Appeal type: Experimental/Investigational
Decision: Upheld

Diagnosis: Small fiber neuropathy
Issue under review: IVIG

Determination:
The health plan should not cover the IVIG.

The patient is an adult male with small fiber polyneuropathy.  

A note indicates the patient is being treated with tizanidine.  The patient returns for followup.  Diagnosed with mild sensory neuropathy by EMG.  He has multiple consultations with neuromuscular specialist.  A small fiber inflammatory polyneuropathy was confirmed by skin biopsy.  Other evaluations have been unrevealing.  He reports easy fatigue, transient leg-arm weakness with activities, persistent "electric pulses," numbness, pressure sensation.  He is assessed as having idiopathic progressive neuropathy and was recommended for followup.

Another note indicated followup.  The patient was treated with prednisone with "excellent results."  He is concerned about taking steroids on a prolonged basis.  He tried duloxetine without benefit.  Side effects.  CSF showed elevated protein.  EMG was unremarkable, but had a positive skin biopsy and was recommended for ongoing treatment.

Per pathology report, the patient had sweat gland nerve fiber density with low normal sweat gland nerve fiber density.  Skin had normal sweat gland nerve fiber density.

Per skin biopsy from right calf, significantly reduced epidermal nerve fiber density consistent with small fiber neuropathy and right foot skin biopsy showed low normal epidermal skin fiber density.

EMG showed predominantly sensory neuropathy and right median mononeuropathy at the wrist.

MRI of brain was normal.  Labs showed sed rate, IgG, total protein, Lyme, C6 double-stranded DNA, RNP, Smith antibody, anti-sclerodermal 70, Sjogren's, antichromatin, anti-Jo-1, anti anticentromere B, CK, and vitamin B12 all normal.  

Lumbar puncture showed immunoglobulin level, oligoclonal band, cell count with diff all WNL as well as Lyme.  Protein was elevated at 62 with myelin basic protein elevated at 2.3.  Assessment was small fiber neuropathy, appendicitis, right carpal tunnel syndrome with recommendation for ongoing care.  PE showed strength was normal on manual muscle testing.  No difficulty getting up from chair.  Foot tapping was normal.  Reflexes were 1+ and symmetric.  Physical exam showed normal vibration sensation, normal pin sensation.  Romberg was negative.  Somatosensory evoked potentials were normal.  

Sural nerve and muscle biopsy were recommended, including teased fiber analysis if chronic inflammatory demyelinating polyneuropathy is suspected, BP and pulse were normal range and there was no finding reported symptom wise or based on any findings of his BP testing, any finding of dysautonomia.  

The medical records do report that the patient has sensory abnormalities reported on EMG testing.  This is not typical of small fiber neuropathy, as typically the EMG and nerve conduction studies are normal in reference to small fiber neuropathy.  The medical records report the patient was considered for a diagnosis of for chronic inflammatory demyelinating polyneuropathy, but the available medical records provided for review do not demonstrate that this diagnosis has been formally made.  As such the available medical records provided for review reflect at present a diagnosis of small fiber polyneuropathy, which is reported to be autoimmune.  

There are no FDA-approved treatments that are demonstrated effective for small fiber polyneuropathy.  Review of peer-reviewed literature does not demonstrate any controlled studies reflecting significant response to treatment of small fiber neuropathy to IVIG demonstrated by controlled studies.  There are studies that reflect positive response for dysautonomia type or autonomic neuropathy variants of small fiber neuropathy, but the available medical records do not indicate the patient has that type.  As such, based on the medical records provided for review, the treatment with IVIG is not supported, congruent with peer-reviewed literature.