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 NB F3 S1 Pathogenesis of Rx in Respi  



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Author19 Posts
  #1

33. An 8-year-old boy is brought to the physician by his parents because of episodes of shortness of breath, nonproductive cough, and wheezing that last 5 to 10 minutes and occur more frequently during the winter. The incidence and severity of these episodes is most likely to be decreased by selective inhibition of which of the following enzymes? A. Cyclooxygenase-1 B. Cyclooxygenase-2 C. Epoxygenase D. 5-Lipoxygenase E. Phospholipase A1 F. Thromboxane synthase




  #2

Looks like asthma. If it is so, blocking phospholipase A2 and lipoxygenase is the treatment. I dont know if it the same as 5-lipoxygenase, and I dont know what epoxygenase is.

Answer looks like D. Pls correct me if wrong.


  #3

I guess D

This patient has Hay fever.

We treat it by using corticoid (Phopholipase A2 inhibitor), antihistamine, and possibly Zileuton (Lipoxygenase) to reduce leucotriene production.



  #4

diagnosis differ but the option chosen is the same. but can hay fever present without runny nose?


  #5

Yeah in this patient I confused between Hay fever and Asthma, but anyway I chose D


  #6

hay fever occurs in the summer usually due to pollen..here he has these in the winterraised eyebrow


  #7

i think its asthma...very common among this age group,specially the trigerring agent is cold..(atopic)..I will choose D...phospholipase 2,will definately relieve the symptoms but in the question stem its asked about selective inhibition....Using a steroid to block phospholipase would result in block of both cycloxygenase and lipoxygenase pathways..


  #8

I agree with D and diagnosis of asthma


  #9

child has asthma(atopic-exposure to cold)-lox inhibitors used(zileuton)


  #10

doesnt thromboxane also cause bronchoconstriction?


  #11

yup, thromboxane also causes bronchoconstriction


  #12

I guess D


  #13

i agree d, except i think that this si an example of intrinsic (non atopic) asthma. so there woudl be no family history, no eosinophis, no IgE etc. in atopic, extrinsic, we'd get MAST cell/eosinophil accumulation.


Edited by twesting2173 on Sep 26, 2006 - 9:58 AM

  #14

I'll go w/ E


  #15

interesting,



  #16

-Lipoxygenase - ziluton ,,, well i think its asthma,, and giving corticosteriods may led to more systemic side effects , n corticosteriods are reserved for severe cases ..



  #17

i will o with phosphlipase A2 inhibitoes certainly is atopic
and well co0rticosteroids seem to be more effective in atopic asthma as oppsoed
lipooxygenase inhibitors



  #18

i go w / D as bec at this if v give steriods effects bonegrowth of child.


  #19

i go w / D as bec at this age if v give steriods effects bonegrowth of child.





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