Does the chronic inflammatory demyelinating polyradiculoneuropathy due to secondary cause differ from primary?

Background: The clinical presentation, neurophysiological findings, and outcome may vary between primary and secondary chronic inflammatory demyelinating polyradiculopathy (CIDP). Objective: To compare clinical and electrodiagnostic features of primary and secondary CIDP.
Setting: Tertiary care teaching referral hospital.
Materials and Methods: The CIDP patients who were diagnosed as per European Federation of Neurological Societies/Peripheral Nerve Society criteria were included and subjected to detailed history and examinations. The clinical disability was graded on a 0-10 scale. Neurophysiology included motor and sensory nerve conductions and F wave studies of all four limbs. Based on investigations for underlying diseases, the patients were categorized into primary or secondary CIDP. Prednisolone was prescribed in all and azathioprine added in resistant cases. The secondary CIDP group received specific treatment in addition. The outcome was assessed at 3 months, 6 months, and last follow-up.
Results: A total of 65 patients aged 17 to 72 years were included and 20 were females. Twenty-five patients had secondary CIDP and include diabetes mellitus (16), POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) (4), monoclonal gammopathy of undetermined significance (2), myeloma (1), lymphoma (1), and malignancy (1). The secondary CIDP patients were older (48.35 vs 41.0 years), had less relapsing remitting (0 vs 6) and more frequent dysautonomia (7 vs 1). The demyelinating features were more marked in primary CIDP group and had better outcome compared with secondary CIDP.
Conclusions: Of the total patients with CIDP, 38.5% of patients had secondary CIDP which was associated with progressive course, less demyelinating features, and worse prognosis.

Keywords
Chronic inflammatory demyelinating polyradiculoneuropathy, electrodiagnosis, idiopathic, outcome, polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes, secondary, treatment