upper airway Flashcards
most common clinical signs associated with nasal conditions?
nasal discharge (unilateral vs. bilateral) sneezing reverse sneezing stertor epistaxis facial deformation ocular discharge
What diagnostics should be considered when working up a condition of the nasal cavity?
CBC/chem +/- UA- MDB thoracic rads sedated oral exam imaging- skull or dental, CT(better than rads at detecting neoplastic changes), MRI- improved visibility because of cross sectional imaging, increasd ability to detect subtle lesions rhinoscopy cytology Bx (imaging preceedes biopsy) culture- fungal/bacterial
Define brachycephalic airway syndrome. What are the congenital and secondary
abnormalities of this syndrome? How do the congenital abnormalities
cause the secondary abnormalities(i.e what is the pathophysiology)?
local chondrodysplasia
stenotic nares, elongated soft palate, everted laryngeal saccules +/- hypoplastic trachea
congenital (primary)- stenotic nares, elongated soft palate, hypoplastic trachea
secondary- elongated soft palate, everted laryngeal saccules (stage 1 laryngeal collapse), hypoplastic trachea
Pathophysiology: higher negative pressure to overcome obstruction–> secondary tissue changes (edema, hypoplasia, collapse)–> decreased airflow with increased obstruction
What are other conditions that can contribute to airway occlusion in these animals?
What clinical signs are seen with brachycephalic airway syndrome?
cardiovascular changes- chronic decreased PaO2 secondary to airway obstruction–> pulmonary vasoconstriction–> V/Q mismatch–> subsequent vasoconstriction/hypertension–> R sided CHF
delayed gastric emptying
clinical presentation:
Asymptomatic- very young, less severely affected animals
mild/moderate- exercise intolerance, increased noise, snoring, snuffing, reverse sneezing, +/- GI signs, secondary mild signs
severe-emergent acute respiratory distress, severe upper airway swelling, hyperthermia, cyanosis, +/- heat stroke, +/- GI signs, +/- lower airway disease (noncardiogenic pulmonary edem, aspiration pneumonia), numerous significant secondary changes
Which components of the syndrome are diagnosed by laryngeal exam?
tonsils, soft palate, arytnoid cartilages (symmetry, evidence of collapse, everted saccules), laryngeal function, mucosal lesions, excess mucus/saliva, masses
In what patients should surgery be recommended? Why is early surgical intervention
recommended?
sx is recommended for any animals presenting signs of BAS/ any brachycephalic dog at time of spay/neuter
early surgical intervention is recommended to prevent secondary changes
When diagnosing an elongated soft palate, what is the landmark used to determine
excessive length? What landmarks are used In surgery to know how much palate to
trim? What are the risks associated with trimming too much palate?
we use the larynx as a landmark to determine excessive length and the tonsils as a landmark to know how much to trim.
Risks: rhinitis/sinusitis
Describe the 3 different stages of laryngeal collapse.
Stage 1- everted laryngeal saccules (they get edematous and evert into the airway)
Stage 2- collapse of cuneiform cartilage
Stage 3- collapse of corniculate cartilage
What other body systems can be affected by the airway obstruction seen in
brachycephalic airway syndrome? What is the pathophysiology in these other systems?
GI delayed emptying, hiatial hernia, esophageal deviation
R sided heart failure from pulmonary vasoconstriction, V/Q mismatch and subsequent hypertention
Why is medical treatment an important component in the management of
Brachycephalic airway disease?
because it reduces the occurence of secondary effects and aspiration pneumonia
What are the most common complications associated with surgical treatment of
brachycephalic airway syndrome?
severe- pharyngeal swelling (acute distress, emergency tracheostomy), vomiting, regurgitation, aspiration pneumonia
Minor- dishiscence of nares (recurrence of stenosis), bleeding, persistent stridor/ sterdor, Rhinitis/sinusitis, voice change
What complications are associated with ventriculocordectomy? What can be done to
minimize this risk?
webbing- leave 1-2 mm ventral cord intact to decrease the risk
Differentials of nasal disease
dental disease and nasopharyngeal polyp
most common indication for nasal planum resection
neoplasia (SCC)
risks and complications of nasal sx
hemorrhage (dorsal, lateral and major palatine arteries)
flap necrosis
oronasal fistula
dishiscence
stenosis of airways
incomplete resection/local recurrence (neoplasia)
What are the disease components of BAS?
nasopharyngeal turbinates
stage 2-3 laryngeal collapse, tonsilar eversion, tracheal collapse, secondary edema, macroglossia
what are the clinical signs associated with elongated soft palate (most common cause of BAS?
inspiratory and expiratory dyspnea (stertor)
extension into the rima glottis–> severe obstruction, loss of protective laryngeal function–> higher risk of aspiration pneumonia
which drugs affect laryngeal function?
Which drugs should be used?
Ketamine, diazepam and large doses of mu agonists
propofol +/- butorphanol or buprenorphine, doxapram improves strength of respiration
Which mode of diagnosis is considered gold standard?
endoscopy/tracheoscopy
Which procedures are used for BAS?
Wedge resection- stenotic nares
soft palate resection- elongated soft palate
excision of everted laryngeal saccules
Which drugs are used pre- op?
Gi protectants and promotility drugs- decreases risk of aspiration pneumonia, treat for 10-14 days prior to sx if symptomatic
anti inflammatories- for soft palate resection and everted saccule excision- Dexamethasone
antiemetics at time of pre op
preoxygenation prior to induction
When would it be appropriate to perform tonsilectomy, unilateral arytnoid lateralization and temporary or permanent tracheostomy?
tonsilectomy- never recommended for BAS unless neoplastic or abscessed
unilateral arytnoid lateralization- only in cases of laryngeal paralysis
temporary or permanent tracheostomy- if no clinical improvement or decompensation
what is epiglottic reversion and how is it diagnosed and treated?
upper airway obstruction caused by laxity of the hyoepiglitticus m. in face of extreme inspiratory effort
tx: surgical pexy of the ventral aspect of the epiglottis and the dorsal base of tongue
Which muscle is responsible for laryngeal abduction? What nerves innervate it?
cricoarytenoideus dorsalis (it contracts during inhalation)
vagus–> recurrent laryngeal n–> caudal laryngeal n.
what are the 3 functions of the larynx?
swallowing
abduction during inhalation and adduction during exhalation (passive)
voice production
clinical signs of laryngeal dz
depends on disease process respiratory stridor exercise intolerance gagging/dysphagia voice change dypnea that doesnt improve with open mouth breathing
which side is best approach to arytnoid lateralization?
L so esophagus is out of the way
Define laryngeal paralysis. What is known about the etiology of this condition?
What are the 2 common age groups for laryngeal paralysis?
dysfunction/damage to the vagus n and its branches affecting function of the cricoartynoideus dorsalis m.
congenital- progressive degeneration of neurons with onset before 1 yr
idiopathic- large breed older, part of generalized neuropathy commonly as secondary to a disease process
Describe the typical history, presenting complaints and clinical signs associated
with laryngeal paralysis.
same as most laryngeal diseases, mild resp stertor to servere respiratory distress and cyanosis
How is a definitive diagnosis made? What method is commonly used? What other
diagnostic tests or evaluations should also be done?
laryngeal exam is definitive dx
US, tracheoscopy, 3 view rads, CHC/chem, UA, TSH, T4, acetylcholine receptor antibody titer
What movements do the corniculate,
cuneiform and arytenoid cartilages have during normal inspiration? What is
different in the dog with laryngeal paralysis? How is this different from the dog
with laryngeal collapse?
arytnoid should abduct during inhalation
in laryngeal paralysis it will close during inhaation
What is the purpose of arytenoid lateralization for treatment of laryngeal
paralysis? Describe the main anatomical change that results from this surgical
procedure.
decreases airway resistance during inhalation by widening the rima glottis
What are the complications of arytenoid lateralization? What medical management
strategies should be recommended in any patient with laryngeal collapse?
medical management- (for mild clinical signs) weight loss, stress reduction, exercise restriction, environmental changes
excessive tension–> aspiration pneumonia
recurrent or persistent signs, seroma intramural hematoma, coughing, gagging, dysphagia, post op megaesophagus
What is the anatomical cause of tracheal collapse? What factors are associated
with the etiopathogenesis of this condition? Explain how small airway diseases
such as chronic bronchitis can affect the trachea.
anatomical cause- laxity of the trachealis muscle–> weakness of tracheal rings
hypocellular tracheal cartilage
decreased water retention secondary to loss of GP and GAG
progressive cough–> squamous metaplasia, reduction of ciliated cells, increased viscosity of secretions
chronic bronchitis can affect the trachea via cough
What is the most common signalment for this condition? What are the clinical signs of
tracheal collapse?
small/toy breeds, middle aged
progressive goose honk cough, waxing and waning dyspnea, exercise intolerance, cyanosis, syncope
How would you definitively diagnosis tracheal collapse? What is the gold standard for
diagnosis and why?
tracheoscopy is the gold standard because we can directly visualize collapse and grade its severity and can obtain samples
What are the differences between medical management for cases that present acutely
versus for the chronic management of tracheal collapse?
see sam notes
External tracheal prosthetic rings are designed to prevent flattening of the tracheal rings
on inhalation and exhalation. Explain how these splints work. What are important
considerations in application of external splints?
external prosthetic tracheal rings- cervical use only, must start and end in area of normal trachea
List advantages and disadvantages of internal tracheal stents
adv- minimally invasive, shortened anesthesia time, cervical or thoracic, immediate improvement
disadv- fluroscopy or endoscopy, $$, shorter lifespan than tracheal rings, moderate to high complication rate
What are the indications for permanent tracheostomy in the dog? What tissues
are sutured in this “ostomy”? How is tension on this suture line reduced?
What is the prognosis after permanent tracheostomy in dogs? What about cats?
indications- untreatable upper airway obstruction
tissues sutured: mucosa and skin
prognosis
dogs- good for indoor dogs
cats- guarded to poor because mucus plugs and soft tracheal cartilage predisposes to tracheal collapse
What are the two primary surgical approaches to the thoracic cavity? Know the
advantages and disadvantages of each. How does the surgeon decide which approach
is most appropriate?
median sternotomy- for bilateral thoracic exploration, cranial mediastinal masses and cranial thoracic trachea, more painful and prolonged recovery because cutting through bone
lateral/intercostal thoracotomy- directed approach to a specific structure, less traumatic since going through muscle layer
Why is complete lobectomy more difficult from a median sternotomy approach?
In what situations would this approach nevertheless be indicated?
What are the advantages /disadvantages of minimally invasive approaches?
total lobectomy is more difficult from a median sternotomy approach because we need access to the hilus
adv- access to the thorax during celiotomy
disadv- cant feel tissue texture
What techniques can be used to perform a complete lobectomy? When is partial
lobectomy preferred over total lobectomy? What methods can be used to perform a
partial lobectomy?
lateral thoracotomy or thoracoscopy
total vs partial- depends on dz process and where lesion is within lobe. Total- diffuse and through multiple lung lobes (neoplasia, abscess, truma)
partial lobectomy can be performed by thoracoabdominal stapler, guillotine suture, 2 rows of continuous suture pattern
Describe etiology, signalment, history and presenting signs, and physical
examination and radiographic findings for lung lobe torsion. Which lobe is most
commonly affected? What is the prognosis, following lobectomy?
large deep chested dogs (right middle or left cranial) and pugs (left cranial)
CS- acute onset, dyspnea, tachycardia, cough, exercise intolerance, hemoptysis
PE findings- pyrexia, pale MM, decreased lung sounds ventrally
Radiographic findings- consolidation, air bronchogram and fluid line
prognosis- good for pugs, guarded for other breeds
List or chart the different types of pneumothorax vs. etiology, signalment, source
of air, and integrity of chest wall. Which is the most common type? Which type
is not traumatic in origin? Which type has the best prognosis?
neoplasia- good prognosis if no LN involvement
trauma (HBC)- most dont require surgical intervention
penetrating chest wounds
How do both pulmonary contusion and pneumothorax result in ventilation/perfusion
mismatch? Why do these patients develop respiratory acidosis,
despite tachypnea?
there is less space for exchange and therefore more CO2 remains in circulation–> resp acidosis
What specific treatment is required for the patient with
severe closed pneumothorax, before oxygen supplementation is of greatest
possible benefit?
thoracocentesis
Why do animals with fractured ribs become hypoxic? What can you do to
alleviate this condition? Much of the dyspnea seen in patients with fractured ribs
and flail chests is a result of another traumatic condition. What is that condition?
What is the recommended treatment for a simple flail chest?
hypoxemia is due to hypoventilation secondary to pain and V/Q mismatch because of contusion
treat conservatively with splint to improve comfort unless severely displaced
What is chylothorax and what are the possible causes? How do we diagnose this
condition?
secondary to impaired or disrupted lymphatic drainage, idiopathic is most common
diagnosis- cytologic evaluation of pleural effusion- triglycerides of fluid>blood, cholesterol of fluid
What are the surgical procedures performed for the treatment of chylothorax? Which of
these procedures helps with the mechanical drainage of chyle from the thoracic cavity?
What is the overall success rate of surgery in dogs? What about cats?
thoracic duct ligation, cysterna chyli ablation, subtotal pericardectomy, +/- omentalization, +/- pleuralport placement (chronic drainage catheter into the abdominal cavity)
dogs have improved outcome compared to cats
What is the long term complication associated with chronic untreated chylothorax?
fibrosing pleuritis
Know the anatomy of the diaphragm
aortic hiatus closer to the spine, esophageal hiatus in the center and caval foramen closer towards sternum
Peritoneopericardial diaphragmatic hernias are always congenital in dogs and
cats. Are these hernias inherited? What concomitant abnormalities may be found?
defect in embryogenesis- unknown cause
may be found with polycystic kidneys (cats), ventricular septal defects and sternal deformaties
What are typical presenting signs and physical examination findings of patients with
peritoneopericardial diaphragmatic hernia?
signs referrable to respiratory, GI, cardiac and neurologic systems
PE- muffled heart sounds, ascites, murmur, +/- concurrent ventral abdominal wall defect
What is the prognosis for the patient with peritoneopericardial diaphragmatic
hernia? Is this a pleural space condition?
excellent prognosis for animals surviving surgery post 24 hrs
not a pleural space condition
How does diaphragmatic hernia result from blunt trauma to the abdominal wall?
Is diaphragmatic hernia a pleural space disease? Why is vomiting a common sign in patients
with chronic diaphragmatic hernia?
the muscle layer of the diaphragm is susceptible to tears which can happen to increased pressure in the abdomen cause by blunt trauma
this is a pleural space disease
vomiting is a common sign in patients with chronic diaphragmatic hernia because irritation of the vagal nerve
What are typical findings on thoracic auscultation in dogs and cats with
diaphragmatic hernia?
PE- muffled lung sounds, Borborygmi auscultated on thoracic auscultation, tachycardia, tachypnea, empty abdomen on palpation
You are presented with a dog that has been hit-by-car 30 minutes ago and has a
diaphragmatic hernia. When would you choose to repair this hernia? What condition might
make you go to surgery sooner?
surgery as soon as patient is stable, go sooner (before stabilized) if stomach is herniated because it can rapidly expand and become herniated
You are presented with a cat that has a chronic diaphragmatic hernia, secondary
to trauma 2 years ago. Describe your course of action with this patient?
US guided thoracocentesis first to look for pleural effusion, ventral midline approach, look for adhesions
What are the intra-operative and postoperative complications of diaphragmatic
hernia repair?
perioperative death, re-expansion pulmonary edema (common in chronic, keep IPPV
Know and understand the various roles of surgery in providing oncologic treatment
most important component of tx of small animals with solid tumors, best chance of curative is the first attempt
Know the indications for incisional versus excisional biopsies as well as the pros and cons of each
procedure
incisional- when sampling large superficial lesions, careful surgical planning necessary due to percieved difficulty with curative sx (size and location of lesion), less invasive sampling have not yielded a dx, can cause seeding of neoplasia in normal tissues. Deep narrow wedge facilitates closure
excisional- removes tumor along with surrounding normal tissue, allows removal of smaller, non-invasive masses in single procedure, should only be considered when treatment would not be altered by tumor types and re-excision possible without great morbidity.
Know the various approaches to removal of a mass and when each is indicated (marginal vs
radical, etc)
Sarcoma- 3cm, carcinoma- 2cm, vaccine associated fibrosarcoma- 5-7cm
intracapsular- rarely if ever
marginal- lipomas and benign masses, malignant- goal is microscopic disease. (mast cell tumors, sarcomas)
wide- removal of 2-3 cm normal issue 3D or 2-3 cm laterally and 1 fascial plane deep (3-4 cm of fat counts as a fascial plane), based on histopath report on grade, mitotic index and degree of differentiation
radical- removal of entire compartment (amputation, hemipelvectomy)
Be able to list and discuss the various important principles of oncologic surgery. What intraoperative
techniques are important?
best chance of cure is at first sx
ability to close wound should not influence aggressiveness if intent is to cure, minimize handling of tumor (dont penetrate tumor capsule, protect normal tissues), ligate blood supply as early as possible (increase in circulating tumor cells perioperatively), excise biopsy tract, excise LN if indicated, lavage tissues, change gloves and instruments and lavage again before closing, AVOID USE OF DRAINS!
identify margins using sutures, dye
Why is it important to understand the flow of lymphatics when working up a patient with a
malignancy?
local draining LN should be aspirated prior to sx and excision is prognostic for multiple tumor types (mammary carcinoma, mast cell tumors, aprocrine gland adenocarcinoma of the anal sac. Sentinel LN mapping uses radioactive material an NS or radiopaque contrast and radiography or CT to tract LN’s that drain mass
Know what type of tumors can be most readily diagnosed from a cytologic sample
those that are very differentiated
