SASx Final Exam - Thoracic/Respiratory Flashcards
Lung lobe torsion is a rare condition resulting in rotation of the lung lobe on its hilus. In what types of dogs do we typically see this?
large, deep chested dogs and pugs
- Large dogs: right middle or left cranial lung lobe
- Pugs: left cranial lung lobe
T/F: When surgically repairing a perineal hernia in an intact male dog, it is recommended to castrate at the time of repair
True
Testosterone may be a predisposing cause for perineal hernias. (Recurrence is 2.7x greater in intact dogs)
This surgical approach to the thoracic cavity allows access to thoracic cavity during celiotomy. It may be used in thoracic duct ligation, surgery of the caudal esophagus, intra-operative CPR/cardiac massage, etc.
transdiaphragmatic
T/F: Radiography is the gold standard for diagnosis of tracheal collapse
False
Tracheoscopy is the gold standard for diagnosis of tracheal collapse
Radiographs can help rule in or rule out tracheal collapse by showing signs for other causes of cough
When is surgical intervention indicated in the case of tracheal trauma?
- When dyspnea persists or worsens with medical management
- If pneumothorax persists > 2-3 days
- Severe tracheal damage is visible
When performing surgery to repair a hernia, what type of suture is typically used?
Monofilament, prolonged absorbable or non- absorbable suture
PDS or Prolene
T/F: Lung lobectomy (for treatment of lung lobe torsion) is associated with a good prognosis
kind of true?
good prognosis in pugs; fair to guarded for other breeds
What breed of dog is overrepresented in the case of hypoplastic trachea with brachycephalic airway syndrome (BAS)?
English bulldog
How do you diagnose chylothorax?
cytologic evaluation of pleural effusion
- Modified transudate, lymphocytic effusion
- Triglycerides in fluid will be higher than in the serum
- Cholesterol in fluid will be lower than in the serum
________ is the most commonly herniated organ
liver
Which component of brachycephalic airway syndrome (BAS) is typically associated with a poorer prognosis?
n/a
There is no single component of BAS associated with poorer outcome
Which of these images shows an actual animal?
Nice job!
For diagnosis of lung lobe torsion, what would you expect to see on thoracocentesis?
serosanguineous or chylous effusion
rarely see evidence of sepsis (bacteria) unless there’s some other secondary problem
What surgical approach is indicated for bilateral thoracic exploration, cranial mediastinal masses, or surgery of the cranial thoracic trachea?
median sternotomy
Important to stay midline with this approach to avoid the internal thoracic arteries on either side of the sternebrae
The major risk associated with nasal surgery is hemorrhage. What arteries should you be aware of in this region?
dorsal, lateral, and major palatine arteries
Other risks and complications include (but are not limited to) flap necrosis, oronasal fistula, dehiscence, stenosis of airways, incomplete resection/local recurrence (for neoplasia)
T/F: Surgery is considered an emergency if the stomach is herniated
True
T/F: The prognosis associated with permanent tracheostomy is generally good for dogs and cats if the underlying disease is a benign process
False
- Prognosis is generally good for dogs if the underlying disease is a benign process.
-
Prognosis is guarded to poor for cats!!
- Mucus plugs very common leading to acute death
- Median survival time ranges from 20-42 days
-
Soft tracheal cartilage may predispose trachea to collapse
- Consider placement of external rings adjacent to tracheostomy site
When anesthetizing patients for diagnosis of brachycephalic airway syndrome (BAS), it is important to avoid drugs that affect laryngeal function. Name a few to avoid:
- Ketamine
- Diazepam (and maybe Midazolam)
- Large doses of pure µ agonists
There are many known causes of chylothorax, but ________ is most common
idiopathic
What is the maximum lung mass (%) that can be acutely removed without being fatal?
65%
The treatment of choice for lung lobe torsion is:
lung lobectomy
This is pretty much the only treatment for lung lobe torsion
-
DO NOT untorse the lung!!
- Avoid release of cytokines and endotoxins (reperfusion injury)
A ________ is the protrusion of an organ through a defect in the wall of the anatomical cavity in which it normally lies
hernia
What three surgical procedures are indicated for treatment of chylothorax?
- Thoracic duct ligation
- Cysterna chyli ablation
- Subtotal pericardectomy
All three procedures can be performed concurrently
What is the #1 condition we see affecting the larynx?
laryngeal paralysis
-
Dysfunction/damage to the vagus nerve and its braches (recurrent laryngeal and caudal laryngeal nerves) affecting function of cricoarytenoideus dorsalis muscle
- Failure of the arytenoid(s) to abduct on inspiration
What types of clinical signs are most commonly seen in patients with chronic diaphragmatic hernias?
respiratory and GI signs
- Dyspnea, exercise intolerance, lethargy
- Vomiting, regurgitation, inappetance
What is the most common component of brachycephalic airway syndrome (BAS)?
elongated soft palate
- Results in both inspiratory and expiratory dyspnea (stertor)
-
Extension into rima glottidis
- Severe obstruction
- Loss of protective laryngeal function
- Anything more than 1-2 mm past tip of the epiglottis is TOO LONG
Tracheal collapse is associated with a progressive cough that sounds like:
“goose honk”
Other clinical signs of tracheal collapse include waxing and waning dyspnea, exercise intolerance, cyanosis, and syncope
You have a patient with lung lobe torsion and you’d like to perform a lung lobectomy. You know what lobe is affected, so what surgical approach is indicated?
intercostal thoracotomy
What anesthetic drug is typically used in diagnosis of brachycephalic airway syndrome (BAS)?
Propofol
- Can also use Butorphanol or Buprenorphine to lower the amount of Propofol that you have to give.*
- If you’ve gone ahead and given these drugs and they’re still not taking good, deep breaths, you can give a dose of Doxopram to stimulate deep respiration.*
- Be prepared to intubate immediately post-exam!*
Animals with flail chest are at risk for all of the following except:
- Pneumothorax
- Pleural effusion
- Pericardial Pendulum
- Pulmonary contusion
Pericardial Pendulum
I don’t actually even know if that’s a thing
This abnormality is due to weakness and separation of the muscles of the pelvic diaphragm:
perineal hernia
________ hernias have mesothelials linings. ________ hernias do not have mesothelial linings.
True hernias have mesothelials linings. False hernias do not have mesothelial linings.
This is the most common abdominal hernia:
umbilical hernia
- Most are congenital and inherited (you should not breed these animals)
-
High risk breeds
- Airedale terrier
- Basenji
- Pekignese
- No sex predilection
What is the most common indication for nasal planum resection?
neoplasia
- Squamous cell carcinoma (SCC) is the most common cause for nasal planum resection.
- Others: lymphoma, malignant histiocytosis, malignant melanoma, basal cell carcinoma, mast cell tumor, HSA
-
Complete vs. unlateral
- Must obtain wide margins (2-3 cm)
-
Completely stage prior to surgery
- LN aspirates, abdominal and thoracic rads, etc.
In a patient with pulmonary cysts, bullae, and blebs, when is surgical intervention recommended?
if medical treatment fails
-
Conservative treatment with thoracostomy tubes for 48-72 hours
- If after that time you’re still getting a ton of air out, it’s probably best to go exploring (surgically)
- Pre-op CT may be helpful in identifying lesions
T/F: Pulmonary cysts, bullae, and blebs are common causes of spontaneous pneumothorax
True!
- Can be secondary to blunt trauma (cysts) or traumatic rupture of alveoli secondary to underlying lung disease
- Other two main causes of spontaneous pneumothorax: heartworm disease and neoplasia
What is the typical signalment associated with tracheal collapse?
middle aged small and toy breed dogs
- Yorkshire terriers, Pomeranians, miniature poodles, and pugs
- No evidence of sex predilection
What imaging modality is the gold standard for diagnosing tracheal collapse?
tracheoscopy
-
Allows direct visualization of collapse
- Grading of severity of collapse
- Allows visualization of tracheal mucosa, dorsal tracheal membrane
- Can obtain samples for cytology and bacterial culture/sensitivity
-
Requires anesthesia
- May incite dyspneic episode!!
Collapse of 75% of the tracheal lumen would be categorized as a Grade ___ tracheal collapse
Grade III
__________ is a congenital communication between pericardium and peritoneal cavity
Peritoneopericardial Diaphragmatic Hernia (PPDH)
-
Commonly associated with other congenital defects
- Polycystic kidneys (cats)
- Ventricular septal defects
- Sternal deformities
- Weimaraners, Cocker spaniels, DLHs and Himalayans may be at increased risk
In the case of tracheal collapse, there is progressive, irreversible degeneration of the lower airway, which results also in laxity of the __________ muscle, leading to weakness of the tracheal rings and ultimately collapse
trachealis muscle
Removal of all lobes of one of the lungs (left/right) is termed:
pneumonectomy
- Indicated for cases where disease is diffuse through the lung (neoplasia, abscess, trauma)
- Performed through lateral intercostal approach
What are the two surgical treatment options for tracheal collapse?
external prosthetic tracheal rings and intraluminal stent
If you suspect a diaphragmatic hernia in your patient, you’ve taken standard radiographs, and you don’t have access to ultrasound, what modality is most helpful for confirming your diagnosis?
positive contrast celiography
- Inject dilute sterile contrast into abdomen
- Look for leakage of contrast in thorax on radiographs
- If you have access to ultrasound, you don’t really need to do this
T/F: Diagnosis of tracheal collapse is based on signalment, history, clinical signs, and PE
False
Diagnosis of tracheal collapse is based on signalment, history, clinical signs, PE, and IMAGING. You cannot make this diagnosis without the use of some sort of imaging
Name a complication associated with rapid expansion of a previously atelectic lung, seen after treatment of a diaphragmatic hernia
Re-expansion pulmonary edema
There is no treatment for this and is almost invariably fatal
How is a perineal hernia most commonly diagnosed?
rectal palpation
- finger will pass through into rectal dilation; can palpate thumb*
- Radiographs, ultrasound, and minimum database can also be helpful*
T/F: Clinical signs and thoracic auscultation may provide enough information for diagnosis of pneumothorax
True
- Thoracic auscultation: dull/absent bronchovesicular sounds dorsally
- Diagnosis can be confirmed with thoracic radiographs
This is the most common type of perineal hernia:
caudal perineal hernia
contents that herniate between the levator ani mm, external anal sphincter mm., and internal obturator mm.
What is the surgical treatment for epiglottic retroversion?
surgical pexy of ventral epiglottis and dorsal tongue
surgical pexy of the ventral aspect of the epiglottis and the dorsal base of the tongue
In which breed of dog do we most commonly see congenital laryngeal paralysis that presents as a progressive generalized degenerative disease and carries a grave prognosis?
Rottweilers
- Onset of signs between 11 and 13 weeks of age
- Ataxia, paresis, head tremors, neurogenic muscle atrophy
- Grave prognosis :(
T/F: If an umbilical hernia is the size of intestines (~finger size) in a small to medium-sized dog, it should be repaired immediately due to increased risk of strangulation
True
What muscle is responsible for laryngeal abduction (opening of the larynx) upon inhalation?
cricoarytenoideus dorsalis
- Innervated by the caudal laryngeal nerve, which is a branch of the recurrent laryngeal nerve, which is a branch of the vagus nerve.*
- So anything that damages any of these nerves or the muscle itself can result in inappropriate function of the larynx*
What are the most common types of primary pulmonary neoplasia?
bronchiolar or alveolar carcinoma
-
These can usually be picked up on 3 view thoracic radiographs
- CT provides additional information regarding LN involvement and invasiveness of mass
- Lung lobectomy indicated for peripheral tumors not involving the hilus
- Good prognosis if no LN involvement
What landmark should we use for level of excision with regard to soft palate resection?
**midpoint of the tonsils**
Based on the grading system for tracheal collapse, what grade would you assign this patient?
Grade 3
What are the main complications associated with external prosthetic tracheal rings for treatment of tracheal collapse?
laryngeal paralysis, tracheal necrosis, pneumothorax
**
Brachycephalic breeds have local chondrodysplasia that results in early ankylosis of _________ and __________ bones. This results in a shortened and broadened skull
Brachycephalic breeds have local chondrodysplasia that results in early ankylosis of basioccipital and basisphenoid bones. This results in a shortened and broadened skull
If you note collapse of the cuneiform cartilage, this is a Stage ___ laryngeal collapse
Stage 2
Air passage through nasal cavities accounts for ____% of airway resistance
~75%
Abnormal anatomy causes external and internal resistance (inability to dilate nostrils)
What surgical treatment for tracheal collapse can be used in the cervical and thoracic trachea?
intraluminal stent
- External prosthetic tracheal rings can only be used on the cervical trachea
This is a salvage procedure for untreatable upper airway obstruction that creates a permanent opening at the level of the proximal cervical trachea:
permanent tracheostomy
T/F: Medical management is going to be the first line of defense in a case of tracheal collapse
True
Surgery for this has a lot of complications and a relatively high failure rate. Only when a patient fails to respond to medical management should surgical intervention be considered
What is considered the “gold standard” for diagnosis of brachycephalic airway syndrome (BAS)?
endoscopy/tracheoscopy
What is the most important imaging modality for investigation of nasal disease?
Computed topography (CT)
- CT will give you a cross-sectional anatomy of the nares and the skull and you’ll be able to get a much better idea of what’s going on*
- (Note: if you’re performing a rhinoscopy too, do the CT first. Rhinoscopy can cause some bleeding, so you don’t want to have that shit all over your nice CT image.*
What is the gold standard surgery for moderate to severe cases of laryngeal paralysis?
unilateral arytenoid lateralization
-
Performing the procedure:
- A. The larynx is exposed through a lateral cervical approach during arytenoid lateralization. Incise the skin and subcutaneous tissue ventral to the jugular vein. Then incise the thyropharyngeus muscle at the dorsal edge of the thyroid cartilage.
- B. Separate the cricothyroid and cricoarytenoid articulations.
- C. Place a suture from the muscular process of the arytenoid to the dorsocaudal aspect of the cricoid or thyroid cartilage.
T/F: Unilateral arytenoid lateralization eliminates the risk of post-operative aspiration pneumonia
No.
- It does not do that.*
- Risk of aspiration pneumonia is always present post-operatively.*
How do we diagnose hypoplastic trachea on radiographs?
measure the tracheal lumen:thoracic inlet ratio
What are the three main functions of the larynx?
swallowing, abduction, voice production
T/F: Surgical intervention should be recommended if a dog presents with any of the components of bracycephalic airway syndrome (BAS)
True
What procedure is shown below?
excision of everted laryngeal saccules
Describe the pathophysiology associated with Brachycephalic airway syndrome (BAS):
-
Higher negative pressure is required to overcome obstruction
-
–> This results in the animal being more prone to secondary soft tissue changes (edema, hyperplasia, collapse)
-
–> This leads to even further decreased airflow with increased obstruction
-
–> This all circles back and it happens all over again.
- –> Wow.
-
–> This all circles back and it happens all over again.
-
–> This leads to even further decreased airflow with increased obstruction
-
–> This results in the animal being more prone to secondary soft tissue changes (edema, hyperplasia, collapse)
After surgical intervention in dogs with brachycephalic airway syndrome (BAS), what severe post-operative complications are important to monitor for?
pharyngeal swelling, vomiting, regurgitation, ASPIRATION PNEUMONIA
What imaging modality is best for diagnosis of lung lobe torsion?
Computed topography (CT)
You can probably see it on radiographs too, but CT is going to be better
What modalities are most helpful for diagnosis of Peritoneopericardial Diaphragmatic Hernia (PPDH)?
radiographs or ultrasound
- These are really the only diagnostic tools you’ll need for this. Contrast studies considered only if diagnosis cannot be made with plain films or ultrasound
-
Radiographic findings
- Enlarged cardiac silhouette
-
Dorsal elevation of trachea
- Overlap of heart and diaphragmatic borders
-
Discontinuity of diaphragm
- Gas-filled structures in pericardial sac
T/F: For treatment of lung lobe torsion, it is important to untorse the lung to allow blood flow back to the affected lobe
NO.
DO NOT UNTORSE THE LUNG!
Avoid release of cytokines and endotoxins (reperfusion injury)
T/F: Congenital laryngeal paralysis is the most common type of laryngeal paralysis that we see in our small animal patients
False
-
Idiopathic laryngeal paralysis is the most common type of laryngeal paralysis that we see in our small animal patients
- Older, large breed dogs
- Part of generalized neuropathy (complete PE and neuro exam is essential!)
- Other causes include hypothyroidism, trauma, immune-mediated (myasthenia gravis), infectious, and toxic (lead, organophosphates) - KNOW THESE**
What is the most common surgical treatment for perineal hernia?
internal obturator muscle transposition
T/F: If your patient has a penetrating chest wound, it is generally best to remove the object penetrating the chest wall immediately to avoid excessive bleeding
NO.
-
Unless you are Clark Kent and have x-ray vision, do not remove objects penetrating the chest wall!!
- Radiographs or CT should be performed to determine the location of the object
- Thoracotomy for removal of the object
How do you reach a definitive diagnosis of laryngeal paralysis?
laryngeal (airway) exam
This can be done with a laryngoscope or rigid scope
- Arytenoids should abduct on inhalation
- Watch for paroxysmal motion (larynx closing on inhalation)
- Assistance required for monitoring of respiratory cycle
- Be prepared to proceed immediately with further diagnostics or surgery based on findings
If you’re performing surgery on a specific structure in the thoracic cavity, what is the surgical approach of choice?
lateral/intercostal thoracotomy
All of the following are complications associated with treatment of chylothorax except:
- Persistent chylous or non-chylous effusion
- Diaphragmatic hernia
- Lung lobe torsion
- Pneumothorax
diaphragmatic hernia
What is the correct order of diagnostics for a nasal tumor?
minimum database → thoracic rads → skull rads → cytology → biopsy → culture
**
