Difference between revisions of "Rhinitis"

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{{review}}
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==Introduction==
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[[Image:Mucoid rhinitis.jpg|right|thumb|200px|<small><center>Mucoid rhinitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
  
{{toplink
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Rhinitis can be acute or chronic.
|backcolour = D1EEEE
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|linkpage =Cardiorespiratory System - Pathology
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Its aetiology can be:
|linktext =Cardiorespiratory System
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:Infectious
|maplink = Cardiorespiratory System (Content Map) - Pathology
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:Allergic
|pagetype =Pathology
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:Toxic
|sublink1=Nasal Cavity - Pathology
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:Traumatic e.g. foreign bodies
|subtext1=NASAL CAVITY
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}}
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Serous cells are usually the first to respond to a noxious agent, releasing secretions into the mucocilliary blanket.
<br>
 
'''For an overview of respiratory infections see [[Respiratory System Inflammation - Pathology]]'''
 
  
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Different forms of rhinitis can be described:
  
==Rhinitis==
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'''Serous rhinitis''' is the typical mild 'runny nose'. There is loss of cilia and hydropic degeneration of epithelial cells. The epithelium becomes susceptible to secondary bacterial infections, including overgrowth of resident nasopharyngeal flora. Goblet cells become stimulated, changing the secretions into a thick opaque mucus.
[[Image:Mucoid rhinitis.jpg|right|thumb|100px|<small><center>Mucoid rhinitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
 
  
*Acute or chronic
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'''Catarrhal rhinitis''' can follow serous rhinitis. It contains mucus, emigrating leukocytes and few sloughed epithelial cells.
*Aetiology
 
**Infectious
 
**Allergic
 
**Toxic
 
**Traumatic e.g. foreign bodies
 
  
*Serous cells usually first to respond to a noxious agent, releasing secretions into the mucocilliary blanket
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'''Mucopurulent''' and then '''purulent rhinitis'''occurs when secondary bacterial infection is severe, migrating [[Neutrophils|neutrophils]] are present in the exudate.
  
*'''Serous rhinitis''' - typical mild 'runny nose'
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More severe damage to the nasal mucosa causes vascular permeability and seepage of large molecular weight proteins, including fibrinogen, into the exudate leading to '''fibrinopurulent''' and '''fibrinous rhinitis'''.
**Loss of cilia and hydropic degeneration of epithelial cells
 
**Epithelium becomes susceptible to secondary bacterial infections, including overgrowth of resident nasopharyngeal flora
 
**Goblet cells become stimulated, changing the secretions into a thick opaque mucus ->
 
*'''Catarrhal rhinitis'''
 
**Contains mucus, emigrating leukocytes and few sloughed epithelial cells
 
*'''Mucopurulent''' and then '''purulent rhinitis'''
 
**When secondary bacterial infection is severe, migrating [[Neutrophils|neutrophils]] pour into the exudate
 
**More severe damage to the nasal mucosa causes vascular permeability and seepage of large molecular weight proteins, including fibrinogen, into the exudate ->
 
*'''Fibrinopurulent''' and '''fibrinous rhinitis'''
 
*'''Fibronecrotic''' and '''ulcerative rhinitis''' are manifestations of very severe damage to the nasal mucosa
 
  
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'''Fibronecrotic''' and '''ulcerative rhinitis''' are manifestations of very severe damage to the nasal mucosa.
  
 
==Chronic rhinitis==
 
==Chronic rhinitis==
*Happens when acute rhinitis fails to resolve - common
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This occurs when acute rhinitis fails to resolve and is common in most species. It is typically catarrhal or purulent in nature.
*Typically catarrhal or purulent
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*In chronic purulent rhinitis
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In chronic purulent rhinitis there is extensive fibrosis of the lamina propria, atrophy of the nasal glands and squamous cell [[Cell Growth Disorders#Metaplasia|metaplasia]]. These all result in impaired local defences.
**Extensive fibrosis of the lamina propria
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**Atrophy of nasal glands
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Usually, the superficial fibrinous membrane can be peeled off without leaving damaged tissue underneath.
**Squamous cell [[Disorders of Cell Growth - Pathology#Metaplasia|metaplasia]]
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*-> Impaired local defences
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Deeper fibronecrotic lesions associated with [[Fusobacterium necrophorum|''Fusobacterium necrophorum'']] appear as a yellowish fibronecrotic membrane, which when removed leaves an ulcerated surface.
*Superficial fibrinous membrane can be peeled of without leaving dmaged tissue underneath
 
*Deeper fibronecrotic lesions associated with [[Fusobacterium|''Fusobacterium necrophorum'']] - yellowish fibronecrotic membrane, when removed, leaves ulcerated surface
 
*May manifest as [[Nasal Cavity Hyperplastic and Neoplastic - Pathology#Nasal polyps|nasal polyps]], [[Nasal Cavity Hyperplastic and Neoplastic - Pathology#Progressive ethmoidal haematoma|progressive haematoma]] in horses and [[Nasopharynx Hyperplastic and Neoplastic - Pathology#Nasopharyngeal polyp of cats|nasopharyngeal polyp]] of cats
 
  
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Chronic rhinitis may manifest as nasal polyps, [[Progressive Ethmoidal Haematoma|progressive haematoma]] in horses and [[Nasopharyngeal Polyp|nasopharyngeal polyps]] of cats.
  
 
==Allergic rhinitis==
 
==Allergic rhinitis==
  
*Occurs in dogs, cats and horses, may occur seasonally in cattle, especially Channel Island breeds
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This occurs in dogs, cats and horses, and may occur seasonally in cattle, especially Channel Island breeds.
*Similar inflammatory changes as above
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*Due to hypersensitivity to inhaled allergens
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There are similar inflammatory changes as above, due to [[hypersensitivity]] to inhaled allergens. [[Eosinophils]] tend to be the dominant infiltrating leukocytes.
*Eosinophils tend to be the dominant infiltrating leukocytes
 
*Grossly:
 
**Pale, thick, oedematous nasal mucosa
 
*Histologically:
 
**Hyperplastic, eroded nasal epithelium, eosinophil infiltrate
 
  
*If chronic -> '''Nasal granuloma'''
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Grossly: the nasal mucosa is pale, thick and oedematous.
**Extends caudally, even to larynx and proximal trachea
 
**Grossly:
 
***Granular hyperplastic epithelium with multiple nodules covered by normal epithelium
 
**Hisologically:
 
***Centre of [[Granulation Tissue|granulation tissue]] surrounded by oedematous lamina propria covered by hyperplastic epithelium
 
***Goblet cell hyperplasia
 
***Eosinophil infiltration
 
  
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Histologically: the nasal epithelium is hyperplastic and eroded with an eosinophil infiltrate.
  
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If the condition is chronic it may become a '''nasal granuloma''', which extends caudally, even to the larynx and proximal trachea.
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:Grossly there is granular hyperplastic epithelium with multiple nodules covered by normal epithelium.
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:Histologically there is a centre of [[Granulation Tissue|granulation tissue]] surrounded by oedematous lamina propria covered by hyperplastic epithelium, goblet cell hyperplasia and eosinophil infiltration.
  
[[Paranasal Sinuses Inflammatory - Pathology#Sinusitis|'''Sinusitis''']] '''is a common sequel to rhinitis'''
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[[Sinusitis|'''Sinusitis''']] '''is a common sequel to rhinitis'''
  
  
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{{Learning
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|flashcards = [[Nasal_Cavity_Flashcards_-_Pathology|Nasal Cavity Pathology Flashcards]]<br>[[Small Animal Soft Tissue Surgery Q&A 10]]
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}}
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[[Category:Respiratory System - Inflammatory Pathology]]
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[[Category:Nasal Cavity - Inflammatory Pathology]]

Latest revision as of 13:18, 19 October 2011

Introduction

Mucoid rhinitis (Image sourced from Bristol Biomed Image Archive with permission)

Rhinitis can be acute or chronic.

Its aetiology can be:

Infectious
Allergic
Toxic
Traumatic e.g. foreign bodies

Serous cells are usually the first to respond to a noxious agent, releasing secretions into the mucocilliary blanket.

Different forms of rhinitis can be described:

Serous rhinitis is the typical mild 'runny nose'. There is loss of cilia and hydropic degeneration of epithelial cells. The epithelium becomes susceptible to secondary bacterial infections, including overgrowth of resident nasopharyngeal flora. Goblet cells become stimulated, changing the secretions into a thick opaque mucus.

Catarrhal rhinitis can follow serous rhinitis. It contains mucus, emigrating leukocytes and few sloughed epithelial cells.

Mucopurulent and then purulent rhinitisoccurs when secondary bacterial infection is severe, migrating neutrophils are present in the exudate.

More severe damage to the nasal mucosa causes vascular permeability and seepage of large molecular weight proteins, including fibrinogen, into the exudate leading to fibrinopurulent and fibrinous rhinitis.

Fibronecrotic and ulcerative rhinitis are manifestations of very severe damage to the nasal mucosa.

Chronic rhinitis

This occurs when acute rhinitis fails to resolve and is common in most species. It is typically catarrhal or purulent in nature.

In chronic purulent rhinitis there is extensive fibrosis of the lamina propria, atrophy of the nasal glands and squamous cell metaplasia. These all result in impaired local defences.

Usually, the superficial fibrinous membrane can be peeled off without leaving damaged tissue underneath.

Deeper fibronecrotic lesions associated with Fusobacterium necrophorum appear as a yellowish fibronecrotic membrane, which when removed leaves an ulcerated surface.

Chronic rhinitis may manifest as nasal polyps, progressive haematoma in horses and nasopharyngeal polyps of cats.

Allergic rhinitis

This occurs in dogs, cats and horses, and may occur seasonally in cattle, especially Channel Island breeds.

There are similar inflammatory changes as above, due to hypersensitivity to inhaled allergens. Eosinophils tend to be the dominant infiltrating leukocytes.

Grossly: the nasal mucosa is pale, thick and oedematous.

Histologically: the nasal epithelium is hyperplastic and eroded with an eosinophil infiltrate.

If the condition is chronic it may become a nasal granuloma, which extends caudally, even to the larynx and proximal trachea.

Grossly there is granular hyperplastic epithelium with multiple nodules covered by normal epithelium.
Histologically there is a centre of granulation tissue surrounded by oedematous lamina propria covered by hyperplastic epithelium, goblet cell hyperplasia and eosinophil infiltration.


Sinusitis is a common sequel to rhinitis


Infectious causes of rhinitis

. VIRAL BACTERIAL FUNGAL PARASITIC
Dogs Canine distemper secondary A. fumigatus Linguatula serrata
. Parainfluenza- 2 . C. neoformans Capillaria aerophila
. Canine herpes virus . . .
Cats Feline viral rhinotracheitis secondary Cryptococcus neoformans Linguatula serrata sometimes
. Feline calicivirus . Aspergillus fumigatus Capillaria aerophila
Horses Equine rhinovirus Strangles Aspergillus spp. Parascaris equorum
. Equine influenza Streptococcus equi subsp. zooepidemicus . .
. Equine rhinopneumonitis Glanders . .
. Equine viral arteritis . . .
Cattle Infectious bovine rhinotracheitis secondary . .
. Parainfluenza- 3 subclinical CAR bacillus . .
. Bovine adenovirus . . .
Sheep Parainfluenza - 3 subclinical CAR bacillus . Oestrus ovis larvae
Pigs Inclusion body rhinitis Atrophic rhinitis . .
. Swine influenza . . .


Rhinitis Learning Resources
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Flashcards
Test your knowledge using flashcard type questions
Nasal Cavity Pathology Flashcards
Small Animal Soft Tissue Surgery Q&A 10