Who to send for MRI

[unchartedem]

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So another one of OCD questions. Who does everyone generally send for MRI with back pain patients. (Besides the obvious frank cord compressions sxs). Like if you have soley foot weakness referred to a particular dermatome and that's it then it's more indicative of a nerve root problem and not compression and I wouldn't consider that an emergency. However where I trained we generally did MRI's for back pain with any type of weakness. The same thing goes for neck pain with a weak triceps extension etc.. I mean bilateral weakness is more concerning however would you still do the MRI for unilateral. Or generally I would just like to hear everyone's personal management.

 

[pratik7]

So another one of OCD questions. Who does everyone generally send for MRI with back pain patients. (Besides the obvious frank cord compressions sxs). Like if you have soley foot weakness referred to a particular dermatome and that's it then it's more indicative of a nerve root problem and not compression and I wouldn't consider that an emergency. However where I trained we generally did MRI's for back pain with any type of weakness. The same thing goes for neck pain with a weak triceps extension etc.. I mean bilateral weakness is more concerning however would you still do the MRI for unilateral. Or generally I would just like to hear everyone's personal management.

good question and one i havent found a good answer for yet. Some of the attendings where i am MRI for any weakness. I had a similar situation 2 days ago with weak ankle flex and numbness to the R plantar foot. Did not MRI. Seems like there is no real rhyme or reason.

 

[GeneralVeers]

good question and one i havent found a good answer for yet. Some of the attendings where i am MRI for any weakness. I had a similar situation 2 days ago with weak ankle flex and numbness to the R plantar foot. Did not MRI. Seems like there is no real rhyme or reason.

For me it's either new-onset symptoms with significant weakness, and marked hypoesthesia, or a change in symptoms for someone with chronic back pain.

Generally if patients can't ambulate they need an MRI.

 

[WilcoWorld]

On EVERY back pain I see I ask these questions:

Are you having fever, neurologic symptoms, incontinence or retention?
Do you have a history of cancer, IV drug use, AAA (personal or family), AVM (personal or family), spinal surgery or recent trauma?
On physical I test for spinal tenderness to percussion, perineal sensation, lower extermity reflexes, strength and sensation. I also palpate femoral pulses.

If they have a red flag history with concerning symptoms, they get an MRI (or CT vs US if it's AAA I'm looking for). If they have objective neuro findings (not just a little paresthesia), they get an MRI.

If they don't have red flags, and the pain has been going on for less than 2 weeks - no imaging, just meds & d/c.

If they have no red flags, but the symptoms have bneen greater than 2 weeks or there was trauma at onset I do an X ray to look for mass or fracture. If this is negative I instruct those with pain > 2 weeks to f/u with a PMD for further imaging, since it could be serious, but needn't be diagnosed in the ED.

This might seem like a lot of work, but the whole thing takes me less than 3 minutes to get through, since I already have it worked out in my head before entering the room. Also, using this approach I do not end up doing many MRI's in the ED, and those that I do are usually positive for something worth knowing about.

 

[WilcoWorld]

I should say that my DDx on back pain is:

Benign muskuloskeletal (I include radiculopathy and sciatica in this category in terms of a diagnostic & theraputic approach).
AAA
AVM
Tumor
Fracture
Abscess
Disc herniation with cauda equina

of course atypical appi, psoas abscess, pyelo et al need to be considered, but we'd be getting a bit far afield if I started talikng about stuff like that.

 

[Hamhock]

Wow! I must, with some embarrassment, say I don't usually consider AVM...in fact, I am not sure what pathophys you are referring to.

Could you (Wilco) explain a bit further?

Thanks, HH

 

[Arcan57]

I'll MRI for new-onset weakness unless I am clearly convinced it's a peripheral nerve issue (just had surgery in lithotomy position, etc). Likewise, if someone has fever plus midline back pain (especially if they are DM or IVDA). I hate multiparous women that come in with back pain and endorse a hx of incontinence, I'll usually ask if it's changed in the last couple of months.

 

[tkim]

Wow! I must, with some embarrassment, say I don't usually consider AVM...in fact, I am not sure what pathophys you are referring to.

Could you (Wilco) explain a bit further?

Thanks, HH

I'm guessing artery of Adamkiewicz.

 

[WilcoWorld]

ArterioVenous Malformation (AVM) is a possible serious cause of spinal cord infarction - the thought is that venous engorgement leads to decreased local perfusion. I only worry about it if there's a previous diagnosis of it or a family history.

 

[TrumpetDoc]

Would you "call in" MRI for isolated myotome weakness? Admit for MRI? Arrange for OP MRI?

 

[gramcracker]

New weakness gets you an MRI. Numbness/tingling/chronic pain generally doesn't.

http://www.thennt.com/mri-vs-x-ray-for-lower-back-pain/

 

[Laryngophed]

I'm guessing artery of Adamkiewicz.

Boom! And you've taught the soon to be M2 something.

Well, you and Wikipedia.