Pulmonology Flashcards
(281 cards)
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.