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