This document provides a differential diagnosis for dyspnea and tachypnea in dogs and cats. It lists potential physiological, upper airway, lower airway, restrictive, systemic, and toxic causes. Physiological causes include exercise, fear, heat, and pain. Upper airway disorders involve the cervical trachea, pharynx, larynx, and nasal passages. Lower airway issues affect the thoracic trachea, bronchi, and pulmonary parenchyma. Restrictive disorders relate to the diaphragm, masses, tumors, and chest wall abnormalities. Systemic factors involve neurologic diseases, metabolic derangements, and shock. Various drugs and toxins can also induce respiratory signs.

1. Veterinary Teaching Hospital
Airlangga University
Small Animal Practice
Differential
Diagnose

2. • Dyspnea, defined as difficult or labored
breathing, can be observed in dogs or cats as
forced or difficult breathing, particularly when
the dog or cat is at rest.
• Tachypnea, defined as increased of respiratory
rate or excessive rapid breathing.

3. Physiological causes
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Exercise
Fear
High ambient temperature
Pain

4. Upper airways disorders
• Cervical tracheal disease
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Extraluminal compression
Foreign body
Hypoplasia/stenosis
Neoplasia
• Extraluminal
• Intraluminal [Adenocarcinoma; Chondroma;
Chondrosarcoma; Leiomyoma; Lymphoma;
Osteochondroma; Osteosarcoma; Plasmacytoma; Polyps;
Rhabdomyosarcoma; Squamous cell carcinoma]
– Tracheal collapse*
– Trauma

5. Upper airways disorders
• Pharyngeal disease
– Elongated or oedematous soft palate* (Dog)
– Enlarged tonsils*
• Laryngeal disease
– Everted saccules* (Dog)
– Laryngeal paralysis* (Dog)
– Neoplasia
– Oedema*

6. Upper airways disorders
• Nasal disease, e.g.
– Aspergillosis
– Foreign body*
– Inflammatory disease*
– Nasopharyngeal polyp
– Neoplasia
– Stenotic nares

7. Lower airways disorders
• Thoracic tracheal disease, e.g.
– Extraluminal compression
– Foreign body
– Hypoplasia/stenosis
– Neoplasia (extra- or intraluminal)
– Tracheal collapse*
– Trauma

8. Lower airways disorders
• Bronchial disease
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Bronchiectasis
Broncho-oesophageal fistula
Chronic bronchitis* (Dog)
Cystic-bullous lung disease, e.g. secondary to
emphysema
– Eosinophilic bronchitis*
– Extraluminal compression
• Enlarged left atrium
• Hilar lymphadenopathy, e.g. [Fungal disease; Granulomatous
disease; Neoplasia]
• Neoplasia

9. Lower airways disorders
• Bronchial disease
– Feline asthma* (Cat)
– Foreign body
– Lungworm
– Neoplasia
– Primary ciliary dyskinesia

10. Lower airways disorders
• Pulmonary parenchymal disease
– Foreign body
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Abscess
Chronic pulmonary fibrosis
Eosinophilic bronchopneumonopathy
Eosinophilic pneumonitis
Eosinophilic pulmonary granulomatosis
Hilar lymph node enlargement
Inhalation pneumonia
– Idiopathic pulmonary fibrosis
– Inflammatory disease
– Irritating gases

11. Lower airways disorders
• Pulmonary parenchymal
– Near drowning
– Neoplasia*
– Paraquat toxicity
– Pneumonia/infectious disease*
• Bacterial, e.g. [Bordetella bronchiseptica;
Chlamydophila psittaci; E. coli; Klebsiella pneumoniae;
Mycobacterium spp; Mycoplasma pneumoniae;
Pasteurellosis]

12. Lower airways disorders
• Parenchymal
– Endogenous lipid pneumonia
– Fungal, e.g. [Aspergillosis; Blastomycosis;
Coccidioidomycosis; Cryptococcosis; Histoplasmosis;
Pneumocystis]
– Parasitic, e.g. [Aelurostrongylus abstrusus; Angiostrongylus
vasorum; Capillaria aerophila; Crenosoma vulpis;
Oslerusspp; Paragonimus kellicotti; Visceral larva migrans]
– Protozoal, e.g. [Toxoplasmosis; Rickettsial]
– Viral, e.g. [Canine distemper virus* (Dog); Feline
calicivirus* (Cat); Feline immunodeficiency virus* (Cat);
Feline leukaemia virus* (Cat)]

13. Lower airways disorders
• Parenchymal
– Pulmonary oedema
– Pulmonary thromboembolism, e.g.
• Cardiac disease
• Heartworm disease
• Hyperadrenocorticism
– Smoke inhalation
– Trauma, e.g.
• Pulmonary contusions
• Pulmonary haemorrhage

14. Restrictive Disorders
• Diaphragmatic hernia, e.g.
– Peritoneopericardial diaphragmatic hernia
– Traumatic*
• Large intra-abdominal mass
• Neoplasia
– Mediastinal
– Thoracic wall
• Pickwickian syndrome (extreme obesity)
• Pleural effusion*
• Pneumothorax*

15. Restrictive Disorders
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Severe ascites
Severe gastric distension
Severe hepatomegaly
Thoracic wall abnormalities, e.g.
– Neoplasia
– Pectus excavatum
– Trauma*

16. Systemic and miscellaneous disorders
• Anaemia*
• Central neurological disease causing damage to
respiratory centres, e.g.
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Head trauma
Hyperthermia*
Hyperthyroidism* (Cat)
Hypoxia*
Metabolic acidosis
Neuromuscular weakness, e.g. polyradiculoneuritis
Shock/hypovolaemia*

17. Systemic and miscellaneous disorders
• Acute respiratory distress syndrome
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Aspiration of acidic substances
Drug reaction
Inhalation injury
Lung lobe torsion
Multiple transfusions
Pancreatitis
Sepsis
Shock
Surgery
Trauma

18. Drugs/toxins
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Benzalkonium chloride
Blue-green algae
Dichlorophen
Ibuprofen
Metaldehyde
Naproxen
Paracetamol (methaemoglobinaemia)
Paraquat
Salbutamol
Strychnine
Terfenadine

19. Thank you….