study of chronic inflammatory demyelinating polyneuropathy [CIDP] in diabetics: clinical features, laboratory findings and response to treatment

ABSTRACT

The association of chronic inflammatory demyelinating neuropathy [CIDP] in diabetics is a recently recognized form of neuropathy. It is important to recognize CIDP occurring in diabetics because, unlike diabetic polyneuropathy, it is treatable. These patients can respond to immune therapies similar to patients with CIDP without diabetes. To study the clinical, electrophysiological, and laboratory features and response to immune modulating treatments in diabetic patients with CIDP. This was a retrospective cross sectional study from January 2009 till December 2012 carried out at Mayo Hospital and National Hospital, Lahore. The inclusion criteria included proven cases of diabetes mellitus with subacute motor weakness fulfilling the research criteria for diagnosis of CIDP. All patients underwent electrophysiological [EP] studies and cerebrospinal fluid analysis [CSF] especially for proteins. Diagnosed CIDP patients were treated with oral prednisolone 1mg/kg body weight along with azathioprine 50-150mg/day. The steroids were gradually tapered after achieving normal muscle strength or a static phase of one month without further improvement in muscle strength. The maintenance dose of prednisolone was continued to complete two years therapy. A course of IVIg [400mg/kg body weight daily for five days] or plasmapharesis [five sessions on alternate days] were used in patients with severe motor weakness to expedite the initial recovery phase. Follow was done at monthly interval for one year and bimonthly for subsequent years. The Hughes functional grading scale was used to assess the outcome. Treatment was considered effective when the patient's condition improved by 1 or more grade on the Hughes scale. There were 10 patients with 6[60%] males and 4[40%] females and M F ratio of 1.51. The mean age of patients was 63.7 + 7.83 years. Mean duration of diabetes mellitus was 11.3 +3.77 years. All patients had Type 2 diabetes mellitus with six patients on Insulin and 4 on oral hypoglycemic agents. Mean duration of motor weakness before treatment was 5.30 + 1.16 months. Mean power as assessed by medical research council [MRC] grading in upper limbs was 3/5 [range 1-5] and lower limbs 1/5[range 0-2]. Seven [70%] patients had mixed demyelinating and axonal picture on EMG, and 3[30%] patients showed predominantly demyelinating type of neuropathy. CSF protein was high in all patients with mean CSF protein of 208.4 + 93.07 mg/dl. Mean duration of follow up after treatment was 25.10 + 15.82 months. Attempt was done to stop immunotherapy after 2 years but relapse occurred in 3 [30%] patients which again responded to steroids. Outcome was assessed by Hughes functional grading scale. Mean Hugh's functional severity grade before treatment was 4.10 + 0.316 and after treatment was 1.30 + 1.16. We conclude that CIDP in diabetics is potentially reversible type of neuropathy and needs careful evaluation for its recognition. The classical demyelinating pattern on EMG may be lacking because of coexistent axonal neuropathy but clinical history of subacute onset predominantly proximal motor weakness [LMN type] and high CSF protein are most sensitive markers to predict response to corticosteroids in these patients. This is more common in males and elderly long standing diabetics. The response to corticosteroids and other immunosuppressive therapies is excellent. The recognition of this entity is important as appropriate management can reverse the disability in these patients