Cramps during exercise and red-brown urine - 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 03-23-2012
USMLE Forums Master
 
Steps History: 1+CK+CS
Posts: 1,406
Threads: 118
Thanked 647 Times in 409 Posts
Reputation: 657
Urine Sample Cramps during exercise and red-brown urine

NOTE: this is a USMLE Consult-"inspired" question, so look away if you plan on using USMLE Consult as a measure of your progress.


----------------------------------------------

A 19-year-old man reports painful cramps during exercise. The cramps are usually followed by a red-brown tint in his urine. Consumption of glucose-containing electrolyte-replacement drinks before exercising does not alleviate the symptoms. Additional tests indicate that he has a mild case of hemolytic anemia. The patient most likely has a deficiency of which enzyme?

A. a-glucosidase
B. Glucose 6-phosphatase
C. branching enzyme
D. liver phosphorylase
E. phosphofructokinase
F. 5a-reductase
__________________
"inflammable means flammable!? What a country."
Reply With Quote Quick reply to this message
The above post was thanked by:
Giorgio (03-23-2012)



  #2  
Old 03-23-2012
DocSikorski's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,353
Threads: 94
Thanked 877 Times in 507 Posts
Reputation: 890
Default

B. G-6-phosphatase.
__________________
Ambition is a dream with a V8 engine. EP
Reply With Quote Quick reply to this message
  #3  
Old 03-23-2012
drhma's Avatar
USMLE Forums Addict
 
Steps History: 1 + CS
Posts: 193
Threads: 29
Thanked 134 Times in 71 Posts
Reputation: 144
Send a message via MSN to drhma
Default

E- phosphofructokinase
??

coz this also happens in muscle phosphrylase deficiency, which is a glyogen disorder
but even after administration of glucose containing compounds.. the ptt cant make use of them.. so PFK should be deficient, besides glucose-6-phosphatase is only found in the liver and would cause hypoglycemia and shock and would have been shown on the pateint when he was very young
it's PFK deficiency [E].. leading to rhabdomyolysis and myoglobinuria [explains the urine colour] its not blood in urine, the anemia is also due to deficient ATP in RBC's due to low enzyme activity... again favors PFK
Reply With Quote Quick reply to this message
 
  #4  
Old 03-23-2012
DocSikorski's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,353
Threads: 94
Thanked 877 Times in 507 Posts
Reputation: 890
Default

Quote:
Originally Posted by drhma View Post
E- phosphofructokinase
??

coz this also happens in muscle phosphrylase deficiency, which is a glyogen disorder
but even after administration of glucose containing compounds.. the ptt cant make use of them.. so PFK should be deficient, besides glucose-6-phosphatase is only found in the liver and would cause hypoglycemia and shock and would have been shown on the pateint when he was very young
it's PFK deficiency [E].. leading to rhabdomyolysis and myoglobinuria [explains the urine colour] its not blood in urine, the anemia is also due to deficient ATP in RBC's due to low enzyme activity... again favors PFK
What PFK r u talking about? I think PFK will be responsible for glucolysis... Not glycogenolysis, he obviously would not make it till 19...

I was looking for muscle phosphorylase (McArdle) but could not find it...

Something buzzed me about Von Gierke...
========

mmyeah, I see only 2 more or less reasonable options - g6p and pfk...
__________________
Ambition is a dream with a V8 engine. EP
Reply With Quote Quick reply to this message
  #5  
Old 03-23-2012
drhma's Avatar
USMLE Forums Addict
 
Steps History: 1 + CS
Posts: 193
Threads: 29
Thanked 134 Times in 71 Posts
Reputation: 144
Send a message via MSN to drhma
Default

its called tarui's disease.. autosomal ressesive PFK deficiency!
i dont know how he lived up till 19, but it makes more sence than any other option, why did the question even mention glucose didnt help? obviolsy coz the defect is in glucose metabolsm ~ glycolysis!
Reply With Quote Quick reply to this message
The above post was thanked by:
DocSikorski (03-23-2012)
  #6  
Old 03-23-2012
johnvega98's Avatar
USMLE Forums Addict
 
Steps History: Step 1 Only
Posts: 122
Threads: 34
Thanked 25 Times in 16 Posts
Reputation: 35
Default

I would go with PFK.
looking in the point of view of glycolisis. If RBC are deficient on this enzyme, they can only make 1 ATP from 2 on the normal. State. Now, when they are been demanded on exercise, they need their maximum ATP and they are limited to 1 ATP, so they lyse which by the follow mechanism produce dark urine.
IF G6P where missing, its via gluconegogenesis, which means that the patient wouldnt be able to deliver glucose from the liver to the body in any state when there is no glucose income, like fasting states not only in during exercising. Plus hepatomegaly due to the fact that the liver cant get out glucose and glycogen is stored there with no where to go. This would be a glycogen storage disease.
Reply With Quote Quick reply to this message
  #7  
Old 03-23-2012
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
Default

As drhma said, this is Type VII GSD: Tarui Dx. Its a deficiency in MUSCLE PFK and has a similar presentation to Type V: McArdle's Dx. Since there is no PFK in the muscle, it cannot break down glycogen effectively during exercise and that leads to pain, weakness and cramping. The dark-red or red-brown urine is Myoglobinuria.

I think the option should've said "MUSCLE phosphofructokinase" instead of just PFK because that gets confusing.

Last edited by Hope2Pass; 03-23-2012 at 10:54 AM.
Reply With Quote Quick reply to this message
  #8  
Old 03-23-2012
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
Default

Here is the source of my information. I didn't know what Tarui Dx is until I saw it here so I did some research and came across this brilliant website. I thought I'd share it with everyone on the forum and not just this thread but here's the source of my info - http://www.agsdus.org/html/whatisgly...gedisease.html
Reply With Quote Quick reply to this message
  #9  
Old 03-23-2012
USMLE Forums Master
 
Steps History: 1+CK+CS
Posts: 1,406
Threads: 118
Thanked 647 Times in 409 Posts
Reputation: 657
Default answer = E.

the answer is E. PFK

i had never heard of Tarui disease before
didnt know the glycogen storage diseases had a type VII "-_-
glad this thread brought it up.
__________________
"inflammable means flammable!? What a country."
Reply With Quote Quick reply to this message
The above post was thanked by:
Dr. Mexito (03-23-2012)
  #10  
Old 03-23-2012
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
Default

Quote:
Originally Posted by Dr.NickRiviera View Post
the answer is E. PFK

i had never heard of Tarui disease before
didnt know the glycogen storage diseases had a type VII "-_-
glad this thread brought it up.
Yeah same here!


Btw, Just wondering, in your questions you right that this is a "usmle consult inspired" question .. does that mean its from the usmle consult because you said you were going through that question bank right now .. OR are these questions similar to the questions in the usmle consult but you just change up the wording a bit ?
Reply With Quote Quick reply to this message
  #11  
Old 03-24-2012
USMLE Forums Master
 
Steps History: 1+CK+CS
Posts: 1,406
Threads: 118
Thanked 647 Times in 409 Posts
Reputation: 657
Default

Quote:
Originally Posted by Hope2Pass View Post
Yeah same here!


Btw, Just wondering, in your questions you right that this is a "usmle consult inspired" question .. does that mean its from the usmle consult because you said you were going through that question bank right now .. OR are these questions similar to the questions in the usmle consult but you just change up the wording a bit ?
the latter.
same concept, written slightly different.
__________________
"inflammable means flammable!? What a country."
Reply With Quote Quick reply to this message
The above post was thanked by:
Hope2Pass (03-24-2012)



Reply

Tags
Biochemistry-, Step-1-Questions

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
Abdominal Distension and Cramps anomali USMLE Step 1 Forum 3 01-08-2012 03:20 AM
Smoky Brown Urine! scopusmount USMLE Step 1 Forum 19 12-18-2011 05:07 AM
Severe Leg Cramps and High TSH! drnrpatel USMLE Step 2 CK Forum 4 10-17-2011 06:24 PM
Swollen eyes and brown urine ricko335 USMLE Step 1 Forum 32 08-03-2011 04:35 AM
Eye swelling and brown urine bacteria! ricko335 USMLE Step 1 Forum 0 07-12-2011 07:05 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)