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46 Cards in this Set
- Front
- Back
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lung lobulation
a. cattle, sheep, pigs b. dogs, cats c. horses |
a. thick pleura extends into lung parenchyma forming distinct 2º lobules w/ interlobular CT septae (absence of collateral circulation)
b. thin pleura & no interlobular septae (no 2º lobules) c. thick pleura & incomplete CT septae |
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2 types of alveolar epithelial cells
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type I epithelium: 40% of cells in alveoli, but covers 95% of alveolar surfaces
type II epithelium: 60% of cells in alveoli, covers only 5% of alveolar surfaces -produce surfactant -progenitor cells for injured type I cells |
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What makes infarction in lungs less common than in other tissues?
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dual blood supply
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respiratory defense mechanisms
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particle deposition (air turbulence, warming of air by engorged turbinate blood vessels)
mucociliary escalator alveolar MPs inflammatory & immune response |
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Obstructive lesions of nasal passages
a. signs b. how to dx c. etiology |
a. unilateral serous nasal discharge, dyspnea, sneezing, +/- fever bilateral purulent discharge
b. -microscopic exam of nasal exudate smear -cytology, biopsy of nasal cavity -rads, CT, MRI c. -neoplasia -adenocarcinoma: most common nasal neoplasm in dogs -LSA: most common nasal neoplasm in cats -SCC: maxillary sinuses of horses -fungal rhinitis: Aspergillus (dogs), Cryptococcus (cats > horses > dogs) -ethmoid hematoma: horses |
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congestion
a. definition b. top etiology c. gross lesions |
a. dilation of alveolar septal caps by RBCs d/t ↓ outflow of venous blood from lungs
b. left heart dz c. diffusely deep red to purple, firm |
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hypostatic congestion
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gravitational settling of blood in lung on down side of animal
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pulmonary edema
a. definition b. causes |
a. excess extravascular accumulation of fluid in lungs, usually in alveolar spaces
b. ↑ capillary hydrostatic pressure (most common): L heart failure ↑ permeability of cap endothelium or alveolar epi endotoxins, corrosive gases, viruses, 100% O2 ↓ plasma oncotic pressure: hypoproteinemia lymphatic obstruction |
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pulmonary thrombi vs. emboli
causes of pulmonary thrombi |
less common than pulmonary embolism
causes: HW dz, hypercoagulatory states, endothelial damage to blood vessels |
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pulmonary infarction
a. predisposing factor b. gross lesions |
a. pre-existing lung dz
b. firm, deep red to dark purple, +/- fibrinous exudate |
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atelectasis
a. definition b. 2 main categories c. gross lesions |
a. incomplete distension or partial to complete collapse of terminal air spaces (too little air)
b. congenital, acquired c. visibly collapsed lobe/lobule, deep red to purple, firm to meaty |
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congenital atelectasis: causes
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-fetal: stillborn fetus
-neonatal -aspiration of amniotic fluid -dystocia --> anoxic damage to respiratory centers during birth -hyaline membrane dz: foals, pigs (uncommon): deficient production of surfactant by type II epithelial cells--> hyaline membranes line many airspaces |
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acquired atelectasis: 2 forms, causes, pathogenesis
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obstructive: most common form of acquired atelectasis
- bronchioles or bronchi obstructed by: o inflammatory exudate or other foreign debris o parasites o neoplastic cells -pathogenesis: air trapped distal to obstructed bronchiole --> air resorbed --> terminal air spaces collapse -occurs most commonly in lobulated lungs (lack collateral ventilation) compression -external compression of lung causes by: o excessive accumulation of fluids, blood, pus, or air in thoracic cavity o space occupying lesions |
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emphysema
a. definition b. 2 forms |
a. excess air in lungs
b. alveolar, intersitital |
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alveolar emphysema
a. pathogenesis b. in domestic animals |
PRIMARILY A HUMAN DZ
a. enzymatic destruction of alveolar walls --> permanent over distension of air spaces distal to terminal bronchioles b. neither permanent over distension of terminal air spaces nor destruction of alveolar walls occurs |
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interstitial emphysema
a. signalment b. predisposing factors |
a. most commonly seen in animals (esp. cattle) w/ lobulated lungs d/t lack of collateral ventilation & thick interlobular septae
b. any condition causing forced expiration -acute interstitial pneumonia -bronchopneumonia -agonal, gasping breathing |
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interstitial emphysema
a. pathogenesis b. gross lesions |
a. bronchioles obstructed or collapse during forced expiration --> air trapped distal to site of collapse --> rupture of air filled alveoli --> air leaks into interlobular septae
b. beaded air bubbles of varying size in interlobular spaces |
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bronchopneumonia
a. site of inflammation b. distribution c. etiology d. species affected |
a. inflammatory exudate in airways (bronchi, bronchioles, alveoli)
b. cranioventral distribution c. bacteria or Mycoplasma d. most common type of pneumonia, esp. in cattle, sheep, pigs b/c they are raised in groups |
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bronchopneumonia: pathogenesis
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bacteria deposited at junction of terminal bronchioles & alveolar ducts (no mucociliary escalator, sharp drop in air velocity) --> inflammation spreads to distally to alveoli & proximally into bronchioles, bronchi --> other parts of lung --> consolidation of lung lobe(s)
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bronchopneumonia: predisposing factors
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stress & viral infections predispose to bacterial infection
temperature, transportation, overcrowding, dirty environment viruses -cattle: BRSV, BVDV, IBRV, PI3V -pigs: influenza, PRRSV, circovirus -dogs: influenza -chickens, turkeys: NCDV, ILTV |
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2 major subtypes of bronchopneumonia
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suppurative
fibrinous |
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suppurative bronchopneumonia
a. time course b. exudate |
a. days to weeks
b. neutrophils, cell debris |
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suppurative bronchopneumonia
a. etiology b. gross lesions |
a. Pasteurella multocida (cattle), Strep suis (pigs), Mycoplasma (pigs, chickens, turkeys), E. coli, other gram pos. bacteria
b. lobular involvement varies: may be normal, inflamed (dark red to dark purple, firm, slightly swollen), or atelectatic (light to deep purple, depressed or sunken) |
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fibrinous bronchopneumonia
a. time course b. exudate |
a. hours to days (more virulent microorgs)
b. fibrin |
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fibrinous bronchopneumonia
a. etiology b. gross lesions |
a. Mannheimia haemolytica (cattle), Actinobacillus pleuropneumoniae (pigs), Pasteurella multocida (cattle, chickens), E. coli (chickens, toxogenic strains: dogs)
majority of lobules in a lobe severely inflamed: firm, swollen, intense red to yellowish red |
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interstitial pneumonia
a. location of inflammation b. etiologies |
a. inflammatory exudate in alveolar septal interstitium
b. toxic gases, viruses, aspirated gastric material, tissue injury, gram neg. septicemia, pancreatitis, reactive O2 species, toxic metabolites |
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interstitial pneumonia: pathogenesis
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injury to capillary endothelium or alveolar epithelium --> leakage of plasma proteins thru interstitium into air spaces --> neutrophils +/- fibrin accumulate in alveolar interstitium w/ some spill over into air spaces --> type II cells lining alveoli MAY proliferate (4-6 d. post injury)
if source of injury persists --> interstitial fibrosis (12-14 d. post injury) |
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interstitial pneumonia
a. gross lesions b. microscopic lesions |
a. DIFFUSE lung lesion (deep reddish purple & slightly firm): may be hard to dx grossly
b. alveolar interstitium thickened by: -edema, neutrophils, fibrin, proteinaceous fluid in air spaces -lymphocytes & neutrophils (most air spaces empty, in contrast to bronchopneumonia) |
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granulomatous pneumonia
a. definition b. gross lesions c. etiologies |
a. chronic pneumonia characterized by presence of epitheliod MPs &/or multinucleated giant cells
b. granulomas have necrotic centers filled w/ pus or caseous exudates encircled by layer of CT c. Mycobacteria, fungi, Rhodococcus equi, foreign objects -resist destruction by inflammatory response & persist in tissues |
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Blastomycosis
a. etiologic agent b. signalment c. signs d. gross lesions |
a. Blastomyces dermatitidis (fungus)
b. 2-5 yo male large breed dogs c. slow insidious onset of wt. loss, cough, dyspnea, exercise intolerance d. granulomatous pneumonia -multiple firm gray-white nodules of varying sizes distributed in all lobes -advanced: diffuse, firm, non-collapsing lung |
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acute respiratory distress syndrome (ARDS)
a. species affected b. clinical signs c. time course d. mortality |
a. dogs, cattle, horses, etc.
b. lethargy, anorexia, coughing, dyspnea of short duration c. acute d. high |
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ARDS: causes
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1º: aspiration of gastric contents, lung trauma, inhalation of toxic gases, viral infections (ex. BRSV), Gram neg. septicemia (ex. Salmonella, E. coli)
2º: any massive tissue trauma, pancreatitis |
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ARDS: pathogenesis
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initiating event --> activation of neutrophils & MPs --> secretion of pro- & anti- inflammatory cytokines --> imbalance of antagonistic cytokines --> cellular injury --> disruption of capillary endothelial & alveolar epithelial barriers --> interstitial edema & alveolar flooding w/ protein rich fluid
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ARDS
a. lesions b. ddx for lesions c. possible outcomes |
a. acute interstitial pneumonia: diffusely firm lung
b. congestion & edema, acute interstitial pneumonia c. death, acute recovery, or chronic recovery w/ alveolar fibrosis beginning 10-14 d. post onset |
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canine distemper virus
a. lung lesions b. common complication c. microscopic lesions |
a. focal or MF firm gray to reddish purple pneumonic areas (interstitial pneumonia)
b. 2º bacterial infections --> suppurative bronchopneumonia, which obscures interstitial pneumonia c. intranuclear or intracytoplasmic inclusion bodies in epithelial cells of lung, kidney, bladder, etc. |
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primary lung tumors
a. species most commonly affected b. less common primary tumors |
a. dogs, then cats, rare in other animals
b. disseminated histiocytic sarcoma, lymphomatoid granulomatosis, carcinoid, ovine pulmonary carcinoma, LSA |
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bronchiolar-alveolar carconoma
a. species affected b. origin |
a. most common primary lung tumor in dogs & cats
b. arises from non-ciliated bronchiolar (Clara) &/or Type II cells in peripheral areas (not near hilus) |
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bronchogenic carcinoma
a. origin b. gross |
a. arises from bronchial epithelium in central hilar location
b. firm, gray to white |
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examples of metastatic lung tumors
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more common than primary lung tumors
mammary carcinoma, malignant melanoma, HSA, osteosarcoma, etc. |
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mesothelioma
a. origin b. species affected c. gross appearance |
a. serosal lining cells on pleural surfaces
b. occasionally calves, dogs, horses c. multiple small firm nodules or villous projections of thickened serosal surfaces |
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hydrothorax: causes
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transudate in thoracic cavity
heart failure, hypoproteinemia, ANTU toxicity, neoplasia |
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hemothorax: causes
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trauma, clotting defects, DIC, neoplasia, pneumonia
usually acute & fatal |
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chylothorax: causes
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neoplasia (LSA), CHF, idiopathic, rupture of lymphatics, trauma
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pneumothorax: causes
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neoplasia, pneumonia, trauma
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pyothorax: causes
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ruptured abscess, pneumonia, trauma (ex. bite wound)
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chronic pleuritis: etiolgies
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-penetrating wound : Nocardia (dogs), Actinomyces (dogs, horses) --> sulfur granules
-pneumonia |
