Respiratory Flashcards
Cough can be evoked by stimulation of cough receptors located where?
Larynx, tracheal, large bronchi. Cough receptors are not found in the lower airway
Describe the sequence of events in a cough
Deep inspiration, rapid expiration against a closed glottis, followed by opening of the glottis, closure of the nasopharynx and forceful expiration through the mouth
Irritation of what structures leads to an expiration reflex?
Vocal cords/larynx or upper trachea
Describe the sequence of events in a expiration reflex
Forced expiration against a closed glottis, not preceded by a large inspiration (“huffing”)
What is the goal of a cough? Of an expiration reflex?
Cough: force clearance of mucus and foreign material from the trachea and bronchi (lower airway disease)
Expiration reflex: prevent entry of noxious material into the airways (upper airway irritation)
Name 4 causes of hemoptysis
Lung tumors, bleeding disorders, PTE, heartworm disease, lung worm disease
What is the scientific name of the French heartworm?
Angiostrongylus vasorum
What is the scientific name of the cat lungworm?
Aelurostrongylus abstrusus
What causes reverse sneezing?
Irritation of the nasopharyngeal mucosa leads to spasming of the pharyngeal muscles, leading to obstruction of air passage
Name 4 differentials for reverse sneezing
Nasopharyngeal foreign body, nasal mites, viral infection, allergic rhinitis, epiglottic entrapment of the soft palate
Stertor occurs from obstruction of airflow in what location?
Nasopharynx - resolves with open mouth breathing
Central chemoreceptors measure what in the arterial blood?
Carbon dioxide levels
Peripheral chemoreceptors measure what in the arterial blood?
Both carbon dioxide and oxygen levels
List 6 causes of hypoxemia
Decreased FiO2, hypoventilation, diffusion impairment, VQ mismatch, right to left cardiovascular shunting, hemoglobin abnormalities
Increased inspiratory effort localizes disease to what portion of the respiratory tract?
Upper airways: nasal passages, pharynx, larynx, extra thoracic trachea
Increased expiratory effort localizes disease to what portion of the respiratory tract?
Intrathoracic trachea, large bronchi, lower airways
A restrictive breathing pattern localizes disease to what portion of the respiratory tract?
Pulmonary parenchyma or pleural space disease
Blood pressure must fall by at least ___% for a minimum of ____ seconds to induce syncope
50% for 10-30 seconds
What are the causes of cardiogenic syncope?
Bradyarrhythmias that result in asystole (sick sinus syndrome, high degree 2nd or 3rd degree AV block). Rapid, sustained ventricular tachycardia.
Define central cyanosis vs peripheral cyanosis
Central = systemic deoxygenation of arterial blood
Peripheral = localized reduction in oxygenated hemoglobin
Name 4 causes of ventilation-perfusion mismatch
PTE, pulmonary infiltration: pneumonia, edema, neoplasia, hemorrhage, fibrosis
Name 3 causes of hypoventilation
Elevated pleural pressure (pleural effusion or pneumothorax), depressed respiratory drive (neurologic disease, toxin) and respiratory muscle failure
A young animal presents with differential cyanosis (cyanosis on the caudal half of the body only). What is your differential diagnosis?
Right to left PDA
Name two oxidants that can result in methemoglobinemia
Acetominophen, benzocaine, nitrites, nitrates
Cyanosis will not improve with supplemental oxygen therapy when it is due to what conditions?
Right to left shunting, methemoglobinemia
Name two treatments of methemoglobinemia
Methylene blue, N-acetylcysteine
What muscle is responsible for opening the glottis by causing external rotation and abduction of the arytenoid cartilages?
Cricoarytenoideus dorsalis muscle
Autosomal dominant, congenital laryngeal paralysis is described in what breed?
Bouviers des Flandres
What anesthetic agents are the best choice for a functional laryngeal exam?
Propofol +/- alfaxalone
What drug can be administered during a functional airway exam to increase respiratory rate and effort?
Doxapram
What is the most commonly used surgical technique to correct laryngeal paralysis?
Unilateral arytenoid lateralization
Aspiration pneumonia occurs post-operatively in what percent of dogs surgically treated for laryngeal paralysis?
10-21%
In cats, laryngeal paralysis is more commonly unilateral. What side is more commonly affected?
Left
Name 3 causes of laryngeal paralysis in cats
Neoplastic invasion, trauma, iatrogenic damage from thyroidectomy
What are the components of Norwich Terrier airway syndrome?
Redundant supra-arytenoid folds, laryngeal collapse, everted laryngeal saccules, narrowed laryngeal openings
Laryngeal collapse most commonly occurs secondary to what condition?
BOAS or other chronic upper airway obstruction
What defines stage I laryngeal collapse?
Eversion of the laryngeal saccules into the glottis. The tissue is then exposed to turbulent airflow, resulting in edema and inflammation
What defines stage II laryngeal collapse?
Cuneiform processes of the arytenoid cartilages lose rigidity and collapse into the laryngeal lumen. Aryepiglottic folds also collapse ventromedially
What defines stage III laryngeal collapse?
Corniculate processes of the arytenoid cartilage collapse toward midline (complete collapse)
How is laryngeal collapse treated?
Removal of everted laryngeal saccules, correction of any upper airway obstruction (stenotic nares, long palate, etc). Can try unilateral arytenoid lateralization or tracheostomy
What nerve innervates the muscles of the larynx
Recurrent laryngeal nerve: cranial portion goes to the cricothyroideus. Caudal goes to all other muscles
Autosomal recessive congenital laryngeal paralysis occurs in what breed and is associated with mono neuropathy of the recurrent laryngeal nerve?
Alaskan Huskies
Congenital laryngeal paralysis in Alaskan Huskies is associated with what other phenotypes?
Blue eyes (92%), white facial markings (76%), oral mucosal tags or tissue bands
Congenital laryngeal paralysis and polyneuropathy in Black Russian Terriers and Rottweilers has been associated with what gene mutation?
RAB3ABP1
Juvenile onset polyneuropathy (motor and sensory involvement) in Americal Staffordshire Terriers was associated with laryngeal paralysis in how many cases?
10/14 (71%)
Dogs with laryngeal paralysis had more abnormal swallowing studies than age matched controls. What phase of the swallowing study was most abnormal?
Liquid phase, worse in cervical and cranial thoracic esophagus
What nerve innervates the cranial esophagus and may be involved in esophageal dysmotility in GOLPP dogs?
Pararecurrent laryngeal nerves
Name 2 risk factors for the development of aspiration pneumonia following unilateral arytenoid lateralization
Administration of opioids, post-operative megaesophagus
What percent of dogs presenting for chronic cough alone (no upper respiratory signs) displayed evidence of laryngeal hyperemia? Laryngeal dysfunction?
Hyperemia in 73%, dysfunction in 19%
In a randomized, controlled clinical trial, did doxepin improved QOL in Labradors with GOLPP?
No. Not at all. Haha
Does Carol Reinero occasionally apply medicinal leeches to sublingual hematomas?
Yes. Yes she does.
Owners reports that the majority of Norwich Terriers with upper airway syndrome have what kind of QOL?
Excellent (81% with QOL scores <3 out of 40)
Vocal fold granulomas have been identified in what type of dog and are thought to result from what processes?
Brachycephalics. Thought to arise from chronic inspiratory effort/air turbulence or GERD => chronic laryngeal inflammation
Describe epiglottic retroversion
Intermittent, spontaneous, epiglottic retroflexion during inspiration, resulting in obstruction of the rim glottis
Dogs with epiglottic retroversion typically present with what clinical signs? What is the typical signalment?
Stridor, dyspnea. Older, small breed dogs, female > male
What percent of dogs with epiglottic retroversion have concurrent upper airway disease?
79%
Surgical correction of epiglottic retroversion decreases respiratory crisis from 62.5% to what?
25%
The two most common laryngeal neoplasms in cats are:
Lymphoma, squamous cell carcinoma
How does the larynx of cats differ from dogs?
The arytenoid cartilages lack cuneiform and corniculate processes, no aryepiglottic folds or laryngeal saccules
What breed is most commonly affected by acquired laryngeal paralysis?
Labradors
Why are clinical signs of laryngeal paralysis worsened by heavy exercise, hot or humid temperatures?
Increased respiratory rate leads to inflammation and edema of the mucosa covering the arytenoids
30% of dogs with laryngeal paralysis have what concurrent disease?
Hypothyroidism (causal link not determined)
In a study of more than 400 cats, what was the most common diagnosis on nasal biopsy?
Rhinitis (53%), followed by neoplasia (33%), followed by polyps (20%)
In a study of more than 400 cats, what was the median age at the time of diagnosis of nasal neoplasia?
11 years
In a study of more than 400 cats, what were the most common nasal tumors
Lymphoma (51%), adenocarcinoma (38%)
In a study of more than 400 cats, polyps were more common in cats with what signalment?
Young male cats
Name 5 systemic diseases that result in nasal signs
Coagulopathies, severe hypertension, hyperviscosity syndromes (multiple myeloma, Ehrlichiosis), systemic infections (Distemper, Ehrlichiosis, Leishmaniasis), Dysautonomia, Vomiting/regurgitation
Dolichocephalic breeds are ____ times more likely to develop nasal neoplasia than mixed breed dogs
2.5
What are the most commonly identified canine nasal tumors?
Adenocarcinoma, undifferentiated carcinoma, chondrosarcoma, squamous cell carcinoma
What bacteria has been identified in cats with chronic rhinitis, but not control cats, suggesting it may be pathogenic?
Mycoplasma
If using antibiotics to treat cats with chronic rhinitis, how long should the antibiotic course be?
6-8 weeks
Is famciclovir virostatic or virocidal?
Virostatic
How does lysine exert an anti-viral effect?
Competes for arginine, an essential animo acid for viral replication
In a study of 42 dogs with nasal foreign bodies, what was the signalment of the dogs?
Young (76% less than 7 years) and large breed (BW 22kg). Mainly presented for sneezing
In a study of 42 dogs with nasal foreign bodies, what was the most common foreign body?
Grass awns (90%)
In a study of 25 dogs with chronic idiopathic lymphocytic rhinitis, how many had endoscopic gastrointestinal lesions?
22 (88%)
Name 4 symptoms of aural inflammatory polyps in cats
Chronic otitis externa, head tilt, otorrhea, Horner’s syndrome, ataxia, nystagmus, circling, facial paralysis
Name 4 potential complications after polyp removal
Horner’s syndrome, vestibular symptoms, facial nerve paralysis, chronic otitis media/interna. Can be temporary or permanent
What percent of cats develop Horner’s after removing a polyp via traction avulsion?
43%
What percent of polyps recur after removal? What is the typical time frame for recurrence?
33-57%. 19 days to 46 months later (anytime, really haha)
What is a feline nasal chondromesenchymal hamartoma?
Inflammatory polyp of the nasal turbinates
What is the most common cause of nasopharyngeal stenosis in dogs?
Aspiration after an anesthetic event
What are the most common causes of nasopharyngeal stenosis in cats?
Chronic inflammatory disease, viral infections, congenital scar tissue development
In cats with a perforate NPS, balloon dilation alone is effective what percent of the time?
50%
Balloon dilation of an imperforate NPS alone has what rate of recurrence?
95%
What substance can be instilled into the region of the NPS after balloon dilation to try prevent recurrence?
0.1% Mitomycin C
If no stent is being placed, what size should be the balloon be for dilation of a NPS?
1mm larger than the measurement of the “normal” nasopharynx
If a stent is being placed, what size should be the balloon be for dilation of a NPS?
50-60% of the diameter of the “normal nasopharynx on CT scan
What is are most common complications with NPS stent placement?
Tissue ingrowth (33% of open stents), chronic infections (23% of open, 54% of closed stents), oronasal fistulas (20%), stent fracture
What percent of patients with a nasopharyngeal stent will develop a complication?
68%
What is the most common form of aspergillosis in cats?
Sino-orbital form - invasive form
In cats, what facial conformation is more predisposed to Aspergillosis infections?
Brachycephalic (> 1/3 cases)
What arm of the immune system is responsible for clearance of fungal infections?
CD4+ Th1 cells, phagocytes
Many cats with sino-nasal aspergillosis present for what clinical sign? How often are nasal signs present?
Ocular signs are most common (unilateral exophthalmos, conjunctival hyperemia, third eyelid prolapse). Nasal signs absent in 40%
What is the treatment for feline Sino-orbital aspergillosis
Posaconazole (most A. viridinutans resistant to others)
What adverse effects have been described in cats given voriconazole?
Severe neurologic effects - hindlimb paraplegia, blindness
Name 4 clinical signs of Aspergillus fumigatus infection in dogs
Chronic mucopurulent nasal discharge, nasal pain, ulceration and depigmentation of the nasal planum, epistaxis
In dogs treated with debridement of Aspergillus plaques and instillation of clotrimazole cream, what percent were cured after one treatment? Overall?
68% after one treatment, 94% overall cure rate
Does topical clotrimazole result in neurologic signs in dogs with cribriform plate lysis?
No
What oral drugs have been shown to be effective in the treatment of refractory canine sino-nasal aspergillosis?
Posaconazole, voriconazole, terbinafine
ELISA testing for Aspergillosis antibodies have what sensitivity and specificity for sinonasal disease?
High specificity (97-98%) but moderate to low sensitivity (30-70%) - so a negative test does not rule out the disease
How much more at risk for aspiration pneumonia are brachycephalic breeds compared to non-brachycephalic breeds?
3.77x increased risk
What is the typical age of onset of aspiration pneumonia in Frechies/Bulldogs compared to pugs?
Frenchies/Bulldogs are young (6-8 months), Pugs older (83 months = 6 years)
What is the most commonly identified risk factor for aspiration pneumonia in brachycephalics?
History of GI signs
What lower airway abnormality has been identified in brachycephalics? Which breed is most affected?
Fixed bronchial collapse (left cranial bronchus most affected). Most common in Pugs
The odds of a brachycephalic dog needing a temporary tracheostomy tube after BOAS surgery increases by what percent with each year of age?
30% (OR 1.3)
Using whole body plethysmography, what was decreased in brachycephalic dogs compared to controls?
Minute volume
In dogs with tracheal collapse, softening of the cartilage rings is secondary to a reduction in what content?
Glycosaminoglycans, chondroitin sulfate
West Highland White terriers have been shown to develop tracheal collapse due to increased pressure from what disease process?
Idiopathic pulmonary fibrosis leading to decreased lung compliance
Name 3 clinical signs of tracheoesophageal or bronchoesophageal fistulas
Chronic cough, recurrent respiratory infections, gas accumulation in the GI tract
Name two canine lungworms capable of causing tracheal granulomas
Oslerus osleri, Filaroides osleri
What parasite has been found in the trachea of cats?
Cuterebra
Cytology of an airway wash in a dog with chronic bronchitis would reveal what abnormalities?
Epithelial hyperplasia, increased numbers of neutrophils, macrophages, and goblet cells
Concurrent administration of what drug with theophylline can lead to theophylline toxicosis?
Fluoroquinolones
What is the characterization of the immune response in eosinophilic bronchopneumonopathy?
Infiltration of eosinophils and CD4+ Th2 cells (likely a hypersensitivity reaction)
What breeds are primarily affected by eosinophilic bronchopneumonopathy?
Siberian Huskies and Malamutes
Name 3 clinical signs of eosinophilic bronchopneumonopathy
Cough, gagging, and retching. Nasal discharge in 50%
How often do dogs with eosinophilic bronchopneumonopathy have a peripheral eosinophilia?
60% of the time
Angiostronglyus vasorum is spread through what intermediate hosts?
Snails, slugs
Name 3 clinical signs of angiostronglyus vasorum infection
Respiratory signs (eosinophilic pneumonitis), bleeding tendencies, neurologic signs
What are the thoracic radiographic findings with Angiostronglyus vasorum infection?
Bronchointerstitial or alveolarintersitial pattern, worse on the peripheral or caudodorsal lungs
What is Kartagener’s syndrome?
Primary ciliary dyskinesia leading to bronchiectasis, complete left-right transposition of viscera, and chronic rhinosinusitis
Autosomal recessive primary ciliary dyskinesia has been identified in many breeds. What breed has a mutation in CCDC39 causing the disease?
Old English Sheepdogs
Other than respiratory disease, name 3 diseases that can be caused by primary ciliary dyskinesia
Otitis media, decreased sperm motility, hydrocephalus, renal fibrosis or dilation of the renal tubules
What are the hallmark respiratory features of primary ciliary dyskinesia?
Recurrent bilateral nasal discharge, repeated episodes of bronchitis or bronchopneumonia since birth
How is primary ciliary dyskinesia diagnosed?
Scintigraphy to demonstrate decreased mucociliary clearance. Electron microscopy of cilia
Primary ciliary dyskinesia is associated with defects in what part of the cilia?
Inner or outer dynein arms
A rhinitis/bronchopneumonia syndrome (similar to primary ciliary dyskinesia) has been identified in what breed?
Irish Wolfhounds
The most widely used CT criteria for diagnosing bronchiectasis is the bronchoarterial ratio. Healthy dogs have a ratio up to what number?
Up to 2
What is the difference in etiology between feline chronic bronchitis and feline asthma?
Chronic bronchitis arises from prior insult resulting in permeant airway damage. Asthma is allergic in origin
Name 3 hallmark features of asthma
Reversible airway inflammation, consequent airway obstruction/airflow limitation, airway hyper responsive and changes (smooth muscle hypertrophy, excess mucus production, bronchial wall edema)
What percent of asthmatic cats have a peripheral eosinophilia?
20%
What percent of asthmatic cats have hyperglobulinemia?
14-50%, depending on the study
In healthy feline airways, what should the eosinophil percentage be in BALF?
<5%
Name 4 parasites that can cause feline bronchial disease?
Aerulostrongylus abstrusus, Eucoleus aerophilus, Dirofilaria immitus, Wolbachia, Toxocara cati
What is the most common cause of spontaneous pneumothorax in cats?
Feline asthma
A recent study examining fluticasone use in feline asthmatics found that what dose is most effective?
44mcg q12 (as effective as 220 mcg)
Daily albuterol use has been shown to cause what in asthmatic cats?
Increased severity of airway inflammation
Nebulization is not beneficial in cats due to what?
Bronchospastic reactions
What is the equation for determining the A-a gradient?
150 - (PaO2 + PaCO2) as determined by ABG
What is a normal A-a gradient? What indicates a V-Q mismatch?
<10 is normal. >20 is a V-Q mismatch
What is the function of brain natriuretic peptide (BNP) in the body?
Promotes natriuresis, increases GFR, causes vasodilation, antagonizes renin system
What causes BNP to increase?
Volume overload, pulmonary hypertension, cardiac dysfunction/heart failure - all things that turn on RAAS and lead to increased fluid
What is NT-proBNP and why is it used as a diagnostic marker instead of BNP?
The prohormone is cleaved into NT-proBNP and active BNP. NT-proBNP has a longer half-life, so more useful diagnostically
NT-proBNP concentrations can increase with what non-cardiac disease?
Azotemia
What two intestinal parasites migrate to the lungs before reaching the intestines and can cause respiratory signs with massive migrations?
Toxocara (roundworms) and Ancylostoma (hookworms)
What is the treatment for lungworms
High dose fenbendazole (50mg/kg PO q24) for 10-14 days
What is a side effect of albendazole that is typically not seen with fenbendazole?
Bone marrow toxicosis
What is the scientific name for the lung fluke in dogs and cats?
Paragonimus kellicotti
What is the intermediate host for Paragonimus kellicotti?
Crayfish
What radiographic changes can be observed with Paragonimus kellicotti infection? What are the clinical consequences of these structures?
Pulmonary bullae and cysts - rupture can lead to hemoptysis or pneumothorax
How is Paragonimus kellicotti detected?
Fecal sedimentation or airway wash
What lung parasite resides in the alveolar space and terminal bronchioles and is transmitted by the direct fecal-oral route?
Filaroides
Most lungworms can be detected on what fecal test?
Baermann
What bacteria causes hemorrhagic, necrotizing pneumonia in dogs?
Streptococcus equi subspecies zooepidemicus
Any coughing cat in the western US should be isolated and tested for what disease?
Plague - Yersinia Pestis
How are cats infected with Yersinia Pestis?
Ingestion of a reservoir host - rodents, rabbits, or flea bite
What is the most common first sign of Yersinia Pestis infection in cats?
Suppurative lymphadenitis (buboes) in the submandibular and cervical lymph nodes
The bubonic form of plague can then spread into one of two forms. Name them
Septicemic plague or pneumonic plague
Cytologic examination of exudate or LN aspirates in a cat with Yersinia Pestis should reveal what?
Bipolar, safety-pin shaped, gram negative rods
What is the treatment for Yersinia Pestis?
Aminoglycosides, fluoroquinolone, tetracyclines, or chloramphenicol
What influenza viruses have caused outbreaks among dogs?
H3N8 (Greyhound kennel outbreak, likely equine origin), H3N2 (avian origin)
What fungal disease is found in young, presumably immunocompromised Miniature Dachshunds and Cavalier King Charles Spaniels?
Pneumocystis carinii
What is the treatment for Pneumocystis carinii?
Potentiated sulfonamides
How does the pathophysiology of cardiogenic and non-cardiogenic pulmonary edema differ?
Cardiogenic edema develops from increased hydrostatic pressure. Non-cardiogenic edema develops from increased vascular permeability +/- epithelial damage
What is the cause of hypoxemia secondary to pulmonary edema?
V-Q mismatch
How do interstitial lung diseases result in respiratory signs?
Restrict effective lung volume and decrease lung compliance
Eosinophilic pneumonia of undetermined origin is more common with what signalment?
Young, female Siberian Husky, Alaskan Malamute, Rottweiler
What are the radiographic findings with eosinophilic pneumonia of undetermined origin?
Dense bronchointerstitial pattern with dense infiltrates that can be mistaken for nodules
What is one of the most common diseases associated with bronchiectasis in dogs?
Eosinophilic pneumonia of undetermined origin
How does pneumocyte injury lead to endogenous lipid pneumonia?
Damaged pneumocytes release cholesterol and overproduce cholesterol-rich surfactant. Lipids are then phagocytose by pulmonary macrophages, which accumulate in the alveoli
What dog breeds are predisposed to idiopathic pulmonary fibrosis?
West Highland White Terriers, Staffordshire Bull Terriers
What is the median survival time of dogs with idiopathic pulmonary fibrosis? Cats?
Dogs: 32 months
Cats: days to weeks :(
Explain the pathogenesis of interstitial lung disease
An initial injury to the distal lung parenchyma occurs (hematogenous or inhaled). In response, resident cells recruit and activate inflammatory cells. With persistent injury, pro inflammatory and profibrotic cytokines lead to pathologic inflammation and fibrosis
Name 3 CT findings consistent with pulmonary fibrosis
Multifocal ground glass opacities, sub pleural honeycombing, traction bronchiectasis, subpleural thickening
Fibrotic interstitial lung disease represents the end stage of progressive damage and reparative processes from diverse causes. It culminates with what common clinical phenotype?
Restrictive lung disease
What is a common co-morbid condition with fibrotic interstitial lung disease?
Pulmonary hypertension
A familial form of acute respiratory distress syndrome caused by mutations in an aniline actin binding protein has been found in what dog breed?
Dalmatians
Name two chemotherapeutic agents that can lead to acute lung injury and fibrosis
Cytarabine and rabacfosadine
What antibiotic can result in pneumonitis and drug-induced interstitial lung disease?
Potentiated sulfonamides
Immune mediated interstitial pneumonitis has been described with what systemic infection?
Leishmania
What is hypereosinophilic syndrome (HES)?
Multisystemic, idiopathic disorder of infiltrating mature eosinophils into organs, commonly including the lungs
What breeds are predisposed to hypereosinophilic syndrome (HES)?
Rottweilers +/- Boxers
Bile acid concentrations were higher in the BALF of what dogs compared to healthy Beagles?
West Highland White Terriers (both healthy and with pulmonary fibrosis) and dogs with chronic bronchitis
What metalloproteinases may be useful biomarkers of idiopathic pulmonary fibrosis in Westies?
Serum MMP-7, BALF MMP-2 and -9
Indoor air pollution (high particulate matter levels) was significantly associated with respiratory disease in what species?
Cats
Endogenous lipid pneumonia has been identified in 3 dogs with what other pulmonary disease?
Neoplasia - 2 adenocarcinoma, 1 squam
Polyethylene glycol can induce what condition if inhaled?
Pulmonary edema (osmotic pull of water into the alveoli)
Dogs with solitary lymphocytosis on BALF were more likely to have what other abnormality on bronchoscopy?
Airway collapse
What was the final diagnosis in dogs with bronchiectasis?
Pneumonia (52%), inflammatory airway disease (36%), eosinophilic bronchopneumonopathy (12%)
Which inhalation method resulted in higher respiratory tract deposition of fluticasone in dogs?
Nebulizer (4.2%); inhaler was 2.3%
What percent of samples obtained by transtracheal wash and endotracheal wash are contaminated by oral bacteria?
Approximately 20% for both
What was the effect of maropitant in dogs with chronic bronchitis?
Decreased cough frequency, but did not decrease inflammation on BAL
What are eosinophilic granulomas?
Intraluminal airway lesions that appear similar to fungal granulomas, but cause is unknown
What is the radiographic or CT appearance of eosinophilic granulomas?
Severe saccular dilation of the bronchi with a large amount of soft tissue attenuating material obstrucing the lumen
What is the bronchoscopic appearance of eosinophilic bronchopneumonopathy?
Yellow-green mucus, bronchiectasis, bronchial collapse, nodular epithelial change
Spirometry can be used to evaluate what conditions in veterinary medicine?
Tracheal collapse, BOAS, feline lower airway disease
Spirometry is capable of measuring what parameters?
Inspiratory/expiratory time and flow rates, tidal volume
Flow volume loops are used to identify what?
Airway obstruction
Flow volume loops are created by what instrument?
Pneumotachograph
On a flow volume loop, which direction is inhalation? Exhalation?
Inhalation is in the negative direction, expiration is in the positive direction
A fixed airflow obstruction (laryngeal mass, etc) will display what on a flow volume loop?
Flattening of BOTH the inspiratory and expiratory curves
A dynamic airflow obstruction will display what changes on a flow volume loop?
Flattening of only the inspiratory phase (upper airway obstruction - tracheal collapse, etc) or only the expiratory phase (lower airway obstruction - chronic bronchitis, etc)
What is lung compliance?
Measure of the distensibility of elastic lung tissue: the change in lung volume for a given change in airway pressure
How can lung compliance be measured?
During positive pressure ventilation
What is lung resistance?
A measure of the amount of pressure requried to deliver a given gas flow. Test of potency of the small bronchi
What does whole body plethysmography measure?
Absolute lung volume and airway resistance - gold standard to determining lung volumes in cases of airway obstruction
How is whole body plethysmography performed?
Animal is placed in a sealed chamber with present air inflow and outlets. The change in barometric pressure caused by inhalation and exhalation is measured to estimate flow rates and lung volume
What is Penh?
Enhanced pause - used to approximate airway resistance. Has a formula that I refuse to memorize
Hypoxemia is defined as a PaO2 lower than ____?
80 mmHg
What is the equation for minute ventilation?
Tidal volume x RR
Carbon dioxide is ____ times more soluble than oxygen?
20x
In a normal animal breathing room air, what is the expected PaO2/FIO2 ratio (PF ratio)?
400 to 500
What is the FiO2 at room air?
0.21
A pulse oximeter reading of >95% is considered normal. What PaO2 does this correspond to?
80-120 mmHg
A pulse oximeter reading of 90% corresponds to what PaO2?
60 mmHg - below this = severe hypoxemia
What is tidal volume?
The volume of air inspired and expired during normal inspiration
What is functional residual capacity?
The volume of air left in the lung after normal expiration
What is residual volume?
The volume of air left in the lung after maximal expiration
What is vital capacity?
The volume of maximal inspiration and expiration
What is the primary phospholipid that makes up surfactant?
Dipalmitoyl phosphatidyl choline
What cell produces surfactant?
Type II alveolar cell
What is the most common inciting cause of ARDS in dogs/cats?
SIRS in one study, pulmonary disease (pneumonia) in another study
How often do patients with ALI or ARDS require mechanical ventilation?
Frequently - one study: 50% (dogs), 80% (cats); another study, recommended in 86%
What is the survival rate for ALI/ARDS?
Very poor - 10-14%
What are the four criteria used in the diagnosis of ARDS?
- Acute onset respiratory distress
- Presence of known risk factors
- Evidence of pulmonary capillary leak without increased pulmonary capillary pressure (bilateral infiltrates in imaging)
- Evidence of inefficient gas exchange
Point of care lung ultrasound with a total B lines score >10 and the presence of >2 sites was indicative of what diagnosis?
Cardiogenic pulmonary edema - 92% sensitive and 94% specific
What is pulmonary lobar emphysema?
Hyperinflation of 1 or more lung lobes due to bronchial obstruction and air trapping. Results in distension of the affected lobe and compression of adjacent structures
What is the common signalment for patients with pulmonary lobar emphysema?
Young animals - suspected congenital or old animals - neoplasia
What lung lobe is most commonly affected in pulmonary lobar emphysema?
Right middle
What is the recommended flow rate for high flow nasal oxygen?
1-2 L/kg/min (higher not well tolerated)
What is an advantage of high flow vs traditional oxygen delivery?
High flow provides continuous positive airway pressure, which improves oxygenation by recruiting alveoli, allowing for more efficient gas exchange, and lessening the work of breathing
The use of high flow oxygen resulted in what benefits in dogs failing traditional oxygen therapy?
Deceased respiratory rate, decreased dyspnea score, and increased SpO2
Virtually all cats with feline herpesvirus infections develop latent infections. Where does latency occur?
Trigeminal ganglion
Reactivation of herpes virus occurs in half of cats. When does it occur and how long does shedding last?
4-12 days after a stressful event. Shedding lasts around 7 days (up to 14 days)
In a study of dogs with aspiration pneumonia, what was the most commonly identified bacteria? Groups of bacteria?
E coli. Gram negative aerobes and anaerobes most common
In one study of dogs with tracheal collapse, what was the most common opportunistic infection?
Pseudomonas
What are the most common bacteria identified in feline pyothorax?
Pasteurella, anaerobes
What lung function parameters are changed in obese cats compared to healthy weight cats?
Decreased tidal volume, minute volume, and peak inspiratory/expiratory flows. No change in Penh (airway resistance)
What is the most common complication with bronchoscopy in cats? What factors can be used to reduce this complication?
Desaturation (30% of cats). Desaturation is decreased by using an endotracheal tube or laryngeal mask airway vs tracheal catheter. Also decreased by administering terbutaline
What is the sensitivity and specificity of NTpro-BNP as a screening test in healthy cats?
Specificity 96%, sensitivity 43% (improved to 71% with heart murmur). So a positive result = heart disease, but a negative result does not exclude heart disease
Dyspneic cats presenting with these clinical signs are more likely to have cardiac disease as cause of dyspnea
Hypothermia, tachycardia, gallop sounds, profound tachypnea (>80 brpm)
What is pulmonary Langerhans cell histiocytosis in cats?
Pulmonary parenchymal infiltration with Langerhans cells, leading to progressive respiratory insufficiency
What is feline progressive histiocytosis?
Most common histiocytic disease in cats. Skin nodules, papules, or plaques. Can invade and affect internal organs
What is the cause of heartworm associated respiratory disease in cats?
Death of immature L5 larvae in the pulmonary arteries => eosinophilic inflammation. Adult worms not required for the disease to occur
Cats with suspected heartworm associated respiratory disease should be treated for what other organism and why?
Wolbachia - can contribute to bronchial hypersensitivity. Give doxycycline
Why does chronic, daily use of albuterol result in worsening inflammation and bronchoconstriction?
Albuterol is a racemic mix of R and S enantiomers. The S enantiomer has slower metabolism/clearance and will accumulate in the lung with repeated use. This one has proinflammatory effects
How do omega-3 polyunsaturated fatty acids act as anti-inflammatory agents?
Reduce the availability of arachiodonic acid in cell membranes for the production of inflammatory eicosanoids
What were the effects of omega-3 fatty acids in asthmatic cats?
Reduced airway hyperresponsiveness but did not reduce airway eosinophilia
Is maropitant effective in reducing airway hyperresponsiveness or inflammation in asthmatic cats?
No. No it’s not
What is constrictive bronchiolitis obliterans?
Subepithelial and peribronchiolar fibrosis and inflammation that surrounds and narrows or obliterates the lumen of the bronchioles
What cases of feline upper respiratory tract disease should not be treated with antibiotics?
Acute onset (<10 days), serous nasal discharge - likely uncomplicated viral infection
In cats or dogs with acute upper respiratory disease and mucopurulent nasal discharge, antimicrobials are only recommended in the first 10 days if which clinical signs are present?
Fever, lethargy, or anorexia. Otherwise, wait 10 days to see if signs resolve
If antimicrobials are prescribed to a cat or dog with an acute upper respiratory disease, what antibiotic is the first line choice? How long should you treat for?
Doxycycline - 7-10 days
What infectious agents cause acute upper respiratory infection in cats and are treated with doxycycline?
Bordetella, C. felis, Mycoplasma
What two antibiotics can cause drug-induced esophagitis and strictures in cats?
Doxycycline and clindamycin
Other than doxycycline, what is an acceptable alternative first line antibiotic for cats or dogs with acute upper respiratory tract infections?
Amoxicillin - if Mycoplasma or C. felis are not suspected
In cats with upper respiratory tract signs lasting longer than 10 days, what is recommended?
Diagnostic workup: CT, rhinoscopy, nasal tissue biopsy for histopathology/culture, Mycoplasma PCR, fungal culture
In cats with chronic upper respiratory tract infections, what antibiotic is recommended and for how long?
Based on culture/sensitivity if at all possible. Treat for 7 days - if a positive effect is seen, continue the drug as long as there is clinical improvement and for at least 1 week past clinical resolution of nasal disease
In cats with relapsing chronic upper respiratory tract infections, what antibiotic should be used?
The previously effective antibiotic should be tried for 48 hours. If no improvement, switch drug classes or to a more active drug in the same class
What virus should always be considered in younger dogs with mucopurulent nasal and ocular discharge?
Distemper
What two organisms may be identified on BAL culture due to endoscope contamination?
Serratia, Stenotrophomonas
If a dog or cat with pneumonia is too unstable for airway sampling, what other test may be performed for bacterial culture?
Blood cultures
In dogs/cats with pneumonia, what route of treatment is recommended in hospital?
Parenteral, regardless of disease severity
In dogs or cats with mild pneumonia (no fever, lethargy, respiratory distress) that is suspected to be due to Bordetella or Mycoplasma, what empiric antibiotic is recommended?
Doxycycline
In dogs with suspected aspiration pneumonia, what empiric antibiotic is recommended?
Ampicillin, Unasyn, or first generation cephalosporins (cefazolin)
In dogs/cats with pneumonia and signs of sepsis, what antibiotics are recommended?
Fluoroquinolone + ampicillin or clindamycin
How long should dogs/cats with pneumonia be treated with antibiotics?
Repeat PE and thoracic radiographs recommended at 10-14 days; make decision to extend treatment based on results
How should pyothorax in dogs/cats be treated?
Fluoroquinolone + penicillin or clindamycin combined with therapeutic drainage of the pleural space +/- lavage
How long should cats/dogs with pyothorax be treated?
Minimum of 3 weeks, ideally 4-6 weeks
What is the passive slow expiratory technique?
A type of physiotherapy performed with the dog in lateral recumbency. One hand is on the chest, the other on the abdomen. As the dog start to expire, continuous pressure is applied to help increase expiration.
The passive slow expiratory technique improved what parameters in dogs with acute dyspnea due to airway fluid accumulation?
Improved P/F ratio, increased O2 free time by 46%), and decreased mortality (13% vs 44%)
How do CRP concentrations differ between dogs with Bordetella pneumonia and aspiration pneumonia?
CRP is much higher in dogs with aspiration pneumonia (118 vs 20)
When antibiotic therapy is discontinued based on a decrease in serum CRP, how much shorter is the treatment duration? How many dogs with pneumonia relapsed?
21 days vs 35 days; none relapsed
If using CRP to montior recovery from pneumonia, how long should antibiotic therapy be continued?
5-7 days after CRP normalizes
Dogs vaccinated with intranasal adenovirus 2, Bordetella, and parainfluenza vaccines tested positive for these organisms on molecular diagnostics for how many days after vaccination?
28 days (highest on days 3-10)
Aerosolized delivery of what antibiotic can be used for Bordetella infections? Clinical response is better with what formulation and in what population of dogs?
Gentamicin - undiluted better than diluted with saline. Dogs with less than 1000 cells /uL in lavage more likely to be cured at 3-4 weeks
How long should dogs with influenza (H3N2) be isolated?
> 21 days, even if clinical signs resolve, can still shed virus
What is the mechanism of action for famciclovir?
Prodrug of penciclovir, which is a nucleoside deoxyguanosine analog
In cats treated with low dose (40mg/kg) vs high dose (90mg/kg) famciclovir, the high dose cats showed…
Significantly greater improvement in clinical signs and shorter treatment courses
What are the most common side effects of famciclovir?
GI upset (diarrhea, vomiting, anorexia, polydipsia)
Feline calicivirus is more likely to be detected on swabs from what location?
Oropharynx
What species of Mycoplasma is significantly associated with lower respiratory tract disease? Which ones are not?
M. cynos is
M. canis, M. edwardii are not
Cats with outdoor access are ___ fold more likely to test positive for heartworm antigens
3 fold
What is the seroprevalence of heartworm disease in cats with respiratory clinical sign?
1% (overall seroprevalence 0.4%)
What is involved in the pathogenesis of Angiostrongylus vasorum induced bleeding? How should they be treated?
Hyperfibrinolysis and hypofibrinogenemia - treat with transexamic acid and plasma transfusions
What cardiac changes are associated with decreased bronchial diameter and cough?
Increased left atrial size and VHS
What are the potential complications with tracheal stent placement and how often do they occur?
Overall complication rate 47%. Stent fracture (25%), infection (58%), tissue ingrowth (20%), progressive tracheal collapse (12%)
What percent of dogs show improvement in clinical signs after tracheal stenting?
Improvement in goose honking or raspy breathing - 89%, improved dyspnea 84%
In one study of 75 dogs, what was the rate of survival to discharge and median survival time of dogs with tracheal stents?
93% survival to discharge, MST 1000 days
Does the presence of mainstem bronchial collapse at the time of tracheal stent placement affect outcome?
Not in the Weisse JAVMA study
What stage of Dirofilaria do microfilariae represent?
L1 larvae
What stage of Dirofilaria larvae infect dogs/cats after a mosquito bite?
L3
In dogs, how long does it take for L3 Dirofilaria larvae to develop to adults? In cats?
Dogs: 4-6 months
Cats: 7-9 months
Dirofilaria repens causes infection where?
Subcutaneous tissues
In cats, early or end-stage death of Dirofilaria can lead to what clinical consequences?
PTE, eosinophilic inflammatory response in the lungs - acute-onset dyspnea and interstitial pattern on rads
The presence of large quantities of Dirofilaria antigens from dead parasites can lead to what in cats?
Systemic anaphylaxis and sudden death
Aberrant Dirofilaria migration is more common in cats than dogs and cause cause what signs?
Body cavity effusions, neurologic signs (blindness, ataxia, paraparesis, seizures)
What tests for Dirofilaria (commonly used in dogs) have low sensitivity in cats?
Microscopic detection of microfilaria and antigen tests
What sex of Dirofilaria adult worms is detected by antigen testing?
Females
Why does heat pretreatment improve the sensitivity of heartworm antigen tests?
Released antigens blocked within circulating immune complexes - increases antigen available for detection
What changes are seen on thoracic radiographs in cats with heartworm disease?
Vascular changes - enlargement, loss of tapering, tortuosity of the right or both caudal pulmonary arteries on VD
Patchy infiltrates around the caudal lobar arteries
In cats infected with Dirofilaria, a self cure occurs in most cases within what time frame?
18-48 months
Why is adulticide (melarsomine) not used in cats?
High risk of triggering PTE or anaphylaxis due to parasite death
What is the recommended treatment for feline heartworm?
Monthly heartworm preventative drugs, prednisone (2mg/kg PO q24 then taper)
Monthly heart worm preventatives kill what stage of the worm?
L3-L4 larvae
The earliest heartworm antigen and microfilariae can be detected post-infection in dogs is?
5 and 6 months, respectively
Heartworm antigenemia may be suppressed until how many months post-infection in dogs receiving preventatives?
9 months
All positive heartworm antigen tests should be confirmed by?
Microfilariae testing (modified Knott’s test), a different type of antigen test, echocardiograph
What are 3 factors that influence the probability of post-adulticide thromboembolic complications?
1) Activity level of the dog
2) Extent of concurrent pulmonary vascular disease
3) Severity of infection (high vs low worm burden)
Melarsomine has been shown to have activity against what stage of worm?
Immature worms between 2-4 months of age
What is the recommended dosing protocol for melarsomine? What is the success rate?
One injection (2.5mg/kg) when one month later, two injections 24 hours apart. Kills 98% of worms
Doxycycline should be administered for how long before melarsomine?
Treat with doxycycline for 1 month, then wait one month before melarsomine
A macrocyclic lactone preventative should be administered for how long before melarsomine?
2 months
What is caval syndrome?
When adult heartworms partially obstruct blood flow through the tricuspid valve and interfere with valve closure
What are characteristic clinical signs of caval syndrome?
Sudden onset lethargy, dyspnea, pale mucous membranes, hemoglobinemia/uria, severe passive congestion of the liver, coarse tricuspid valve murmur, jugular pulsations
