Improved diagnosis for patients with immune-mediated neuropathies

Diagnosis of acquired immune mediated diseases affecting peripheral nerves like
Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) and Multifocal Motor
Neuropathy (MMN) currently relies on extensive electrophysiological conduction
studies (NCS) in addition to neurological examination. However, the proximal
parts of the nerves (brachial plexus and major part of upper leg and
lumbosacral plexus) cannot be reliably studied, so that diagnosis may be missed
and patient may not receive proper immunosuppressive or -modulatory treatment.
In patients presenting with monomelic/focal motor deficits, an important
differential diagnosis is that between MMN and focal/monomelic Spinal Muscular
Atrophy (fSMA). MMN in contrast to fSMA can be treated. However, the
above-mentioned limitations of NCS at proximal sites may hinder the distinction
between both disease entities.

MRI and ultrasound (US) are promising techniques to serve as important adjunct
tools to establish diagnosis of immune mediated neuromuscular disorders, as
they allow for visualization of the proximal parts of the nerves.
In the current diagnostic guidelines, increased signal intensity on T2-weighted
MRI, associated with a diffuse nerve swelling of the brachial plexus already is
one of the supportive diagnostic criteria for MMN. New MRI and US techniques
may be of additional value.

In this explorative study we will compare the results of extensive NCS
measurements, muscle strength assessment, sensory examination, assessment of
clinical disability, MRI and US in MMN and CIDP patients. These results will be
used to study the nerves of fSMA patients with an equal clinical presentation
as MMN patients, with emphasis on the proximal nerve parts. Patients will be
recruited from an existing database and if possible new patients will be added.

Future prospects: replace (part of) the extensive NCS by the imaging techniques
which will be less time consuming, less painful, thus more patient friendly,
and hopefully an important aid to the diagnosis.

Evaluate the added value of new MRI and US techniques for the diagnosis of
neuromuscular disorders such as MMN and CIDP and the MMN-mimic fSMA.

Observational, diagnostic, cross-sectional.

Patients with MMN, CIDP and patients with focal motor deficits, currently
diagnosed as fSMA, will be included. In case no recent (n<6 months) NCS is
available this will be performed. Patients will undergo MRI and US of either
arms or legs and brachial or lumbosacral plexus. To assess disease severity
muscle strength and clinical disability will be measured.
Participation in this study will in no way interfere with any treatment
decision.
Risks for undergoing NCS, MRI and ultrasound are minimal, provided precautions
have been made to exclude those who are not allowed to enter the MRI scanner. A
routine AMC questionnaire will be used. Only individuals with recent traceable
MRI feasible prostheses will be included.
There are no direct benefits for participants.