Respiratory Pathology I and II Flashcards
the upper resp tract
Name the main protective mechanisms of the lungs
- mucociliary apparatus –> for physical filtration
- secretion of defensins, antioxidants, collectins, IgA, lactoferrin –> for the innate and acquired immune systems
- alveolar macrophages and other immune cells
- high P450 enzyme activity, sensitive to toxic metabolites
Define choanal atresia
no communication between the nasal cavity and the nasopharynx
Nasal bot fact file
Oestris ovis flies
sheep are primary hosts
affected animals lose weight and BCS
may invade through cribiform plate and cause encephalitis
Define rhinitis and list common causes. Name the types of rhinitis
inflammation and irritation of the MM of the nose
causes depend on breed, commonly viral, fungal, bacterial, tumours, foreign bodies, etc…
Types of Rhinits :
- pseudomembranous (no ulceration)
- fibronecrotic (firm adheration of fibrin)
- acute (loss of cilia, hyperplasia, inflammatory cells present)
- chronic (epithelial attenuation or metaplasia, polyps, fibrosis. classified based on inflammatory infiltrate)
- allergic (sporadic and seasonal)
- toxic
- atrophic (seen in pigs, caused by strains of Bordetella and Pasteurella
Define the guttural pouch in horses and explain why it can be a problem
Guttural pouch is a diverticulum of the auditory tube in horses. can develop empyema (liquid build uo) or tympany (air build up) and affect nearby cranial nerves
List possible pathologies of the larynx
laryngeal oedema
laryngitis
laryngeal paralysis in horses
laryngeal paralysis in dogs
laryngeal chondritis (ulceration at rostral margin of arytenoid cartilage)
Name common pathological findings of the trachea
[ froth is a common PM finding in the trachea, especially in herbivores ]
brachycephalic airway syndrome
tracheal collapse
tracheal oedema and haemorrhage syndrome
Define pneumothorax and list the different types
Air or gas in the pleura that causes atelectasis due to a loss of negative pressure.
spontaneous, may be 1st or 2nd. due to rupture of pulmonary bullae or underlying lung disease
traumatic, accidental puncture of the thoracic wall and visceral pleura
Define hydrothorax
clear, watery transudate (colourless to light yellow) in the pleural and thoracic cavity.
low in protein and cell count
caused by increased venous pressure, lymphatic obstruction and hypoproteinaemia
chronically, makes pleura opaque with fibrosis and hyperplasia
Define chylothorax
accumulation of milky, high triglyceride lymph fluid in pleura and thoracic cavity, often idiopathic
Define haemothorax
blood in the pleura, usually traumatic
Define pleuritis and explain the different types
inflammation of the pleura. often caused by infectious agents that arrive in the pleura via blood or from lung penetrating lesions.
fibrinous -> loose strands or large plaques of fibrin with lakes of fluid
pyothorax -> creamy, suppurative exudate
chronic -> lots of adhesions but seldom affects lung function
Define pulmonary hypoplasia
reduced lung weight, often also resulting in reduced numbers of alveoli. normally caused by conditions that compress the lungs
Define atelectasis
incomplete expansion of the lungs, making it look darker and sunken with a fleshy-firm texture. will not float in water.
may be obstructive (airway obstruction) or compressive (space-occupying lesions)
Define emphysema
air filled spaces in the connective tissue and parenchyma, called blebs and bullae respectively. grossly, lung is pale and puffy
alveolar -> abnormal, permanent enlargement of alveoli due to septa destruction. no fibrosis.
interstitial -> subpleural and within interlobular septa. means there is air in the connective tissue and lymphatics
Define and describe a lung oedema
air spaces in the lung are filled with liquid. lungs are wet, heavy, collapsed and ooze fluid when cut open.
causes include hydrostatic pressure, increased permeability, etc…
Define a pulmonary thromboembolism (PTE)
An embolism that has ended up in the pulmonary tract.
in situ thrombi = microscopic, dissolve by themselves
embolic thrombi = grossly visible, end up in the lungs from veins
Define lung infarction
The infarction of a segment of the lung due to blockage of the blood supply. rare, due to dual blood supply acting as a natural back-up.
Name the different types of haemorrhages found in the lugns
pulmonary haemorrhage : multifocal to patchy, severe can cause haemoptysis or sudden death, common causes are abscesses eroding into vessels
equine exercise induced pulmonary haemorrhage (EIPH) : common in racehorses, pathogenesis incompletely understood
Define pulmonary hypertension
when pulmonary arterial pressure is >30 mmHg, often due to vascular remodelling or an imbalance between dilation and constriction factors
lesions occur with secondary hypertension
Define and explain airway disease
airway disease is the specific targeting of airways, due to a combination of necrosis and inflammation.
CS : coughing, impaired defences, failure to ventilate alveoli
Define bronchitis and explain the pathogenesis
Bronchitis is the inflammation of the bronchi, caused by viral, bacterial, irritants, allergens, etc…
Pathogenesis : exudate -> sloughing of ciliated cells -> epithelial attenuation -> necrosis -> (fibrosis)
if stimulus is removed, there is healing
Define bronchiectasis and describe the pathogenesis
Bronchiectasis is the permanent dilation of bronchi due to chronic obstruction and infection. Bronchi are unable to clear exudates from airways and cannot function.
Pathogenesis : destruction of walls -> luminal obstruction -> proteases from inflammatory cells weaken airway walls -> wall is pulled wider and wider -> may eventually inspissate
Define bronchopneumoniaa
An exudative lesion of the broncho-alevolar junction, indicating an airborne entry of pathogens and/or foreign material
grossly : consolidation, lungs are dark red-purple, may ooze fluid, firm texture
lobular = affected and unaffected lobular, slow expansion
lobar = entire lobe consolidated, often with pleuritis
resolves is the agent is destroyed by the immune system
sequestrum includes a mass of necrotic lung, purulent exudate, fibrous capsule presence, foul smell, firm texture and grey-red in colour
Interstitial and bronchointerstitial disease definition and causes
Damage and inflammation of the septa with a wide range of lesions
non-infectious causes : anaphylaxis, hypersensitivity, interstitial lung disease, neonatal distress, lipid pneumonia, alveolar filling disorders
Name the different patterns of types of interstitial disease
eosinophilic interstitial pneumonia - see lymphoma and carcinoma commonly, seldom fatal, responds to steroids
eosinophilic pulmonary granulomatosis - CS include cough and nodular lesions with eosinophils/macrophages/fibrosis
acute interstitial lung disease of cattle - high fatality, CS includes open mouth breathing and dyspnoea. see lobular lesions in lung, red, rubbery, fail to collapse. cause unknown
donkey pulmonary fibrosis - common, incidental most likely, cause unknown
idiopathic pulmonary fibrosis of cats - uncommon, cause unknown, see patchy lesions of septa thickened by smooth muscle and fibrosis
