Diabetes Mellitus Type 1 and Multiple Sclerosis: Case Report and Literature Review

Introduction: Type 1 diabetes mellitus and multiple sclerosis are organ-specific inflammatory and autoimmune diseases, with multiple common characteristics and etiopathogenic features, more than expected between two autoimmune diseases. Case Report: We describe the case of a male patient with type 1 diabetes mellitus diagnosis at the age of 29 years. After the diagnosis he kept excellent metabolic control with a decrease of his HbA1c from 11.7% to 5.7% in six months, with glargine and lispro insulin. About nine months after the diagnosis of type 1 diabetes mellitus, he started complaining about floating paresthesias in the limbs, more intense in the distal part of the lower limbs, without other symptoms. Diabetic neuropathy and other etiologies, including metabolic causes were excluded and, as symptoms persisted, he was referred to a neurologist, who diagnosed multiple sclerosis. Discussion: Diabetic neuropathy is the main but not single cause of neurological symptoms in diabetic patients. Multiple pathologies should be considered as differential diagnoses, secially the amyloidotic polyneuropathy, because of it is prevalence in Portugal. Multiple sclerosis is a less frequent hypothesis, but with increasing evidence of a shared etiopathogenesis with type 1 diabetes mellitus. Multiple risk factors have been implied in the association of both diseases, including genetic and environmental factors, as viral infections, exposure to chemical products, endocrine disruptors and inadequate levels of vitamin D. Early diagnosis is crucial, but not always obvious, as neurological symptoms in diabetes are more frequently due to diabetic neuropathy and multiple sclerosis diagnosis implies the exclusion of multiple other pathologies.