The Dyspnoeic Dog and Cat Flashcards
Classes of disease causing dyspnoea…
Obstructive Loss of thoracic capacity Pulmonary parenchyma disease Pulmonary vascular disease Metabolic causes
In what situations does obstructive disease cause dyspnoea?
- When it causes significant obstruction of the LRT
e. g. brachycephalic - When it causes obstruction of a large number of small airways of the LRT e.g. asthma
Give examples of obstructive causes of dyspnoea…
Nasal obstruction - Rhinitis - FB - Neoplasia - Polyp Trauma Foreign body Laryngeal paralysis Tracheal collapse Brachycephalic obstructive airway disease - Soft palate - Stenotic nares - Laryngeal collapse Fillaroides Extralumenal mass lesions Asthma
When does loss of thoracic capacity create dyspnoea?
When space occupied by the lungs is compromised e.g. fluid/air in pleural space/organ displacement/neoplasia
Differential diagnosis for loss of thoracic capacity as a cause of dyspnoea?
Pleural effusion Pneumothorax Neoplasia Ruptured diaphragm Cranial abdominal organ displacement PPDH (pericardio-peritoneo-diaphragmatic hernia)
What is PPDH (pericardio-peritoneo-diaphragmatic hernia)?
Congenital abnormality where the peritoneal cavity and pericardial sac remain continuous in later life
Why does pulmonary parenchymal disease cause dyspneoa?
Compromises gas exchange
e.g. diseases of alveolar wall and interstitium, alveolar flooding, abnormal pulmonary vascular supply
Differential diagnosis for pulmonary parenchymal disease as a cause of dyspneoa?
Bronchopneumonia Pulmonary oedema - Cardiogenic Neoplasia Pulmonary haemorrhage Pulmonary fibrosis LRT parasites Abnormal pulmonary vascular supply
Pulmonary vascular causes of dyspneoa..
Pulmonary hypertension
- Compromises pulmonary perfusion due to increased right ventricular afterload
Pulmonary thromboembolic disease
- Under perfusion of areas of lung
- Depends on degree of obstruction/vessel involved
Non-respiratory causes of dyspnoea…
Hyperthermia Obesity Excitement/exercise Anaemia Acidosis CNS disease Endocrine disease Neuromuscular disease Thoracic wall abnormalities
Initial assessment of dyspnoeic patient (sounds you would hear)
Differentiate between types of dyspneoa:
Obstructive = noise and increased respiratory effort
- Laryngeal paralysis usually larger dogs
- Tracheal collapse usually smaller dogs
Pleural = decreased noise on auscultation
Pulmonary = increased respiratory noise (wheezles and crackles)
What must you think about first when presented with a dyspnoeic patient?
Is it an emergency?
URT obstruction
- Establish airway
- Anaesthesia and intubation
- Tracheostomy
Pleural
- Effusions/pneumothorax
- Thoracocentesis
How is the cause of dyspnoea best diagnosed?
Thoracic radiography
Haematology and biochemistry
BAL
How does thoracic radiography help in diagnosing the dyspnoeic patient?
Best method of confirming the involvement of lung parenchyma
- Pulmonary disease = alveolar pattern
- Pleural disease = white out
- Absence = obstructive
How can haematology and biochemistry help in diagnosing the dyspnoeic patient?
Look for evidence of inflammatory disease and discriminate between predominantly eosinophilic inflammation (asthma, pulmonary infiltrate with eosinophils, parasitism) and neutrophilic inflammation
