Pulmonology Flashcards
Side effects of bronchodilators?
Tachycardia, skeletal muscle tremors, inhibit uterine motility, hypokalaemia, airway inflammation if inhaled.
Can get tolerance due to receptor downregulation with chronic use. Corticosteroid use can mitigate beta receptor loss.
Methylxanthine mechanisms of action?
Theophylline - relax bronchial smooth muscle (phosphodiesterase inhibitor? 3/4 - no breakdown cAMP/cGMP so no inflamm mediator release from mast cells and no smooth muscle contraction)
Might be anti-inflamm - enhance activity corticosteroids?
Imp mucocilliary clearance?
Other suggestions - adenosine antagonism, altered intracellular calcium handling
SE - CNS stim, diuresis, cardiac stim - latter two mild
What is aminophylline?
80 % theophylline, can be used interchangeably with intermediate release theophylline
How is theophylline metabolised?
90 % liver 10 % excreted unchanged in urine
How might you monitor theophylline tx?
Can measure trough conc - < 10 - 20? Might get anti inflamm below this level
SEs of theophylline?
Restless, GI. Can reinstate at lower dose.
Cardiac stim poss but uncommon. More potent than caffeine or theobromine.
What inhibits theophylline metabolism?
Enrofloxacin, erythromycin and cimeditine
Increase metabolism theophylline?
Rifampin, phenobarbital
Glucocorticoid airway effects?
Inhibit cytokine, chemokine, adhesion molecule production.
Decreased inflammatory prostaglandin, leukotriene and platelet activating factor.
Mast cells NOT affected
Enhance bronchodilators (modify receptor/augment muscle relaxation)
Decrease the sensitisation of the resp mucosa and then can taper
Potency of fluticasone versus dexamethasone
18 x potency
Response of cats with bronchitis to fluticasone?
Reduced need for oral pred
Reduce bronchial hyper responsiveness and bronchoconstriction
Decreased inflamm cells/prostaglandin in BAL fluid
Systemic effects inhaled steroid?
Probably HPA axis suppression but no lymphocyte number/function changes
T/F: leukotrienes are important in the pathophys of feline asthma
No - imp in human not cat
Guaifensin mechanism action?
Expectorant - stim bronchial secretion via vagal or increases particle clearance
Acetylcysteine resp mechanism of action?
Exposed compound sulfhydryl groups interact with dilsulfide bonds on mucoprotein
But may be irritant to resp mucosa and bronchoconsstriction in cats when nebulised
What predicts pulmonary antibiotic concentration?
Concentration of drug in epithelial lining fluid in alveolus. Might be more predictive of drug in airway secretions.
NB in disease different - diseased ELF may be diff and alveolar wall might be disrupted.
Haematogenous - invasion via interstitium
What properties favour epithelial lining fluid antibiotic penetration?
High lipophilicity, high potency (low MIC) and increased conc free drug in interstitial fluid
Macrolide, quinolone and tetracycline AB ELF conc much higher than plasma.
Beta lactam and aminoglycosidees might diffuse to interstitial space and help in the presence of infection, inflammation and barrier disruption.
FHV and calicivirus - DNA or RNA? Genetic variation?
FHV: DNA, antigen stable
Calici: RNA, multiple strain varied virulence
What other infectious agents are implicated in feline URT infections?
Chlamydia felis, Bordetella, Mycoplasma, Strep canis
Clinical signs go each pathogen?
Calici - mouth, eyes, nose lower airway. NB systemic and joints. Less severe signs cf FHV
FHV: eyes, nose, mouth, lungs (lysis turbinates), skin
Bordetella: trachea, bronchi lower airway, eyes, nose
Chlamydia - eyes, mild upper airway
Most appropriate AB for feline URT?
Doxycycline - chlamydia and mycoplasma
Why are beta lactase not effective cf mycoplasma?
No cell wall
Lysine use?
Essential AA, interferes with FHV replication in vitro.
Not found to be effective.
Mechanism of action of oseltamivir?
Neuramininidase inhibitor.
Only primary bacterial nasal cavity diseases in dogs?
Pasteurella, bordetella
Most common site of oronasal fistula?
Maxillary third incisor, first and second premolar, mesial root third premolar
Therapy for nasal parasites?
Pneumonyssus caninum, ivermectin 2 doses
Use milbemycin if MDR1 mutation
Eucoleus boehmi - ivermectin or fenbendazole
Most common cause of canine fungal rhinitis?
Aspergilus fumigatus
What causes bony destruction in aspergillosis?
Inflammatory response to fungus
NB dysregulation of TLR and NOD
Success of anti fungal tx for aspergillosis?
Around half first tx, 70 % multiple
What antifungals might be synergistic?
Terbinafine plus azole
Immune dysregulation in LPR?
TLR/NOD dysreg in nasal mucosa
Other factors in LPR?
Higher transcription of fungal genes using PCR when compared with neoplasia - is hypersensitivity to commensal fungus an issue? Oral antifungals may yield dramatic improvement/resolution on rare occasion.
What is xeromycteria?
Dry nose - loss of lateral nasal gland secretion - facial nerve parasympathetic supply can be affected by otitis media
Tear production normal because preganglionic not affected
What would you use an antigen latex agglutination serologic test for?
Cryptococcus in cats - v sens and spec when pronase step is used to degrade ABs binding to the capsular antigen
Cryptococcus culture?
Used for sub typing/susceptibility but NB false pos - commensal
What is galactomannan?
Polysach component fungal cell wall - poorly sensitive, better specificity but not perfect (cats)
Immune mediated clearance (cats) causes poor sens
How might you design a PCR specific for particular Aspergillus species?
Look at gene sequence analysis of partial betatubulin or calmodulin genes
Secondary bacterial infection in feline rhinosinusitis?
pasteurella, E coli, Corynebacterium, Bordetella, Strep, Pseudomonas, Actinomyces, Bacteroides, Mycoplasma
Doxycycline activity against most
AB for penetration of bone?
Clindamycin
T/F: different Aspergillus species produce different clinical presentations in cats?
True - A fumigatus the species doesn’t cause sino-orbital aspergillosis, another in the A fumigatus complex
What anti fungal not useful for A fumigates complex in cats?
Fluconazole - widespread resistance
Therapy for Sino-orbital aspergillus in cats?
Poss use azole with amphotericin B/terbinafine to imp outcome
Cryptococcal recrudescent infection in cats?
15 - 20 % casess
Primary and secondary components of BOAS?
Primary: stenotic nares, turbinate distortion and overgrowth, narrow nasal cavity, soft tissue in nasopharynx and oropharynx, elongated and thickened soft palate, macroglossia, tracheal hypoplasia, redundant oesophagus, gastric stasis, pyloric hypertrophy/stenosis
Secondary: worsening turbinate deviation, worsening of soft tissue in pharynx, worsening of thick soft palate
Everted saccules laryngeal collapse, bronchial collapse, hiatal hernia, GERD, eosphagitis, pyloric hypertrophy worsening, gastroduodenitis
T/F: pug bronchial collapse worsens post-BOAS surgical outcome?
False. But is correlated with laryngeal collapse.
What breeds are overrepresented for components of BOAS?
Pug - bronchial and laryngeal collapse, distorted and protruding turbinates
Bulldog - tracheal hypoplasia, macroglossia, oesophageal redundancy,
What is the major cause of nasal stenosis in BOAS?
Alar cartilage
What middle ear abnormality occurs with nasopharyngeal disease?
Bullous effusion - 34 % cats nasopharyngeal disease, 100 % caudal nasopharyngeal disease
Follicular nasal hyperplasia in nasopharynx?
Poss nasal mites
Histopath of nasopharyngeal polyp?
Fibrovascular connective tissue and mixed inflamm cells, stratified squamous columnar/ciliated columnar epithelium, often ulcerated
How do you decrease polyp recurrence rate?
Steroids
What ‘polyps’ occur in the nasal cavity of young cats?
Mesenchymal hamartomas
Where do nasal polyps live in dogs?
Caudal nasal cavity attached to caudal turbinates, rostral nasopharynx
What drug should you have ready when balloon dilating nasopharyngeal strictures?
Atropine as can get vagal mediated bradycardia
Breeds associated with congenital laryngeal paralysis?
Husky, bouvier de flandres (auto dom nerve degen), bull terrier, white GSD
Larpar polyneuropathy?
Dalmatian, rottie, Pyrenean mountain dog
Many idiopathic get generalised neuro signs in a year
Acquired larpar breeds?
GRet, st Bernard, Newfie, Irish setter, leonberger
What exacerbates larpar?
Humidity, exercise, heat, stress, obesity
Oedema of mucosa on arytenoids ensues
What impact would temporary tracheostomy have on larpar case?
Has been assoc with negative px following surgery - more likely to have major complications
T/F: the management for unilateral larpar is tieback?
False - not usually severely clinically affected until bilateral and only unilateral tiebacks are performed.
T/F: in larpar surgery the arytenoid should be pulled as laterally as possible
No - might increase risk postop aspiration pneumonia if increase surface area of rima glottis beyond epiglottal margins, with no improvement in clin signs or outcome
Predictors of complication/poor outcome in larpar?
Pre-op asp pneumonia, oesophageal dysfunction, generalised neuropathy, temp tracheostomy preop, concurrent neoplasia
Difference between canine and feline larpar?
Cats have signs with unilateral, L > R
Degeneration tracheal rings?
Hypocellularity, decreased glycosaminoglycan, glycoprotein, chondroitin sulphate and calcium
Can’t retain water
Factors causing progression to symptomatic tracheal collapse?
obesity, recent endotracheal intubation, respiratory infection, cardiomegaly, cervical trauma, and inhalation of irritants or allergens, chronic bronchitis, pulm oedema, upper airway obstruction, periodontal disease
Tracheal mucosa changes in tracheal collapse?
Loss of epithelium, fibrinous membrane formation, and squamous metaplasia with polypoid proliferation evident in advanced cases.
Decreased ciliated cells, hyperplasia of sub endothelial glands and increased viscous mucous
How many tracheal collapse cases symptomatic at 6m?
25 %
Success of extraluminal prosthesis for tracheal collapse?
Decreased clin signs 75 - 85 %
High rate complications and most had extra thoracic collapse (no intrathoracic due to even higher morbidity)
Success tracheal stenting?
75 - 90 % improvement with less complications
Landmarks for trach stent?
Cricoid cartilage, carina
Where does granulation tissue develop after stenting?
Cranial aspect - movement or coughing
Could consider colchicine?
Does tracheal stent fracture affect prognosis?
No - not if restent
When should you trust a positive BAL culture?
> 1.7 x 10^3 CFU/ml, no squamous cells or simonsiella, increased. neuts
Mediator of smooth muscle contraction in feline asthma?
Mast cell serotonin
Histamine role less certain
Cytokine array in feline asthma?
Th2 with IgE
IgE, NO, IL4, IFNgamma and TNF in BAL and serum but can’t be used diagnostically
Cat breed predip for asthma?
Siamese
Normal cat eosinophils on BAL?
Up to 20 - 25 % cell population
Significance of mycoplasma in lower airway in cats?
Not normal - only pathogen. Mycoplasma can degrade neutral endopeptidase, which degrades substance P, which causes bronchoconstriction and oedema. Ioslated from 25 % cats lower airway dz
Klebsiella and Pseudomonas can be recovered from healthy airways
What are leukotrienes?
Arachidonic acid derived eicosanoids
Leukotrienes, including LTE4 are not found in cats with asthma and leukotriene metabolism or receptor blockers don’t improve feline asthma
One case report advocated zafirlukas/montelukast (cysteinyl leukotriene receptor 1 blocker)
Fluticasone mechanism of action?
18 x affinity dex for steroid receptor.
Inhibit inflamm cells and their mediators.
Plasma levels don’t predict therapeutic effects. Clinically effective absorption into airway mucosa might be delayed 1-2w
What predisposes animals to pneumonia?
Concurrent dz or environmental stressors
Causes of peracute severe pneumonia in cats and dogs?
Strep equi zooepidemicus, E coli, usually associated with stressor
Puppies with CAP?
Bordetella half, gram neg enteric half
Risk factors for MDR pathogens in HAP?
AB in 90 d, hosp in 90d, current hosp > 48h, high MDR in hosp
Phases of aspiration lung injury?
Phase 1 - 1-2h, direct pulmonary parenchymal injury
Phase 2 - ALI, neutrophilic infiltrate to alveoli, start several hours and progress 24-48h
Risk factors for gastric colonisation with bacteria?
SI obstruction/ileus
Gastrroparesis
Feeding tube
Tx gastroprotectants (esp G neg)
Risk factors for aspiration pneumonia in dogs?
Laryngeal paralysis, oesophageal disease, vomiting, neuro disease, recent GA
Most frequent bacteria in canine aspiration pneumonia?
E coli
Mycoplasma
Pasteurella
Staph
Some no pos culture and most have two or more organisms
Outcome aspiration pneumonia?
80 % recovery
One study found poor px = more than one lung lobe affected, another found no corr with XR
No diff choice of AB
How to prevent aspiration pneumonia?
Position, enteral feeding esp nasogastric, promotility, gastric pH modification
Cytokine profile in EBP?
Th2 - increased CD4+ in BAL, increased eotaxin
Also upreg collangenolysis
Increase metalloproteinase 8/9/13
What does BWBP measure?
Barometric whole body plethysmography - HPenh300 index (conc histamine required to increase enhanced pause by 300 %) - decreased in EBP, returns to N after tx
What predicts most poor response to tx in EBP?
Abrupt cessation meds or irregular parenteral depository steroid inj
What secondary immunosuppressive could you use in EBP?
Ciclosporin
What is the main receptor involved in eosinophil recruitment?
CC chemokine receptor type 3
Most commonly affected lung lobes for torsion?
Right middle, right cranial
Sensitivity of cytology for neoplastic pleural effusion?
50 %
FIP and effusion content?
If albumin > 48 % or alb:glob <0.81, FIP unlikely
What does the thoracic duct drain?
Lymph from intestine, liver and hindlimbs
Bacterial population pleural effusion?
Often mixed so give aerobic, anaerobic and g pos/neg cover - amoxiclav and enro
How long to wait in pyothorax off before surg management
Cat - if no resolution effusion after one week
Dogs - improved outcome with surg intervention from the start (might be because more FB in dogs cf cats), however recent studies show excellent outcome with medical/no evidence for surgical superiority
Survival rate pyothorax?
> 50 %, recurrence < 5-10 %
Marked increase survival rate for those alive at 24h
Why might pericardectomy be an effective tx for chylothorax?
If causing RHS increased cardiac pressure
Chylothorax breed predisposition?
Afghan, shiba inu
Himalayan, siamese
How to dx chylous effusion?
Trigs usually 10xhigher cf serum, can decrease if affected animal anorexic
Benzopyrone?
Might be of use in chylothorax - improve macrophage function and chyle resorption.
Rutin
Surgical management to chylothorax?
Thoracic duct ligation (20 - 50 and. 50 - 80 dog and cat have chylothorax or serosanguinous discharge persisting)
Omentalisation
Pericardectomy (80 % cats respond)
Pleuroperitoneal shunting
Pleural port
When to place chest drain in pneumothorax?
Severe > 1l air or >3 taps req in 24h
What helps to seal lung after traumatic pneumo?
High pulm thromboblastin
Breeds for spontaneous pneumo?
Deep chested, husky, gret
Secondary pneumothorax other than traumatic?
Dog - neoplasia PTE pneumonia
Cat - heartworm airway dz
What would you use blood patching for?
Pneumothorax - fresh whole blood
Pulmonary consequences of PTE?
Bronchoconstriction, VQ mismatch, hypoxia, hyperventilation, regional loss of surfactant, pulmonary infarction
Atelectasis, oedema and effusion
What is oligemia?
Hypoperfused lung, best identified on DV/VD XR
Pleural effusion in PTE?
Not common, cat > dog
Radioscintigraphic perfusion scan pulmonary?
V sens for PTE but not specific
Selective pulmonary angiography = gold standard
Benefit of O2 supp in PTE?
Relieve hypoxaemia, dilate pulm vessels, reduce pulmonary hypertension, improve RV function
Need to optimise perfusion also
Difference in factor suppression UFH versus LMWH?
1:1 and 4:1 anti-10 anti-2 ratio respectively
Latter more bioavailable and has prolonged half life, decreased protein binding, renal clearance
Less effects plt function and vascular permeability so less haemorrhage events
How to prevent PTE?
Minimise vascular stasis by optimising perfusion and mobility
Minimise vascular injury with IV Cath management
Alter haemostat system with antithrombotic drugs
Why low dose aspirin?
Inhibit thromboxane synth and spares prostacyclin
Arrhythmias in pulmonary hypertension?
Pronounced sinus arrhythmia, isolated APC/VPC, AFib, AV block
What equation is used to calculate a pressure gradient?
Bernoulli
What should be included in this equation?
Theoretically right atrial pressure and RV diastolic pressure
Ranges for normal pulmonic/TR regurg?
2.5 - 3.5
2 - 2.2
BUT some normal dogs have TR around 3. TR jet present 80 % normal dogs.
Severity of PH?
< 50 mild
< 80 mod
> 80 severe
Correlation Doppler echo with right heart cath?
Acceptable but less good if PH less severe (humans)
TR affected by rv contractility and volume overload - underestimate if impaired contractility or high diastolic pressure
Opposite overest
Also underest if incorrect alignment
Other echo PH diagnostics?
Pulmonary flow profile
What other echo changes PH?
Eccentric, concentric or mixed hypertrophy in mod to severe PH
Concentric more common congenital
Flatten IV septum, paradoxical septum motion, PA dilation (aortic:pulm < 1)
Tx for PH other than sildenafil?
Calcium channel blockers
What pathways can be targeted in PH?
Prostaglandin-cAMP pathway (PGI2//cAMP/PDE3+4/AMP) - PDE3/4 inh (pimobendan)
NO-cGMP pathway (Larginine/NOsynthase/NO/cGMP/PDE5) - sildenafil PDE 5 inh
Endothelin pathway (endothelin converting enzyme/calcium) - ET receptor antagonist
Why sildenafil effective in lungs?
Lots of PDE5
Also - imp myocardial contractility, decreased vent afterload, facilitate natriuretic peptide, blunt adrenergic stim
Negative px indicators in PH?
Mod/severe dz, RHS CHF, survive first week
CT in idiopathic pulmonary fibrosis?
Ground glass opacity, sub pleural and parenchymal bands, peribronchovascular interstitial thickening, traction bronchiectasis
Corr dz severity
Concurrent IPF pulm dz?
Bronchial/tracheal collapse
Scope IPF?
Expiratory dynamic airway collapse due to poor lung compliance and high elastic recoil, more likely if bronchotracheomalacia
BAL - one study in westies inflamm (concurrent chronic bronchitis?)
What interstitial lung diseases would PH be common in?
50 % IPF, not PIE
IPF histopath?
Patchy extensive alveolar fibrosis, epithelial cell hyperplasia, squamous metaplasia, inflamm
Eucoleus Boehmi?
Nematode, nose, dogs
Eggs in faeces.
Earthworms transport host?
Golden barrel eggs double plug
Look like Eucoleus aerophilus, eggs ls smaller and pitted shell
Mammomonogamus eirei?
South Am, cats, nose.
Eggs faeces and nasal flush.
Fenbendazole
Blood test for Cuterebra?
ELISA IgG ABs
Linguatula serrata?
Arthropod. Dog. Nose. Europe/Middle East
Eggs nasal secretions, intermediate host ruminant. Dog ingest sheep offal.
Oslerus osleri?
Granulomatous nodules tracheal bifurcation. Young dogs. US/Aus.
Direct life cycle. Faeces and saliva.
Nodules 10 w post exposure, immature worms in trachea. PPP 12-18w
Spont pneumo reported
Egg/larvae BAL, larvae faecess (less reliable, 33% sens, need zinc sulphate centrifug)
Fenbendazole/ivermectin +/- debulk
Oslerus rostratus
Cats. US Middle East Southern Europe.
Bronchial submucosa, slug intermediate host.
Filaroides hirthi
Alveoli/terminal bronchioles. Dogs.
Direct life cycle. PPP 32 - 35 d.
Faecal transmission. Autoinfection. Endemic breeding colonies. Might have no clin signs.
Eggs/larvae BAL/faeces. Latter less sens. Zinc sulphate centrifug again.
Fenebendazole/ivermectin
Aelurostrongylus abstrususs
Cat. Terminal bronchioles/alveolar duct.
Mollusc intermediate host.
Can be subclin, GA death, occ pneumothorax.
Baermann - larvae, sens 85 - 90 %
Pharyngeal PCR highly sens and spec
Crenosoma vulpis?
Dogs. Frequent Canada.
Indirect slug/snail intermediate.
Bronchi-bronchioless.
19 - 21 d PPP
BAL larvae 50 - 75 % sens
Baermann more sens zinc sulf
Intermittent shed need 3 sample over 7 d
Milbemycin
Eucoleus aerophilus
Tracheobronchial mucosa, cats and dogs. Masses.
3-6w PPP
Direct life cycle. Earthworm transport host. Rare human case.
PCR for faeces highly sens spec
Fenbendazole, ivermectin, moxidectin/imidacloprid
Paragnominus kellicotti?
Trematode. Dogs and cats. US. Snail and crab intermediate host.
Metacertaria infective in crab. Exit GI into peritoneal cavity and go through diaphragm. Pulm cysts right caudal lung lobe.
Spont pneumo reported
Fenbendazole or praziquantel.
Histopath soft palate changes in BOAS?
Increased stroma, increased salivary tissue, muscle degeneration and necrosis
What causes vocal cord granulomas?
Excess contact and GERD
Norwich terriers?
Redundant supra-arytenoid folds, laryngeal collapse, everted saccules, narrowed laryngeal openings
Cartilage failure and degeneration
Describe the grades of laryngeal collapse
1 - sacules
2 - cuneiform process
3 - corniculate process
Name the cartilage components of the larynx
Arytenoid
Epiglottis
Cricoid
Thyroid
Nerve - caudal laryngeal
Cricothyroid muscle controlled by CRANIAL laryngeal
Cats no cuneiform/corniculate
Prevalence of hypothyroidism in larpar?
30 %
Area for most pronounced tracheal collapse?
Cervicothoracic junction
What is cervical lung lobe herniation associated with?
Intrathoracic tracheal collapse
Factors impacting stent prognosis?
Presence of bronchomalacia, concomitant lower airway dz
Yorkie specific tracheal collapse presentation?
W shaped tracheal ring
Exposure to smoke causes chronic bronchitis?
No evidence for this
Is partial bronchial collapse always a sign of disease?
No - can find in healthy ageing dogs
How to increase sensitivity for airway inflammation?
Brushing instead of BAL might be more sensitive for chronic bronchitis
What impact does obesity have on respiratory function?
Limits exercise, worsens cough, impairs lung function, increases airway hyperresponsiveness
Concurrent signs/problems in EBP?
50 % nasal discharge, 60 % peripheral eosinophilia, 50 % bronchiectasis
BAL fluid marker for EBP?
Procollagen 3 aminoterminal propeptide - fibrotic change?
Pathophys primary ciliary dyskinesia?
Ineffective or uncoordinated ciliary function and therefore mucous clearance
What is Kartagener’s syndrome?
Bronchiectasis, situs inverts and chronic rhinosinusitis
Genetic PCD?
OES
Situs invertus?
50 % PCD
Concurrent issues with PCD dogs?
Otitis media, infertility, renal fibrosis, dilation renal tubules
Ciliated epithelia/microtubules
Diagnosis of PCD?
OES - Taqman assay Scintigraphy TEM (distinguish from secondary?) - ultrastructural changes include absence of dynein arms, radial spoke defects, nexin link defects, axonemal disorganisation, micro tubular transposition
Irish wolfhound PCD?
No - they get a juvenile rhinosinusitis/bronchopneumonia but no PCD
Definition of bronchiectasis?
Abnormal, permanent dilation and distortion of subsegmental airways
Chronic inflamm damages elastic bronchi components and bronchial wall
Resp secretions not cleared
CFTR and bronchiectasis?
Mutations in dogs but not assoc with bronchiectasis
What might cause focal bronchiectasis?
Obstruction eg FB
Aspergillus and bronchiectasis?
Localised cavitatary
Breeds for bronchiectasis?
ACS, mini poodle, husky, ESS, usually > 7yo
Gold standard dx bronchiectasis?
CT - dilation, lack of tapering, lobar consolidation
Bronchoarterial ratio?
Surgery for bronchiectasis?
Only if focal
What is bronchomalacia and what causes it?
Weakness principal/small bronchi walls
Static common brachycephalic.
Dynamic - with tracheal collapse, inflamm/infection
Large breeds often have static and dynamic
NOT associated with cardiomegaly.
Both lungs 50 %, infectious 50 %
Peripheral eosinophilia in asthma?
Around 20 %, not corr with BAL
BAL fluid cytokines in asthmatic versus healthy cats?
ET 1 increased exp
NO DIFF IL4/IFgamma/TNFalpha
Repeat BAL in treated asthmatics
70 % BAL still inflamm despite clin imp
What bronchodilator not to use in cats?
Racemic mixture albuterol increases airway inflamm experimentally
How do you calculate the A-a gradient?
((0.21 X 714) - (PaCO2/0.8)) - Pa02
< 15 N, > 20 VQ mismatch
Increased A-a gradient?
Impaired oxygen diffusion or VQ mismatch
Hypoventilation?
Increased carbon dioxide, normal A-a gradient
Hypoxaemia with normal A-a gradient?
Low inspired oxygen
What causes dyspnoea with normal XR?
Aspiration pneumonia, PTE, ARDS
What causes dyspnoea with cranioventral alveolar XR?
Bact/asp pneum, haemorrhage
What causes dyspnoea with perihilar XR?
CHF
What causes dyspnoea with caudodorsal/peripheral XR?
Mycotic, parasitic, protozoal, rickettsial pneumonitis, noncard pulm oedema, haemorrhage
What causes dyspnoea with other alveolar XR?
PTE, drowning smoke viral parasitic pneumonia, neoplasia, atelectasis
What causes dyspnoea with bronchial XR?
Asthma, CB, EBP, peribronchial cuffing oedema and inflammation, bronchial calcification
What causes dyspnoea with interstitial XR?
Unstructured: IPF, lymphoma,
Structured > unstructured: neoplasia, mets, fungal, eosinophilic pneumonia, FB reaction
Structured: abscess/cyst
Any: haematoma
What causes dyspnoea with vascular XR?
Heartworm, thromboembolic dz, pulm hypertension, CHF
What Angiostrongylus larvae are detected in faeces?
L1
How often are anaerobes involved in bacterial pneumonia?
25 % cases
Most common bacteria dog and cat pneumonia?
Dog - Strep, E coli, Pasteurella
Cat - Mycoplasma, Pasteurella, Bordetella
Predisposing factors for bacterial pneumonia?
Recumbency, debilitation, immunosuppression, immunodeficiency, defective respiratory defence, damage to the respiratory epithelium
Where would a haematogenous pneumonia XR pattern be?
Dorsocaudal
ISCAID AB pneumonia recommendation?
Empirical approach - ampicillin or clindamycin with a quinolone
Recheck at 14 d and make change depending on clin condition
What factors impact the pathogenic potential of aspirated material?
pH, bacterial load, particle size, volume, tonicity
Polyethylene glycol particularly bad as draws interstitial fluid into lung
Most common XR findings in aspiration pneumonia?
25 % only interstitial.
Mostly patchy/focal alveolar.
R mid/cranial, caudal left cranial. > 1 involved in 1/3 cases
Respiratory Mycoplasma?
M. cynos dogs/cats, common bacterial isolate in combination but not sole pathogen. PCR reasonable sens/spec,
Testing for influenza?
Haemagglutination - specific subtype
Antigen/virus isolation/PCR - shedding peak 2-3d post inf
What immunoglobulin deficiency predisposes which breeds to P carinii?
CKCS - IgG
Mini dach/pom - IgA
Stain for P carinii?
Grocott Gomori methenamine
NOT ZOONOTIC!
Why are lungs resistant to oedema?
Tight junctions between alveolar epithelial cells, lots of lymphatic drainage (peribronchovascular space)
What mediates removal of pulmonary oedema alveolar fluid?
Active transport of sodium and chloride provides osmotic gradient
What arrhythmia might you see in pulmonary disease?
Pronounced sinus arrhythmia (vagal stim)
Criteria for ventilation?
PaO2 < 60 SpO2 < 90 PaCO2 > 60 with O2 supp
Negative prognostic indicators in eosinophilic pneumonia?
Hypereosinophilic syndrome, bronchiectasis
XR changes in feline IPF?
Any - common see in conjunction with neoplasia
Steroids, antibiotics after drowning?
Steroids don’t improve survival, ABs don’t decrease risk bacterial pneumonia.
Pentoxyfylline could decrease risk of ARDS (nonspecific PDE inhibitor)
What does carbon monoxide do?
Impairs O2 binding with Hb (carboxyHb) - looks normal on pulse ox
Prognostic indicators for smoke inhalation?
Imp 1st day = good
Resp deterioration past one day/burns/need for vent = bad
What is a pulmonary bleb?
Accumulation of air between layers of the visceral pleura
Imaging for pulmonary bullae?
XR insensitive (5 - 50 %), CT 75 %
Causes of emphysema?
Distension/rupture of alveolar from lost pulmonary elasticity and lung function.
Congenital lobar emphysema (then affects other lobes)
Idiopathic
Bronchial obstruction
Classic emphysema XR?
Lobar hyperinflation, vessels extend to edge of lobe
Most common lung lobes affected by torsion?
R middle, R cranial, R caudal, L caudal
How often would pleural fluid culture be positive in lung lobe torsion?
Reported around 1/3, Pseudomonas/Ecoli
Px lung lobe torsion?
60 % recovery, pug good px
Delayed mortality due to pneumo/chylous/torsion other lobes
Classification of pulmonary hypertension?
I - pulmonary arterial disease II - left heart disease/pulmonary venous hypertension III - pulmonary disease IV - thromboembolic disease V - miscellaneous
Inducers of pulmonary vasculature vasoconstriction and vasodilation?
Constrict - endothelin I (also causes muscle hypertrophy/collagen proliferation), prostaglandin, hypoxaemia, serotonin.
PDGF (hypertrophy smooth muscle)
Dilate - NO, increased oxygen, prostacyclin
How do you modify the Bernoulli equation to take into account volume overload?
By appearance of right atrium - normal add 5 mmHg, dilated add 10, signs R CHF add 15
Most accurate when added to TR velocity
XR predictor of pulm hypertension in small dogs?
Short axis vertebral heart score/sternal contact length
NT-proBNP and troponin in pulm hypertension?
NT proBNP - increased in respiratory disease dogs with pulmonary hypertension versus non-PH counterparts
Increased in MVD with PH but can’t distinguish from MVD without PH
NB decreases when manage MVD with pimobendan
Might corr with peak TR
Troponin - increased in resp disease, can’t distinguish PH
How might a PDE5 inhibitor help in pulmonary hypertension?
Inhibit breakdown of cGMP, NO pathway
Also decreases remodelling and fibrosis
When should a PDEE5 inhibitor be used in pulm hypertension?
Moderate if syncope and no CHF or after CHF drugs added
Severe regardless of any other factor
Imatinib? Mechanism of action and benefit in pulm hypertension?
TKI - might decrease PDGF to decrease remodelling
What drug might be useful as a sildenafil alternative?
Tadalafil - longer acting
Blood gas analysis in PTE?
Increased A-a gradient, hypoxaemia with hypercapnia
Non-recruitable/trapped lung?
Non recruitable - immature fibrin presents reexpansion
Trapped lung - thickening and constriction of the pleura - can’t reexpand even with negative pleural pressure
How much fluid/air do you need to remove from pleural space to improve ventilation?
5 - 30 ml/kg
NT pro BNP use in pleural effusion?
Cats - pleural eff NTproBNP v sens/șpec for cardio versus non cardio
Evidence of chronic pleural effusion?
Rounded lung margins
Light’s criteria for pleural effusion?
Protein:LDH ratio - increase LDH or ratio > 0.5 = exudate
What is the problem with diagnosing cardiac causes of pleural effusion?
If moderate pleural effusion (> 17 - 22ml/kg), increase CVP by 4.5 cm H2O (misdx)
What does it suggest if ascites is present with right atrial tamponade?
Chronic
How many chylothorax cases have a cause?
50 %
What ribs could fracture with resp distress in cats?
9 - 13
Viral components of canine infectious respiratory disease?
Enveloped: Parainfluenza, herpesvirus, coronavirus,
Non env: CAV
Influenza, pneumovirus
Prevalence of Bordetella in healthy and acutely coughing dogs?
45 and 80 %
What toxin does Bordetella produce and what does it do?
Tracheal cytotoxin, ciliostasis and loss
Adenylate cyclase inhibits neutrophil phagocytosis
Bordetella diagnosis?
Culture 50 % PCR 100 % sense
Cytokines- coccobacilli adhere to ciliated cells
Diagnosis of VS feline calici?
Antigen in liver
Dx regular FCV?
Virus isolation most sensitive, or RT PCR
Where does chlamydia need to be?
Intracellular
Dx pcr
Eyes - keratitis/ulcer less common cf FHV
How can you decrease brachy anaesthesia risk?
Do BOAS surgery - subsequent GAs lower risk
IgE in serum feline asthma?
Serum allergen specific 78 % of cases, usually polysentitised
Evidence allergic dz, not corr with severity or airway eosinophilia
HOWEVER another study found no diff number of cats with pos serum IgE response in healthy/asthmatic (more pos allergen response in each cat with asthma)
Most common in asthma = mites (storage/dust - no control cat pos)
This is blood allergy testing
Raltegravir? What is it and why would you use it?
Retroviral integrase inhibitor. Interfere DNA polymerase.
May decrease duration FHV shedding and ameliorate eye and resp signs.
Nucleoside analoges can be used but viral mutation can lead to resistance.
Famciclovir? Mechanism and use?
Diacetyl 6 deoxy derivative of penciclovir
Acyclic guanosine analogue, inhibits herpesviral DNA polymerases
Variable oral absorption in cats and metabolism to penciclovir saturable (this is rate limiting)
Need high oral dose for tear excretion.
High dose may decrease duration and severity of clin signs in FHV vs low dose
Other studies found no benefit in acute upper resp dz when compared with doxycycline alone, however low number FHV in that study. Might decrease shedding?
Tracheal stent outcome?
93 % survival discharge
MST 1000d (male/younger longer)
89 % imp goose honk cough/raspy breathing/dyspnoea
Major comp 50 % in follow up
Mainstem bronchial collapse no effect on outcome
Half had malformation (W cartilages). No diff in outcome.
Is bronchial wall thickness to pulmonary artery ratio useful for chronic bronchitis dx on CT?
No
Why do alaskan huskies get congenital laryngeal paralysis?
MONOneuropathy recurrent laryngeal nerves - neurological atrophy of cricoarytenoideus dorsals muscle
40 % spontaneously improve
Variable penetrance autosomal recessive
Blue eyes, white facial markings. oral mucosal tags/tissue bands
How to treat nasopharyngeal stenosis best?
Balloon dilation alone - 0 % dogs 50 % cats
Overall after stent - 78 %
High risk complication
Cysterna chyli ablation in cats with chylothorax?
No improvement cf thoracic duct lig and pericardectomy alone
Risk factors for aspiration pneumonia in larpar?
Post surg - mega-o, opioids
NOT pre-op asp pneum, metoclop doesn’t help
Periop cisapride CRI might help
What clinical exam finding suggests cardiac dz in cat with pleural eff?
Low temp
When would mesenchymal stem cells have beneficial effect in feline asthma?
Delayed - may decrease airway inflamm, hyperresponsiveness and remodelling
Theoretically, why would maropitant be helpful in feline asthma?
Tachykinins from sensory nerves and immune cells bind NK1 receptors in the lung and cause neurogenic airway inflamm
However, no decrease eosinophilic inflamm or clin signs in experimental cats
What drug predicts survival in pulm hypertension?
Sildenafil
What is the pulmonary interstitium?
Anatomic space lined by endothelium cells and alveolar epithelial cells, with fibrous connective tissue.
NB interstitial lung disease can also involve other parenchyma
Drugs associated with interstitial lung dz?
TMPS cytarabine bleomycin lomustine. rabacfosadine. nitrosurea inhalant chemo XRT
Cytokine changes in IPF WHWTs?
TGFbeta1 (signalling protein smad increased in tissue, increased pathways for activating storing and signalling), increased assoc cytokine activin B in BAL
In comparison to healthy westies
Lung - CCL2, 7, 14, IL8, fibroblast activation protein alpha
BAL - CCL2, IL8, ET 1, PIIINP
Serum - CCL2 ET1
Westies in general - increased blood IL8, TGFbeta, KL6
Cause of IPF?
Risk factors - genetic, poor ventilation, old house, grooming in parlour
Bile acids increased in BALF - micro aspiration?
Pos precipitants, fungal hypersens?
Prognostic factors IPF?
CT findings predict severity (ground glass mild, focal reticular/mosaic/traction bronchiectasis more severe) and survival time. Serum CCL2 predict survival.
PaO2 and 6min walk test don’t predict
IPF same as human dz?
No - mixture of usual interstitial pneumonia and non-specific interstitial pneumonia
Infectious agents in chronic bronchitis/EBP?
No diff number PCR pos for M cynos/canis or Bb
EBP dogs had higher loads of Bb and Bb pos had higher neut counts, also more likely Bb pos if worse severity
What brachycephalic dogs have most GI?
Poss bulldogs (esp French) > pug
What is important about Lingatula serrata?
Zoonotic
Bronchomalacia in tracheal collapse?
45 - 83 % cases, most common right middle/left cranial bronchi
Anything different between eosinophilic and neutrophilic airway dz in cats?
Eosinophilic might be younger
What Mycoplasma species are thought to be pathogenic in canine LRT?
Cynos, probably not canis, spumans or edwardii
Bile acids in BAL?
Increased in IPF Westies and healthy westies, also increased other inflamm pulm dz, versus healthy beagles
CRP and SAA in bacterial pneumonia?
Increased, decreased with tx, can guide tx (stop 5-7d after normalise - shorten AB duration with no increase relapse). Not corr with severity.
Serology for feline Aspergillus?
IgG most sens and spec, IgA OK
Combining no value - IgA inferior
Most common cause sinonasal/sinoorbital aspergillus?
A. fumigatus, A. felis
Maropitant in chronic bronchitis?
Tachykinin NK1 neurogenic pathway - cough and airway inflamm, substance p sensitise cough receptors?
Decrease cough, no change inflamm
