McArdle's versus Von Gierke's

[Buckeye(OH)]

I had the following question on USMLERX and IMMEDIATELY pulled the trigger on McArdle's - wrong, its Von Gierke's but I cannot for the life of me determine how I was supposed to get that from the question.


23yom notices that he fatigues easily and gets muscle cramps. Also notes that while exercising, often needs to "catch his strength" by resting periodically. Dx muscle biopsy shows enzyme deficiency. Which glycogen storage dx is most likely?


I mean, if they would have mentioned something about +/- lactic acidosis, this would have been easy, but as its written im lost

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[GOGETA]

Also when they talk about Von they always say something about the kidney, and they talk about Mcalders they just say they get tired.

theres somethig about the glucose and fructose Ijust forgot what it is

I saw a crazy mod. in a forum saying that the guy got tired really quick wile doing sex and that could be Mcalder, hey if it works for him amen to that.

I had the following question on USMLERX and IMMEDIATELY pulled the trigger on McArdle's - wrong, its Von Gierke's but I cannot for the life of me determine how I was supposed to get that from the question.


23yom notices that he fatigues easily and gets muscle cramps. Also notes that while exercising, often needs to "catch his strength" by resting periodically. Dx muscle biopsy shows enzyme deficiency. Which glycogen storage dx is most likely?


I mean, if they would have mentioned something about +/- lactic acidosis, this would have been easy, but as its written im lost

 

[blz]

I had the following question on USMLERX and IMMEDIATELY pulled the trigger on McArdle's - wrong, its Von Gierke's but I cannot for the life of me determine how I was supposed to get that from the question.


23yom notices that he fatigues easily and gets muscle cramps. Also notes that while exercising, often needs to "catch his strength" by resting periodically. Dx muscle biopsy shows enzyme deficiency. Which glycogen storage dx is most likely?


I mean, if they would have mentioned something about +/- lactic acidosis, this would have been easy, but as its written im lost

There must be a trick to the question because when I read that scenario I see McArdle's disease. I mean they did a muscle bx and saw an enzyme defect in the muscle, how the hell can you dx von gierke's from a muscle biopsy?

 

[HeroOfChaos]

There must be a trick to the question because when I read that scenario I see McArdle's disease. I mean they did a muscle bx and saw an enzyme defect in the muscle, how the hell can you dx von gierke's from a muscle biopsy?

Yeah, I don't get it either. McArdle's is MUSCLE glycogen phosphorylase deficiency, and the textbook symptom is exercise induced muscle cramps - whereas Von Gierke's only involves the liver and is a glucose 6-phosphatase deficiency in the liver, textbook is hypoglycemia in between meals and hepatomegaly.

I'm scratching my head as well - is the OP confused or maybe he stated his question wrong??

 

[blz]

McArdles classically gets muscle cramps from the increased glycogen in MUSCLE that can't be broken down.....whereas Von Gierkes deficiency is in the ability to break down LIVER glycogen

you may be getting caught up on the mnemonic in FA...ie von gierkes becomes LIKE a muscle....ie it can't make glucose from G6P now...just like muscle

the OP obv knows this, that's why he chose McArdles. Explain why it's von gierke's.

 

[GOGETA]

I think they made a mistake, besides who you think they are Goljan

 

[Idiopathic]

So there is a type of VG where a muscle enzyme would be abnormal. I think its Type III that has a problem with alpha-glucosidase and cant debranch. HOWEVER, the classic McArdles case is an otherwise healthy young adult who gets painful muscle cramps with exercise. Von Gierke patients are much sicker. This is definitely Mcardles

 

[PhatGtDmB]

for all i can tell, the answer is McArdle's and was a mistake on usmlerx (btw why are you using this qbank?)

 

[Buckeye(OH)]

Yeah, I don't get it either. McArdle's is MUSCLE glycogen phosphorylase deficiency, and the textbook symptom is exercise induced muscle cramps - whereas Von Gierke's only involves the liver and is a glucose 6-phosphatase deficiency in the liver, textbook is hypoglycemia in between meals and hepatomegaly.

I'm scratching my head as well - is the OP confused or maybe he stated his question wrong??

Nope, the question was paraphrased as it was worded in the question. I only paraphrased so as not to post copyrighted info.

 

[blz]

It was probably a mistake on USMLERx's part. I found another question that was wrong and reported it using the comment box.

 

[basupran]

Edit: they did make a mistake since they included the muscle bx indicates an enzyme deficiency. You were right.

 

[blz]

Edit: they did make a mistake since they included the muscle bx indicates an enzyme deficiency. You were right.

Explain how they used a muscle biopsy showing an enzyme deficiency to diagnose it.