Pathology of the Respiratory System 1: Introduction...

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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

Particle Deposition in the Respiratory Tract (Filtration)

10-2 µm

Mucociliary Clearance

~ 100 cilia/cell

~ 1,000 strokes/minute

10-2 µm

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~ 100 cilia/cell

~ 1,000 strokes/minute

10-2 µm

> 10 µm

2 microns

Pulmonary Alveolar Macrophage (PAMs)

Pulmonary Phagocytosis

How good are these defence mechanism?

0 2 4 8 12 24

Hours post aerosol

Bacterial Clearance after Aerosol

Normal

Viruses

Stress

Dehydration

Lung edema

Uremia

Ammonia

Immunodeficiency

Impairment of defencemechanisms?

THE CONDUCTING SYSTEM

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• 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

NASAL HEMORRHAGE

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

Purulent

Fibrinous

Granulomatous

Infectious Bovine

Rhinotracheitis (IBR)Parainfluenza

Equine Viral

Rhinopneumonitis

Feline Rhinotracheitis Canine Distemper Inclusion Body Rhinitis

(Cytomegalovirus)

Viral Rhinitis in Domestic Animals

• Very common, but often mild and self-limiting• Unless complicated with a bacterial infection

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

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

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

Atrophic 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

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

Rhinitis in dogs

Courtesy of Dr Darcy Shaw

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

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!

Cryptococcosis

Image: Dr Richard Malik

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

Canine Nasal Carcinoma

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

Enzootic nasal carcinoma(Enzootic ethmoidal carcinoma)

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!

Pathology of the Respiratory System 1: Introduction...

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