Arthritis & Renal stones - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
Home
USMLE Articles
USMLE News
USMLE Polls
USMLE Books
USMLE Apps
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 08-12-2011
Hope2Pass's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,684
Threads: 213
Thanked 1,600 Times in 660 Posts
Reputation: 1610
Correct Answer Arthritis & Renal stones

A 47 year old patient presents with painful arthritis in the right big two and uric acid renal stones. He has been taking allopurinol for his condition. What biochemical defect would likely be found in this patient?

A) Defect in urea synthesis
B) Abnormal purine degradation pathway
C) Inability to synthesize non-essential amino acids
D) Defective topoisomerases
E) Increased levels of leukotrienes
Reply With Quote Quick reply to this message
The above post was thanked by:
struggle (08-12-2011)



  #2  
Old 08-12-2011
whocares13's Avatar
USMLE Forums Addict
 
Steps History: Step 1 Only
Posts: 145
Threads: 8
Thanked 76 Times in 57 Posts
Reputation: 86
Default

B) Abnormal purine degradation pathway
Reply With Quote Quick reply to this message
The above post was thanked by:
Hope2Pass (08-12-2011)
  #3  
Old 08-12-2011
drnirajmavani's Avatar
USMLE Forums Veteran
 
Steps History: Step 1 Only
Posts: 268
Threads: 14
Thanked 103 Times in 69 Posts
Reputation: 113
Default

D). Defective topoisomerases- there would be defective enzyme that relieves DNA supercoling . this leads to increased DNA strand breakage, which ultimately releases excess of purines which are degraded to form uric acid..
Reply With Quote Quick reply to this message
The above post was thanked by:
Hope2Pass (08-12-2011)
 
  #4  
Old 08-12-2011
USMLE2011m's Avatar
USMLE Forums Veteran
 
Steps History: Step 1 Only
Posts: 277
Threads: 36
Thanked 159 Times in 95 Posts
Reputation: 169
Default

Is it b?
__________________
Set your mind to it, and you will be there.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message
The above post was thanked by:
Hope2Pass (08-12-2011)
  #5  
Old 08-12-2011
dr.Irina's Avatar
USMLE Forums Veteran
 
Steps History: 1 + CK
Posts: 229
Threads: 6
Thanked 73 Times in 62 Posts
Reputation: 83
Default

B) Abnormal purine degradation pathway
Reply With Quote Quick reply to this message
The above post was thanked by:
Hope2Pass (08-12-2011)
  #6  
Old 08-12-2011
pass7's Avatar
USMLE Forums Guru
 
Steps History: 1+CK+CS+3
Posts: 406
Threads: 30
Thanked 141 Times in 109 Posts
Reputation: 151
Default

Quote:
Originally Posted by Hope2Pass View Post
A 47 year old patient presents with painful arthritis in the right big two and uric acid renal stones. He has been taking allopurinol for his condition. What biochemical defect would likely be found in this patient?

A) Defect in urea synthesis
B) Abnormal purine degradation pathway
C) Inability to synthesize non-essential amino acids
D) Defective topoisomerases
E) Increased levels of leukotrienes

B) Abnormal purine degradation pathway
Reply With Quote Quick reply to this message
The above post was thanked by:
Hope2Pass (08-12-2011)
  #7  
Old 08-13-2011
Hope2Pass's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,684
Threads: 213
Thanked 1,600 Times in 660 Posts
Reputation: 1610
Correct Answer B) Abnormal Purine Degradation Pathway

The correct answer is B) Abnormal Purine Degradation Pathway.

Explanation -

This patient has gout, characterized by painful joints due to the precipitation of uric acid crystals caused by excessive production of uric acid (a minority of cases are associated with underexcretion of uric acid). Kidney disease is also seen due to accumulation of uric acid in the tubules. The disease mostly affects males, and is frequently treated with allopurinol, an inhibitor of xanthine oxidase. Xanthine oxidase catalyzes the sequential oxidation of hypoxanthine to xanthine to uric acid.


A defect in urea synthesis (choice A) would result in the accumulation of ammonia.

Phenylketonuria is a disease in which tyrosine cannot be produced from phenylalanine (choice C) usually due to deficiency of phenylalanine hydroxylase. It is characterized by a musty body odor and mental retardation.

Defective topoisomerases (choice D) would affect DNA unwinding, and therefore replication.

Leukotrienes (choice E) are potent constrictors of smooth muscle and would more likely lead to bronchoconstriction.
Reply With Quote Quick reply to this message
The above post was thanked by:
drnirajmavani (08-13-2011), whocares13 (08-13-2011)



Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
Where you live. Leave blank if you don't want to tell.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Orlistat and Oxalate Kidney Stones! evavar USMLE Step 1 Forum 2 05-19-2011 07:34 AM
UW question about renal stones tkourkou USMLE Step 2 CK Forum 5 03-18-2011 02:47 PM
3 c's of ESWL resistant kidney stones Dr.B.SHRAVYA USMLE Step 2 CK Mnemonics 0 01-02-2011 04:29 AM
radioluscent kidney stones Dr.B.SHRAVYA USMLE Step 2 CK Mnemonics 0 01-02-2011 04:26 AM
Vitamin C toxicity and Kidney Stones! lemontea88 USMLE Step 1 Forum 10 12-21-2009 10:04 PM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)