Tuesday, August 29, 2006

Barohn's PN phenotypes

1. Symmetric proximal and distal weakness with sensory loss. GBS or CIDP, is treatable

2. Symmetric distal sensory loss with or without weakness. This is untreatable with immunomodulators and is the most common PN. Within category the most common types are CSPN (cryptogenic sensory peripheral neuropathy) and metabolic, a category that includes diabetic neuropathy and alcoholic neuropathy. Rarer causes include hereditary sensory neuropathies.

3. Asymmetric distal weakness with sensory loss. This includes mononeuritis multiplex, consider vasculitis, motor sensory variant and HNPP (hereditary nerve pressure palsies) or MADSAM (multifocal acquired distal sensory and motor neuropathy, or Lewis Sumner syndrome) which is diagnosed with EMG. Rarer causes are infection (HIV, sarcoid, lyme) or involvement of single nerves or roots (eg. CTS).

4. Asymmetric proximal and distal weakness with sensory loss. Proximal means it may include elbow extensors, hip girdle muscles, neck muscles, knees, covering c5-T1 or L2-S1). Consider polyradiculopathy or plexopathy, due to DM, plexopathies, polyradiculopathy due to neoplasia, carcinoma, lymphoma, and hereditary neuropathy

5. Asymmetric distal weakness without sensory loss eg. progressive footdrop. Category includes ALS (especially with UMN signs), progressive muscular atrophy including regional forms (brachial or leg) juvenile monomelic atrophy, multifocal acquired motor neuropathy

6. Symmetric sensory loss (like number 2) but with UMN signs (crossed adductors, Babinski) think B12 deficiency, ALD, MLD or combination of diabetic/CSPN with cervical spondylosis diagnosis of exclusion)

7. Symmetric weakness without sensory loss-- consider SMA (Kennedy s. includes bulbar, chromosome five includes neck weakness). With bilateral footdrop may have normal EMG. CMT SNAPs are abnormal. overlaps MD and NMJ

8. Focal midline proximal symmetric weakness with neck extensor weakness (ALS, myopathy, MG, oculopharyngeal d., Kennedy s.)

9. Sensory asymmetric proprioceptive loss without weakness. Looks like neuronopathy (CA) but NORMAL SNAPS, abnormal roots on MRI suggest autoimmune, +/- treat with IVIG

10. Autonomic dysfunction

Exceptions to above
1) Mononeuritis multiplex including vasculitis presents symmetrically in one third

2) CIDP -- MMN and MADSAM may be asymmetric distal

3) Demyelinating CMT has no proximal weakness

4) DADS phenotype looks like pattern 2 at bedside but on exam has prolonged latiencies.

1 comment:

Legend in my own mind said...

Interesting to find your blog. I have been diagnosed with Lewis Sumner, as confirmed by Mayo Clinic last March. My original diagnosis was CIDP from UCLA about three years ago. I will give you some data, as you may be interested, as people with this disorder are far and few between? The asymetry of my weakness is certainly what caused my primary Neurologist to refer me back out for re-confirmation of dx. The sensory distribution is more symetric. I have bi-lateral foot drop, but right is grade 1/5 while left is about 3/5. However, left quad is 4+/5 while right quad is now 3+/5, but has recovered slightly from 2+/5. Also, left tricep was 2/5 six months ago during severe exacerbation, but has recovered to 3+/5. Hands are a bit more symetric in weakness. Also, right hip flexor is weakened. Also, I have 20 dioptre esotropiea - which has recovered from a 45 dioptre deviation from last January. Increased facial numbness, especially around lips, plus bad flares of diplopeia from 6th cranial nerve damage is always a hallmark when I have an increase in symptoms. I am treated with IVIG, which slows progression and allows some healing over time. I have also had pheresis during more acute periods. I tried mycolphenolate but discontinued because of neutropenia. I tried IV Solumedrol, which was an absolute disaster - as it seemed to accelerate an episode. I am a 44Y male, otherwise in excellent health, who was very athletic prior to onset of disease.