pathology of the respiratory system 2: conducting system...
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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
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PATHOLOGY OF THE CONDUCTING SYSTEM
• Transitional System
• Exchange System
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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
GUTTURAL POUCHES
Guttural Pouch Mycosis
Frbrinonecrotizing eustachitis
GUTTURAL POUCHES
Guttural Pouch Mycosis
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
Guttural Pouch Mycosis
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
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
TRACHEITIS AND BRONCHITIS
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
TRACHEITIS AND BRONCHITIS
Viral +
bacterial tracheitis
Viral tracheitis
Primary bronchiolar lesions are rare in domestic animals
Club (Clara) Cells
TRANSITIONAL SYSTEM – BRONCHIOLES
Normal bronchiole
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DISORDERS OF THE TRANSITONAL SYSTEM
Recurrent Airway Obstruction
Feline Asthma
TRANSITIONAL SYSTEM – BRONCHIOLES
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
TRANSITIONAL SYSTEM – BRONCHIOLES
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)
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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
LUNG – CIRCULATORY DISTURBANCES
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”
LUNG – CIRCULATORY DISTURBANCES
Pulmonary Hyperemia / Congestion
LUNG – CIRCULATORY DISTURBANCES
Etiology
Trauma (blunt trauma, fractured rib)
Coagulopathy (anticoagulant, thrombocytopenia, DIC)
Ruptured vessels (abscesses, aneurysms)
Exercise induced pulmonary hemorrhage (horses)
Pulmonary Hemorrhage
LUNG – CIRCULATORY DISTURBANCES
Pulmonary Hemorrhage Etiology
Trauma (blunt trauma, fractured rib)
Coagulopathy (anticoagulant, thrombocytopenia, DIC)
Ruptured vessels (abscesses, aneurysms)
Exercise induced pulmonary hemorrhage (horses)
LUNG – CIRCULATORY DISTURBANCES
Pulmonary Hemorrhage Etiology
Trauma (blunt trauma, fractured rib)
Coagulopathy (anticoagulant, thrombocytopenia, DIC)
Ruptured vessels (abscesses, aneurysms)
Exercise induced pulmonary hemorrhage (horses)
LUNG – CIRCULATORY DISTURBANCES
Pulmonary Hemorrhage Etiology
Trauma (blunt trauma, fractured rib)
Coagulopathy (anticoagulant, thrombocytopenia), DIC
Ruptured vessels (abscesses, aneurysms)
Exercise induced pulmonary hemorrhage (horses)
LUNG – CIRCULATORY DISTURBANCES
Pulmonary Hemorrhage Etiology
Trauma (blunt trauma, fractured rib)
Coagulopathy (anticoagulant, thrombocytopenia), DIC
Ruptured vessels (abscesses, aneurysms)
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
LUNG – CIRCULATORY DISTURBANCES
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
1
1
2
Lung infarcts
3
LUNG – CIRCULATORY DISTURBANCES
Pulmonary thromboembolism (PTE)
1
1
2
LUNG – CIRCULATORY DISTURBANCES
Pulmonary thromboembolism (PTE)
LUNG – CIRCULATORY DISTURBANCES
Other forms of emboli
A special thanks to Dr. Alfonso López for providing the
material for these lectures!
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