Endocrine Abstracts

Introduction: Type 1 diabetes mellitus (T1DM) and multiple sclerosis (MS) are organ-specific autoimmune diseases. Their association, first described in a study in Sardinia, left questions about their clustering, clarified by the Familial Autoimmune and Diabetes Study, which showed for the first time an highly increased prevalence of MS in adults with T1DM, reinforced by further epidemiological studies that also revealed increased risk of T1DM in MS patients.

Clinical case: A caucasian male, 29 years, was diagnosed with T1DM, after an inaugural ketoacidosis episode. He had no family history of diabetes or neurological diseases. Blood tests: normal thyroid function, ACTH, cortisol, lipid levels; HbA1c 11.7%; C-peptid 0.38 ng/ml (0.8–3.9); 27.5 mg microalbuminuria/24h; positive glutamic acid decarboxylase 2 autoantibodies. He had no diabetic retinopathy or other visual changes. After discharge he kept good clinic and analitical control; his HbA1c reduced to 5.7% in four months. Suddenly, he started complaining about intermittent floating paresthesias in limbs’ extremities, without hypoesthesia, burning sensation, muscle weakness, or other symptoms. B12 vitamin, folic acid levels were normal; celiac disease antibodies negative. Monofilament test, electromyography, and nerve conduction study were normal. As symptoms persisted, he was refered to a neurologista. Brain MRI showed multiple infracentimetric lesions, suggesting primary demyelinating disease. He was diagnosed with MS.

Conclusions: T1DM and MS are autoimmune inflammatory diseases affecting respectively pancreatic β-cells or myelin sheath in central nervous system.

Pathophysiology underlying this co-occurrence remains unclear, although envolves T-cell mediated imune abnormalities. HLA haplotypes were considered mutually exclusive for MS and T1DM, but autoimune diseases’ genetic susceptibility envolves several genes.

This patient was diagnosed with MS one year after being diagnosed with T1DM, which may suggest simultaneous activation of autoimmune pathways.

The mechanism explaining the association between these two diseases still needs further clarification, leading to improvement in prevention and therapy.