Unit 1 Flashcards
What are the defense functions that the respiratory epithelium specifically has
A basement membrane, goblet cells to produce mucous, ciliated cells, Type 1 and 2 alveolar cells
What makes up the mucociliary apparatus
A gel layer, a sol layer, ciliated cells, goblet cells, and BALT
Give some examples of things that can negatively impact the mucociliary apparatus
Dehydration, low humidity, anesthesia, aerosols, airway disease, Infections, having head tied up (LA), congenital defects
What is the difference between type 1 and 2 alveolar cells
Type 1- “lining” cells- make up >95% of the surface area of the alveoli
Type 2- secrete surfactants but can also proliferate/differentiate into type 1
What are the roles of the alveolar macrophages
They phagocytize organisms/particles (major innate immunity effector)
Immune system recruitment
cytokine production
What is BALT
bronchiole alveolar lymphoid tissue- local secondary lymphoid tissue
can orchestrate acquired immune responses
What is lactoferrin
an antimicrobial peptide produced by serous cells and neutrophils that inhibits bacterial growth by sequestering iron and producing peroxide to attack LPS (kills gram negs)
What is lysozyme
an antimicrobial peptide produced by serous cells, neutrophils, macrophages, and epithelial cells that attacks peptidoglycan (kills gram positives)
What are pattern recognition receptors
receptors on the membrane/in cytosol of white blood cells and epithelial cells that recognize specific substances that indicate infection or injury and activate immune responses
What are pathogen- associated molecular patterns (PAMPs) and give an example
A PRR that uses something on an infectious organism to recognize the intruder
ex. TLR-4–> bacterial LPS
What are damage- associated molecular patterns (DAMPs) and give an example
A PRR that recognizes non-infectious host or “self” problems
ex. DNA following tissue injury
What is the primary location of action of IgA
the nasal cavity and upper airway (URT and mucosal surfaces)
What is the primary location of action of IgG
Lower airway/alveoli
pulmonary interstitium
What does stertor sound like
snoring, snorting, snuffling
aka Uga!
What are the broad causes for stertor
excess extra-thoracic tissues or accumulation of secretions, can occur with inhale or exhale
Where may you think the disease is localized to if an animal has stertor
to the nasal passages or nasopharynx
What does stridor sound like and when does it occur (in regards to inspiration or expiration)
intense, high-pitched wheezing primarily during inspiration
what is the most concerning breath sound
stridor (= “die”dor)
give me 4 differentials for stridor
laryngeal paralysis or collapse, upper tracheal collapse, laryngeal/tracheal obstruction (fb, mass, swelling)
What causes crackles and give some differentials
The snapping open of small airways that have collapsed or accumulated fluid/debris
ex. from pulmonary edema or fibrosis, pneumonia, pulmonary hemorrhage, atelectasis
what is the timing of wheezes
early expiration or end inspiration
What are some differentials for wheezes
asthma, lower airway obstruction, anaphylaxis
what is the normal respiratory rate for a dog and cat
dog- 18-34, cat- 16-40
What is the location associated with obstructive inspiratory dyspnea and give some differentials
extra-thoracic obstruction
laryngeal/tracheal obstruction- laryngeal paralysis, tracheal collapse, mass
What are the locations associated with obstructive expiratory dyspnea and give some differentials
intra-thoracic- asthma, bronchitis
parenchymal lung disease- interstitial pneumonia, pneumonitis
What causes restrictive dyspnea
pleural space disease- pneumothorax, pleural effusion
What is a A-line vs. a B-line
A-lines are horizontal lines caused by reverberation artifact from air in the lungs
B-lines are vertically oriented “comet tail” appearing artifact meaning there is a wet or infiltrated lung
Briefly explain how pulse oximetry works
It measures unabsorbed light and emits red and infrared lights (oxygenated blood absorbs infrared and deoxygenated absorbed red light)
What is hypoxemia defined as in terms of SpO2 and PaO2
when SpO2 is 93% or less and PaO2 is less than or equal to 80 mmHg
In what animals is open mouthed breathing really bad
horses and cats
A horse has periodic unilateral epistaxis that isn’t too bad. What might he have
ethmoid hematoma
A 1 week old piglet is sneezing and has tear staining and nasal discharge. What might he have
atrophic rhinitis
Which pathogen causes non progressive and progressive atrophic rhinitis
non progressive- bordatella bronchiseptica
progressive- pasturella multocida
What disease causes turbinate atrophy in piglets
progressive atrophic rhinitis
What are secondary causes of bacterial sinusitis
tooth root abscess (in the rostral or caudal maxillary sinuses, premolars most common)
masses
iatrogenic- dehorning, nasogastric reflux (horses under anesthesia)
What are clinical signs associated with retropharyngeal abscess
dysphagia, excessive salivation, stertor
What are the common causes of retropharyngeal abscesses in cows and sheep/goats
cattle- iatrogenic- dose syringe or coarse feed
sheep/goats- caseous lymphadenitis (from corynebacterium pseudoturberculosis
What are causes of retropharyngeal abscesses in horses
Pharyngeal trauma- eating stemmy hay or nasogastric tube placement
Strangles
A horse farm calls you because they have a horse with fever, depression, mucopurulent nasal discharge, and a swollen guttural pouch. After examining the horse and treating it what recommendation should you make
This is likely strangles and is highly contagious so the horse should be isolated from others and the farm should not allow any horses to enter or leave (in the state if Georgia this is reportable and the farm will be quarantined) also any shared equipment should be thoroughly cleaned and sanitized
What 2 traits does streptococcus equi equi have to help it succeed
m-protein which helps to resist phagocytosis and is immunogenic
Polysaccharide capsule to help with attachment and resist phagocytosis
What is the most common lymph node to abscess with strangles
submandibular
What are some nerve issues strangles can cause
dysphagia, facial paralysis, Horner’s
What is the gold standard for strangles diagnosis
aerobic culture (not normal flora)
What are some immune-mediated complications following strangles
Purpura hemorrhagica
myositis
myocarditis
glomerular nephritis
At what stage of strangles should you not treat it with antibiotics
when it is in the lymphadenopathy stage (not early or late). Will stop them from being able to develop immunity for the future and once antibiotics were stopped the Strangles would likely come back
what is the risk with using the strangles vaccine
it can still cause purpura hemorrhagica
when is the only recommended time to use the strangles MLV IN and what precaution should be considered in regards to giving it
only if there is a significant risk of infection
You should remember the horse might sneeze some of the vaccine out and it can infect and cause an abscess if there is any little cut on the horse (so don’t give any other vaccines that day)
A horse has a history of periodic epistaxis and then one day the owner comes to the barn to discover the horse is dead from severe bilateral epistaxis. What likely happened
The horse likely had guttural pouch mycosis
What may you see on endoscopy of a horse with guttural pouch mycosis
gray/white/yellow/black fibronecrotic fungal plaques over an artery or maybe blood clots
What is the best course of treatment for guttural pouch mycosis
obstruct the carotid artery on the affected side
Which breeds are more prone to laryngeal hemiplegia
Taller breeds
What occurs during laryngeal hemiplegia and what side is more commonly affected
The arytenoid cartilage is not abducted properly during inspiration, the left side is more commonly affected
Can be from any injury to the vagus or recurrent laryngeal nerve
Which equine herpes virus can cause more systemic issues (lymphocyte associated viremia)
EHV-1
What is EHV pathogenesis
Vascular endothelial cells
-vasculitis and tissue necrosis
How do you diagnose EHV
Viral isolation or PCR on the Buffy coat or nasal swab/wash
When do you want to vaccinate horses for EHV
At risk horses every 6 months and pregnant mares (killed vaccine) at 5,7,9 months of gestation
What are the clinical signs of equine influenza virus
Cough, fever, nasal discharge, inappetance in any aged horse
What is the pathogenesis for EIV
Viral replication—> cell death—> lesions in lower airway and impaired mucocilliary clearance—> prime set up for secondary bacterial infections
T/F there isn’t a vaccine for EIV
False
How long should you rest horses who have had EIV
One week for every 1 day of fever
What virus causes fever, conjunctivitis, abortions, fatal pneumonia in foals, and has carrier stallions
Equine arteritis virus
Which equine virus causes mild respiratory signs and submandibular lymphadenopathy
Equine rhinitis virus
Which virus causes fatal respiratory disease in SCID Arabian foals
Equine adenovirus
What is the distribution of pneumonia
Cranioventral
How are pleuropneumonia and bronchiopneumonia different
Bronchiopneumonia affects the lungs while pleuropneumonia affects that and the pleural space (causing pleural effusion and fibrin)
Name some risk factors for pneumonia in horses
Travel (esp. head tied), general anesthesia, esophageal obstruction (choke)
What is the most common isolate for pneumonia in horses
Streptococcus equi zooepidemicus
What disease can have clinical signs of pleurodynia (pleural pain, which may look like laminitis because the horse doesn’t want to walk) and pectoral edema
Pneumonia
What is the best way to diagnose pneumonia
Transtracheal aspirate
What is the treatment for pneumonia
Broad spectrum oral or parenteral antibiotics (penicillin, gentamicin, metronidazole, enrofloxacin)
Supportive care
Anti-endotoxin therapy (meglumine, polymixin B, low dose flumixin)
What bacteria affects foals ages 3 weeks to 6 months and can also cause swollen joints, yellow eyes
Rhodococcus Equi
Where can Rhodococcus equi be found (like on cytology)
Intracellularly in the alveolar macrophages
How do you get a presumptive and definitive diagnosis for R. Equi
Presumptive- signalment and leukocytosis + hyperfibrinogenemia, imaging
Definitive- Transtracheal aspirate or PCR for vap A
How do you treat Rhodococcus equi
Macrolide + rifampin
(Macrolides- erythromycin, azithromycin, clarythromicin)
What are important side effects with the drugs used to treat Rhodococcus equi
Macrolides- hyperthermia and fatal diarrhea in adults
Rifampin- stains all body secretions orange-red
Describe the 2 forms of equine asthma syndrome
Recurrent airway obstruction aka severe equine asthma, typically >7 years old, coughing and tachypnea at rest, heave line
Inflammatory airway disease aka mild to moderate equine asthma, young/any age, no clinical signs at rest usually cough with exercise
What would you see on a bronchioalveolar lavage of a horse with asthma
Increased neutrophils and maybe eosinophils and mast cells, maybe mucus and Curschmann’s spirals
What would you see on radiographs of a horse with heaves (RAO)
Bronchointerstitial pattern
What is the most important management for equine asthma
Environmental- limit airborne allergens
What are the two medical mainstays of treatment for equine asthma
Steroids and bronchodilators
A horse who lives with a donkey presents coughing and with nasal discharge but doesn’t have a fever. What are you thinking it could be?
Lungworms- dictyocaulus arnfieldi
How do you diagnose lungworms
Baermann for species with larval shedding or fecal flotation to ID eggs
Infection often not patent in horses
What are the lung worm types for cattle and pigs
Cattle- Dictyocaulus viviparus
Pigs- Metastrongylus apri
What is the treatment for lung worms
Avermectin anthelmintics
You see a cow with blood pouring out of its nose and mouth, what type of pneumonia can cause this and how
Metastatic pneumonia from rumen acidosis causing a liver abscess which has septic emboli with go to the lungs causing a pulmonary aneurism
What are important pathogens for bronchiopneumonia in cattle (bacterial and viral- just the ones highlighted in class)
Viral- BRSV, coronavirus
Bacterial- Mannheimia haemolytica (also mycobacteria bovis)
In a calf with bronchopneumonia what might you see
Fever, lethargy, depression, increased respiratory effort
Which is the most common cause of morbidity in stocker/feedlot calves
Respiratory disease/shipping fever
T/F recently castrated feedlot bulls are at a higher risk of developing bronchiopneumonia
True
How can you reduce the risk of BRD
Feeding high quality nutrition (waste or saleable milk or >4L of milk per day)
Administration of vaccines to dry cows prior to calving
Reducing stress and over crowding
T/F Mannheimia haemolytica has few serotypes because they are all pathogenic
False, there are 12 serotypes and only some are pathogenic
Describe 2 virulence factors that Mannheimia haemolytica has that help it cause damage
Leukotoxin which helps it bind to neutrophils to cause necrosis and has the neutrophils release their own digestive enzymes causing damage
LPS which also binds to neutrophils and can cause more neutrophils to be recruited, the activation of neutrophils, and endothelial cell activation
You are called out to a feedlot because several of their bulls are sick and a few have died. You do a necropsy and see lungs covered in fibrin and are necrosed. What disease is this likely to be
Mannheimia haemolytica
What is the gold standard treatment for M. haemolytica
Antibiotics- the best are tulathromycin, fluoroquinolones (enrofloxacin and danofloxacin), and florfenicol
You go out to a farm who has suddenly had a cow die from severe epistaxis and hemoptysis causing exsanguination. What disease could have caused this and what is your recommendation for the farmer
Metastatic pneumonia secondary to septic emboli causing thrombosis of the vena cava as a sequalae to rumen acidosis from improper rations high in fermentable carbohydrates
The farmer needs to get a more balanced ration
What would you look for on ultrasound if a cow might have metastatic pneumonia
What would you see on necropsy
On ultrasound you would find the caudal vena cava and see if it is dilated (not a triangular shape but round) which shows dilation because of a thrombotic occlusion
On necropsy you would see intrapulmonary hemorrhage (really bloody lungs)
How can you treat metastatic pneumonia
Prognosis is usually pretty poor, the best thing to do is nutritional management to prevent the loss of more cows
You are called out to a farm because a cow is standing there gasping for air/ has a loud grunt on expiration. It also happens to be springtime. What disease are you concerned about?
Interstitial pneumonia or “fog fever”
Other than lush pastures what are some other causes of interstitial pneumonia in cows
BRSV infection, Perilla mint ketone, 4-ipomeanol (moldy sweet potatoes)
What is the best thing to do if a farm has cows dying of fog fever
Carefully remove unaffected animals from the pasture, no specific treatment for animals showing clinical signs
You are called out to another feedlot (gosh they have a lot of unhealthy cattle). There are some calves around 12 months old that have a moist cough and seem to be in a lot of pain, they are also dyspneic with stertor. What disease are you concerned about
Necrotic laryngitis
What is the pathophysiology of necrotic laryngitis
Ulcers develop on the larynx from viral infections causing coughing or swallowing and erosion of the membranes which then allows F. Necrophorum (a respiratory commensal) to invade and necrose the arytenoid cartilage
Quick! You rush out to a farm for a 6 month old calf that is struggling to breath. When you get there he has stertor to his breathing and you think it could be necrotic laryngitis. Being the smart vet you are you know the calf needs steroids and antimicrobials but what can you do to help it breathe now?!
A tracheostomy can help until the steroids have time to kick in
