resp notes Q and A 2 Flashcards
Consider the three main routes by which bacteria enter the pleural cavity.
What additional lesions might be observed at necropsy, to suggest the likely route of infection?
- Hematogenous: there may be fibrinous exudates on other serosal surfaces: pericarditis, peritonitis, polyarthritis, meningitis.
- External penetrating injury: there may be traumatic lesions in the chest wall.
- Extension from an underlying lung lesion: the primary lesion in the lung (e.g. bronchopneumonia) should be visible, with careful inspection.
Which two pleural conditions are most likely in a cat with hypertrophic cardiomyopathy?
Hydrothorax or chylothorax.
Creamy pleural exudates could represent chylothorax or pyothorax. How would laboratory analysis of the fluid distinguish these?
- Chylothorax: lymphocytes, and higher triglyceride concentration in pleural fluid vs serum.
- Pyothorax: neutrophils.
How does the reason for atelectasis and dyspnea differ in pneumothorax compared to hydrothorax?
- Hydrothorax: the simple presence of fluid leaves less room in the chest for lungs to expand. The physical presence of the fluid causes the atelectasis.
- Pneumothorax ruins the ability to expand the lungs: expansion of the chest wall is now inefficient in creating a negative intrathoracic pressure, and the lungs don’t inflate as much as normal.
What are the three related bacteria that commonly cause bronchopneumonia in cattle?
Mannheimia haemolytica, Bibersteinia trehalosi, Histophilus somni, Pasteurella multocida.
What pathogen causes caseonecrotic bronchopneumonia with polyarthritis in cattle?
Mycoplasma bovis.
Histophilus somni causes polyarthritis and bronchopneumonia, without foci of caseous necrosis.
List two causes or diseases resulting in diffuse interstitial pneumonia in cattle.
- Idiopathic interstitial pneumonia, feedlot cattle.
- Toxic lung disease such as 3-methylindole in pastured cattle (fog fever).
- BRSV.
- Endotoxemia or septicemia.
- Larval migration (Dicytocaulus, Ascaris).
What are the two reportable (immediately notifiable) lung diseases of cattle?
Bovine tuberculosis.
Contagious bovine pleuropneumonia.
List three different lung lesions resulting from liver abscesses.
- Embolic pneumonia with multiple lung abscesses
- Acute diffuse interstitial pneumonia
- Pulmonary embolism: thrombi filling pulmonary arteries
What is the specific location of Dictyocaulus viviparus in adults?
Bronchial lumen, in caudal lobes.
Describe the gross lesions resulting from respiratory infection with bovine herpesvirus-1.
Fibrinous and erosive rhinotracheitis.
Describe the two different manifestations of Histophilus somni infection in the respiratory tract of feedlot cattle.
Cranioventral bronchopneumonia, fibrinous pleuritis.
Bovine:
What disease causes erosions in the nasal cavity and trachea?
What disease causes erosions in the oral cavity and esophagus?
IBR (BHV-1) causes respiratory lesions. BVDV causes lesions of the digestive system. The exception is systemic BHV-1 infection (only in calves <2 months old), which can include esophageal and rumental lesions).
What is the most likely specific cause of single focal soft white nodules in the dorsocaudal lung and bronchial lymph node of a cow?
Mycobacterium bovis (bovine tuberculosis). Lung cancer could cause this lesion in dogs and cats but is so rare in cattle that you will never see a case.
Describe the pathogenesis of 3-methylindole toxicity in cattle.
Tryptophan in feed is converted by rumen microbes to 3-methylindole, which is converted by type II pneumocytes to reactive intermediates that cause lung injury.
