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Case discussion Migratory lower limb paraesthesia in a 22 yr old

Kris

Well-known member
Yes you read the title right.

22 yr old male who presented for results followup (had an STI screen via another doctor - these were normal).

On the way out the door says "oh can I ask you about something that has been bothering me?" - I think we're all familiar with this sort of situation.

He goes on to describe 'pins and needles' on the backs of both his lower legs (ie calves), present for a couple of weeks. Not always in the same location, not always both calves at the same time. No motor symptoms. No back pain. No history of trauma, no change in footwear or daily activities. No exacerbating or relieving features. These symptoms are not interfering with anything he does day-to-day, they're "just there".

No other symptoms of note on a full systems review (which I had to complete at his next consult).

He is otherwise fit and well, no significant past medical history. No regular medicines. He does not think there is any relevant family history. He denies any illicit drug use.

On initial examination he had no objective deficit to light touch or pain, and power + coordination was normal. Gait was normal. Upper limb and cranial nerves grossly normal. Unremarkable cardiorespiratory exam.

When he returned for followup he described this sensation having now resolved in the former distribution - now reporting 'pins and needles' on the soles of his feet. On this occasion he did appear to have some objective deficit to light touch - and variable answers when examination was repeated (eg 'yes' to S1 on initial exam then inconsistent when examined again). Normal touch and pain were felt normally both sides each time.

Unsurprisingly, bloods were unremarkable (FBC, E/LFT, TFTs, B12, inflammatory markers and an HbA1c).

This is the sort of presentation which used to terrify me before I moved to GP!
 

WongD

New member
Unfortunately, we all have to manage a degree of uncertainty, but time is your ally with this case given the absence of red flags or bad company.

It doesn't sound like cramping is a feature which can sometimes point to a neuromuscular issue.

Testing of sensory modalities can be quite inconsistent at times and features that you should focus attention would include:
1. Pattern of sensory deficits
2. More than one modality involved carried by the same long tract (spinothalamic, dorsal columns)
3. Presence of motor weakness
4. Areflexia or hyperflexia (e.g. loss of ankle jerks in a length dependant large fibre neuropathy.
- Keep in mind, patients can have symmetrically brisk reflexes as a normal variant - asymmetry, the presence of ankle clonus (> 4 beats) or other UMN features would be supportive of pathology associated with the brisk reflexes found.
5. Bowel/ bladder disturbance

Yet you've done a comprehensive examination including neurological which is reassuring and could avoid unnecessary testing!

The next step is to try to localise the lesion neuroanatomically and to get a pure sensory presentation with no other features such as weakness or areflexia, I'm hard pressed to find an intellectually satisfying answer.

A brain or spinal cord lesion is highly unlikely given the history and examination as you would require bilateral cortical lesions and there's nothing else to suggest spinal cord pathology let alone any other UMN signs on examination.
Multiple sclerosis always features as a question in referrals.
Although it doesn't discriminate gender, young white females are the prototypic group.
And then the tempo isn't quite fitting. The natural history of demyelinating lesions tend to progress over days to weeks reaching the nadir of deficit before improving over once again over a similar timeframe.
So his pre-test probability of such is low.

With the distribution of his findings you might be considering a bilateral S1 radiculopathy but given the patchy nature of it, the inconsistency and if the ankle jerks are still present along with his young age and lack of trauma, this would be quite unlikely.

Sensory polyneuropathies tend to be length dependant (eg. diabetes and alcohol) which doesn't fit

STIs/ infectious causes can be an underlying etiology with various neuropathies out of interest.

An interesting condition I've seen is Wartenberg's migrant sensory neuritis, its a 'migratory mononeuritis multiplex' quite benign in nature, involves multiple cutaneous nerves over a period of time, triggered by stretching or trauma to the nerve, may have pain first, then numbness in that distribution and may or may not recover - pure sensory
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2910306/
[IMG alt="An external file that holds a picture, illustration, etc.
Object name is 415_2010_5530_Fig1_HTML.jpg"]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2910306/bin/415_2010_5530_Fig1_HTML.jpg[/IMG]

Fig. 1
Localization and frequency of sensory deficits in all patients at initial visit either by history taking or neurological examination. Colors indicate the number of times deficits were observed: green 1, yellow 2, blue 3, purple 4, red 5

It's quite uncommon - although possible I'm dubious it's that.


It would be remiss of me not to mention FND or Functional neurological disorders given the prevalence - a possible differential
I've attached a very useful guide recently published in Australian doctor
Previous terms include somatoform/ psychogenic/ conversion disorder/ hysteria / non organic
- patients respond better to the term FND so that is the preferred term at current

FND can occur in isolation or with other 'organic' pathology - be aware of the latter. There's some good tips in the guide.


Would you perform an MRI Brain/ Spinal Cord or Nerve conduction study?
- I don't think there's any strong reason to do so unless any else changes clinically.

Overall and pragmatically, I'd agree with a watch and wait approach and I don't think you could commit to a diagnosis at this point in time. Time is your ally in this case.
 

Attachments

Kris

Well-known member
Thanks for that very comprehensive reply @WongD - I now know where to direct ALL my confusing vaguely neuro-related cases. Joking here.


Testing of sensory modalities can be quite inconsistent at times and features that you should focus attention would include:
1. Pattern of sensory deficits
2. More than one modality involved carried by the same long tract (spinothalamic, dorsal columns)
3. Presence of motor weakness
4. Areflexia or hyperflexia (e.g. loss of ankle jerks in a length dependant large fibre neuropathy.
- Keep in mind, patients can have symmetrically brisk reflexes as a normal variant - asymmetry, the presence of ankle clonus (> 4 beats) or other UMN features would be supportive of pathology associated with the brisk reflexes found.
5. Bowel/ bladder disturbance
This is a good list, will note for future patients as well as this guy.

A brain or spinal cord lesion is highly unlikely given the history and examination as you would require bilateral cortical lesions and there's nothing else to suggest spinal cord pathology let alone any other UMN signs on examination.
Multiple sclerosis always features as a question in referrals.
Although it doesn't discriminate gender, young white females are the prototypic group.
And then the tempo isn't quite fitting. The natural history of demyelinating lesions tend to progress over days to weeks reaching the nadir of deficit before improving over once again over a similar timeframe.
So his pre-test probability of such is low.
This was the similar conclusion I came to, though not quite as well reasoned as yours. I bet you get a lot of ?MS type referrals, such is the nature of that disease.

An interesting condition I've seen is Wartenberg's migrant sensory neuritis, its a 'migratory mononeuritis multiplex' quite benign in nature, involves multiple cutaneous nerves over a period of time, triggered by stretching or trauma to the nerve, may have pain first, then numbness in that distribution and may or may not recover - pure sensory
I've never heard of Wartenberg's migrant sensory neuritis but I'll have a look at the article. Will keep in mind particularly if the pattern of paraesthesia has changed again at next visit!

It would be remiss of me not to mention FND or Functional neurological disorders given the prevalence - a possible differential
I've attached a very useful guide recently published in Australian doctor
Previous terms include somatoform/ psychogenic/ conversion disorder/ hysteria / non organic
- patients respond better to the term FND so that is the preferred term at current

Haven't had to have this discuss with a patient as yet though I can certainly see how FND would be easier to absorb than 'psychogenic' for a lot of people. Particularly those that lead with 'this isn't all in my head...'
 

Kris

Well-known member
Update on this patient - he returned and said his symptoms had totally resolved in one leg, and now has only mild paraesthesia in the sole of one foot, which he thinks is less noticeable.

Moral of the story is...
 

Jon

Member
Staff member
Update on this patient - he returned and said his symptoms had totally resolved in one leg, and now has only mild paraesthesia in the sole of one foot, which he thinks is less noticeable.

Moral of the story is...
Moral: "I told you so?" ;)
 
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