Pathology of the Respiratory Pathology of the Respiratory System: General Responses to System: General Responses to

InjuryInjury

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NOT TO BE REPRODUCED

Respiratory PathologyRespiratory Pathology

Respiratory disease important in all speciesRespiratory disease important in all speciesEconomic importanceEconomic importanceClinical importanceClinical importance

Diagnosis is a challenge, both clinical and Diagnosis is a challenge, both clinical and morphologicmorphologic

NOT TO BE REPRODUCED

Pathology of Respiratory SystemPathology of Respiratory System

Respiratory injury and response Respiratory injury and response -- OutlineOutlineGeneral General Upper respiratory tractUpper respiratory tractLower respiratory tract Lower respiratory tract Pleura and thoracic cavityPleura and thoracic cavity

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InjuryInjury

Types of injuryTypes of injuryPrimary or secondaryPrimary or secondaryCell specific or nonCell specific or non--specificspecific

Importance in repair processImportance in repair processAre stem cells injured?Are stem cells injured?

NOT TO BE REPRODUCED

Causes of Injury: Cell SpecificCauses of Injury: Cell Specific

Ciliated cell injury Ciliated cell injury Bacteria e.g. Bacteria e.g. BordetellaBordetella, , MycoplasmaMycoplasma sppsppViruses e.g. influenza, paramyxovirusViruses e.g. influenza, paramyxovirusAir pollutants (NOAir pollutants (NO22 , SO, SO22 , O, O33 , O, O22))

Clara cell injury Clara cell injury Metabolically activated Metabolically activated xenobioticsxenobiotics (3 methylindole)(3 methylindole)

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Clara Cell NecrosisClara Cell Necrosis

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Clara Cell NecrosisClara Cell Necrosis

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Causes of Injury: NonCauses of Injury: Non--specificspecific

Some viruses Some viruses Chemicals (caustic agents)Chemicals (caustic agents)Foreign bodiesForeign bodies

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NOT TO BE REPRODUCED

Response to Injury is Limited Response to Injury is Limited

But can vary somewhat depending onBut can vary somewhat depending onCausative agentCausative agentRoute of exposureRoute of exposureSeverity of exposureSeverity of exposureHost defenseHost defense

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Diagnostic AidsDiagnostic Aids

Type of inflammatory responseType of inflammatory responsePresence of causative agent Presence of causative agent Presence of a specific agentPresence of a specific agent--induced change induced change e.ge.ginclusion bodiesinclusion bodiesSpecial stainsSpecial stainsImmunohistochemistryImmunohistochemistry (IHC)(IHC)Electron microscopyElectron microscopy

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Response to InjuryResponse to Injury

EdemaEdemaNecrosisNecrosisInflammationInflammationCell proliferationCell proliferationFibrosisFibrosisGranuloma formationGranuloma formation

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Consequences of Airway InjuryConsequences of Airway Injury

Early Morphologic ChangesEarly Morphologic ChangesInflammationInflammationEpithelial hyperplasia Epithelial hyperplasia –– regenerative or due to irritant regenerative or due to irritant effects e.g. mucous cellseffects e.g. mucous cellsEpithelium Epithelium metaplasiametaplasia –– effect on effect on mucociliarymucociliary escalator escalator e.g.e.g.

MucousMucousSquamousSquamous

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Response to Injury Response to Injury -- ProliferationProliferation

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Mucous HyperplasiaMucous Hyperplasia

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Consequences of Airway InjuryConsequences of Airway Injury

Adverse EffectsAdverse EffectsAirway hyperAirway hyper--reactivity and reactivity and bronchoconstrictionbronchoconstrictionModified mucus productionModified mucus productionDecreased Decreased mucociliarymucociliary clearanceclearanceInflammationInflammationEpithelial proliferationEpithelial proliferationObstruction Obstruction –– complete or incompletecomplete or incompletePredisposition to infectionPredisposition to infectionFibrosisFibrosis

NOT TO BE REPRODUCED

Chronic Effects of Airway Chronic Effects of Airway InjuryInjury

FibrosisFibrosisMural Mural -- fibrosingfibrosing bronchiolitisbronchiolitisIntralumenalIntralumenal –– bronchiolitisbronchiolitis obliteransobliteransCan lead to Can lead to atelectasisatelectasis (complete obstruction) or (complete obstruction) or emphysemaemphysema

Destruction of surrounding tissueDestruction of surrounding tissueBronchiectasisBronchiectasisAbscess formation/Abscess formation/empyemaempyema if infectedif infected

Extension of infection e.g. pneumoniaExtension of infection e.g. pneumoniaNeoplasiaNeoplasia

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Chronic Effects of Airway InjuryChronic Effects of Airway Injury

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Chronic Effects of Airway InjuryChronic Effects of Airway Injury

NOT TO BE REPRODUCED

Consequences of Lung Consequences of Lung Parenchymal InjuryParenchymal Injury

EdemaEdemaDecreased surfactant (Decreased surfactant (→→ atelectasis)atelectasis)Decreased defense mechanismsDecreased defense mechanismsEpithelial proliferation/Epithelial proliferation/neoplasianeoplasiaInflammationInflammationFibrosisFibrosisPredisposition to infectionPredisposition to infectionImmune mediated diseaseImmune mediated disease

NOT TO BE REPRODUCED

Repair of Injury to the LungRepair of Injury to the Lung

Repair can occur if Repair can occur if Stem cells are availableStem cells are availableBasement membrane is intactBasement membrane is intactInflammation is not too severeInflammation is not too severeInciting agent is removedInciting agent is removed

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Consequences of Basement Consequences of Basement Membrane DamageMembrane Damage

Chronic disease: fibrosisChronic disease: fibrosisSevere destruction of tissueSevere destruction of tissue

Emphysema Emphysema AbscessAbscessSequestrationSequestration

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Consequences of Basement Consequences of Basement Membrane Damage Membrane Damage -- LungLung

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Diagnosis of Respiratory DiseaseDiagnosis of Respiratory Disease

Clinical disease, individual and group/herd Clinical disease, individual and group/herd Pulmonary functionPulmonary functionClinical pathologyClinical pathologyAnatomic pathology Anatomic pathology –– gross, microscopic, electron gross, microscopic, electron microscopy, IHCmicroscopy, IHCBacteriology Bacteriology -- culture, PCR, serologyculture, PCR, serologyVirology Virology –– as bacteriology, virus isolation as bacteriology, virus isolation ParasitologyParasitologyToxicology Toxicology –– analytical, feed microscopyanalytical, feed microscopy

NOT TO BE REPRODUCED

Pathology of Respiratory SystemPathology of Respiratory System

Respiratory injury and responseRespiratory injury and responseUpper Respiratory TractUpper Respiratory Tract

Developmental AbnormalitiesDevelopmental AbnormalitiesNon infectious DiseaseNon infectious DiseaseInfectious DiseaseInfectious Disease

Lower Respiratory Tract Lower Respiratory Tract Pleura and thoracic cavityPleura and thoracic cavity

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Upper Respiratory System Upper Respiratory System Developmental AbnormalitiesDevelopmental Abnormalities

ExamplesExamplesMaxillary sinus cysts Maxillary sinus cysts -- horsehorseCiliary Ciliary dyskinesisdyskinesis -- dogdogTracheal hypoplasia Tracheal hypoplasia -- dogdogEpiglottal Epiglottal hypoplasiahypoplasia -- horsehorse

NOT TO BE REPRODUCED

Upper Respiratory System: Upper Respiratory System: Noninfectious Disease Noninfectious Disease

Tracheal collapse (dogs, horses)Tracheal collapse (dogs, horses)Laryngeal paralysis (dogs, horses)Laryngeal paralysis (dogs, horses)

Idiopathic laryngeal hemiplasia (roarer)Idiopathic laryngeal hemiplasia (roarer)

Laryngeal edemaLaryngeal edemaSmoke inhalationSmoke inhalation

NOT TO BE REPRODUCED

Noninfectious Disease:Noninfectious Disease:Differentials for Differentials for EpistaxisEpistaxis

TraumaTraumaInvasive intranasal lesionInvasive intranasal lesion

Fungal infectionFungal infectionNeoplasiaNeoplasia

Bleeding disorder Bleeding disorder –– genetic, infectious, or genetic, infectious, or toxic origintoxic originExercise induced pulmonary hemorrhage Exercise induced pulmonary hemorrhage (EIPH) (EIPH) -- horseshorses

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Proliferative Lesions Proliferative Lesions of Nasal Cavityof Nasal Cavity

Nasal polyps (cats, horses)Nasal polyps (cats, horses)Ethmoid Ethmoid hematomahematomaNasopharyngeal polyps Nasopharyngeal polyps -- catscatsGranulomatous rhinitisGranulomatous rhinitis

NeoplasiaNeoplasiaCarcinomaCarcinomaSarcomaSarcoma

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ProliferativeProliferative Lesions Lesions of Nasal Cavityof Nasal Cavity

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Neoplasia of the Nasal Cavity:Neoplasia of the Nasal Cavity:

Mainly dogs, also cats and horsesMainly dogs, also cats and horses80% malignant80% malignantClinical Signs Clinical Signs

Unilateral or bilateral mucoid or bloody dischargeUnilateral or bilateral mucoid or bloody dischargeIntermittent sneezingIntermittent sneezingObstruction of nasolacrimal ductObstruction of nasolacrimal ductFacial swellingFacial swellingBony erosionBony erosionNeurologicNeurologic signs occasionallysigns occasionally

NOT TO BE REPRODUCED

NeoplasiaNeoplasia of the Nasal Cavityof the Nasal Cavity

NOT TO BE REPRODUCED

Noninfectious Diseases of Upper Noninfectious Diseases of Upper Respiratory SystemRespiratory System

Smoke inhalationSmoke inhalationThermal injury Thermal injury

Laryngeal/tracheal necrosis with fibrinLaryngeal/tracheal necrosis with fibrin

Also chemical induced pulmonary edemaAlso chemical induced pulmonary edema

NOT TO BE REPRODUCED

Infectious Upper Respiratory Infectious Upper Respiratory Disease Disease

Balance of microbial flora upsetBalance of microbial flora upsetOften viral, especially herpes viruses Often viral, especially herpes viruses Bacterial disease secondaryBacterial disease secondaryPossible Possible sequellasequella –– osteomyelitisosteomyelitis, , meningitis, meningitis, otitisotitis

NOT TO BE REPRODUCED

Infectious Upper Respiratory Infectious Upper Respiratory DiseaseDisease

CattleCattle*Infectious bovine *Infectious bovine rhinotracheitisrhinotracheitis (IBR)(IBR)

HorsesHorses*Equine rhinopneumonitis*Equine rhinopneumonitisStrangles (Strangles (Strep Strep equiequi))

PigsPigs**PseudorabiesPseudorabiesAtrophic rhinitis (Atrophic rhinitis (Past Past multocidamultocida))

*Herpes viruses*Herpes viruses

NOT TO BE REPRODUCED

Infectious Upper Respiratory Infectious Upper Respiratory DiseaseDisease

DogsDogsCanine distemper virusCanine distemper virusInfectious Infectious tracheobronchitistracheobronchitisAspergillosisAspergillosis

CatsCats*Feline viral rhinotracheitis*Feline viral rhinotracheitisCalicivirusCalicivirusCryptococcosisCryptococcosis

*Herpes viruses*Herpes viruses

NOT TO BE REPRODUCED

Pathology of Respiratory Pathology of Respiratory SystemSystem

Upper Respiratory TractUpper Respiratory TractLower Respiratory TractLower Respiratory Tract

Lung lesion distribution Lung lesion distribution Developmental AbnormalitiesDevelopmental AbnormalitiesNon Infectious DiseaseNon Infectious DiseasePneumoniasPneumoniasNeoplasiaNeoplasia

Pleura and thoracic cavityPleura and thoracic cavity

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Gross Lung ExamGross Lung Exam

Lesion distributionLesion distributionDiffuseDiffuseLocally extensiveLocally extensiveFocal/Focal/multifocalmultifocal

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Diffuse Pulmonary DiseaseDiffuse Pulmonary Disease

EdemaEdemaAtelectasisAtelectasisInterstitial pneumoniaInterstitial pneumoniaMineralizationMineralizationEmphysemaEmphysema

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Normal and Pulmonary EdemaNormal and Pulmonary Edema

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Locally Extensive Pulmonary Locally Extensive Pulmonary DiseaseDisease

CranioventralCranioventralbronchopneumoniabronchopneumonia

BacterialBacterialAspirationAspiration

Granulomatous pneumoniaGranulomatous pneumoniaOther: lobe torsionOther: lobe torsion

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Locally Extensive Pulmonary Locally Extensive Pulmonary Disease Disease –– Lobe Torsion Lobe Torsion -- DogDog

NOT TO BE REPRODUCED

Focal/Multifocal Pulmonary Focal/Multifocal Pulmonary DiseaseDisease

AbscessAbscessGranulomaGranuloma

BacterialBacterialMycoticMycoticParasiticParasiticParticulatesParticulates

InfarctInfarctNeoplasiaNeoplasia

NOT TO BE REPRODUCED

Developmental Lung AnomaliesDevelopmental Lung Anomalies

RARERAREAccessory lungsAccessory lungsPulmonary Pulmonary hypoplasiahypoplasia –– cattlecattlePulmonary cystPulmonary cystSurfactant deficiency Surfactant deficiency –– horses horses MelanosisMelanosis –– pigs, cattle, sheeppigs, cattle, sheepBronchial hypoplasia with lobar emphysemaBronchial hypoplasia with lobar emphysema–– dogsdogs

NOT TO BE REPRODUCED

Developmental Lung AnomaliesDevelopmental Lung Anomalies

NOT TO BE REPRODUCED

Developmental AbnormalitiesDevelopmental Abnormalities

Pulmonary Pulmonary hypoplasiahypoplasiaGeneticGeneticPrimary, e.g., viral: border disease, swine influenza, Primary, e.g., viral: border disease, swine influenza, MenangleMenangle virus.virus.Secondary, e.g., to diaphragmatic hernia.Secondary, e.g., to diaphragmatic hernia.

Surfactant deficiency Surfactant deficiency -- diffuse diffuse atelectasisatelectasis..PrematurityPrematurity, e.g., lambs., e.g., lambs.Hyaline membrane disease ("barkers") in foals, pigs Hyaline membrane disease ("barkers") in foals, pigs

NOT TO BE REPRODUCED

Pulmonary MineralizationPulmonary Mineralization

Diffuse lesion (pumice lung)Diffuse lesion (pumice lung)Etiology Etiology

UremiaUremiaPrimary hyperparathyroidismPrimary hyperparathyroidismHypercalcemia of malignancyHypercalcemia of malignancyVitamin D toxicosisVitamin D toxicosisGross and microscopic Gross and microscopic –– interstitial pneumoniainterstitial pneumoniaOther organs affectedOther organs affected

Focal Focal microlithiasismicrolithiasis –– old dogsold dogs

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Pulmonary Mineralization Pulmonary Mineralization --DogDog

NOT TO BE REPRODUCED

Air in tissuesAir in tissues

Alveolar emphysemaAlveolar emphysema

Rupture of alveolar septa Rupture of alveolar septa -- humanhuman

Equine pulmonary emphysema (COPD, heaves)Equine pulmonary emphysema (COPD, heaves)

Interstitial emphysema (cattle)Interstitial emphysema (cattle)

Air in the interlobular septae and Air in the interlobular septae and subpleurallysubpleurallyFocal: secondary to Focal: secondary to atelectasisatelectasis, scarring, incomplete , scarring, incomplete obstruction of airways, or pneumonia.obstruction of airways, or pneumonia.

Senile "emphysemaSenile "emphysema““-- aged dogs, cats, horsesaged dogs, cats, horses

Abnormalities of Inflation Abnormalities of Inflation ––EmphysemaEmphysema

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Alveolar EmphysemaAlveolar Emphysema

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Abnormalities of Inflation Abnormalities of Inflation –– Alveolar Alveolar Emphysema Emphysema -- HorseHorse

NOT TO BE REPRODUCED

Abnormalities of Inflation Abnormalities of Inflation ––Interstitial Emphysema Interstitial Emphysema -- CowCow

NOT TO BE REPRODUCED

AtelectasisAtelectasis

Diffuse or multifocalDiffuse or multifocalCongenital atelectasisCongenital atelectasisAcquired atelectasisAcquired atelectasis

Compression collapseCompression collapseObstructive (focal)Obstructive (focal)Congestive or hypostatic atelectasisCongestive or hypostatic atelectasis

NOT TO BE REPRODUCED

AquiredAquired AtelectasisAtelectasis -- DogDog

NOT TO BE REPRODUCED

Circulatory DisturbancesCirculatory Disturbances

Diffuse pulmonary edemaDiffuse pulmonary edema

HemorrhageHemorrhage

Petechia, ecchymosisPetechia, ecchymosis

EIPHEIPH

Embolism, thrombosis, infarctionEmbolism, thrombosis, infarction

Pulmonary hypertensionPulmonary hypertension

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Pulmonary Edema Pulmonary Edema –– CowCow

NOT TO BE REPRODUCED

CardiogenicCardiogenic EdemaEdema——DogDog

NOT TO BE REPRODUCED

CardiogenicCardiogenic EdemaEdema——DogDog

NOT TO BE REPRODUCED

Mechanisms ofMechanisms ofPulmonary EdemaPulmonary Edema

Altered hemodynamicsAltered hemodynamicsIncreased capillary hydrostatic pressureIncreased capillary hydrostatic pressureDecreased plasma oncotic pressureDecreased plasma oncotic pressure

Increased permeability of airIncreased permeability of air--blood barrier blood barrier (noncardiogenic)(noncardiogenic)Lymphatic obstructionLymphatic obstruction

Note normal location of Note normal location of lymphaticslymphaticsAirway obstructionAirway obstruction

NOT TO BE REPRODUCED

Pulmonary Edema Pulmonary Edema -- Increased Increased Capillary Hydrostatic PressureCapillary Hydrostatic Pressure

CardiogenicCardiogenic –– most commonmost commonHypervolemicHypervolemic -- iatrogeniciatrogenicAcute CNS injury Acute CNS injury -- epinephrine release epinephrine release -- direct or via cardiac injury (braindirect or via cardiac injury (brain--heart heart syndrome)syndrome)

NOT TO BE REPRODUCED

Pulmonary Edema Pulmonary Edema -- Increased Increased Capillary Hydrostatic PressureCapillary Hydrostatic Pressure

CardiogenicCardiogenicToxic Toxic –– e.g. e.g. fumonisinsfumonisins, gossypol, gossypolNutritional Nutritional –– e.g. vitamin E/selenium e.g. vitamin E/selenium deficiencydeficiencyDegenerativeDegenerativeCardiomyopathyCardiomyopathyCongenital heart defectsCongenital heart defects

NOT TO BE REPRODUCED

Pulmonary Edema Pulmonary Edema –– PigPig

NOT TO BE REPRODUCED

Increased Permeability Increased Permeability of Airof Air--Blood BarrierBlood Barrier

Endothelial/epithelial injury Endothelial/epithelial injury ––inhalation/inhalation/boodborneboodborne exposureexposure

Toxic e.g. smoke, Toxic e.g. smoke, paraquatparaquat, oxygen, oxygenViralViralBacterialBacterial

InflammationInflammationAnaphylaxisAnaphylaxisHypoxemiaHypoxemia

NOT TO BE REPRODUCED

Embolism, Thrombosis, Embolism, Thrombosis, InfarctionInfarction

Embolism/ThromboembolismEmbolism/ThromboembolismInfectiousInfectiousNeoplasticNeoplasticAsepticAseptic

ThrombosisThrombosisInfarction rare due to dual blood supplyInfarction rare due to dual blood supply

NOT TO BE REPRODUCED

Embolism, Thrombosis Embolism, Thrombosis -- CowCow

NOT TO BE REPRODUCED

HemorrhageHemorrhage

PetechialPetechial hemorrhagehemorrhageSepticemiaSepticemia

EcchymoticEcchymotic hemorrhagehemorrhageCoagulation defectsCoagulation defects

Other Other TraumaTrauma

Method of euthanasia Method of euthanasia

NOT TO BE REPRODUCED

Limited types of responseLimited types of responseDiagnosis/EtiologyDiagnosis/Etiology

PalpationPalpationDistribution of lesionsDistribution of lesionsPathologyPathologyAncillary information (clinical, laboratory)Ancillary information (clinical, laboratory)

Inflammation of the Lung: Inflammation of the Lung: PneumoniaPneumonia

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Types of PneumoniaTypes of Pneumonia

BronchopneumoniaBronchopneumoniaInterstitial pneumoniaInterstitial pneumoniaEmbolic pneumoniaEmbolic pneumoniaGranulomatous pneumoniaGranulomatous pneumonia

NOT TO BE REPRODUCED

BronchopneumoniaBronchopneumonia

Inflammation of airways and adjacent parenchymaInflammation of airways and adjacent parenchymaInhaled agentsInhaled agents

BacteriaBacteriaGenerally suppurativeGenerally suppurativeAnteroventralAnteroventralAspirationAspiration

NOT TO BE REPRODUCED

BronchoBroncho--pneumonia pneumonia --

PigPig

NOT TO BE REPRODUCED

Bronchopneumonia: BacterialBronchopneumonia: Bacterial

Generally young, stressed animalsGenerally young, stressed animalsPredispositionPredisposition

StressStressViral infectionViral infectionImmune deficiency/suppressionImmune deficiency/suppression

NOT TO BE REPRODUCED

BronchopneumoniaBronchopneumonia

Classical stagesClassical stagesHyperemia plus edema (minsHyperemia plus edema (mins--hrs)hrs)Red hepatization (2Red hepatization (2--3 days)3 days)Gray hepatization (5Gray hepatization (5--7 days)7 days)Resolution (7 days to 4 weeks)Resolution (7 days to 4 weeks)

NOT TO BE REPRODUCED

BronchopneumoniaBronchopneumonia

Common sequelaeCommon sequelaeDeath (hypoxemia, toxemia)Death (hypoxemia, toxemia)SepticemiaSepticemiaPleuritisPleuritisChronic bronchopneumoniaChronic bronchopneumoniaAbscessesAbscessesBronchiectasisBronchiectasisAtelectasisAtelectasis

NOT TO BE REPRODUCED

Interstitial PneumoniaInterstitial Pneumonia

Inflammation of interstitiumInflammation of interstitium--generally without generally without airway involvementairway involvementDiffuse distributionDiffuse distributionNonNon--suppurativesuppurativeExposure via blood or inhalationExposure via blood or inhalation

NOT TO BE REPRODUCED

Interstitial Interstitial Pneumonia Pneumonia --

HorseHorse

NOT TO BE REPRODUCED

Interstitial Pneumonia Interstitial Pneumonia -- FoalFoal

NOT TO BE REPRODUCED

Etiology ofEtiology ofInterstitial PneumoniasInterstitial Pneumonias

ViralViralBacterial Bacterial MycoticMycoticProtozoalProtozoalOther parasiticOther parasitic

ToxicToxicHypersensitivityHypersensitivity

NOT TO BE REPRODUCED

Interstitial PneumoniaInterstitial Pneumonia

Lesion lacks etiologic specificityLesion lacks etiologic specificityAcute exudative phase (ARDS)Acute exudative phase (ARDS)Subacute proliferative phase (3 days)Subacute proliferative phase (3 days)Chronic phase (7Chronic phase (7--14 days)14 days)

NOT TO BE REPRODUCED

SubacuteSubacute Interstitial Pneumonia Interstitial Pneumonia --CowCow

NOT TO BE REPRODUCED

Interstitial PneumoniaInterstitial Pneumonia

Possible sequelaPossible sequelaResolutionResolutionFibrosisFibrosisPersistencePersistenceBacterial bronchopneumoniaBacterial bronchopneumonia

NOT TO BE REPRODUCED

Bronchointerstitial PneumoniaBronchointerstitial Pneumonia

Microscopic diagnosis onlyMicroscopic diagnosis onlyComponentsComponents

Interstitial pneumonia (nonInterstitial pneumonia (non--suppurative)suppurative)BronchiolitisBronchiolitis

EtiologyEtiologySome viruses e.g. Some viruses e.g. herpesvirusherpesvirus, BRSV, BRSVMycoplasmaMycoplasma

NOT TO BE REPRODUCED

Multifocal LesionsMultifocal Lesions

AbscessAbscessBronchogenicBronchogenicSeptic emboliSeptic emboliAspirationAspiration

Foreign bodyForeign bodyGranulomaGranulomaNeoplasiaNeoplasia

NOT TO BE REPRODUCED

MultifocalMultifocalAbscesses Abscesses --

HorseHorse

NOT TO BE REPRODUCED

Embolic PneumoniaEmbolic Pneumonia

EtiologyEtiologyBacterial (abscesses) Bacterial (abscesses)

Vegetative Vegetative endocarditisendocarditisSepticemiaSepticemiaRuptured liver abscessRuptured liver abscess

Mycotic (granulomas)Mycotic (granulomas)Rumen ulcersRumen ulcersGI ischemiaGI ischemia

Foreign body (e.g. iv injection, hair)Foreign body (e.g. iv injection, hair)

NOT TO BE REPRODUCED

Pulmonary EmboliPulmonary Emboli

NOT TO BE REPRODUCED

Granulomatous PneumoniaGranulomatous Pneumonia

Inhaled or bloodInhaled or blood--borne agentsborne agentsLarge areas are affected vs. pulmonary Large areas are affected vs. pulmonary granulomasgranulomasMultifocal to locally extensive distribution Multifocal to locally extensive distribution Agent persists and incites Agent persists and incites granulomatousgranulomatousresponseresponseEtiology: mycotic, bacterial, particulatesEtiology: mycotic, bacterial, particulates

NOT TO BE REPRODUCED

GranulomatousGranulomatous Pneumonia Pneumonia -- DogDog

NOT TO BE REPRODUCED

Tuberculosis Tuberculosis -- CowCow

NOT TO BE REPRODUCED

Tuberculosis Tuberculosis -- CowCow

NOT TO BE REPRODUCED

PneumoconiosisPneumoconiosis

AnthracosisAnthracosisAsbestosisAsbestosisSilicosisSilicosisClay Clay -- bentonitebentonite –– cat litter ?????cat litter ?????

NOT TO BE REPRODUCED

Pneumoconiosis Pneumoconiosis -- AnthracosisAnthracosis

Species: dogs, Species: dogs, humans, etc, living humans, etc, living in citiesin citiesDisease: benign Disease: benign accumulation of accumulation of carboncarbon

NOT TO BE REPRODUCED

Pneumoconiosis Pneumoconiosis -- AsbestosisAsbestosis

Species: man, dog, cattleSpecies: man, dog, cattleLesionsLesions

Inflammation, fibrosis, asbestos bodiesInflammation, fibrosis, asbestos bodiesMesotheliomaMesothelioma

Pathogenesis: macrophage and epithelial injuryPathogenesis: macrophage and epithelial injury

NOT TO BE REPRODUCED

Pneumoconiosis Pneumoconiosis -- SilicosisSilicosis

-- Species: humans, horses, wildlife and zoo Species: humans, horses, wildlife and zoo animalsanimals

-- Origin: mines, sandblasting, sand flouncingOrigin: mines, sandblasting, sand flouncing-- Pathology: progressive Pathology: progressive granulomatousgranulomatous diseasedisease-- Pathogenesis: Pathogenesis: cytotoxicitycytotoxicity to macrophagesto macrophages

NOT TO BE REPRODUCED

Silicosis Silicosis –– Rat (Exp)Rat (Exp)

NOT TO BE REPRODUCED

Pneumoconiosis Pneumoconiosis -- SilicosisSilicosis

NOT TO BE REPRODUCED

Aspiration PneumoniaAspiration Pneumonia

Etiology/predisposing factorsEtiology/predisposing factorsIatrogenicIatrogenicCleft palateCleft palateAnesthesiaAnesthesiaCNS disorderCNS disorderWhite muscle diseaseWhite muscle diseaseImproper force feedingImproper force feedingPrenatal stressPrenatal stress

NOT TO BE REPRODUCED

Aspiration Pneumonia cont.Aspiration Pneumonia cont.

Response to aspirated materialResponse to aspirated materialLesionLesion

BronchopneumoniaBronchopneumoniaDistributionDistribution

AnteroventralAnteroventral/locally extensive/locally extensiveMultifocalMultifocal

SeveritySeverityIdentification of foreign materialIdentification of foreign material

NOT TO BE REPRODUCED

Aspiration Pneumonia Aspiration Pneumonia -- MouseMouse

NOT TO BE REPRODUCED

Fetal Aspiration PneumoniaFetal Aspiration Pneumonia

Fetal hypoxia and acidosis (fetal distress)Fetal hypoxia and acidosis (fetal distress)Relaxation of anal sphincter with release of Relaxation of anal sphincter with release of meconiummeconium into amniotic fluidinto amniotic fluidLoss of Loss of glossalglossal reflex allows aspiration of reflex allows aspiration of amniotic fluid containing amniotic fluid containing squamessquames and and meconiummeconiumMay also aspirate pathogens if May also aspirate pathogens if placentitisplacentitispresentpresentInflammation results Inflammation results –– easily missedeasily missed

NOT TO BE REPRODUCED

Lesions Lesions Interstitial pneumoniaInterstitial pneumoniaBronchointerstitial pneumoniaBronchointerstitial pneumonia

Rarely kill without bacterial infectionRarely kill without bacterial infectionDiagnosisDiagnosis

Viral PneumoniasViral Pneumonias

NOT TO BE REPRODUCED

Can lead to secondary infectionCan lead to secondary infectionDepress macrophage functionDepress macrophage functionImpair mucociliary clearanceImpair mucociliary clearanceAllow bacterial multiplicationAllow bacterial multiplication

Can lead to airway hyperreactivityCan lead to airway hyperreactivity

Viral InfectionViral Infection

NOT TO BE REPRODUCED

Major Viral DiseasesMajor Viral Diseases

Especially importantEspecially importantHerpesvirusesHerpesviruses

Can remain latent till stress occursCan remain latent till stress occursCan remain carrierCan remain carrier

InfluenzaInfluenzaAvian influenza Avian influenza –– also felids, humans affectedalso felids, humans affectedCanine influenza Canine influenza –– equine mutationequine mutation

ParamyxovirusesParamyxoviruses

NOT TO BE REPRODUCED

AirAir--borne (aerogenous)borne (aerogenous)Bronchopneumonia (AV)Bronchopneumonia (AV)

Hematogenous: diffuse, multifocal (interstitial or Hematogenous: diffuse, multifocal (interstitial or embolic pneumonia)embolic pneumonia)Secondary toSecondary to

Infection: virus, mycoplasma, chlamydiaInfection: virus, mycoplasma, chlamydiaStress e.g. shippingStress e.g. shippingOther e.g. environmental conditionsOther e.g. environmental conditions

Bacterial PneumoniaBacterial Pneumonia

NOT TO BE REPRODUCED

Bacterial Pneumonia (cont)Bacterial Pneumonia (cont)

Bacterial injuryBacterial injuryEstablishment by evasion of host defense Establishment by evasion of host defense systemsystemEndotoxinsEndotoxinsExotoxinsExotoxinsetcetc

DiagnosisDiagnosis

NOT TO BE REPRODUCED

Mycobacterial DiseaseMycobacterial Disease

Zoonotic disease, reportableZoonotic disease, reportableMycobacterium tuberculosis Mycobacterium tuberculosis (tuberculosis)(tuberculosis)

Man, cattle, dog, primateMan, cattle, dog, primateM. bovisM. bovis

Man, cattle, swine, elephant, lionMan, cattle, swine, elephant, lionM. aviumM. avium

Avian, swine, primate, dogAvian, swine, primate, dogRecent concerns in deer, elk Recent concerns in deer, elk

NOT TO BE REPRODUCED

MycobacteriosisMycobacteriosis

Most systems can be affectedMost systems can be affectedRuminants: primary pulmonaryRuminants: primary pulmonaryPigs: ingestion, can disseminate to lungPigs: ingestion, can disseminate to lung

Pathology: granulomasPathology: granulomasPathogenesisPathogenesis

NOT TO BE REPRODUCED

Etiologic agentsEtiologic agentsCryptococcus Cryptococcus neoformansneoformans, C. , C. gattigattiHistoplasmaHistoplasma capsulatumcapsulatumAspergillus spp.Aspergillus spp.BlastomycosisBlastomycosis dermatiditisdermatiditisCoccidiodesCoccidiodes immitisimmitis

Mycotic PneumoniaMycotic Pneumonia

NOT TO BE REPRODUCED

AspergillosisAspergillosis

CanineCanineNasal Nasal Disseminated if Disseminated if immunosuppressedimmunosuppressed

Avian Avian –– pulmonary, air sacs pulmonary, air sacs (invasive/noninvasive)(invasive/noninvasive)Equine Equine -- gutteralgutteral pouch infectionpouch infection

Pulmonary Pulmonary granulomasgranulomas (embolic)(embolic)

Bovine Bovine –– secondary to secondary to rumenalrumenal ulcersulcersPulmonary granulomas (embolic)Pulmonary granulomas (embolic)Placental leading to abortionPlacental leading to abortion

NOT TO BE REPRODUCED

Mycotic/ProtozoalMycotic/Protozoal Pneumonias Pneumonias Secondary to Secondary to ImmunosuppressionImmunosuppression

ToxoplasmaToxoplasma gondiigondiiCat, dog, man, etc. (zoonosis)Cat, dog, man, etc. (zoonosis)Frequently associated with distemper, Frequently associated with distemper, AIDSAIDS

PneumocystisPneumocystis sppsppFoals, pigs. man, laboratory animalsFoals, pigs. man, laboratory animals

NOT TO BE REPRODUCED

Parasitic (Verminous) Parasitic (Verminous) PneumoniaPneumonia

Effect on hostEffect on hostObstruct airwaysObstruct airwaysGranulomas, Granulomas, multifocalmultifocal, , caudocaudo--dorsal dorsal Necrosis leading to loss of functionNecrosis leading to loss of functionSecondary bacterial bronchopneumoniaSecondary bacterial bronchopneumoniaHypersensitivity reactionHypersensitivity reactionOften see eosinophilsOften see eosinophils

NOT TO BE REPRODUCED

MuelleriusMuellerius sppspp -- SheepSheep

NOT TO BE REPRODUCED

Toxic Lung InjuryToxic Lung Injury

NOT TO BE REPRODUCED

Cell Specific Toxic InjuryCell Specific Toxic Injury

Ciliated cells Ciliated cells -- NONO22 , SO, SO22 , O, O33

Mucous cells Mucous cells -- smoking, SOsmoking, SO22

NonciliatedNonciliated (Clara) cells/olfactory (Clara) cells/olfactory epithelium epithelium -- metabolically activated agents metabolically activated agents e.g. 3 e.g. 3 methylindolemethylindoleEndothelial cells Endothelial cells –– pyrrolizidinepyrrolizidine alkaloids, alkaloids, oxygen, oxygen, endotoxinendotoxinEpithelial type I cells Epithelial type I cells –– paraquatparaquatMacrophages Macrophages -- silicasilica

NOT TO BE REPRODUCED

Mechanisms of ToxicityMechanisms of Toxicity

Direct acting e.g., oxygen (high Direct acting e.g., oxygen (high concconc))Indirect actingIndirect acting

Metabolic activation e.g., 3 Metabolic activation e.g., 3 methylindolemethylindoleCyclic oxidation of parent compound Cyclic oxidation of parent compound egeg, , paraquatparaquatImmune mediated e.g., asthmaImmune mediated e.g., asthma

XenobioticXenobiotic interaction e.g., with oxygen interaction e.g., with oxygen

NOT TO BE REPRODUCED

Mechanisms of ToxicityMechanisms of Toxicity

NOT TO BE REPRODUCED

EtiologyEtiology33--methylindole: cattle, sheep, goatsmethylindole: cattle, sheep, goats44--ipomeanol: cattleipomeanol: cattlePerilla frutescensPerilla frutescens ketone: cattle, horsesketone: cattle, horsesPyrrolizidine alkaloids: cattle, horses Pyrrolizidine alkaloids: cattle, horses swine, sheep (mainly hepatic)swine, sheep (mainly hepatic)

Paraquat: dogs, cats, manParaquat: dogs, cats, manChemotherapeutic agents e.g. Chemotherapeutic agents e.g. bleomycinbleomycin

Pathology: interstitial pneumoniaPathology: interstitial pneumonia

Chemically Induced (Toxic)Chemically Induced (Toxic)Pulmonary InjuryPulmonary Injury

NOT TO BE REPRODUCED

Smoke InhalationSmoke Inhalation

Injury due toInjury due toThermal injury (URT)Thermal injury (URT)Chemical injury (LRT)Chemical injury (LRT)

LesionsLesionsLaryngeal/tracheal necrosis with fibrinLaryngeal/tracheal necrosis with fibrinDelayed pulmonary edemaDelayed pulmonary edemaSoot particles often seenSoot particles often seen

NOT TO BE REPRODUCED

ImmuneImmune--Mediated DiseasesMediated Diseases

Type I hypersensitivity: IgE mediatedType I hypersensitivity: IgE mediatedAsthma or anaphylaxisAsthma or anaphylaxis

Type III hypersensitivity : IgE mediatedType III hypersensitivity : IgE mediatedHypersensitivity Hypersensitivity ““pneumonitispneumonitis””

Type IV hypersensitivity : cell mediatedType IV hypersensitivity : cell mediatedGranulomatous diseaseGranulomatous disease

NOT TO BE REPRODUCED

AnaphylaxisAnaphylaxis

Species: cattle, horses, catsSpecies: cattle, horses, catsType I hypersensitivityType I hypersensitivityEtiologyEtiology

Iatrogenic: antibiotic injection, vaccinationIatrogenic: antibiotic injection, vaccinationRuptured liver abscess, etcRuptured liver abscess, etc

PathologyPathologyPulmonary edema with eosinophilsPulmonary edema with eosinophilsAirway constrictionAirway constriction

NOT TO BE REPRODUCED

Hypersensitivity PneumoniasHypersensitivity Pneumonias

Equine Allergic Equine Allergic PneumonitisPneumonitis/Chronic /Chronic Obstructive Pulmonary Disease (COPD) Obstructive Pulmonary Disease (COPD) –– types types I and III hypersensitivityI and III hypersensitivityType III hypersensitivity to organic antigens e.g. Type III hypersensitivity to organic antigens e.g. humans, cattlehumans, cattleDrug hypersensitivityDrug hypersensitivity

NOT TO BE REPRODUCED

Parasitic HypersensitivityParasitic Hypersensitivity

Parasitic infection in cattleParasitic infection in cattleDictyocaulusDictyocaulus vivaparousvivaparous

Parasitic infectionParasitic infection in dogsin dogsDirofilariaDirofilaria immitis immitis larvaelarvae

NOT TO BE REPRODUCED

Primary Lung NeoplasiaPrimary Lung Neoplasia

Rather rare in domestic animalsRather rare in domestic animalsGenerally in old animalsGenerally in old animalsMost epithelialMost epithelialGenerally solitary Generally solitary Clinical signsClinical signsDiagnosisDiagnosis

NOT TO BE REPRODUCED

Primary neoplasiaPrimary neoplasiaEpithelial Epithelial -- carcinomascarcinomasMesenchymal tumorsMesenchymal tumorsLymphomatoid granulomatosisLymphomatoid granulomatosis

NeoplasiaNeoplasia

NOT TO BE REPRODUCED

From Lopez (2006)From Lopez (2006)

NOT TO BE REPRODUCED

NeoplasiaNeoplasia -- CarcinomaCarcinoma

NOT TO BE REPRODUCED

NeoplasiaNeoplasia –– Carcinoma Carcinoma -- DogDog

NOT TO BE REPRODUCED

Secondary (metastatic) neoplasiaSecondary (metastatic) neoplasiaMore commonMore commonAdenocarcinomaAdenocarcinoma (mammary, thyroid)(mammary, thyroid)Osteosarcoma /chondrosarcomaOsteosarcoma /chondrosarcomaHemangiosarcomaHemangiosarcomaLymphosarcomaLymphosarcomaHistiocyticHistiocytic sarcomasarcoma

NeoplasiaNeoplasia

NOT TO BE REPRODUCED

Pathology of Respiratory SystemPathology of Respiratory System

Respiratory injury and responseRespiratory injury and responseUpper respiratory tractUpper respiratory tractLower respiratory tract (lung)Lower respiratory tract (lung)Pleura and thoracic cavityPleura and thoracic cavity

NOT TO BE REPRODUCED

Diseases of the Pleura and Diseases of the Pleura and Thoracic CavityThoracic Cavity

Pleuritis/PyothoraxPleuritis/PyothoraxHydroHydro--, Chylo, Chylo--, Hemo, Hemo--thoraxthoraxPneumothoraxPneumothoraxMineralizationMineralizationNeoplasticNeoplastic -- mesotheliomamesothelioma

NOT TO BE REPRODUCED

UremicUremic MineralizationMineralization

NOT TO BE REPRODUCED

Pleuritis/PyothoraxPleuritis/Pyothorax

PrimaryPrimarySecondarySecondary

Extension of pneumoniaExtension of pneumoniaRuptured lung abscessRuptured lung abscessTraumatic penetrationTraumatic penetration

Bite woundBite woundAwnAwn

NOT TO BE REPRODUCED

NocardiosisNocardiosis -- CatCat

NOT TO BE REPRODUCED