Shannon Martinson http://people.upei.ca/smartinson/
Pathology of the Respiratory System 1: Introduction, Pathology of the Nasal Passages
Shannon Martinson, Jan 2017
http://people.upei.ca/smartinson/ VPM 222 Systemic Pathology
INTRODUCTION
López, A and Martinson SA. Respiratory System, Mediastinum and Pleura: In, Pathological Basis of Veterinary Disease, 6th Edition. Zachary Ed. Elsevier. 2017
• Dr. Paul Hanna is the coordinator for this course • The guidelines and calendar for VPM 222 are available at:
http://people.upei.ca/hanna • There are excellent tutorials and quizzes available at : • http://people.upei.ca/lopez
INTRODUCTION: STRUCTURE AND FUNCTION
Transitional
Exchange
Conducting
INTRODUCTION: STRUCTURE AND FUNCTION
Respiratory Tract Functions
GAS EXCHANGE
Phonation Temperature regulation
Blood Pressure regulation
Olfaction Acid-base Detoxification
Enzymes Hormones Inflammatory Mediators
Respiratory insult can affect any of these functions!
INTRODUCTION: NORMAL FLORA
Despite the presence of flora in the conducting system - the exchange system remains sterile
INTRODUCTION: DEFENCE MECHANISMS
Air filtration
Mucociliary clearance
Phagocytosis
Immunity
Detoxification
INTRODUCTION: DEFENCE MECHANISMS
Particle Deposition in the Respiratory Tract
10-2 microns
> 10 microns
2 microns
www.pinterest.com/pin/522276888018218157/
> 10 µm
INTRODUCTION: DEFENCE MECHANISMS
Air filtration
www.merckvetmanual.com
Mucociliary clearance
INTRODUCTION: DEFENCE MECHANISMS
10-2 µm
~ 100 cilia/cell ~ 1,000 strokes/minute
INTRODUCTION: DEFENCE MECHANISMS
Phagocytosis 2 microns
Pulmonary Alveolar Macrophage (PAMs)
How good are these defence mechanisms?
INTRODUCTION: DEFENCE MECHANISMS
0
20
40
60
80
100
120
140
0 2 4 8 12 24
% b
ac
teri
a in
lu
ng
Hours post aerosol
Bacterial Clearance after Aerosol
Normal
Virus
Viruses
Stress
Dehydration
Lung edema
Uremia
Ammonia
Immunodeficiency
INTRODUCTION: DEFENCE MECHANISMS
How good are these defence mechanism?
Impairment of defence mechanisms
THE CONDUCTING SYSTEM
www.merckvetmanual.com
• Nasal passages • Sinuses • Guttural pouches • Larynx • Trachea • Bronchi
NASAL CAVITY – NORMAL GROSS AND MICROSCOPIC ANATOMY
Squamous
Ciliated
Olfactory
Histology
Turbinates = Bone lined by mucosa: • Dorsal (nasal) • Ventral (maxillary) • Ethmoidal
Circulatory Disturbances
Rhinitis
Sinusitis
Sinus / Nasal tumours
Guttural Pouch Diseases
Laryngitis
Tracheobronchitis
DISORDERS OF THE CONDUCTING SYSTEM
DISORDERS OF THE CONDUCTING SYSTEM – CIRCULATORY DISTURBANCES
Nasal Congestion / Hyperemia
The submucosa is well-vascularized: congestion and hyperemia are common
DISORDERS OF THE CONDUCTING SYSTEM – CIRCULATORY DISTURBANCES
Nasal Hemorrhage • Bleeding from the nose Epistaxis
• Bleeding into the sputum (coughing up blood) Hemoptysis
http://calfology.com/library/wiki/epistaxis
DISORDERS OF THE CONDUCTING SYSTEM – CIRCULATORY DISTURBANCES
Nasal Hemorrhage • Bleeding from the nose Epistaxis
• Bleeding into the sputum (coughing up blood) Hemoptysis
Nasal Hemorrhage
DISORDERS OF THE CONDUCTING SYSTEM – CIRCULATORY DISTURBANCES
• Bleeding from the nose Epistaxis
• Bleeding into the sputum (coughing up blood) Hemoptysis
Other causes of epistaxis in horses: • Exercise induced pulmonary
hemorrhage (EIPH) • Guttural pouch mycosis • Ethmoidal hematoma • Nasal cysts
Differentials for epistaxis in any species:
• Trauma • Foreign body • Nasal neoplasia • Pulmonary hemorrhage
Progressive Ethmoidal Hematoma (PEH)
DISORDERS OF THE CONDUCTING SYSTEM – CIRCULATORY DISTURBANCES
• Horse with unilateral epistaxis • Can be seen with endoscopy • Surgical excision possible
• May recur
• Pedunculated mass on ethmoid • R/O tumor • Etiology unknown
DISORDERS OF THE CONDUCTING SYSTEM – NASAL INJURY AND REPAIR
• Degeneration
• Loss of attachment
• Necrosis
• Exfoliation
• Ciliated epithelium
• Highly vascularized
• Abundant glands
• Repair
• Pre-ciliated cells
• Mitosis
• Cell differentiation
• Healed epithelium
• Normal function
DISORDERS OF THE CONDUCTING SYSTEM - INFLAMMATION
Rhinitis Clinical signs: • Nasal discharge • Unilateral or bilateral
Classification according to exudate:
• Serous • Catarrhal (Mucus) • Suppurative (Purulent) • Fibrinous • Granulomatous
DISORDERS OF THE CONDUCTING SYSTEM - INFLAMMATION
Rhinitis
Mucopurulent
Virus + Bacteria
DISORDERS OF THE CONDUCTING SYSTEM - INFLAMMATION
Rhinitis
Purulent
Fibrinous
Granulomatous
Pyogenic bacteria
Fungus, FB, Allergies
Toxin producing bacteria
DISORDERS OF THE CONDUCTING SYSTEM - INFLAMMATION
Rhinitis Viral Rhinitis in Domestic Animals
Infectious Bovine Rhinotracheitis
Feline Rhinotracheitis
Parainfluenza Equine Viral
Rhinopneumonitis
Canine Distemper
Inclusion Body Rhinitis
(Cytomegalovirus)
• Very common, but often mild and self-limiting • Unless complicated with a bacterial
infection • Take swabs / collect fresh tissues for viral
testing! • Do bacterial culture to check for secondary
infection
SPECIES SPECIFIC EXAMPLES OF RHINITIS
Infectious Bovine Rhinotracheitis (IBR)
Etiology: Bovine herpesvirus-1 (BoHV-1)
• Affects cattle • Transient fever, rhinitis and
tracheitis • Lesions: Hyperemia, nasal /tracheal
mucosal necrosis • With 2⁰ bacterial infection →
fibrinonecrotizing rhinitis/tracheitis • Viral testing: PCR, FAT
Bronchopneumonia is an important sequela
SPECIES SPECIFIC EXAMPLES OF RHINITIS
Strangles
• Affects horses • Outbreaks with high
morbidity / low mortality • Lesions:
• Suppurative rhinitis • Regional lymphadenitis • Visceral spread (Bastard
Strangles) • Laboratory tests: Bacterial
culture
• Purpura Hemorrhagica - Immune-mediated vasculitis • Can occur after infection/vaccination for Strep equi
Image: Dr J Löfstedt
Etiology: Streptococcus equi ssp equi
Annually notifiable disease
Rhinitis
SPECIES SPECIFIC EXAMPLES OF RHINITIS
Atrophic Rhinitis
• Affects pigs • Lesions:
• Facial deformities • Atrophic conchae
(turbinates) • No exudate • Effect on growth rates? • Predispose to pneumonia?
Etiology: Pasteurella multocida + Bordetella bronchiseptica
Diagnosis: • Cross section snout at the 1-2nd
premolars • Check for the size of meatuses • Septal deviation
Rhinitis
SPECIES SPECIFIC EXAMPLES OF RHINITIS
Atrophic Rhinitis Etiology: Pasteurella multocida + Bordetella bronchiseptica
Diagnosis: • Cross section snout at the 1-2nd
premolars • Check for the size of meatuses • Septal deviation
Normal
SPECIES SPECIFIC EXAMPLES OF RHINITIS
Atrophic Rhinitis Etiology: Pasteurella multocida + Bordetella bronchiseptica
Image: Dr Darcy Shaw
SPECIES SPECIFIC EXAMPLES OF RHINITIS
Rhinitis in Dogs
Multifactorial:
• Viral:
• Canine distemper virus
• Encephalitis is more important!
• Canine Adenovirus-2
• Canine Parainfluenza virus-1
• Canine herpesvirus 1
• Canine Influenza virus
• Secondary bacterial infections:
• Bordetella bronchiseptica
• Escherichia coli
• Streptococcus spp
• Staphylococcus spp
Image: Dr Darcy Shaw
SPECIES SPECIFIC EXAMPLES OF RHINITIS
Rhinitis in Dogs Fungal agents:
• Aspergillus spp • Cryptococcus
Feline Viral Rhinotracheitis
SPECIES SPECIFIC EXAMPLES OF RHINITIS
Etiology: Felid herpesvirus 1 (FeHV1)
Image: Dr Laura Ross
• Transient rhinitis, sinusitis,
and conjunctivitis in kittens
• Keratitis and corneal ulcers
• Become latent carriers
• Predisposes to bacterial
infection and pneumonia
• Bordetella bronchiseptica
• Pasteurella multocida
• Streptococcus spp
SPECIES SPECIFIC EXAMPLES OF RHINITIS
Chlamydophila felis
• Also causes transient rhinitis, sinusitis, conjunctivitis in
kittens
Other cause of rhinitis in cats
Feline calicivirus
• Also causes transient rhinitis, sinusitis, conjunctivitis in
kittens
• Oral ulcers*
• Limping kitten syndrome (arthritis)
vssabac.rs
Listnerd.com
SPECIES SPECIFIC EXAMPLES OF RHINITIS
Cryptococcosis
• Fungus is acquired from environment
• Lesions: Granulomatous rhinitis /nasal dermatitis +/-
pneumonia
• Humans are also susceptible – but don’t acquire infection
from cat
Image: Dr Richard Malik
Etiology: Cryptococcus neoformans and Cryptococcus gatti
RHINITIS
Common Sequelae of Infectious Rhinitis
Sinusitis Pharyngitis
Guttural pouch infection
Meningitis
Otitis Lymphadenitis
INFLAMMATION OF THE SINUSES = SINUSITIS
• Similar types of injury and inflammatory response to nasal cavity • POOR DRAINAGE – exudate tends to accumulate!
INFLAMMATION OF THE SINUSES = SINUSITIS
Sinus mucocele • Sinus filled with mucus
Sinus empyema • Sinus filled with pus
Special thanks to Dr Alfonso Lopez for providing me with the material for these lectures
