.
- Oxidative stress. substances from tobacco smoke, alveolar damage and inflammatory cells all produce oxidants, which may beget more tissue damage and inflammation. Proven in mouse model with NRF2 gene mutation. NRF2 target genes are all associated with smoking-related lung disease in humans.
- Infection: does not initiate it but exacerbates the disease process
The idea that proteases are important is based in part on the observation that patients with a genetic deficiency of _ have markedly enhanced tendency to develop pulmonary emphysema which is compounded by smoking.
Antiprotease a1-antitrypsin (AAT) which normally inhibits action of elastase and so without AAT elastase is unchecked and destroys the elastic tissue of the alveoli
emphysema is a condition characterized by dilation of air spaces with 1 (dec or inc) elasticity and 2 (dec or inc) compliance
- decreased
2. Increased
which type of emphysema is commonly due to smoking? due to AAT deficiency?
Smoking = Centriacinar AAT = panacinar , smoking exacerbates
what are the signs, symptoms and physical findings of emphysema?
- signs and Symptoms: dyspnea, classic pursed-lip breathing;
- Physical findings: decreased breath sounds on auscultation, increased anterior-posterior diameter (barrel chest), hyperresonant to percussion, flattened diaphgram on Xray
- decreased diffusion capacity –> increased ventilatory rate –> normal ABG
- patients will lean forward, have a prolonged expiration through pursed lips.
Pink Buffer (end stage) - impaired expiratory airflow measured through spirometry
How is emphysema treated?
- smoking cessation, ambulatory O2
- bronchodilators, inhaled steroids, oral/IV steroids and antibiotics
A 50-year-old Caucasian male presents to the Emergency Department complaining of shortness of breath and unintentional weight loss over the past several months. On physical examination, the patient appears quite thin and breathes through pursed lips. Breath sounds are decreased in all lung fields. The patient’s chest x-ray shows increased A-P diameter. Which of the following findings is expected on spirometry?
- Increased FEV1
- Decreased FEV1/FVC
- Decreased TLC
- Normal FEV1 but increased FVC
- Normal lung values
- Decreased FEV1/FVC
The patient described is suffering from Chronic Obstructive Pulmonary Disease (COPD), specifically emphysema. In emphysema, both FEV1 (forced expiratory volume in 1 second) and FVC (forced vital capacity) are decreased, however, FEV1 is decreased more, therefore FEV1/FVC is decreased.
A patient with a1-antitrypsin deficiency is warned by his physician that his increasing dyspnea may be worsened by his continued cigarette smoking. Which of the following factors, released by both neutrophils and alveolar macrophages, is responsible for the patient’s condition?
- Major Basic Protein
- Antibodies against alpha-3 segment of collagen IV (COL4A3)
- Mucus
- Surfactant
- Elastase
- elastase
The patient is suffering from emphysema caused by his genetic disorder, a1-antitrypsin deficiency. This condition can be worsened by smoking-mediated increased release of elastase from macrophages and neutrophils.
what causes do emphysema patients usually die of?
- coronary artery disease
- respiratory failure
- Right sided heart failure
- massive collapse of lungs secondary to pneumothorax
_ is a term used to designate dilation of alveoli in response to loss of lung substance elsewhere. It is best exemplified by hyperexpansion of residual lung parenchyma following surgical removal of a diseased lung or lobe
Compensatory hyperinflation
_ is expansion of lung because of trapped air but without septal wall destruction.
Obstructive overinflation
what are common causes of obstructive overinflation?
tumor or foreign objects, asthma with: 1) partial obstruction = ball - Valve allows air in but not out; and 2) complete obstruction + collateral air flow through pores of Kohn
Bullous emphysema is term for large subpleural blebs or bullae that can occur in any form of emphysema near apex, sometimes near TB scars. What is the occasional complication associated with it?
pneumothorax
Interstitial emphysema is entrance of air into _
connective tissue stroma of lung, mediastinum or subQ tissue
what is interstitial emphysema caused by?
alveolar tears (cough + alveolar obstruction as in empysema), punctures, or trauma or mechanical ventilation
_ is defined as persistant cough with sputum production for at least 3 months in at least 2 consecutive years, in absence of any other cause.
chronic bronchitis. common among smokers and polluted cities. Falls in one end of the sepctrum of COPD
Primary or initiating factor in the genesis of chronic bronchitis is exposure to noxious inhaled substances such as tobacco smoke and dust from grain, cotton, and silica. Explain the pathogenesis that follows
- Mucus hypersecretion (IL13, histamine) in large airways, hypertrophy of submucosal glands in trachea and bronchi –> increased goblets cells and mucous production
- Inflammation –> cellular damage involving neutrophils, lymphocytes and macrophages –> inflammation/fibrosis –> chronic airway obstruction
- Infection: does not initiate but exacerbates disease process
Explain the pathophysiological changes seen in chronic bronchitis
- imbalance or proteinase/anti-proteinases, inflammation, oxidative stress, and inhibited repair processes,
- central and peripheral airways involved
- results in hyperplasia of bronchiolar mucus glands and fibrosis of terminal bronchioles
- ciliary dysfunction
what are two most common cause of chronic bronchitis?
- smoking
- cystic fibrosis
what are some signs and symptoms of chronic bronchitis?
Symptoms: dyspnea, productive cough
PE: wheezing and crackles on auscultation, prolonged expiration, classic pursed lip breathing,
- Blue bloater (end stage): chronic alveolar hypoxia leads to pulmonary HTN, edematous due to right heart failure; cyanosis of skin
How is chronic bronchitis treated?
- conservative: smoking cessation, home O2
- Pharmacological: bronchodilators and inhaled steroids for long term maintenance; systemic steroids and abx for acute exacerbations; roflumilast for severe disease
_ is a chronic disorder of the conducting airways, usually caused by an immunological reaction, which is marked by episodic bronchoconstriction due to increased airway sensitivity to a variety of stimuli; inflammation of bronchial walls; and increased mucus secretion
asthma
_ is manifested by recurrent episodes of wheezing, breahtlessness, chest tightness and cough, particularly at nigh and/or in the early morning
asthma
what are the two categories of asthma
- Atopic : allergen sensitization and immune activation, positive family history
- Non-atopic: no evidence of allergen sensitization. Family history is less common.
In either can have diverse triggers such as infection, irritants, cold air, stress, exercise, and even drugs such as aspirin
Atopic asthma is most common type and is a classic example of _ hypersensitivity reaction
IgE-mediated (Type I)
_ can be used to diagnose actopic asthma.
high total serum IgE levels or evidence of allergen sensitization by serum radioallergosorbent tests (RAST)
How do patient’s with aspirin-sensitive asthma present?
Occur in pts with recurrent rhinitis and nasal polyps, they experience an asthmatic attack and urticaria. Attack is triggered by inhibiting COX pathway leading to rapid decrease in prostaglandin E2 which normally inhibits enzymes that generate proinflammatory mediators like leukotrienes B4, C4, D4, and E4 which are thought to be the major players in aspirin-induced asthma
Explain the pathogenesis of atopic asthma
- Caused by exaggerated TH2 responses to normally harmless environmental antigens in genetically predisposed people. TH2 secrete cytokines (IL4, IL5, IL13) and other cytokines such as IL17 and IL19 that promote inflammation and stimulate B cells to produce IgE and other Ig. –> airway dysfunction via release of potent inflammatory mediators and remodeling of airway wall –> increased local secretion of GF, induction of mucus glands hypertrophy, smooth muscle proliferation, angiogenesis, fibrosis and nerve proliferation.
Explain the acute/early response of atopic asthma
- airborne antigens react first with mast cells on epithelial surface causing an increased permeability, access to submucosal mast cells, enhanced type 1 response.
- direct stimulating of subepithelial vagal (parasympathetic) receptor resulting n constriction
- sum total in bronchoconstriction, edema, mucous secretion
Explain the late phase response in atopic asthma
- swarm of leukocytes (eosinophils, neutrophils, and more T cells (TH17)) drawn by chemotactic factors from mast cells, airway epithelium, and vascular endothelium and other leukocytes
- Eosinophils major basc protein = epithelial damage and airway constriction
What are the major mediators that which play a role in asthmatic attack
- major bronchospasm mediators such as Leukotrienes C4, D4, and E4 prolongs bronchoconstriction and increased vascular permeability and increased mucus secretion; acetylcholine which can also bronchoconstrict
- minor bronchoconstriction and vasodilators: histamine; prostaglandins D2; platelet activating factor. these factors are more important in chronic or nonallergic asthma
- unknown role but suspected: IL1, IL6, and TNF alpha are proinfllammatory cytokines
Polymorphism in what gene has the strongest and most consistent association with asthma or allergic disease?
IL13 on chromosome 5q
Polymorphism in gene encoding _ a metaloproteinase may be linked to increased proliferation of bronchial smooth muscle cell and fibroblast, thus contributing to bronchial hyperreactivity and subepithelial fibrosis
ADAM33
Increased serum levels and expression of _ are correlted with asthma severity, airway remodeling, and decreaesd pulmonary function
YKL-40, a chitinase-like glycoprotein expressed and secreted by many cells
Although infection is not a cause or trigger for asthma, URI with what virus has a 10 to 30 fold increased risk of devleoping persistent and/or severe asthma?
rihonovirus type C and RSV
A characteristic finding in sputum or bronchoalveolar lavage specimens of asthmatic patients include_
- Curschmann spirals which may result from extrusion of mucus plugs from subepithelial mucous gland ducts or bronchioles;
2) Charcot-Leyden crystals composed of eosinophil protein called galectin 10
What specific changes are taken place in “airway remodeling” as seen in asthma
- thickening of airway wall
- subbasement membrane fibrosis
- increase in size of submucosal glands and number of airway goblet cells
- hypertrophy and/or hyperplasia of bronchial wall muscle
How does a patient with asthma attack present?
cardinal signs are: chest tightness, dyspnea, wheezing and coughing (w/wo sputum production) triggered by bronchospasm that can spontaneously resolve or resolve with intervention.
- Attacks last minutes to hours
- in most severe form (status asthamaticus) where ventilatory function can be impaired (and fatal), asthma symptoms may last for hours to day and are refractory to retreatment
How is an asthma attack diagnosed?
- increaed in airflow obstruction from baseline,
- difficulty with exhalation
- peripheral blood eosinophilia and finding of eosinophils, curschman spirals, and charcot leyden crystal in sputum
_ is a disorder in which destruction of smooth muscle and elastic tissue by chronic necrotizing infections leads to permanent dilation of bronchi and bronchioles
Bronchiectasis
what are some causes of bronchietasis?
- congential or hereditary conditions including CF (secondary to infection with pseudomonas or aspergillus), intralobar sequestraiton of lung, immunodeficiency states, and primary ciliary dyskinesia and kartagener syndromes
- Infection, including necrotizingpneumonia (common are aspergillus which is common to CF or asthma pts)
- Bronchial obstruction due to tumor, foreign bodies, or mucus impaction; in each instance the bronchietasis is localized to obstructed lung segment
- Associated with other disease such as rheumatoid arthritis, SLE, IBD, COPD, postransplantation
- 1/4-1/2 of cases are idiopathic
Obstruction and infection are the major conditions associated with bronchiectasis. What are the predisposing factors that which leads to bronchiectisis?
- CF: defective ion transport leads to defective mucocilary action and airway obstruction by thick viscous secretion –> infection –> widespread damage to airway walls –> destruction of supporting smooth muscle and elastic tissue -> dilated bronchi and obliterated bronchioles. –> fibrosis (bronchiolitis obliterans)
- Primary ciliary dyskinesia: autosomal recessive with cilary dysfunction due to defects in ciliary motor proteins contributes to retention of secretion and recurrent infection –> bronchiectasis. These pts also develop Kartagener syndrome due to abnormal ciliary function which is needed for organ development in chest and abd. Kartagener syndrome is marked by situs inversus or partial lateralizing abnormality associated with bronchietasis and sinusitis
- Allergic bronchopulmonary aspergillosis occurs in pts with asthma and cystic fibrosis who develop periods oexacerbation and remission that may led to proximal bronchietasis and fibrotic lung disease. High association with aspergillus fumigatus senstization which leads to activation of TH2 and that recruits eosinophils and other leukocytes.
Explain the gross and histologic finding of bronchietecsis
Gross: lower lobes bilaterally unless caused by a focal obstruction (tumor or foreign body aspiraiton) in which case there are focal lesion; airways are dilated up to 4x, some ares look like cysts filled with pus
Histologic: acute inflammatory exudate associated with desquamination of epithelium or even ulcerations; chronic - pseudostratification and squamous metaplasia, almost always with fibrosis, organism can be cultured at any phase, often H influenze or aspergillus
How does bronchiectasis present clinically?
- severe, persistent cough; expectoration of foul smelling, sometimes bloody sputum; dyspnea nad orthopnea in severe cases; on occastion hemoptysis. paroxysms of cough are frequent when pt rises in the morning as the change in position causes collections of pus and secretion to drain into bronchi.
- Obstructive respiratoyr insuffieciency can led to marked dyspnea and cyanosis.
- due to modern therapy mortality is decreased and cor pulmonale, brain abscess, amyloidosis are less frequent complications
The classic functional abnormalities of restrictive lung disease include _
- reduction in diffusion capacity
- reduction in lung volume
- reduction in lung compliance
These eventually leads to right sided heart failure associated with cor pulmonale
_ refers to a clinicopathologic syndrome marked by progressive interstitial pulmonary fibrosis and respiratory failure
Idiopathic pulmonary fibrosis (IPF)
What environmental factors and genetic factors are associated with IPF?
- Environmental factors: smoking, metal fumes, wood dust, farming, hair dressing, and stone polishing. All these cause recurrent alveolar epithelial cell damage
- Genetic factors: Most people who smoke or have other environmental exposure do not get the disease thus indicating there is a genetic link. (A) Germline loss of function mutation in TERT and TERC which encode components of telomerase. 15% of familial IPF have telomerase gene defects and 25% of sporadic IPF are associated with abnormal telomerase shortening; (B) mutation gene for surfactant–> folding defects –> activating of unfolded protein response to type II pneumocytes –> pneumocytes more susceptible to environmental insults; (C) increased secretion of MUC5B, a mucin that make alveolar epithelial cells susceptible to injury or exaggerated downstream events leading to fibrosis
- these injuries to alveolar cells set in motion event that lead to increase local production of fibrogenic cytokines such as TGF-b
IPF is a disease of older people, rarely appearing before the age of _
50.
In the pathway to fibrosis as seen in IPF, activated fibroblasts exhibit signaling abnormalities that lead to increased signaling through which pathway?
PI3K/AKT pathway
Explain how IPF appear grossly and histologically
Gross: lungs are cobblestoned, due to retraction of scars along the interlobular septa. Cut surface shows firm, rubbery white areas of fibrosis which occur in subpleural regions along interlobular septa preferentially.
Histo: patchy interstitial fibrosis. Early: fibroblastic foci. later: honeycomb fibrosis (hyperplastic type II pneumoncytes or bronciolar epithelium)
what are the clinical signs of IPF?
- starts insidiously with gradual increasing dyspnea on exertion and dry cough. Most are 55-75 of age.
- hypoxemia, cyanosis and clubbing occur in late course
- 3 yrs survival rate
- tx: lung transplant
why is it important to distinguish a patient with nonspecific interstitial pneumonia vs interstitial pneumonia?
Nonspecific interstitial pneumonia pts have a better prognosis with proper treatment
Histologically nonspecific interstitial pneumonia is divided into cellular and fibrosing patterns. Explain the difference
Cellular: mild to moderate chronic interstitial inflammation with lymphocytes and few plasma cells in uniform or pathcy distribution
Fibrosing: diffuse or patchy interstitial fibrotic lesions of roughly same stage of development.
Clinically how to pts with nonspecific interstitial pneumonia present?
- dyspnea, cough of several months
- female in their 6th decade
- on CT: bilateral symmetric, lower lobe reticular opacities
- younger pts with cellular patterns vs fibrosing pattern have better prognosis
What are the characteristic clinical and histologic findings of cryptogenic organizing penumonia?
aka bronchiolitis obliterans organizing pneumonia (this name is nor preferred).
- Clinical: cough, dyspnea, patchy subpleural or peribronchial areas of airspace consolidation on radiograph.
- histo: polypoid plugs of loose organizing CT (Masson bodies) within alveolar ducts, alveoli, and bronchioles. CT are all same age and lung architecture is normal. No interstitial fibrosis (Note: if there is fibrosis then it’s probably due to infection or inflammatory injury of lungs and prognosis depends on underlying cause), and no honeycomb lung.
- pts recover spontaneously, tho some may need steroid for up to 6 months
what autoimmune diseases commonly have pulmonary involvement?
- Rheumatoid arthritis (RA) (30-40% have pulm involvement)
- SLE
- Scleroderma
What pulm disorders are associated with RA?
- chronic pleuritis w/wo effusion
- diffuse interstitial pneumonitis and fibrosis
- intraplulm rheumatoid nodules
- follilcular bronchiolitis
- pulm HTN
What pulm disorders are associated with scleroderma?
- diffuse interstitial fibrosis (nonspecific interstitial pattern more common)
- pleural involvement
what pulm disorders are associated with SLE
- patchy, transient parenchymal infiltrates, or occasional severe lupus pneumonitis
- pleurisy and effusion
What is Pneumoconioses defined as?
inhalation of small dust particles (coni = latin for dust)
What factors determine the development of penumoconiosis?
- amount of dust retained in lung and airways - dust concentration in air, and retainment in lung is influenced by smoking that destroys mucociliary clearance
- size, shape, and buoyancy of particles. Most dangerous size are 1-5 microns cuz these are able to reach terminal airway
- Particle solubility and physiochemical reactivity. Small particles of injurious substance with high solubility are more likely to cause acute lung injury. Larger ones resist dissolution and my persist within lung for years –>evoke fibrosing cllagenous pneumoconioses as seen in silicosis
- possible additional effects of other irritants
- substance that activate inflammasome amplify the intensity and duration of local reaction cuz they activate both innate and adaptive immune response
- Tobacco makes it all worse esp asbestos
- Genetic predisposition.
Coal worker’s pneumoconiosis ranges from asymptomatic form known as _ 1_to progressive massive fibrosis where contaminated 2 in the coal dust favor the progressive disease.
- antracosis
2. silica
Coal worker’s pneumoconiosis (CWP) ranges from asymptomatic form known as _ 1_to progressive massive fibrosis where contaminated 2 in the coal dust favor the progressive disease.
- antracosis
2. silica
How is simple coal worker’s pneumoconiosis characterized by?
Coal macules and coal nodules. Coal macules are carbon-laden macrophages; nodules also contain a delicate network of collagen fibers, upper lob es (high ventilation) and upper zone of the lower lobes.
Rheumatoid nodules in lungs can be complicated by coal worker’s penumoconiosis in a syndrome called __
Caplan’s syndrome
1-2 cm fibrotic centers is seen what form of coal worker’s pneumoconiosis?
Complicated CWP
What are clinical findings of CWP?
- usually benign causing little decrement in lung fxn.
- progressive massive fibrosis leads to pulm htn, and cor pulmonale.
- No association with lung cancer
- no susceptibility to TB
- once advanced disease is reached, no further exposure to coal dust does not improve course, like silicosis
pertinent epidemiology of silicosis include _
- workers in foundaries, sandblasting, mining industries, repair, rehabilitation or demolition of concrete
- African Americans at higher risk than whites
Explain the pathogenesis of silicosis
- crystalline form more fibrogenic such as quartz
- after inhalation its phagocytosed by macrophages –> inflammasome –> release of inflammatory mediators IL1, IL18.
Silicosis commonly found in what part of the lung?
Hilar lymph nodes and upper zones of lungs
Silicosis starts off as tiny barely palpalble pale blackened nodules in the hilar lymph nodes and upper zones of lungs, but as it progresses it forms _
Hard, collagenous scars where some can forms central softening and cavitation due to superimposed TB or ischemia.
_ is Characteristic finding on radiograph of progressive silicosis
eggshell calcification as sheets of calcification in lymph nodes.
The histologic findings of silicosis include _
central area of whorled collagen fibers with more peripheral zone of dust laden macrophages. These can be polarized to find birefringent silicate particles (silica is weakly birefringent)
Explain the clinical course of silicosis
- on radiograph: fine nodularity in upper zone.
- pulm fxn either normal or only moderately affected early on with no SOB until progressive massive fibrosis supervenes.
- impair macrophages function –> increased susceptibility to TB unlike CWP
- DOUBLES THE RISK OF DEVELOPING LUNG CANCER
Localized fibrous plaques or rarely diffuse pleural fibrosis, recurrent pleural effusion, parenchymal interstitial fibrosis, lung carcinoma, mesothelioma, laryngeal, ovarian cancers, all have been implicated to chronic exposure to _
asbestos
Asbestos occur in two forms serpentine and amphibole. 1) Which one is responsible for 90% of exposure as it’s used in industry? and 2) which one is less common but more pathogenic in that it induces mesothelioma.
- Serpentine - more likely to cleared by mucociliary action
- Amphibole - small enough to reach lung instersitium quickly by escaping mucociliary action
Note: both are equally fibrogenic, nonetheless
Explain how smoking and asbestos exposure are synergistic
- both are oncogenic, mediated by free radicals generated by both
- The carcinogen in tobacco smoke onto asbestos fibers is the basis for synergy for developing lung carcinoma.
- smoking destroys mucociliary action thus making asbestos easier to make it down to lung parenchyma.
- risk of carcinoma is increased by 55 fold with both
Explain how injury occurs with asbestos exposure.
Once phagocytosed by macrohagess, asbestos fibers activate inflammasome and stimulate and release proinflammatory factors and fibrogenic mediators
- Starts in bifurcation of small airways and ducts where they land and penetrate.
- macrophages and alveolar/interstitial macrophages tries to clear the fibers. long term exposure leads to persistent release of mediators, ROS, protease, cytokines, growth factors –> interstitial pulmonary inflammation and interstitial fibrosis
how is diffuse pulmonary interstitial fibrosis from asbestos distinguished from fibrosis from other pneumoconiosis?
Presence of asbestos bodies which are golden brown, fusiform or beaded rods with translucent center and consistent of asbestos fibers coated with an iron-containing proteinaceous material
- Ferruginous bodies may be also seen (iron-coated protein comlex)
_ are the most common manifestation of asbestos exposure, and are well circumscribed plaques of dense collagen found on anterior and posterolateral aspect of parietal pleura and over domes of diaphragm.
Pleural plaques. –> restrictive lung disease -= normal FEV1/FVC ratio and low FVC
Asbestosis affects which parts of the lung most commonly?
Lower lobes including entire respiratory unit
What drugs are commonly known to cause fibrosis and drug induced lung disease?
- bleomycin (chemo)
- amiodarone —> pneumonitis
- illict IV drugs
Radiation induced lung disease is pretty common can manifest as acute radiation pneumonitis (lymphocytic alveolitis or hypersensitivity pneumonitis) 1-6 months after irradiation, manifested with fever, dyspnea out of proportion to the volume of lung, pleural effusion and infiltrates that usually corresponds to area of irradiation. Presence of what cells are characteristic of radiation damage?
Atypia of hyperplastic type II cells and fibroblasts. Epithelial cell atypia and form cells within vessel walls in particular are characteristic.
Sarcoidosis presents in many clinical patterns, but most common, 90% of cases, occur where?
bilateral hilar lymphadenopathy or lung involvement