It could be several different things, ranging from MBD to impaction to injury.
From your comments it appears that you suspect MBD. MBD, if caught at the onset of symptoms, is usually reversible. Are you dusting the crickets with a calcium product that also contains vitamin D3? You should be. Actually, I suggest feeding it mice pinkies for awhile instead of crickets.
If it hasn't defecated lately, or has defecated very little, try soaking it in tepid water that comes up to the lower part of the sav's shoulders. I'd let it soak for about 30 minutes or so at a time, a few times a day until it does have a good bowel movement.
Is there anything in the sav's cage that could've fell on it, injuring it?
More details about the cage setup & the sav's conditions would help pinpoint the cause. There are a lot of people here that can & will help you but you need to give us more to go on.
Best wishes!
HH
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Due to political correctness run amuck,
this ol' hillbilly is now referred to as an:
Appalachian American

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