L7: Pathology Of The Resp. System (Abbott) Flashcards
Mucociliary escalator
- made up of ciliated epithelium + goblet cells
- traps and removes foreign particles
- target of most viruses
URT Anomalies
- Cysts
- Ciliary dyskinesia (immotile cilia syndrome) –> chronic recurrent pneumonia, infertility
- Brachycephalic airway syndrome
- Tracheal collapse
Brachycephalic syndrome components**
- stenotic nares
- elongated soft palate
- everted laryngeal saccules
- hypoplastic trachea
-can –> laryngeal edema
Metabolic problems of URT
- calcification/metastatic mineralization –> gritty texture, raised firm plaques/streaks
- due to hypervit. D, renal failure, hypercalcemia of malignancy
Chars. Of Primary nasal tumors
- epithelial and mesenchymal
- dolicocephalic breeds
- usually benign
- CS and pathology similar to infectious rhinitis** (epistaxis, nasal d/c)
Ddx of primary nasal tumor
Infectious rhinitis**
FB
Fungal granuloma
Non-neoplastic masses of the URT**
- Polyps in the nasopharynx and eustachian tubes(cats)**
- CS: nasal d/c, sneeze, gag, phonation change
- may result from inner ear inflammation
- firm pedunculated nodules
Metastatic neoplasms of the URT
- LSA (cats)
- OSA
- Melanoma
- etc.
Describe nasal aspergillosis
White to tan, destroys architecture, locally infiltrative
Describe nasal adenocarcinoma
White to tan, irregular, infiltrative
Ddx: cancer, fungus
Describe nasal fibrosarcoma
- white/tan, homogenous, spongy, expansile, destroys bone
- football shape
Describe chondrosarcoma in URT
Red to pink, mottled, multinodular, gelatinous
Ddx: cryptococcus (would be more friable and irregular)
Viral URD in cats
-80% of cases = FHV or FCV
-FHV:
oral ulcers RARE*
Usually only URT involved
Infects epithelial cells of the resp. Tract
-FCV:
Less severe URT signs
Oral and nasal ulcerations common*
More commonly causes necrotizing bronchiolitis and bronchointerstitial pneumonia
More virulent strain causing disseminate hepatocellular necrosis and mild inflammatory infiltration
Pneumonia more common
-Chlamydophila causes major conjunctivitis
CIRD causes
Parainfluenza virus Adenovirus Bordetella Mycoplasma Etc.
Canine parainfluenza virus chars.
- causes minimal rhinitis, tracheitis, bronchitis, interstitial pneumonia
- replicates in resp. Epithelial cells and macs
- concurrent infection w/ distemper, adenovirus
Chars. Of Canine Adenovirus
- replicates in bronchiolar epithelium**
- produces a severe necrotizing and proliferative bronchitis and bronchiolitis**
Describe nasal aspergillosis
- necrotic center
- bone destruction
- friable
- tan to green/gray
- caseous
Common pathogenesis for most resp. Viruses***
- disrupt defense mechanism (infection epi cells and macs)
- loss of ciliated cells, epithelial lining, decreased mucous layer
- alter Ag presentation and cytokine release of macs
—> increased susceptibility to secondary infection***
Fungal URT pathogens
Rhinosporidium
Cryptococcus
Penicillium
Aspergillus
Describe rhinosporidiosis
- multinodular, red
- Df: adenocarcinoma, SCC, hemangiosarcoma
Key feature of oslerus osleri
Nodules at bifurcation of the trachea
CS: dry chronic cough
3 lung systems
- Conductive
- Transitional
- Exchange
Causes of mineralization of the lung
Chronic hypercalcemia due to uremia or hypervitaminosis D
Describe endogenous lipid pneumonia
Tan, expansive, greasy, friable
Cause: trauma or free radicals cause cascading effect of cell necrosis and lipid release from cell membranes
Aspiration of hairball medication –>
EXOGENOUS lipid pneumonia
Primary epithelial neoplasms of the lung
- rare, but almost always malignant
- older animals
- can met to LN, airways, exfoliative carcinomatosis
- Bronchogenic carcinoma (most common in dogs)
- Bronchiolar carcinoma
- Alveolar carcinoma
- Multipotent: Bronchioalveolar carcinoma
- Bronchiolar gland: Adenocarcinoma (most common in cats)
Describe primary epithelial neoplasms
Single large nodule, white/tan/gray, smooth to umbilicated, invasive and expansive
Primary MESENCHYMAL tumors of the lung
OSA
Chondrosarcoma
Granular cell tumor
Undifferentiated sarcoma
Metastatic neoplasms of the lung
OSA
HSA
Mammary gland carcinoma
Blood borne mets
Pulmonary carcinoma can met to the digits in cats
Primary complaint = lameness, without respiratory signs**
Describe HSA mets in lung
Multifocal raised nodules, red to dark red, bleed if cut
Feline Asthma
- Type I hypersensitivity –> Recurrent episodes of bronchoconstriction, edema and inc. mucous production
- CS: periodic cough, dyspnea
- idiopathic
- lower airway dz
Causes of viral pneumonia in dogs
Distemper Parainfluenza CAV-2 CHV-1 Influenza
Pathogenesis of Canine Distemper***
1) oronasal route of infection
2) replicates in lymphoid tissues/tonsils and alveolar macs
3) migrates to lungs hematogenously and causes DIFFUSE INTERSTITAL PNEUMONIA**
5) affects resp/aimentary/urogenital tract –> CS –> subacute encephalitis –> death or recovery
- synergistic concurrent infection w/ CPiV, CAV2, Bordetella
- affects URT and LRT
URT lesions of distemper
Rhinitis (mucopurulent and erosive) Conjunctivitis Pharyngitis Tracheitis Bronchitis
LRT lesions of distemper
Bronchitis
Bronchiolitis
Bronchointerstitial pneumonia (+/- 2ary bacterial pneumonia)
Non-respiratory lesions of distemper**
Gastroenteritis Lymphoid atrophy** Dermatitis, Hyperkeratosis Conjunctivitis, Retinitis Cystitis, urethritis Encephalomyelitis** Ameloblast necrosis, enamel hypoplasia
Dx of distemper
- necropsy
- histo
- Ag detection in lung, stomach, urinary bladder**
Bronchopneumonia MOA***
Found in cranial lung lobes as it follows path of least resistance once mucocilliary escalator gone. Causes local lesions
Route of exposure: aspiration or inhalation
Chars. Of CHV-1**
- generalized dz**
- multifocal hemorrhage and necrosis**
- rhinotracheitis in older dogs
- 2ary bronchopneumonia
Bacterial pneumonia
- usually BRONCHOPNEUMONIA (cranioventral, inhalation, suppurative, granulomatous)
- can be EMBOLIC to INTERSTITIAL (diffuse, multifocal)
CHars. Of INTERSTITAL pneumonia***
Diffuse
Non-collapsing lungs
Hematogenous spread (most likely)
Causes of bacterial pneumonia
Bordetella
Mycobacterium
Mycoplasma
Strep, etc.
Chars. Of mycotic pneumonia
Multifocal Granulomatous Inhaled or hematogenous spread Tracheobronchial LN enlarged Nodular to multinodular Tan Caseous Mottled
Blasto, Histo, Coccidiodes, Pneumocystis, Cryptococcus
Mycetoma
A mycotic lesion that looks like a tumor
Parasitic pneumonia
1) Heartworm –> endarteritis, possibly hypersensitivity, lung infarcts
- can cause granulomatous pneumonia
2) Filaroides hirthi (dogs)
- lung worms IN bronchioles and alveoli
- eosinophilic nodules
3) Toxoplasma –> interstitial pneumonia via hematogenous
4) Aelurostrongylus abstrusus (cat) –> multifocal subpleural granulomas, snail IH
5) Paragonimus kellicotti –> multiple large cysts, pneumothorax, dyspnea, PTE, crayfish IH for flukes
Toxic pneumonia causes
1) Paraquat
- activated by pulmonary enzymes
- causes necrosis of alveolar cells, diffuse interstitial fibrosis with hematogenous spread, diffuse lung enlargement
2) uremia
3) antineoplastic human drugs
Ruptured lymph vessel –> chylothorax
:)
Nocardia, Actinomyces, Bacteroides –> pyothorax, sulfur granules
:)
Fxs of Upper Resp. System**
- filtering of inhaled debris
- warming of air
- removal of inhaled particles (mucociliary escalator)
