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Pathology of the Respiratory System 1: Introduction, Pathology of the Nasal Passages
Shannon Martinson, Feb 2016
http://people.upei.ca/smartinson/ VPM 222 Systemic Pathology
INTRODUCTION
Conducting
Transitional
Exchange
INTRODUCTION: STRUCTURE AND FUNCTION
Respiratory Tract FunctionsPhonation Temperature
regulationBlood Pressure
Olfaction Acid-base Detoxification
Enzymes Hormones InflammatoryMediators
INTRODUCTION: STRUCTURE AND FUNCTION
INTRODUCTION: NORMAL FLORA
Tracheal Air
INTRODUCTION: NORMAL FLORA
INTRODUCTION: DEFENCE MECHANISMS
Air filtration
Mucociliary clearance
Phagocytosis
Immunity
Detoxification
Particle Deposition in the Respiratory Tract (Filtration)
10-2 microns
> 10 microns
2 µm
INTRODUCTION: DEFENCE MECHANISMS
> 10 microns
INTRODUCTION: DEFENCE MECHANISMS
Particle Deposition in the Respiratory Tract (Filtration)
10-2 µm
INTRODUCTION: DEFENCE MECHANISMS
Mucociliary Clearance
~ 100 cilia/cell
~ 1,000 strokes/minute
10-2 µm
INTRODUCTION: DEFENCE MECHANISMS
Mucociliary Clearance
www.merckvetmanual.com
~ 100 cilia/cell
~ 1,000 strokes/minute
10-2 µm
INTRODUCTION: DEFENCE MECHANISMS
Mucociliary Clearance
10-2 µm
> 10 µm
2 microns
Pulmonary Alveolar Macrophage (PAMs)
INTRODUCTION: DEFENCE MECHANISMS
Pulmonary Phagocytosis
How good are these defence mechanism?
0
20
40
60
80
100
120
140
0 2 4 8 12 24
% b
ac
teri
a i
n l
un
g
Hours post aerosol
Bacterial Clearance after Aerosol
Normal
Virus
Viruses
Stress
Dehydration
Lung edema
Uremia
Ammonia
Immunodeficiency
Impairment of defencemechanisms?
INTRODUCTION: DEFENCE MECHANISMS
THE CONDUCTING SYSTEM
www.merckvetmanual.com
• Nasal passages• Sinuses • Guttural pouches • Larynx• Trachea • Bronchi
Squamous (+)
Ciliated (+++)
Olfactory (++)
NASAL CAVITY – NORMAL GROSS AND MICROSCOPIC ANATOMY
HistologyAnatomy
DISORDERS OF THE CONDUCTING SYSTEM
Circulatory Disturbances
Rhinitis
Sinusitis
Sinus / Nasal tumours
Guttural Pouch Diseases
Laryngitis
Tracheobronchitis
Congestion / Hyperemia
NASAL CONGESTION / HYPEREMIA
The submucosa is well-vascularized: congestion and hyperemia are common
NASAL HEMORRHAGE
• Coughing blood from the lungs or airways Hemoptysis
• Bleeding from the noseEpistaxis
NASAL HEMORRHAGE
Courtesy of Dr. J Lofstedt
• Coughing blood from the lungs or airways Hemoptysis
• Bleeding from the noseEpistaxis
NASAL HEMORRHAGE
• Coughing blood from the lungs or airways Hemoptysis
• Bleeding from the noseEpistaxis
Epistaxis in all species:
• Trauma
• Foreign body
• Nasal neoplasia
• Pulmonary hemorrhage (aneurysm)
Horses
• Exercise induced pulmonary hemorrhage
• Guttural pouch mycosis
• Ethmoidal hematoma
• Nasal Cyst
• Pedunculated mass• Ethmoidal concha• Looks like a tumor• Unilateral epistaxis• Surgical excision
NASAL HEMORRHAGE
Equine Ethmoidal Hematoma
NASAL INJURY AND REPAIR
• Degeneration
• Loss of attachment
• Necrosis
• Exfoliation
• Ciliated epithelium
• ~250 cilia/cell
• Highly vascularized
• Abundant glands
• Repair
• Pre-ciliated cells
• Mitosis
• Cell differentiation
• Healed epithelium
• Normal function
Clinical signs:
• Nasal discharge
• Unilateral or bilateral
Classification according to exudate:
• Serous
• Catarrhal (Mucus)
• Suppurative (Purulent)
• Fibrinous
• Granulomatous
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Mucopurulent rhinitis
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Purulent
Fibrinous
Granulomatous
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Infectious Bovine
Rhinotracheitis (IBR)Parainfluenza
Equine Viral
Rhinopneumonitis
(EVR)
Feline Rhinotracheitis Canine Distemper Inclusion Body Rhinitis
(Cytomegalovirus)
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Viral Rhinitis in Domestic Animals
• Very common, but often mild and self-limiting• Unless complicated with a bacterial infection
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Species specific examples of rhinitis in domestic animals
• Etiology: Bovine herpesvirus-1 (BoHV-1)• Affects cattle• Transient fever, rhinitis and tracheitis• Lesions: Hyperemia, nasal /tracheal
mucosal necrosis• Viral testing: PCR, FAT, isolation
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Infectious Bovine Rhinotracheitis (IBR)
With secondary bacterial infections: • Fibrinous /
fibrinosupurative rhinitis and tracheitis may occur
Bronchopneumonia is an important sequela
• Etiology: Streptococcus equi ssp equi• Streptococcus equi
• Affects horses• High morbidity / Low mortality• Lesions:
• Suppurative rhinitis• Lymphadenitis• Visceral spread (Bastard Strangles)
• Laboratory tests: Bacterial culture
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Strangles
• Purpura Hemorrhagica• Immune-mediated vasculitis • Can occur after infection
with or vaccination for Streptococcus equi
Courtesy of Dr Jeanne Löfstedt
• Etiology: Controversial• P multocida / B bronchiseptica
• Affects pigs
• Lesions:
• Facial deformities
• Atrophic conchae (turbinates)
• Growth rates?
• Predispose to pneumonia?
• Diagnosis:
• Cross section snout at the 1-2nd
premolars
• Check for the size of meatuses
• Septal deviation
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Atrophic Rhinitis
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
• Etiology: Controversial• P multocida / B bronchiseptica
• Affects pigs
• Lesions:
• Facial deformities
• Atrophic conchae (turbinates)
• Growth rates?
• Predispose to pneumonia?
• Diagnosis:
• Cross section snout at the 1-2nd
premolars
• Check for the size of meatuses
• Septal deviation
Atrophic Rhinitis
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Atrophic Rhinitis
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Atrophic Rhinitis
Multifactorial
• Viral:
• Canine distemper virus
• Canine Adenovirus-2
• Canine Parainfluenza virus-1
• Canine herpesvirus 1
• Secondary bacterial infections:
• Bordetella bronchiseptica
• Escherichia coli
• Streptococcus spp
• Staphylococcus spp
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Rhinitis in dogs
Courtesy of Dr Darcy Shaw
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Other causes of rhinitis in dogs:
• Canine influenza virus
• Fungal agents:
• Aspergillus spp
• Cryptococcus
Courtesy of Dr Darcy Shaw
Rhinitis in dogs
• Etiology:
• Felid herpesvirus 1 ( FeHV1)
• Transient rhinitis, sinusitis, conjunctivitis in
kittens
• Can cause keratitis and corneal ulcers
• May predispose to bacterial infection and
pneumonia
• Bordetella bronchiseptica
• Pasteurella multocida
• Streptococcus spp
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Feline Viral Rhinotracheitis
• Feline calicivirus
• Causes similar disease / lesions
• Accompanied by oral ulceration
• Chlamydophila felis
• Causes similar disease / lesions
• Etiology:
• Cryptococcus neoformans
• Cryptococcus gatti
• Fungus is acquired from environment
• Lesions: Granulomatous rhinitis /nasal
dermatitis +/- pneumonia
• Humans are also susceptible!
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Cryptococcosis
Image: Dr Richard Malik
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Common Sequelae of Infectious Rhinitis
INFLAMMATION OF THE NASAL CAVITY = RHINITIS
Common Sequelae of Infectious Rhinitis
Sinusitis Pharyngitis
Guttural pouch
infection Meningitis
Otitis Lymphadenitis
• Similar types of injury and inflammatory response to nasal cavity
• POOR DRAINAGE
INFLAMMATION OF THE SINUSES = SINUSITIS
• Exudate tends to accumulate
• Sinus Empyema (Pus)*• Sinus Mucocele (Mucus)*
INFLAMMATION OF THE SINUSES = SINUSITIS
• Low incidence in domestic animals
• Most common in dogs and cats
• Epithelial >> mesenchymal, or round cell in
origin
• Benign << Malignant
• Invasive and occasionally metastatic
TUMORS OF THE NASAL CAVITY AND SINUSES
Nasal carcinoma Multilobular tumour of bone
Lymphoma
• Clinical Signs:
• Persistent nasal discharge
• Epistaxis
• Airflow obstruction
• Facial deformity (+ / -)
• Exophthalmia (+ / -)
• Neurological signs
• Diagnosis:
• Radiographs / CT / MRI
• Rhinoscopy
• Nasal biopsy
TUMORS OF THE NASAL CAVITY AND SINUSES
Canine Nasal Carcinoma
TUMORS OF THE NASAL CAVITY AND SINUSES
TUMORS OF THE NASAL CAVITY AND SINUSES
TUMORS OF THE NASAL CAVITY AND SINUSES
Enzootic nasal carcinoma(Enzootic ethmoidal carcinoma)
• Etiology: Retrovirus (Enzootic nasal tumour virus: ENTV)• Affects small ruminants • Incidence in some areas is high• Clinical signs: Respiratory distress, epistaxis, nasal discharge, weight loss
Retrovirus
TUMORS OF THE NASAL CAVITY AND SINUSES
Enzootic nasal carcinoma(Enzootic ethmoidal carcinoma)
TUMORS OF THE NASAL CAVITY AND SINUSES
Tumour-like conditions: • Nasal / Nasopharyngeal polyps• Pedunculated masses in the
nasal passage, auditory canal, sinuses or pharynx• Cats • Horses • Other spp less commonly
Questions?
A huge thanks to Dr López for providing me with the materials for these lectures!