35F with history of Crohn’s disease on Humira and mild peripheral vascular
insufficiency presents with 6 months lateral forefoot pain and swelling,
with no trauma.
In August, after 3 months of symptoms, she had a lidocaine, dexamethasone
and kenalog injection into the proximal 4th intermetatarsal space that gave
her 50% pain relief reported at 2week follow up.
MRI shows selective atrophy and edema of the of the 4th dorsal (red arrow)
and 3rd plantar interossei (blue arrow) muscles.
I don’t see a mass or other pathology.
The LPN looks normal.
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The consulting neurologist said that they could evaluate the MPN and LPN,
but cannot select out smaller branches in the foot with nerve conduction
studies.
Do you have any suggestion as to the cause of this subacute or acute on
chronic denervation atrophy and edema of these interossei?
Any advice how to sort this out, or what to do for this patient/
Thank you.
Hilary
1 thought on “35F 6 months pain and swelling lateral forefoot, MRI, Please Help”
hilary.umans
I received 2 very worthwhile responses I’m sharing in their entirety:
For these peripheral injections we prefer to use betamethasone as they seem
to have a lower incidence of localized soft tissue atrophy (anectodotally).
The article above suggest kenalog can be neurotoxic so potentially a small
lateral plantar nerve branch may have been indirectly damaged by the
steroid (or
Direct nerve damage from needle placement) leading to these subacute
denervation changes.
Anectodally we have seen interosseous muscle atrophy with repeated IMB
steroid injections over time.
Article above also suggests there may be improvement over time in muscle
atrophy, but not sure how much recovery will occur here given the amount of
fatty infiltration.
Regards,
Nadir Omar, Pacific Radiology Group NZ
And from Caio Nery
The first hypothesis that came to my mind regarding this patient was a
thrombosis located in the intermetatarsal compartment (especially in its
lateral portion). The original pain could have been explained by the joint
inflammatory condition, but the current condition could YES have been
caused by the injection of a liquid volume into the compartment.
Despite the chronic evolution, it may be interesting to explore the
compartment and relieve its internal pressure. The muscles may not recover,
but the pain should disappear!
*Prof. Dr. Caio Nery*
Professor Associado – Medicina e Cirurgia do Pé
Departamento de Ortopedia e Traumatologia – Escola Paulista de Medicina
Hospital Israelita Albert Einstein
The fact that the symptoms existed for 3 months before the injection and
didn’t change substantially afterwards leaves us guessing as to the initial
pathology—-if there was any imaging corollary. We can’t know because there
was no baseline MRI prior to the injection. This is all too common….and
unfortunate in this case.
The referrer agrees with Dr. Nery’s comments and will consider exploring
and decompressing the compartment.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3903862/
For these peripheral injections we prefer to use betamethasone as they seem
to have a lower incidence of localized soft tissue atrophy (anectodotally).
The article above suggest kenalog can be neurotoxic so potentially a small
lateral plantar nerve branch may have been indirectly damaged by the
steroid (or
Direct nerve damage from needle placement) leading to these subacute
denervation changes.
Anectodally we have seen interosseous muscle atrophy with repeated IMB
steroid injections over time.
Article above also suggests there may be improvement over time in muscle
atrophy, but not sure how much recovery will occur here given the amount of
fatty infiltration.
Regards,
Nadir Omar, Pacific Radiology Group NZ
And from Caio Nery
The first hypothesis that came to my mind regarding this patient was a
thrombosis located in the intermetatarsal compartment (especially in its
lateral portion). The original pain could have been explained by the joint
inflammatory condition, but the current condition could YES have been
caused by the injection of a liquid volume into the compartment.
Despite the chronic evolution, it may be interesting to explore the
compartment and relieve its internal pressure. The muscles may not recover,
but the pain should disappear!
*Prof. Dr. Caio Nery*
Professor Associado – Medicina e Cirurgia do Pé
Departamento de Ortopedia e Traumatologia – Escola Paulista de Medicina
Hospital Israelita Albert Einstein
The fact that the symptoms existed for 3 months before the injection and
didn’t change substantially afterwards leaves us guessing as to the initial
pathology—-if there was any imaging corollary. We can’t know because there
was no baseline MRI prior to the injection. This is all too common….and
unfortunate in this case.
The referrer agrees with Dr. Nery’s comments and will consider exploring
and decompressing the compartment.
Thanks to Nadir and Caio for their responses.
Hilary
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