VMED 02610: Pathobiology II Systemic Pathology – Respiratory System Lecture 2

What are the divisions of the pharynx

nasopharynx, oropharynx, laryngopharynx

What is the purpose of the pharynx

Crossroads of air and food passages

What does the soft palata seperate

separated the naso- and oropharynx

What are the components of the opening of the pharynx

choanae, Eustachian tubes, larynx, esophagus

What are the lymphoid tissues of the pharynx

tonsils, pharyngeal lymphoid follicles

What are the components of swallowing in the pharynx

soft palate & epiglottis seal the airway

What is Pharyngitis

Generally associated with upper respiratory or upper alimentary inflammation

What animal commonly gets Pharyngeal diverticulitis

in pigs

How do pigs get Pharyngeal diverticulitis

 Lodged barley awns → affect swallowing

What animal can get a Perforation of pharyngeal wall

in sheep, cattle, and pigs

Perforation of pharyngeal occurs when

Improper use of drenching guns

What is Equine Pharyngeal Lymphoid Hyperplasia

• Common cause of partial upper airway obstruction, particularly in 2 - and 3- year-old racehorses

•  Cause is undetermined

•  Chronic antigenic stimulation from bacteria and environmental factors

What is a physical characteristics of Pharynx • Equine Pharyngeal Lymphoid

Hyperplasia

 White foci on the dorsolateral walls

What animal commonly gets nasopharyngeal polyp

• Mostly in cats

Where can the nasopharyngeal polyp arise from

• Arise in the middle ear

 Sequelae of focal chronic inflammation

We know that in nasopharygeal polyp that it arises in the middle ear but where can it extend to and what can they cause

• Can extend into the nasopharynx, where they can obstruct normal breathing

What is composed of Nasopharyngeal polyp

• Composed of inflamed fibrovascular tissue

What are the components for Guttural Pouches

• Diverticula of the auditory (Eustachian) tubes in equids

• Slit-like openings into pharynx

What are the structures that are closely to the Guttural Pouches

 Internal & external carotid arteritis

 Cranial nerves VII, IX, X, XI, XII

What is the function of the Guttural Pouches

pressure equalization, brain cooling

What is the definition of Eustachitis:

inflammation of the Eustachian tube

What is the bacteria of Guttural Pouch Empyema

 Streptococcus equi

What is Guttural Pouch Empyema

 Accumulation of purulent exudate; may inspissate

 Secondary to suppurative nasal/pharyngeal inflammation

What is Eustachitis:

inflammation of the Eustachian tube

What fungi relaltes to Guttural Pouch Mycosis

 Aspergillus fumigatus

Describe Guttural Pouch Mycosis

 Usually unilateral

 Diphtheritic fungal plaques

What is Sequalae in Guttural Pouch Mycosis

 Invasion into carotid artery

 Epistaxis

 Exsanguination

What kind of material is the larynx made of

Cartilaginous structure

What animals contain Laryngeal saccules:

dogs, horses

What nerve is innervated in the larynx

Innervated by recurrent laryngeal nerve

What is the function of Larynx

airway protection and regulation, vocalization, cough reflex

Equine Laryngeal Hemiplegia sounds like what

 “Roaring”

What is the cause of Equine Laryngeal Hemiplegia

Cause is unknown

What are the features/characteristics of Equine Laryngeal Hemiplegia

 Usually left-sided hemiplegia

 Degeneration of the left recurrent laryngeal nerve

 Results in atrophy of the left cricoarytenoid muscles

Laryngeal Paralysis (Dogs) occurs when

 Usually bilateral in large breed dogs

which dogs breeds have Laryngeal Paralysis (Dogs) (hereditary)

 Hereditary in Siberian husky and Bouvier des Flanders

Hyperemia and edema occur with

inhalation of irritant materials, inflammation, trauma, and anaphylaxis

Hemorrhage can occur with

sepsis and dyspnea

Laryngitis usually associated with

• pharyngitis and/or tracheitis

What bacteria is accioated with Necrotic Laryngitis

 Fusobacterium necroforum

What does necrotic laryngitis look like grossly

yellow-grey, fibrinonecrotic exudate

Where can we see lesions in Necrotic Laryngitis (Calf Diphtheria)

 Can see lesion in tongue, cheeks, palate, pharynx

Are necrotic laryngitis opportunistic pathogens ?

 Opportunistic pathogen that produces exotoxins and endotoxins

How does the bacteria that creates necrotic laryngitis get in

Gains mucosal entry through viral or traumatic lesions

What does the trachea look like

• C-shaped hyaline cartilage rings

 Resist collapse during inspiration

What is the function of the trachea

• Conducts air

Where does the trachea bifurcate

• Bifurcates into the primary bronchi

What is Trachea Hypoplasia

 Reduction in luminal diameter of entire trachea

What animals do you see Trachea Hypoplasia

 Brachycephalic breeds

 Inherited in English bulldog and Boston terriers

What is Dorsoventral Flattening

 Tracheal collapse

What animals will you see Dorsoventral Flattening

 Miniature dog breeds

 Involves widening of the tracheal muscle

Primarily what animal can get Lateral Flattening

 Primarily horses

 Much less common that dorsoventral flattening in dogs

What is Lateral Flattening

 Scabbard trachea

 Involves lateral compression of the trachea

What is Tracheitis

 Often associated with rhinitis (rhinotracheitis) or laryngitis (laryngotracheitis)

 Similar types of exudates and causes as with rhinitis

What does Parasitic Tracheitis look Grossly:

protruding submucosal nodules at the tracheal bifurcation

What is the histology for parasite tracheitis

 Nodules of adult worms with mild inflammation

• foreign body inflammation of dead worms

What is the nematode causes Parasitic Tracheitis

Oslrus oslei

What animals are affeected by parasitic tracheitis

dogs