Respiratory Flashcards
What value of pulmonary artery pressure is diagnostic for pulmonary hypertension when measured by right heart catheterisation?
≥25mmHg
What is the difference between pre-capilary and post-capillary pulmonary hypertension?
Background: PHT is an interplay between pulmonary blood flow, vascular resistance and pulmonary venous pressure.
Pre-capillary PHT is associated with an increase in pulmonary capillary wedge pressure ≥15mmHg
Pre-capilary PHT implies that there is pathology of the blood vessels themselves whereas pre-capillary suggests an increase in pressure that is not dependent on the vasaculature (e..g left-sided cardiac disease)
What value of tricuspic velocity implies pulmonary hypertesions?
≥3.4 m/s
What are the diagnostic criteria for low, intermediate and high risk of pulmonary hypertension?
Low = TR <3.0m/s with 0 - 1 sites of PHT
Medium =
- TR ≤ 3 with 2 sites of PHT
- TR 3.0 - 3.4 with 0 - 1 sites of PHT
- TR ≥3.4 with 0 sites of PHT
High:
- TR < 3.0 with 3 sites of PHT
- TR 3.0 - 3.4 with≥2 sites of PHT
- TR >3.4 with ≥1 sites of PHT
What are the echocardiographic sites of pulmonary hypertension and their signs?
Ventricals: flattening of the IVS, underfilling of the LV, RV hypertrophy, RV systolic dysfunction
Pulmonary Artery: Enlargement, Increased PR velocity, RPAD index < 30%, RV doppler acceleration time, systolic notching of the dopple RV outflow
RA and CVC: RA enlargement, enlargement of the caudal vena cava
What are the conditions that need to be pressent in order to diagnose PHT secondary to left-heart disease?
- Left atrial enlargement needs to be present as this indicates pulmonary artery wedge pressure being increased
- Demonstration of left heart disease (e.g. MMVD needs to be present)
What are the clinical findings suggestive of pulmonary hypertension?
Syncope
Respiratoy distress at rest
Activity or exercise terminatin in respiratory distress
Right-sided heart failure
+/- Tachypnoea at rest
+/- Increased respiratory effort at rest
+/- Prolonged post-exercise tachypnoea
+/- cyanotic or pale MM
Group 1 PHT
Pulmonary arterialhypertension
Group 2 PHT
Left heart disease
Group 3 PHT
Respiratory disease/hypoxia
Group 4 PHT
Thromboembolic disease
Group 5 PHT
Parasitic disease
Group 6
Multifactorial or unclear mechanisms
What are the thoracic imaging findings that suggest PHT (5 points)?
- Tortuous, blunted or dilated pulmonary arteries
- Asymettrical radiolucent lung fields
- Patchy or diffuse alveolar infiltrates
- Bulge in the pulmonary trunk
- Right sided cardiac enlargement
What are the CT findings that can suggest PHT (6 points)?
Pulmonary trunk to descenting aorta ratio >1.4
Evicdence of RA and RV enlargement
Decreased pulmonary vein to pulmonary artery ratio, increased RV to LV ratio
Presence of pulmonary arterial filling defects
Mosaic attentuation pattern on an inspiratory scan that does not go away with an expiratory phase
Perivascular patterns
What are the three groups of treatment for pulmonary hypertension?
Decrease risk of progression or complications from pulmonary hypertension
Target the underlying disease or factors contributing to pulmonary hypertension
Specific treatment of pulmonary hypertension
What strategies can be applied to mimise the risk of diease progression and complications from PHT (5 points)?
Exercise restriction
Prevent respiratory pathogens (vaccination and deworming)
Avoid pregnancy (may exacerbate PHT)
Avoid high altitude and air travel
Avoid non-essential procedures that require a GA
In which group of PHT disorders is sildenafil not reccomended?
Left heart disease since the cause is really post-capilary hypertension and in L>R shunting (can consider in R>L shunting). In both these scenarious increasing pulmonary blood flow can result in pulmonary oedema. However, it can be considered in LHD as long as CHF is not present and they have syncope thought to be due to PHT
When can the use of tPA be considered in cases of PHT?
In group 4 disease where RV dilation and systolic dysfunction, hypotension and collapse are all present (essentially there aren’t other options)
What condition can sildenafil be given in group 1 (pulmonary arteria hypertension)?
In hospital, due to the risk of pulmonary oedema development
What treatments, other than sildenafil, can be considerd in PHT but do not have sufficient evidence for or against?
Pimobendan
Milrinone (an IV PDE3 inhibitor)
rTKIs (inhibit the action of PDGF)
L-arginine (when combins with oxygen it forms NO)
How should patients wit pulmoanry hypertension be monitored?
- Clinical assessment:
- RR, Reff, RCHF
- At baseline, 2 weeks after starting therapy and q 3 - 6 month therafter - Echocardiography: at clinicians discretion
- Other:
- 6 minute walk tests
- Repeat thoracic imaging and pulse oximetry
What is the success rate of lateral wall resection compared to TECALBO?
40-55% success for LWR vs. 90% for TECALBO
What are the potential neurological complications of ear surgery?
Horners - more common in cats
Facial nerve paralysis
Vestibular signs
What is the genetic basis for congenital sensorioneural deafness in the following breeds?
a) Collies, Austrailian Shepherds, Shelties, Great Danes
b) Bull Terriers, Bulldogs, Great Pyrenees and Dalmatians
c) Dobermans
d) Cats
a) Dominant in merle variants
b) Autosomal recessive in piebalds
c) not stated
d) Autosomal dominant with incomplete penetrance
Categories of DDx for nasal disease
Stenosis
Foreign bodies
Oronasal communication
Rhinitis
Neoplasia
Non-malignant masses (e.g. fungal)
% of cases of chronic nasal discharge that are due to neoplasia?
30%
Identify the structures in this picture of a larynx
Which breeds are commonly affected by acquired laryngeal paralysis?
Labrador (most common)
Golden Retriever
St. Bernard
Newfoundland
Irish Setter
Brittany Spaniel
What are the main DDx for laryngeal paralysis?
- Congenital: genetic or laryngeal paralysis-polyneuropathy complex
- Trauma affecting the recurrent laryngeal nerve
- Neoplasia affecting the RLN (e.g. thymoma, lymphoma, thyroid carcinoma)
- Neuromuscular diseases: e.g. GOLPP
Which breeds suffer from:
a) Congenital laryngeal paralysis
b) Congenital laryngeal paralysis-polyneuropathy
a) Bouvier des Flandres, Huskeys and Malamutes, Bull Terriers, GSD
b) Dalmatians, Rottweilers, Leonburgers, Pyrenean Mountain Dogs
What structure should be considered in the evaluation of dogs with laryngeal paralysis?
Thoracic imaging to identify for evidence of megaoesophagus
Which is the best induction agent for allowing laryngeal motion when performing airway examination?
Thiopental
Which breed gets a concurrent laryngeal paralysis and laryngeal collapes syndrome?
Norwich Terriers
What are the three clinical stages of laryngeal collapse?
- Eversion of laryngeal saccules into the glottis
- Collapse of the cuneiform process into the laryngeal lumen
- Collapse of the carnuculate process causing complete airway obstruction
Treatment options for laryngeal collapse?
- Sacculectomy
- Relief of airway obstruction (e.g. BOAS surgery)
- Unilateral laryngoplasty
- Permanent tracheostomy
What are the main causes of laryngeal stenosis?
Bilateral ventriculochordectomy
Trauma or chronic inflammatory laryngeal disease
What is the normal inspiratory:expiratory ratio in small animals?
1:1 to 1:2 (inspiratory to expiratory)
How does stertor differ to stridor?
Stertor is a low pitched sound originating from the nasopharyngeal meatues whereas stridor is a high pitched sound originating from the larynx or trachea. It can worsen with exercise (in contrast to stertor)
What advanced imaging technique can be used to assess for pulmonary perfusion?
Tc 99 nuclear imaging
What is the minimum size required generally for a TTW?
15kg
What additional radiographic view may be helpful in diagnosing tracheal collapse?
Rostrocaudal veiw
Grades of tracheal collapse
Grade I: Tracheal membrane is slightly pendulous, cartilage maintains normal shape, and lumen size is reduced by 25%.
Grade II: Tracheal membrane is widened and pendulous, cartilage is partially flattened, and lumen size is reduced by 50%.
Grade III: Tracheal membrane is almost in contact with the ventral trachea, cartilage is nearly flat, and lumen size is reduced by 75%.
Grade IV: Tracheal membrane is lying on dorsal cartilage, cartilage is flattened and may invert, and lumen is essentially closed.
What are the medical treatment options for tracheal collapse?
Corticosteroids (systemic or inhaled)
Stonazalol
Anti-tussives (hydrocodone, butorphanol, codeine, diphenoxylate, maropitant)
Bronchodilators (theophylline, terbutaline, albuterol)
What are the surgical treatments for the following?
a) Intra-thoracic tracheal collapse
b) Cervical tracheal collapse
a) Intraluminal stents
b) Extraluminal rings (better prognosis)
What are the main tumour types encountered in the trachea?
Young dogs get osteochondroma
Older dogs: MCT, SCC, adenocarcinoma, osteosarcoma, extramedullary plasmacytoa, leiomyoma, fibrosarcoma
What are the reasons for tracheal granuloma formation, how are these treated?
○ Complication of intraluminal stenting
○ Parasitic
§ Oslerus osleri
§ Filaroides osleri
Cuteribri larvae (cats)
Treat with corticosteroids
What are the three diagnostic criteria to allow a diagnosis of chronic bronchitis?
- Chronic cough (>2 months)
- Evidence of excessive mucus or mucus hypersecretion
- Exclusion of other chronic cardiopulmonary diseases
- Evidence of excessive mucus or mucus hypersecretion
Which breeds of dog are overrepresented in eosinophilic bronchopneumopathy?
Siberian Huskies and Malamutes
How is eosinophilic bronchopneumopathy suggested based on ETW?
The BALF should be >50% eosinophils
DDx for eosinophilc bronchopneumopathy?
- GIT Worms (migrating larval migrans)
○ Strongyloides
○ Ascaris
○ Toxocara canis
○ Ancyclostoma- Occult heartworm infection
- Angiostrongylus
- Other worms:
○ Capillaria aerophilia
○ Oslerus osleri
○ Filaroides hirthi
Crenosoma vulpis
What are the components of Kartagener’s syndrome?
Bronchiectasis
Left to right transposition of the vicera (situs invertus)
Chronic rhinusitis
For which breed is there a genetic test available for primary ciliary dyskinesia and what is its mode of inheritance?
Old English Sheepdog - CCDC39 gene
Autosomal recessive
Other than respiratory signs, what may be seen with primary ciliary dyskinesia
○ Otitis media
○ Female infertility
○ Asthenosteratopspermia
○ Hydrocephalus
○ Renal fibrosis/renal tubule dilation
What are the main clinical signs to prompt a hunt for primary ciliary dyskinesia
In a young dog:
Recurrent bilateral nasal discharge
Repeated episodes of bronchitis or bronchopneumonia
What is the gold standard for diagnosis of ciliary dyskinesia?
Showing a functional issue with scintigraphy and TEM to demonstrate structural abnormalities with the cilia.
What does the following image indicate?
Cliated epithelia, some of the cilia have a lack of central dynein rings suggestive of primary ciliary dyskinesia
What disease should be expected if a dog that has recently had a bronchial foreign body removed suddenly develops a pleural effusion?
Bronchooesophageal fistula, consider contrast imaging followd by surgical correction
What is the reason for formation of broncholithiasis?
Can occur secondary to any chronic infectious or inflammatory condition
Which breed is static bronchomalacia often seen in
Brachycephalic dogs, in contrast to dynamic collapse which is seen in cases of tracheal collapse
What distributions of cell populations would be expected in the following from a cat?
a) Eosinophilc BAL
b) Neutrophilic BAL
○ Eosinophilic BAL: >20% eosinophils with neutrophils WNL/>50% eosinophils (suggests FAAD?)
Neutrophilic BAL: >20% neutrophils with eosinophils WNL/>50% neutrophils (suggests CB?)
What parasitic diseases should be considered when evaluating a cat for lower airway disease?
○ Aelurostrongylus abstrusus
○ Troglostrongylus breviour
○ Eucoleuos aerophilis
○ Dirofilaria immitis
* Toxocari cati
What condition should be considred in a young cat with a history of cough that develops a spontaneous pneumothorax?
Feline lower airway disease
What are the 5 mechanisms of hypoxaemia, which will have a normal or increased A-a gradient, which will improve with O2 therapy?
Hypoventillation - normal A-a gradient, increased PCO2
V/Q mismatch - increased A-a gradient that will improve with supplementation
R-L shunting - increased A-a gradent that will not improve with O2 supplementation
Diffusion impairment - increased A-a gradient, improves with O2 supplementation
Reduced inspired O2 - increased A-a gradient, will resolve with O2 supplementation
Pragnimus kellicotti
- What is it
- What is the intermediate host
- Life cycle in mammalian host
- Clinical signs
- Diagnostic features
- Diagnostic method
- Treatment
- Tremtode lung fluke
- Crayfish, particularly in the midwest and southeast united states
- Migration from the GI to the peritoneaum, through the diaphragm and then into the subpleural tissues where they encyst. Eggs are coughed up and swallowed
- Can be clinically silent, bullae rupture can lead to pneumothorax, haemorrhage and haemoptysis
- Bullae and cysts
- Ova can be visualised in lavage fluid or using faecal sedimentation techniques
- Fenbendale (10 days) or praziquantel
Paragmonius kellicoti egg
Whats this?
Paragmonius kellicoti egg
Filaroides
- Epidemiologic features
- Radioraphic signs
- Diagnosis
- Treatment
-More common in research colonies, young and immunocompromised patients
- Bronchinterstitl or alveolar infiltrates
- Zinc sulfate faecal flotation, demenstration of ova in lavage fluid
- Fenbendazole, ivermectin
Whats dis?
Filaroides egg
Filaroides egg
Aulurostrongylus abstrusus
- What is it?
- Intermediate host
- Radiographic signs
- Diagnosis
- Treatment
- Feline lungworm
- Molluscs
- Diffuse nodular interstital pattern (can look like FAAD)
- Baerman’s, airway lavage - demonstrate larvae
- Fenbendazole, ivermectin, selamectin
Crenosoma vulpis
- What is it
- Intermediate host
- Diagnosis
- Treatment
- Canine only pulmonary parasite (a lungworm)
- Molluscs
- Baerman’s sedimentation or zinc flotation - demonstration of larvae
- Fenbendazole, Ivermectin, Milbemcin
Oslerus osleri
- What is it
- Diagnosis
- Similar pathogen to filaroides
- Zinc sulfate flotation
Eucoleus
- What it causes
- Diagnosis
- Eosinophilc pneumonia through embedding in tracheal and bronchial mucosa
- Faecal flotation or airway lavage
Trogostrongylus
Domestic and wild cat airway worm
What are the ISCAID reccomendations for treatment of bacterial pneumonia (generally speaking)
Doxycycline for dogs without systemic involvement
Fluroquinolone +/- penicillin or clindamycin if systemic signs are present
What is the advantage/disadvantage of N-acetylcystine nebulisation?
It should break down mucus disulfide bonds thus loosening respiratory secretions, however, it causes severe bronchoconstriction so use is limited
Which bacterial organism is responsible for necrotising haemorrhagic pneumonia?
Streoptococcus equi zooepidemicus
Yersina pestis
- What is it
- Where is it
- How is it spread, what is the reservoir
- What is the treatment?
- It is the plague and can cause systemic (supprative lymphadenitis) or pneumonic disease
- Risk area is most of the Western USA such as New Mexico and Colorado
- Rodents are the nartural reservoir and it is spread by fleas or by ingestion of reservoir hosts. It can also be spread via aerosole
- Aminoglycosides or tetracyclines seem to be first line but ettinger also mentions fluroquinolones and chloramphenicol. Also treat for fleas.
What is this?
Gram negative safety-pin shaped rods, consistent with yersinia pestis
Yersinia pestis cytology
Which protozoa may cause a pneumonia?
Toxoplasma
Which fungal pathogens are more likely to result in a fungal pneumonia?
Blastomyces
Histoplasmosis
Coccidiodes
Aspergillus
Cryptococcus
What are the more common interstitial lung disease?
Eosinophilic pneumonia
Lipid pneumonia
Idiopathic pulmonary fibrosis
What condition has been associasted with lipid pneumonia in cats?
Atypical mycobacterial pneumonia
What BAL finding could indicate lipid pneumonia?
Foamy macrophages
Definition of pulmonary bullae vs. blebs
Bullae - air pockets within pulmonary parenchyma, are not lined by epithelia
Blebs - air formed when air escapes from the lung and gets trapped in the visceral pleura
DDx for pulmonary bullae
Idiopathic
Parasitic
Neoplastic
Infectious disease conditions
Congenital (Bronchopulmonary dysplasi)
Radiographic appearance of congenital emphysema
Lobar hyperinflation
Extension of blood vessels to the lobe margin
Contralateral mediastinal shift
Caudal displacement of the diaphragm
Atelectasis of other lung lobes
Pneumothorax
Predisposed breeds to lung lobe torsionb
Afgan hounds (can get chylothorax with or without lung lobe torsion)
Pugs
Most common sites of lung lobe torsion
- Left cranial lung lobe
- Right middle lung lobe
- Right cranial lobe
- Right caudal lobe
- Left caudal lobe
Prognosis of dogs with lung lobe torsion
60% recover with surgery
Pugs may have a better prognosis
What is the equation for pulmonary arterial pressure?
RV output x pulmonary vascular resistance
What heart sound can be noted with pulmonary hypertension?
Split or loud S2
Modified bernoilli equation
Pressure gradient = 4x(peak velocity)^2
What is the alternative to sildenafil in terms of PDE5 inhibitors?
Tadalafil
Which TKI has been studied most in dogs with PHT?
Imatinib - inhibits PDGF activation
In what time frame might D-dimer measurement be useful in determining if PTE has occured?
Within 1 - 2 hours as they have a very short half life
What are the indications for chest tube placement over thoracocentesis?
Recurrent or continuous pneumothorax or effusions
Infectious eitiology (pyothorax)
What are the main DDx for chylothorax?
- Increased venous pressure
○ Right sided heart failure
○ Pericardial effusion
○ Dirofilariasis
○ Cardiomyopathy
○ Tricuspid dysplasia
○ Thromboembolic disorders- Compression of the thoracic duct
○ Neoplasia
○ Thymoma
○ Fungal granulomas
○ Lung lobe torsion - Trauma (uncommon)
○ Concurrent with traumatic diaphragmatic herniation
○ Thoracic surgery
○ Blund or penetrating trauma
○ Severe coughing or vomiting
Idiopathic (most common in dogs, possibly most common in cats)
- Compression of the thoracic duct
What stain can demonstrate chylomicrons in chylous fluid
Sudan III or IV
What diagnostic criteria for cholesterol/triglycerides can be applied for diagnosis of chylothorax?
- Fluid cholesterol:TG <1 is diagnostic
- TG significantly higher than serum
○ Typically 12 - 200x greater - Cholesterol significantly lower than serum
- TG significantly higher than serum
Which breeds are predisposed to chylothorax?
Afgan hound
Mastiffs
Sheltland Sheepdog
Shiba Inu
MoA of rutin
Possibly through stimulation of macrophage activity which breaks down chyle proteins and may enhance re-absorption
What is a normal width of the mediastinum?
<2x width of the spine
What is the relationship between pneumomediastinum and pneumothorax?
Pneumothorax can be caused by pneumothorax but not the other way around
What signalment is more common in animals with mediastinal cysts?
Older cats
Are cats or dogs more likely to develop mediastinal lymphoma?
Cats - parcularly younger cats
What disease should be tested for in cats with mediastinal lymphoma?
FeLV as it is commonly associated with mediastinal lymphoma
When and why does thymic haemorrhage occur?
It occurs in young animals (<2 years old) and it thought to be due to involution of the mediastinum
Treatment of thymoma vs. mediastinal lymphoma?
Surgery or RT for thymoma, CHOP/LOPP for lymphoma
What type of lymphoma is thymoma typically caused by?
T-cell
Most common bacteria identified in pyothorax in order
Pasteurella spp., actinomyces/nocardia, enteric anaerobes
Most common causes of pyothorax in dogs vs. cats
Dogs: migrating foreign material
Cats: bite wounds and parapneumonic spread
What are the characteristics of pyothorax fluid?
Smelly
Neutrophilic with sepsis
Sulfur granules can indicate nocardia/actinomyces
Indications for surgical mnagement of pyothorax
Failure to respond to medical management
Migrating foreign bodies
Pulmonary abscesation
Pleural fibrosis suspected
Being a dog - surgery associated with better long term outcomes
