PRACTICAL: Respiratory pathology 1 Flashcards
Common cause of hydrothorax
CHF - e.g. DCM
Causes - secondary atelectasis - 4
- Hydrothroax - Haemothorax - Pneumothorax - Pressure from an intrathoracic SOL
What does this show?
Interstitial emphysema (also some alveolar emphysema)
Define emphysema
lung condition where the alveoli are enlarged. causes breathlessness.
What abnormalities are shown in this lung?
- increased cellularity (inflammatory cells) - necrosis of alveolar walls - pink band = ‘hyaline membrane’ lining most alveoli
What happens when type 1 pneumocytes are lost in tryptophan poisoning?
allows a protein rich fluid to enter the alveoli from the blood. During respiration, this fluid dries out and becomes a membrane (‘hyaline’) lining the alveoli and preventing gas exchange. Animal dies of hypoxia and the interstitial emphysema (and also oedema) is a reflection of the laboured and rapid RR in an attempt to compensate for the hypoxia.
Name 4 features of the URT and LRT that prevent airborne infections
Nasal chambers, epiglottis, mucociliary escalator and alveolar macrophages.
What area of the respiratory tract is most vulnerable to infection? Why?
Bronchiolar-alveolar junction (absence of ciliated epithelium, narrow luminal diameter and turbulent and slow air flow).
What does this show?
Suppurative bronchopneumonia
How does suppurative bronchopneumonia lead to bronchiectasis?
An unresolving bronchopneumonia leads to plugging of airways with exudate. This causes more irritation with infiltration of more inflammatory cells across the wall of the airway. This progressively weakens the wall of the airway which dilates, aided by the absorption of air distal to the blockage. Finally when the bronchiolar wall repairs by fibrosis, the bronchiole remains in this permanently dilated state. This is bronchiectasis.
In this normal lung, what are structures 1 and 2?
1 = an alveolus 2 = a bronchiole (note the convoluted epithelium due to the contraction of the smooth muscle in the wall)
What is the blue asterisked material in the airway lumen?
Thickened (inspissated) mucus - produced by goblet cells
How might RAO/Heaves/ COPD be alleviated?
Move the horse outside, or reduce dust and/or mould/spores in the stable. Symptomatic therapy for bronchiolitis could include anti-inflammatory, bronchodilator and mucolytic drugs. Soak the hay to reduce the spores/use better quality hay with less dust/move to non-hay bedding (mats etc)
What is wrong with these lungs from a newborn animal?
Partial primary atelectasis – primary since they have never previously been inflated and partial as only some lobules are affected.
Causes - pulmonary oedema
Many possible causes. Cardiac failure Acute brain damage, Excessive fluid therapy Damage to pulmonary epithelium or endothelium such as with inhaled toxic gasses. NB Pulmonary oedema is also frequently seen at necropsy secondary to euthanasia with barbiturates.
What does this show?
pulmonary oedema
