I get a bit confused on some of this CIDP. I assume that if you have Idiopathic Small Fiber Neuropathy, they have ruled out CIDP. I wonder how the distinction comes in as small fibers are c fibers and alpha delta (thinly myelinated fibers)....so myelinated fibers are affected in small fiber neuropathy. It must be based on lymphocytic infiltration, and if your epidermal nerve fiber biopsy does not show lymphocytic infiltration and/or you have no other inflammatory markers, it must be dubbed 'idiopathic SNF'. Is this a correct deduction?

The below quote is from

http://www.emedicine.com/neuro/topic467.htm

"The term chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) has been used to identify patients with a chronically progressive or relapsing symmetric sensorimotor disorder with cytoalbuminologic dissociation and interstitial and perivascular endoneurial infiltration by lymphocytes and macrophages. In many ways, CIDP can be considered the chronic equivalent of acute inflammatory demyelinating polyradiculoneuropathy (AIDP), the most common form of Guillain-Barré syndrome (GBS).

A number of variants of CIDP have been described that have immune or inflammatory aspects and electrophysiologic and/or pathologic evidence of demyelination in common. No consensus exists on the best approach to the nomenclature of these disorders. CIDP is a major subset of chronic acquired demyelinating polyneuropathies (CADP). In this context, CIDP is considered when patients have a symmetric proximal and distal motor predominant disorder.

CIDP variants include patients with predominantly sensory symptoms, those with a distal symmetric disorder (DADS), those with multifocal sensorimotor neuropathy or sensorimotor mononeuropathy multiplex with prominent conduction block (also known as Lewis-Sumner neuropathy), and those with CIDP with associated CNS demyelination or with other systemic disorders.

The following disorders are considered distinct from CIDP because they have specific pathophysiologic features and respond to treatments differently than do patients with CIDP: Demyelinating neuropathies associated with immunoglobulin M (IgM) paraproteins, including those with anti–myelin-associated glycoprotein (MAG) antibodies; polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome; and multifocal motor neuropathy."