Respiratory Flashcards by Gethin Edwards

What are the airway defence mechanisms? (6)

Aerodynamic filtration
Mucociliary escalator
Antibacterial agents - lysozymes lactoferrins
IgA
Protective reflexes
Leucocytes

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How does aerodynamic filtration occur?

Coiled turbinates = turbulence = particles >10um caught in mucosa
Bronchi filters particles >3um

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How does mucociliary escalator work?

mucus carpet + cilia beating
physical barrier, prevents dehydration, dilutes soluble gases + Contains antibacterials

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What are the factors affecting escalator?

Change in viscosity (Temp, dehydration, inflammation)
Injury to epithelium (trauma, infection, chronic irritation => Epithelial metaplasia)

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What are the protective reflexes?

Cough
sneeze

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What are the protective leukocytes?

Macrophages
neutrophils

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How does viral infection affect epithelial cells?

1.Impaired function
2.Cell death + inflammation
3.Poor mucociliary clearance
4.2* bacterial infection
5. Purulent discharge and neutrophils
6.Cell mediated immunity + Antibodies => healing

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Diseases of upper airway.
What are the developmental abnormalities?

1.Cleft palate
2.Guttural pouch tympany
3.Brachyocephalic airway syndrome

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Diseases of upper airway.
What are the circulatory disturbances?

1.Epistaxis (blood from nares) - causes = inflm, trauma, neoplasia, clotting defects

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Diseases of upper airway.
What are the inflammatory conditions?

1.Acute inflammation
2.Chronic inflammation
3.URT infection

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What are the 5 signs of inflammation?

Redness
Swelling
Heat
pain
Loss of function

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What is a polyp?

a growth of tissue (seen in cats and horses), if not removed will cause chronic inflammation

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What are the causes of airway inflammation?

irritants
foreign bodies
parasites
infections - viral, fungal, bacterial

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What is a viral, bacterial and fungal URT infection?

Viral = IBR
Bacterial = Strangles - guttural pouch empyema
Fungal = Aspergillus fumigatis

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Larynx + trachea.
What are the Developmental abnormalities?

Hypoplastic trachea (young brachy dogs) - decreased tracheal diameter
Tracheal collapse (Minature + toy breeds) - flattening of cartilage rings
= dyspnoea

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Larynx + trachea.
What are the Degenerative diseases?

Laryngeal paralysis - choke chain trauma - damage to recurrent laryngeal nerve = atrophy of cricoarytenoid muscles
Equine laryngeal hemiplegia (roaring) - atrophy of LEFT cricoarytenoid M.

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Larynx + trachea.
What are the Circulatory disturbances?

Laryngeal oedema - causes = local trauma intubation, irritants(smoke), acute respiratory infections, chondritis, allergic reactions

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Larynx + trachea.
What are the Inflammatory diseases?

Tracheitis/laryngitis

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Why are bronchioles vulnerable to damage?

Lack supporting cartilage
few cilia
no mucus

What is bronchiolitis obliterans?

1.loss of epithelium + attachment of exudate
2.exudate infiltrated by WBCs then fibroblasts = polyp formation = lesion in bronchiolar lumen

What does chronic bronchitis/bronchiolitis lead to?

-increased mucus production - goblet cell + gland hyperplasia + goblet cell metaplasia
-Thickening of mucosa - epithelial + Smooth M. hyperplasia, inflammatory cells+fibrosis
-airway obstruction = dyspnoea, collapse, decreased blood oxygenation

What are the causes of chronic bronchitis?

1.Cattle lungworm - dictyocaulus viviparus - larval migration = blockage of bronchioles
-adult worm = migration = increase mucus + thickening of mucosa
2.Recurrent airway obstruction (Horse) - type iii hypersensitivity to allergens in mouldy hay = increased mucus + mucosa thickening

What are the clinical signs of recurrent airway obstruction?

Cough
Mucopurulent exudate
Exercise intolerance
Forceful expiration = abdominal hypertrophy

What do the 2 types of pneumocytes do?

Type 1 = involved in the process of gas exchange between the alveoli and the capillaries
Type 2 =secretion of pulmonary surfactant + repair damage, can also differentiate to type 1 to replace lost type 1s as only type 2 can proliferate

Disease of lung parenchyma. What are the Developmental abnormalities?

Congenital melanosis - v rare

Disease of lung parenchyma. What are the Abnormalities of inflation?

1.Atelectasis - Incomplete distension of lung - lung collapse 2.Emphysema - Excessive inflation of lung

What are the causes of atelectasis?

i. Complete internal obstruction of airway ii. External compression of airway or lung iii. Pneumothorax (partial pressure vs elastic recoil) iv. Recumbancy (hypostatic atelectasis) in LAs v. Defective surfactant production (neonates)

What are the causes of emphysema?

i. Forced respiratory efforts – eg. pneumonia etc. ii. Obstructive airway disease (partial)

What are the consequences of emphysema?

1. loss of lung elasticity – early airway collapse + trapping of air (increased dead space) 2. loss of pulmonary capillaries – reduced alveolar perfusion 3. fibrosis of remaining alveolar walls (in horses) – inhibits gas exchange – reduced compliance (greater expiratory effort

Disease of lung parenchyma What are the circulatory disturbances?

A. Pulmonary oedema B. Pulmonary embolism C. Pulmonary haemorrhage

What are the 4 different types of embolisms?

1. Thromboemboli (sterile or infected) 2. Tumour cells - metastases 3. Fat 4. Air Infarction if block a major vessel

What are the common causes of infected thromboemboli?

a) Right heart bacterial endocarditis b) Joint / navel infections c) Liver abscesses

What are the causes if pulmonary haemorrhage?

1. Pulmonary thromboembolism 2. Trauma (eg dog RTA) 3. Inflammation 4. Abscesses/Tumours (erode vessels) 5. Exercise induced pulmonary haemorrhage (in horses) - occurs in >75% of racehorses

Disease of the lung parenchyma What are the inflammatory conditions?

1. Bronchopneumonia 2. Interstitial pneumonia 3. Embolic pneumonia 4. Granulomatous pneumonia

What are the common causes, route of entry and distribution of bronchopneumonia?

a) Bacteria (incl mycoplasmas) b) Aspiration of food / GI contents c) Viruses Route of entry: Inhalation Distribution: Cranioventral

What are the common causes, route of entry and distribution of bronchopneumonia?

a) Bacteria (incl mycoplasmas) b) Aspiration of food / GI contents c) Viruses Route of entry: Inhalation Distribution: Cranioventral

How does Bovine pneumonic Mannheimiosis / Pasteurellosis (Shipping fever) occur in calves?

1. Recently weaned and assembled suckled calves 2. Stress, viral infections, + other factors impair respiratory defence mechanisms 3. M. haemolytica colonisation of lower respiratory tract 4. Lysis of alveolar macrophages and neutrophils 5. Release of WBC lysosomal contents. 6. Acute damage to bvs leads to fibrinous bronchopneumonia (+ toxaemia)

Causes, sites of injury, distribution and routes of entry of interstitial pneumonia?

Primary sites of injury: Alveolar epithelium + capillary endothelium Causes: viruses, bacteria, protozoa, helminths, irritants, allergy and toxins. Routes of entry: 1. Inhalation 2. Haematogenous Distribution = diffuse

What are the changes of chronic interstitial pneumonia?

1. Interstitial fibrosis 2. Chronic inflammatory cells 3. Persistence of type II pneumocytes 4. Smooth muscle hyperplasia

Causes, distribution and routes of entry of embolic pneumonia?

Causes = hepatic abscess, right heart valve endocarditis, joint/navel infections distribution = random disseminated foci routes of entry = haematogenous

What can embolic pneumonia lead to?

fibrosis + resolution chronic pneumonia rupture = pyothorax, pneumothorax

Causes, distribution and routes of entry of granulomatous pneumonia?

Causes = bacterial = mycobacteria - caseous Parasites = heartworm, viral (FIP), Fungi, Foreign bodies Distribution = variable, nodular foci Routes of entry = inhaled, haematogenous

What are the degenerative diseases of the pleura?

pneumothorax = loss of pressure in lungs

What are the causes of pneumothorax?

rupture of abscess perforation of lung/trachea penetration of thoracic wall

What are the circulatory disturbances of the pleura?

Pleural effusion - pneumothorax, hydrothorax, haemothorax, chylothorax, Pyothorax

What is the inflammatory conditions of the pleura?

Pleuritis - classified by type of exudate - fibrinous, suppurative, granulomatous

What are the causes of pleuritis?

pneumonia bacteraemia pyothorax FIP virus lung lobe torsion