A comparative study of chronic inflammatory demyelinating polyradiculoneuropathy with and without diabetes mellitus J. Kalita, U. K. Misra and R. K. Yadav Department of Neurology, Sanjay Gandhi PGIMS, Lucknow, India Keywords: CIDP, diabetes, nerve conduction, neurophysio- logy, outcome, polyradiculoneuropathy, steroid Received 9 November 2006 Accepted 12 March 2007 Diabetes mellitus (DM) is occasionally associated with chronic inflammatory demy- elinating polyradiculoneuropathy (CIDP) raising the question of coexistence or etio- logical link. The study compares, neurophysiological and outcome of CIDP patients with and without DM. Consecutive CIDP patients were subjected to detailed clinical evaluation, haematology, serum chemistry, vasculitis profile, paraproteins, myeloma screening and cerebrospinal fluid (CSF) examination. Electrodiagnostic (EDx) tests included motor and sensory conduction and F-wave studies. The patients were treated with oral prednisolone 1 mg/kg/day with or without azathioprine 1–2 mg/kg and followed up for 6 months. The clinical and EDx finding in CIDP with and without DM were compared. Thirty-five CIDP patients were included and nine had DM. CIDP with diabetes (CIDP-D) had higher frequency of autonomic dysfunction. In CIDP-D, motor (38.9% vs. 16.7%) and sensory (40.7% vs. 14.1%) nerve conductions were more frequently unrecordable or had reduced compound muscle action potential (CMAP) amplitude. F-waves were also more frequently unrecordable in CIDP-D (28.8% vs. 12.8%) compared with idiopathic CIDP (I-CIDP). The degree of con- duction block was more in I-CIDP. At 6-month follow up, I-CIDP patients improved better than CIDP-D. CIDP-D patients present with higher frequency of autonomic dysfunction, electrophysiological evidences of associated axonal loss and had a poorer outcome at 6 months compared with I-CIDP. Introduction Chronic inflammatory demyelinating polyradiculo- neuropathy (CIDP) is characterized by the occurrence of symmetrical weakness in both proximal and distal muscles, which progressively increases for more than 2 months. Diabetic peripheral neuropathies has been categorized into number of different clinical types. The two main proposed pathophysiological mechanisms are nerve ischaemia and metabolic derangements, but im- mune and inflammatory mechanisms may also play a role in diabetic neuropathy. CIDP in diabetes has been reported previously [1,2,3], but there is controversy whether the clinical, cerebrospinal fluid (CSF), elec- trodiagnostic (EDx) and histopathological features distinguish CIDP with and without diabetes mellitus (DM). The exact mechanism of CIDP in diabetics is unknown. Lozeron et al. [3] reported CIDP in nine of 100 consecutive diabetic patients with symptomatic neuropathy. Sharma et al. [4] noted that the odds of occurrence of CIDP in diabetics were 11 times higher than those in non-diabetics. It is controversial whether CIDP in diabetics is a random association, or has a causal relationship. DM is a growing problem. In 2000, the prevalence of diabetes was 3.1% in India, 5.2% in the developed world and 6.3% in USA [5]. In 2004, the prevalence of DM in India was 4.3% [6]. We have not found any study from India on association of CIDP with diabetes. In this communication, we report the clinical, EDx, CSF findings and response to oral prednisolone in idiopathic CIDP (I-CIDP) and com- pare these with CIDP patients having DM (CIDP-D). Materials and methods Between January 2001 and July 2005, consecutive pa- tients with CIDP diagnosed on the basis of American Academy of Neurology (AAN) criteria were included [7]. The study was duly approved and patients consented for the tests. The patients were subjected to detailed clinical evaluation. Duration of weakness, sensory symptoms, ataxia, palpitation, fainting, impotence, swallowing dif- ficulty, diarrhoea, urinary symptoms and other auto- nomic symptoms were noted. Presence of cranial nerve palsy and respiratory insufficiency were also recorded. Muscle power of various groups of upper and lower limbs was assessed on a 0-V MRC (Medical Research Council) scale. Pinprick, joint position, touch and vibration senses Correspondence: Usha K. Misra, Professor and Head, Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raebareily Road, Lucknow 226014, India (tel.: 91 522 2666004-8, Ex.No: 2167; fax: +91 0522 668017; e-mail: drukmisra@rediffmail.com, ukmisra@sgpgi.ac.in). 638 Ó 2007 EFNS European Journal of Neurology 2007, 14: 638–643 doi:10.1111/j.1468-1331.2007.01798.x