Test 1- Respiratory Flashcards
The upper respiratory tract is found where
In general the upper respiratory tract is the portion of the respiratory system located outside the thoracic cavity.
What are the 3 systems in the RT?
- Conducting system
- Transitional system
- Exchange system
Conducting system
Conducting system: MORE ROSTRAL SYSTEMIncludes the nasal cavity, paranasal sinuses, larynx, trachea and bronchi. The mucosa of this system is primarily lined by pseudostratified ciliated epithelium and goblet cells.
Transitional system :
Transitional system : consists exclusively of bronchioles(lined by simple cuboidal epithelium) which are lined by Clara cells (detoxification of xenobiotics), non-ciliated secretory cells and only a few ciliated cells. Healthy bronchioles do not have goblet cells( goblet cells are in most other places).
Exchange system
Exchange system: Composed of alveolar ducts and millions of alveoli; thin-walled structures enveloped by a rich network of capillaries, the pulmonary capillaries. Alveoli are lined by epithelial
type I (membranous) and type II (granular) pneumocytes (also called pneumonocytes).
Type II- produce surfactant
Type I- more common
What is the blood supply to the lungs?
The lungs have a dual blood supply: Through the pulmonary arteries which conduct deoxygenated blood from
the right side of the heart, and the bronchial arteries, which carry oxygenated blood.
In addition to gas exchange, the respiratory system is also involved in
In addition to gas exchange, the respiratory system is also involved in phonation, olfaction, temperature regulation, acid–base balance, blood pressure regulation etc.
Normal Flora
Normal Flora – Restricted only to the most proximal region of the conductive system: nasal cavity, nasopharynx, larynx and trachea.
The distal portions of the respiratory tract are considered to be sterile.
The majority of the flora in the RT are ….
Even though the majority of the organisms of the normal respiratory flora are harmless others are potentially pathogenic; e.g.: Mannheimia haemolytica, Bordetella bronchiseptica.
2 Defense Mechanisms in the RT
Non-specific (non immune- mediated):
Mucous trapping
Mucociliary clearance (mucociliary escalator- movement of the cillia moving the mucus)
Phagocytosis
Air turbulence (generated by coughing and sneezing).
*smokers loose the ability to do mucous trapping and mucocillary escalator- thus they can only use air turbulence and phagocytosis)
Specific (immune-mediated):
Antibody production
Antibody-mediated phagocytosis
Cell-mediated immunity
Pulmonary Macrophages
Alveolar Macrophages (“PAMs”)
Intravascular Macrophages (“PIMs”> ruminants, cats, pigs and horses)- macrophages that live in the pulmonary capillaries- function is to get rid of bacteria, viruses that may reach the lungs through the blood
In dogs, humans and laboratory rodents the cells responsible for removing circulating bacteria and other particles from blood are
In dogs, humans and laboratory rodents the cells responsible for removing circulating bacteria and other particles from blood are the Kupffer cells (liver) and splenic macrophages.
NOT PIMs as in ruminants, cats, pigs and horses
What happens when animals have an infection?
Animals suffering from a respiratory viral infection
have notably suppressed defence mechanisms which make them susceptible to bacterial colonization within the airways.
Viruses are not the only factor known to predispose to bacterial pneumonia, other causes are:
Stress
Dehydration
Pulmonary edema
Uremia
Ammonia
Immunosuppression/ immunodeficiency
Pig normal lungs, AVC
Nasal Cavity
Ethmoidal hematoma – MOST COMMON cause of epistaxis in horses
Pedunculated tumor-like lesion in older horses. The exact etiology of this lesion is unknown.
Lesion in the nasal tubinates
PRESENTS WITH EPISTAXIS!!!
Ethmoidal hematoma – MOST COMMON cause of epistaxis in horses
Pedunculated tumor-like lesion in older horses. The exact etiology of this lesion is unknown.
Fibrinous rhinitis – mid-sagittal section of the head – Calf with IBR
Infectious Bovine Rhinotracheitis (formation of diphtheritic membrane)-
happens a lot in younger cattle- CAUSED BY BOVINE HERPES VIRUS I
fibrin hemoorhage- VERY CHARACTERISITIC of IBR
Oestrus ovis, nasal bot in sheep – worldwide distribution
Aberrant migration of Oestrus ovis larva, sheep-Texas A&M.
bot fly can go into the brain to cause an encephaltitis
Atrophic rhinitis in pigs.
causes deventation in the snout
Atrophic rhinitis in pigs.
Multifactorial disease in growing pigs. - There can be several organisms isolated
Currently is thought to be the result of a combined infection of Bordetella bronchiseptica and Pasteurella multocida types D and A.
Mostly in younger pigs
Damages the nasal turbinates
Post-mortem cut by the second molar- you will usually see symmetry
The atrophy is mostly seen in the ventral turbinates.
Atrophic Rhinitis- the atrophy of the turbinates is caused by the decreased osteoclast activity
Normal Pig
The toxigenic strains of P. multocida produce cytotoxins which inhibit osteoblastic activity and promote osteoclastic reabsorption of the nasal turbinates. “The ventral scroll of the ventral nasal turbinate is the area most commonly and consistently affected”…
Inclusion Body Rhinitis – Porcine Cytomegalovirus (suis herpesvirus 2 [SHV-2]) infection, Pig, AVC, OI- Induces cytomegalolity in the cells. Glandular cells will have basophilic or amphophlici (grey) inclusion bodies- this confirms the diagnosis
Usually in pigs 3-5 weeks of age. Fatal systemic infection occurs occasionally in younger suckling pigs (less than 3 weeks of age)- this is where you see the most fataties.
Nasal submucosal glands with large basophilic Intranuclear inclusions (SHV-2).
Feline herpesvirus 1 (Feline viral rhinotracheitis [FVR]): rhinitis, conjunctivitis; usually in immunosupressed animals
Disease can be in the upper and lower RTS
vesicles, tongue – Feline calicivirus, Noah’s Arkives- presents very simliar to FHV
Morphologic Diagnosis?
Cat, feline calicivirus – ulcerative glossitis
Feline Calicivirus (FCV). Mild oculonasal discharge in addition to vesicular and ulcerative stomatitis - diffuse interstitial pneumonia may also occur.
Cat, diffuse interstitial pneumonia, FCV.
Diffucult to diagnosis grossly
Inflammation is mostly in the interstitium
Granulomatous rhinitis, dog due to Rhinosporidium seeberi (aquatic protistan parasite)- in Lousisana, MI- dogs who like to play in ponds
Guttural pouch tympany in a foal- YOUNG HORSES
guttural pouch is filled with air- NOT PAINFUL
Strangles, Streptococcus equi, lymph node and guttural pouch involvement
this is extremely painful because this is inflammation(euchchitis= inflammation of the guttural pouch)
you will see neutrophils mostly in suppurative exudate
Strangles, Streptococcus equi, lymph node and guttural pouch involvement
Inflammation of the guttural pouch, horse (guttural pouch empyema) due to “strangles”-TAMU
Medial compartment of the guttural pouch(9-12) is associated with cranial nerves and the internal carotid- Thus THEY CAN HAVE NEURO SIGNS
“Chondroids”
also called Inspissated exudate
Dried exudate
can look like hyaline cartilage- why they are called chondroids
Guttural Pouch mycosis- fungus can damage internal cartoid a.(unique to fungul infection) - so they can present with epistaxis. This can happen in horses of any age.
- Caused by infection with Aspergillus fumigatus or other Aspergillus species.
- Involvement of cranial nerves (VII, IX, X, XI, XII) is common and result in a variety of clinical signs.
- Erosion of the wall of the internal carotid artery can lead to epistaxis or fatal hemorrhage
Guttural pouch Mycosis- horse.
Mdx?
Multifocal, ulcerative and necrotizing eustachitis
Guttural pouch mycosis, horse
blue arrows- lumen of the internal cartoid a.
Guttural pouch mycosis, horse
Guttural pouch mycosis
you can see blood in the lumen
Guttoral pouch mycosis, horse
What is the difference between Type I and Type II pneumocytes
Type I- More numerous but more succeptible to injury
Type II- can proliferate after injury and can replace the Type I pneumocytes that are destroyed
-Produce surfactant
Guttoral pouch mycosis, horse, AVC, Dr. A. Lopez.
Guttoral pouch mycosis
Which special stains are often used to visualize fungi within tissue sections?
GMS (Gomori’s methenamine silver) stain and PAS (Periodic Acid Shiff) stain.
Nasal Squamous Cell Carcinoma, Cat
slow to metasize, but they invade surrounding tissues
Nasal neoplasia
Nasal carcinoma,
10 year-old dog, AVC
can lead to bleeding and secondary bacterial infections
Enzootic nasal carcinoma (or adenocarcinoma), sheep mostly but can be in cattle
Etiology: Enzootic Nasal Tumor virus (ENTV, an ovine beta-retrovirus)
Tumors are rarer in large animals
Necrotic laryngitis (Calf diphtheria)
Secondary infection by Fusobacterium necrophorum following trauma or viral infection (IBR). Can also occur as part of oral necrobacillosis in calves and swine.
Plaques of ulceration covered by fibrinonecrotic exudate- very characterisitic
Laryngeal hemiplegia (paralysis) – “roaring” horses. Atrophy of the left dorsal cricoarytenoid muscle.
Usually the result of an idiopathic neuropathy affecting the left recurrent laryngeal nerve.
Tracheal collapse: Mainly in toy and miniature dog breeds; occasionally seen in horses, cattle and goats.
results in widening of the trachea
Dorso-ventral flattening of the trachea and concomitant widening of the dorsal tracheal membrane, pony
May result in coughing and exercise intolerance/ respiratory distress
Mainly in toy and miniature dog breeds
IBR- infectious bovine rhinotrachtitis, RED NOSE Cattle
Ulcerative and necrotizing laryngo-tracheitis- almost pathopneumotic
lesions in the upper respiratory tract and can lead to pneumonia; also can see edema of the mucosa
Systemic Herpesvirus infection in neonatal calves
IBR- also can produce abortions and neo-natal death
Canine infectious tracheobronchitis (Kennel cough)
- A variety of infectious agents are often isolated from affected dogs but there is consensus that Bordetella bronchiseptica usually plays a primary role.
- CAV-2, CPIV-2 and to a lesser extend canine distemper virus and Mycoplasma spp., have predisposing roles.
chronic bronchiolitis-emphysema complex
Horses and ponies– chronic bronchiolitis-emphysema complex, “heaves”, “broken wind”, Recurrent Airway Obstruction (RAO). Asthma-like syndrome (used to be known as Chronic Obstructive Pulmonary Disease (COPD)
Severe heaves. The head &neck are extended and the horse shows nasal flaring with mucoid nasal discharge
‘‘Heave line.’’ The hypertrophy of external abdominal oblique muscles as a result of expiratory efforts suggests that the horse has been chronically affected by heaves.
Reoccurent Airway Obstruction (RAO), Heaves. Mucous accumulation contributes to the lower airway obstruction in RAO.
“ Clinical signs are caused by resistance to airflow in the lung because of diffuse bronchoconstriction. They are usually worst in winter when horses stay housed indoors and the ventilation of barns is not optimal”
allergens in the environment trigger this
horse, HE stained histo slide Exposure to aeroallergens are implicated in the pathogenesis of the disease.
not dry hay;
you will see eosinophils because there is an allergic reaction
Blood-Air Barrier
Blood-Air Barrier: Composed of the vascular endothelium, basement membrane of the endothelial cell, basement membrane of the type I pneumocyte and the cytoplasm of the of the type I pneumocyte.
Exercise-induced pulmonary haemorrhage (EIPH)
Exercise-induced pulmonary haemorrhage (EIPH): Relatively common condition in race horses.
-Follows strenuous exercise.
-Epistaxis is present in only 1-10% of affected horses.
- Frequency increases with age and the severity of exertion.
- Probably the result of marked elevations in arterial and capillary pressures during strenuous exercise.
- Haemorrhage occurs in the dorso-caudal portions of the caudal lung lobes.
- Massive pulmonary haemorrhage may be the only detectable lesion in horses that die during exercise .
Epistaxis and pulmonary hemorrhage are relatively common in cattle with vena cava thrombosis
common in feedlot cattle
pulmonary edema, pig
when you open the cavity, the lungs will not collapse- this is how you know there is edema. Also many times you will see rib impressions
Pulmonary edema, pig
frothy
fluid can be present in the interstitum
Pulmonary edema
Main pathogenic mechanisms:
- ↑ hydrostatic pressure (cardiogenic edema).
- ↑ vascular permeability: Injury to the blood-air barrier
- Obstruction to lymphatic drainage: Neoplasia
involving thoracic lymph nodes or vessels.
chronic pulmonary edema and congestion
horse with left sided congestive heart failure
chronic pulmonary edema
edema
increased pulmonary alveolar macrophages
HE-stain, dark brown pigment(hemosiderion) within the cytoplasm of alveolar macrophages, UCVM
Heart Failure Cells
Iron (Perl’s) stain – Hemosiderin-laden macrophages (“heart failure cells” –> siderophages) within alveoli – UCVM.
What pigment is this?
Pigmentary disturbances: Pulmonary anthracosis
Carbon
you see this in poluated cities
Pulmonary atelectasis – bovine fetus; also in stillborn animals
Patchy pulmonary atelectasis due to aspiration of meconium and amniotic fluid-calf, 1 day old, AVC.
Bullous emphysema: Large focal air-filled spaces (bullae) _>rupture may lead to fatal pneumothorax.
Cow with “fog fever”; cow pulmonary edema emphysema
alveolar emphysema- clear bubbles
The emphysema can get very large and involve neighboring alveoli(bullous emphysema)- these will decrease the negative pressure and you get pneumothroax
Bovine, interstitial emphysema
connective tissue is extended and there are air bubbles
BRSV, heifer, Cornell files – Syncytial cells
greyish discoloration is normal in ruminats
There are rib impressions- that tells us that the lungs are enlarged
syncital cells in the lower right- they have mulitple nuclei
BRSV- damage to the respiratory epithelium; more syncitum cells
Chronic suppurative bronchopneumonia, Calf, OVC.
Chronic suppurative bronchopneumonia, Calf,
Abscessation and bronchiectasis( look like absycesses that can be differeniated via histology) are Common sequels of chronic suppurative pneumonia.
Fibrinous bronchopneumonia, OVC.
lots of fibrin- characterisitic
Pneumonic mannheimiosis, steer, from McGavin.
bluish discoloration/uleration and on the surface, you see lots of fibrin
differential dx: Histophilius somni- looks just like this
Pneumonic mannheimiosis: Marbling appearance of the
pulmonary parenchyma.
Mannheimia haemolytica biotype A, serotype 1 is responsible for the severe pulmonary lesions (areas of necrosis etc.)
What type of necrosis? fibrinous nerotizing pneumonia- loss of microscopic details, but perservation of the over all archetecisure
Fibrinous pneumonia, cattle-Cornell files
Chronic necrotizing bronchopneumonia, heifer, UCVM. Mycoplasma bovis was cultured from the lesions, OI, 2008.
Mycoplasma bovis
Necrotizing bronchopneumonia, heifer,
Positive immunoperoxidase staining of M. bovis antigens, from McGavin’s, 2012
Multifocal granulomatous pneumonia, M. bovis, cow, Dr. King-Cornell’s file.
Dictyocaulus filaria –sheep, goats Dictyocaulus arnfieldi –equids (horses, donkeys)
Terminal bronchi from the right caudal lung lobe, pig. Slaughterhouse specimen, St. Kitts. Lung worms are admixed within slightly turbid mucoid exudate. Morphologic dx?.., etiologic dx?…
Diffuse alveolar damage –formation of hyaline membranes –
“fog fever”
Pathogenesis of toxic and allergic pneumonias (“AIP”) in cattle
Suppurative bronchopneumonia, sheep – Pasteurella multocida – from McGavin’s.
Multifocal subpleural pneumonitis – Muellerius capillaris sheep
Interstitial pneumonia-foal, Equine Viral Rhinopneumonitis, Texas A&M, JE.
Interstitial pneumonia due to adenovirus or Pneumocystis carinii Infection are common complication in Arabian foals with SCID (Inherited disorder- autosomal recessive trait- characterized by lack of B and T lymphocytesdie before 5 months of age)
very common in HIV- very similar disease reported in Jack Russell Terriers
Pneumocystosis, Pig, AVC. Foamy( due to Fungi) eosinophilic proteinaceous material within alveoli. Fungal organisms are detected with Gomori’s methenamine silver stain (GMS).
Adenovirus infection, foal, HE.
Interstitial pneumonia due to Pneumocystis carinii infection with concomitant Rhodococcus equi infection in a foal (Arabian CID foal).
6-week-old foal, Chronic pyogranulomatous pneumonia –Rhodococcus equi,
6-week-old foal, Chronic pneumonia –Rhodococcus equi,
Mdx: Pyogranulomatous pneumonia(not suppuralative)
Cytokines, lysosomal enzymes and bacterial toxins are responsible for extensive caseous necrosis of the lungs and recruitment of large numbers of neutrophils, macrophages and giant cells containing numerous intracytoplasmic organisms. Affected foals develop chronic coughing and weight loss.
“Any foal with bronchopneumonia unresponsive to routine broad-spectrum antibiotic therapy should be suspected of having R. equi bronchopneumonia” Equine practice, vol 14 (1): 15-18, 1992.
Foal, Rhodococcus equi– Texas A&M pyogranulomatous enterocolitis/ lymphadenitis
cecum with R. equi
Horse, idiopathic broncho-interstitial pneumonia. Note prominent Type II pneumocyte hyperplasia., HE
Horse, embolic Aspergillus infection (Mycotic pneumonia), Texas A&M, Dr. John Edwards.
embolic- secondary to hematagneous spread
This is an example of embolic pnuemonia
fungal- eosinophilic reaction
Interstitial pneumonia, feeder
pig – highly suggestive of viral pneumonia
Right: Pneumocystosis, Pig, AVC. Foamy eosinophilic proteinaceous material within alveoli. Fungal organisms are detected with Gomori’s methenamine silver stain (GMS). Infections with Pneumocystis carinii are common in pigs with PRRS and PMWS.
- *Pig, enzootic pneumonia**- Multifactorial disease,
- Mycoplasma hyopneumoniae* is the main pathogen involved. The organism induces a suppurative or cattarrhal bronchopneumonia with BALT hyperplasia that is quite characteristic. This highly contagious disease of pigs is influenced by immune status and management factors such as crowding, poor ventilation, humidity and temperature fluctuation in the barns. The disease is characterized by low mortality unless complicated with secondary pathogens.
Porcine Enzootic Pneumonia : Mycoplasma pneumonia (Mycoplasma hyopneumoniae, young piglet, UCVM, O.Illanes. Multifactorial disease.
M. hyopneumonia- looks like salmon
neutrophils in airways
Mycoplasma pneumonia, young piglet, UCVM, OI. The bronchopneumonia is mild to moderate (low mortality) unless complicated with Pasteurella multocida, Arcanobacterium pyogenes, Bordetella bronchyseptica, Haemophilus spp., Mycoplasma hyorhinis etc.).
hyperplasia of the bronchial tissue
Young pig
Glasser’s disease(Haematophilius parasuis)
3-month-old pig, fibrinous pleuritis and pneumonia,
may be a component of Glasser’s disease (Haemophilus parasuis) CVM, Western University of Health Sciences, O.Illanes
Porcine Contagious Pleuropneumonia,
Actinobacillus pleuropneumoniae
dorsal part of the caudal lung lobe-
Porcine Contagious Pleuropneumonia,
Actinobacillus pleuropneumoniae,
Top: Cut surface, contagious
pleuropneumonia, pig
Broncho-interstitial pneumonia, canine distemper
Aspiration pneumonia, dog.
Granulomatous pneumonia, Blastomyces dermatitidis, dog -OVC
Dog, mycotic pneumonia (granulomatous pneumonia). Left: Blastomycosis,
Histoplasmosis
Uremic pneumonitis, dog.
stain for mineral or Ca+=
Cat- Aelurostronglylus abstrusus
lesions primarily in the caudal lung lobes
Aelurostrongylus abstrusus
Snails and slugs are the intermediate hosts. Subpleural nodules contain larvae and eggs, HE.
Aelurostronglylus abstrusus
Cat, pulmonary adenocarcinoma,- malignant
arises from the bronchial epithelium
Ovine pulmonary carcinoma (pulmonary adenomatosis).
Metastatic neoplasms are relatively common. Primary pulmonary neoplasms, largely carcinomas are relatively rare but more common in aged dogs and cats.
In pic on the left- hemanigosarcoma
right- Metastic thyroid gland carcinoma
Mdx: Melanoma, metastatic
Hydrothorax, 8-y-old dog, AVC
Chronic liver disease (end-stage liver, cirrhosis).- Etiology
Hemothorax, dog with ruptured aortic aneurism.
could be result of trauma
Chylothorax, mink,
Fibrnous pleuritis, horse.
“shipping fever”; strep. equi subsp. zooepidemicus
Pyothorax, Pasteurella Multocida, cat
usually ass. with a ruptured pulmonary abysess
Chronic pleuritis with “sulfur granules”, nocardiosis (Nocardia asteroides), Cat.
Mesothelioma – In domestic animals seen mainly in cattle – can be congenital. In humans has been associated with inhalation of asbestos (mining, construction, ship building).
Not very common in animals, but when we do see them, they are in cattle
Fibrinosuppurative pleuropneumonia, rabbit –P. Multocida,
Pasteurellosis is a common disease in domestic rabbits. P.multocida can result in rhinitis (“snuffles”), pneumonia, abscesses, reproductive tract infections, ear infections and septicemia.
Emu,
Mycotic airsacculitis – Aspergillus spp.
thickened, with fibrin exudate on the air sacks
Emu, granulomatous pneumonia – Aspergillus, spp.
Ddx: neoplasia, or mycoplasma
