Pathology of the Respiratory System 2: Conducting System ...people.upei.ca/smartinson/RESP-Lecture-2_2016_SAM.pdf · Guttural Pouch Mycosis • Etiology: • Aspergillus fumigatus

Pathology of the Respiratory System 2: Conducting System, Transitional System, Lung

Shannon Martinson, March 2016 http://people.upei.ca/smartinson/ VPM 222 Systemic Pathology

PATHOLOGY OF THE CONDUCTING SYSTEM

• Nasal passages • Sinuses • Guttural pouches • Larynx • Trachea • Bronchi

www.merckvetmanual.com

PATHOLOGY OF THE CONDUCTING SYSTEM

• Transitional System

• Exchange System


DISORDERS OF THE CONDUCTING SYSTEM

Circulatory Disturbances

Rhinitis

Sinusitis

Sinus / Nasal tumours

Guttural Pouch Diseases

Laryngitis

Tracheitis / Bronchitis

GUTTURAL POUCHES

• Ventral dilation of the Eustachian tubes in horses • Connects middle ear to

pharynx • 300-500ml volume

• Important things are present in the wall of the pouch! • Internal carotid artery • Cranial nerves

• Facial (7) • Glossopharyngeal (9) • Vagus (10) • Hypoglossal (12) • Accessory (11)

• Atlanto-occipital joint

FMVZ-UNAM

GUTTURAL POUCHES

FMVZ-UNAM

GUTTURAL POUCHES

Tympany Empyema Mucocele Mycosis Hemorrhage

Diseases of the Guttural Pouches

• First few days of life → 1 year old • Enormous swelling • Nonpainful with minimal distress • Valvular action of the nasopharyngeal

orifice (Eustachian tube) • Arabian and German warm-blood

horses

GUTTURAL POUCHES

Guttural Pouch Tympany

Knottenbelt DC, Pascoe RR, Diseases and Disorders of theHorse, Saunders, 2003

https://encrypted-

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GUTTURAL POUCHES

Guttural Pouch Empyema • Follows purulent rhinitis

• Etiology: Streptococcus equi (Strangles) is common

• Clinical signs: • Purulent nasal discharge • Painful swelling • Dysphagia • Respiratory distress

FMVZ-UNAM

GUTTURAL POUCHES

Guttural Pouch Empyema

FMVZ-UNAM

GUTTURAL POUCHES

Guttural Pouch Mycosis • Etiology:

• Aspergillus fumigatus

• Often in stabled horses – moldy hay

• Gross lesions:

• Fibrinonecrotic plaques

(diphtheritic membrane) on the

mucosa of the guttural pouches

GUTTURAL POUCHES

Guttural Pouch Mycosis • Etiology:

• Aspergillus fumigatus

• Often in stabled horses – moldy hay

• Gross lesions:

• Fibrinonecrotic plaques

(diphtheritic membrane) on the

mucosa of the guttural pouches

DE Freeman, 2015. Update on Disorders and Treatment of the Guttural Pouch. Vet Clinics North America 31 (1), 63-89

http://www.sciencedirect.com/science/article/pii/S0749073914001084

GUTTURAL POUCHES

Guttural Pouch Mycosis

Frbrinonecrotizing eustachitis

GUTTURAL POUCHES


Acute hemorrhage

Fresh flood filling the guttural pouch

Cornell

Chronic hemorrhage

Organized blood clot in guttural pouch

Cornell

Sequellae:

• Erosion through the internal carotid artery with massive (even fatal) epistaxis

Cornell GUTTURAL POUCHES


Sequellae:

• Cranial nerve deficits • Cerebral Infarcts

DE Freeman, 2015. Update on Disorders and Treatment of the Guttural Pouch. Vet Clinics North America 31 (1), 63-89

http://www.sciencedirect.com/science/article/pii/S0749073914001084

LARYNX

Necrotic Laryngitis = Calf diphtheria

• Etiology: Fusobacterium necrophorum

• 2⁰ pathogen

• Follows viral infection or trauma

• Clinical signs:

• Fever, anorexia, depression

• Halitosis, moist cough, dyspnea

http://krowy.blog.pl/files/2014/07/coughingcow.jpg

LARYNX

Necrotic Laryngitis = Calf diphtheria

http://krowy.blog.pl/files/2014/07/coughingcow.jpg

• Gross lesion: • Plaques of fibrinonecrotic exudate

adhered to necrotic laryngeal mucosa • Sequelae:

• Asphyxiation • Aspiration pneumonia • Toxemia, Fusobacteremia

Frbrinonecrotizing laryngitis, locally extensive, severe, subacute

TRACHEA AND BRONCHI - NORMAL

TRACHEITIS AND BRONCHITIS

Chantal Albert AVC ‘2007

Canine Infectious Respiratory Disease Kennel Cough

Canine Infectious Tracheobronchitis


Multifactorial in Etiology:

• Viral:

• Canine Adenovirus-2

• Canine Parainfluenza virus-1

• Canine herpesvirus 1

• Secondary bacterial infections:

• Bordetella bronchiseptica

• Escherichia coli

• Mycoplasma cynos

• Streptococcus spp

• Clinical signs: • Harsh dry cough, retching / gagging • Productive cough, purulent nasal discharge,

depression, fever suggest secondary bacterial infection / pneumonia present

Chantal Albert AVC ‘2007

Canine Infectious Respiratory Disease Kennel Cough

Canine Infectious Tracheobronchitis


Viral +

bacterial tracheitis

Viral tracheitis

Primary bronchiolar lesions are rare in domestic animals

Club (Clara) Cells

TRANSITIONAL SYSTEM – BRONCHIOLES

Normal bronchiole


DISORDERS OF THE TRANSITONAL SYSTEM

Recurrent Airway Obstruction

Feline Asthma


Recurrent Airway Obstruction (RAO) Chronic Obstructive Pulmonary Disease (COPD)

“Heaves” video

• Etiology:

• Hypersensitivity response to

inhaled particulates (moldy hay,

endotoxin)

• Stabled horses

• Genetic predisposition?

• Clinical Signs

• Exercise intolerance

• Flared nostrils

• Increased expiratory effort

• Heave line

• Hypertrophy of abdominal

muscles IVIS

http://www.youtube.com/watch?v=oKpxhgzGNKc&feature=related


Recurrent Airway Obstruction (RAO) Chronic Obstructive Pulmonary Disease (COPD)

“Heaves”

Normal bronchiole Goblet cell metaplasia

Mucous difficult to remove via mucociliary clearance

EXCHANGE SYSTEM – ALVEOLI (LUNG)


Cranial lobe

Cranial lobe

Caudal lobe Caudal lobe

Lobes

Middle lobe

NORMAL LUNG

Notable species differences

Lobules

Accessory lobe

(not pictured)

Notable species differences

NORMAL LUNG

Species Lobation Lobulation

Pigs Well-defined Well-defined

Cattle Well-defined

Well-defined

Sheep/Goats Well-defined Poorly defined

Dog Well-defined Poorly defined

Cat Well-defined Poorly defined

Horse Poorly defined Poorly defined

NORMAL LUNG

• Salmon pink • Dry sponge-like texture • Deflated – retract from the thoracic

wall normally

1. Capillary Endothelium 2. Basal lamina 3. Type 1 Pneumocytes

NORMAL LUNG

Blood-Air Barrier

DISORDERS OF THE LUNG

Congenital

Pigmentary deposition

Circulatory Disturbances

Inflation disturbances

Pneumonia

Neoplasia

DISORDERS OF THE LUNG

Circulatory Disturbances Congestion and Hyperemia

Hemorrhage

Thrombosis

Embolism

Edema

LUNG – CIRCULATORY DISTURBANCES

Normal lungs varies in colour according to the amount of blood within the organ

Pale Red


Pulmonary Hyperemia / Congestion

• An excess of blood within blood vessels in a part of the body due to an active process (increased arterial flow)

Hyperemia

• An excess of blood within blood vessels in a part of the body due to a passive process (decreased venous outflow)

Congestion

“Heart Failure Cells”


Pulmonary Hyperemia / Congestion


Etiology

Trauma (blunt trauma, fractured rib)

Coagulopathy (anticoagulant, thrombocytopenia, DIC)

Ruptured vessels (abscesses, aneurysms)

Exercise induced pulmonary hemorrhage (horses)

Pulmonary Hemorrhage


Pulmonary Hemorrhage Etiology














Coagulopathy (anticoagulant, thrombocytopenia), DIC






Coagulopathy (anticoagulant, thrombocytopenia), DIC


Exercise induced pulmonary hemorrhage (EIPH - horses)

• Etiology and pathogenesis unknown

• Clinical signs: • Epistaxis following

exercise • Reduced athletic

performance? • Hemorrhage and

hemosiderin laden macrophages in alveoli


Pulmonary thromboembolism (PTE)

Thrombi may also develop as a result of: • Exogenous / endogenous steroids • Glomerular Disease • Heartworm infection in dogs

Significance? • Small airway constriction • Reduced surfactant production • Pulmonary edema • Atelectasis • Infarcts

• Hypoxemia • Hyperventilation • Dyspnea

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1

2

Lung infarcts

3



1

1

2




Other forms of emboli

A special thanks to Dr. Alfonso López for providing the

material for these lectures!

Documents

Pathology of the Respiratory System 2: Conducting System ...people.upei.ca/smartinson/RESP-Lecture-2_2016_SAM.pdf · Guttural Pouch Mycosis • Etiology: • Aspergillus fumigatus