Coexistence of Type 1 Diabetes Mellitus and Periventricular Heterotopia in a Child: A Case Report.

Dear Editor,

Type 1 diabetes mellitus (T1DM) is characterized by a chronic, progressive, and immune-mediated destruction of the insulin-producing beta-cells (β-cells) in the pancreatic islets of Langerhans. It may occur in association with other autoimmune diseases involving other endocrine tissues, such as thyroid and adrenal glands, or non-endocrine tissues, such as gastric and intestine mucosa.[1] Heterotopias are malformations of cortical development characterized by the presence of normal brain cells in abnormal positions. They can be classified into three groups, based on their location: periventricular, subcortical, and leptomeningeal. Neurological manifestations have been described, including seizures, mental motor retardation, and neuropsychiatric disorders, including schizophrenia, depression, anxiety, and autism.[2]

Various diseases that have been reported in association with T1DM include Rett syndrome, neurofibromatosis type 1, Crohn’s disease, celiac disease, glutaric aciduria type 1, and spinal muscular atrophy.[3456] Here we report the case of a Turkish 8-year-old boy with T1DM and periventricular heterotopia.

An 8-year-old boy presented with partial onset of secondarily generalized seizures. On taking history, the patient was followed by T1DM for 2 years in another hospital. He was born in the 40th gestational week by normal delivery with 3300g of birth weight to consanguineous parents (first cousins). At the age of 6 years, he was diagnosed to have T1DM when he had presented with ketoacidosis. His glycemic control had been optimal with regular insulin therapy. We learned that the patient had a seizure 2 months ago. The serum glucose level at the seizure was found to be 53mg/dL and it was said that the patient’s seizure was thought to be due to hypoglycemia. On examination, vital signs, and the results of physical and neurological examination were found to be normal. The results of laboratory examinations (complete blood cell count, liver enzymes, kidney function parameters, serum electrolytes, and glucose rate) were normal. The patient was administered Levetiracetam (LEV) monotherapy. LEV had started and his seizures were ceased. Interictal electroencephalography showed epileptiform abnormalities in right temporal regions. Magnetic resonance imaging (MRI) of the brain revealed heterotopia in posterior horn of the right lateral ventricle [Figure 1]. Stanford–Binet test was performed and mild intellectual disability was detected.

Figure 1:

Magnetic resonance imaging of the brain showing heterotopia in the right lateral ventricle

Seizure or epilepsy is observed in patients with T1DM. Metabolic abnormalities of diabetes mellitus such as hyperglycemia and hypoglycemia could have a damaging effect on the central nervous system, which may cause seizure; indeed, in endocrine disorders, seizures could be the result of neuroinflammation, autoimmunity, or metabolic disturbances.[7] Focal epilepsy may be the first symptom of diabetes mellitus in some patients, and can lead to the discovery of diabetes mellitus. Some studies also described several transient changes in MRI following seizures. These brain parenchymal changes are typically hyperintense on T2-weighted and fluid-attenuated inversion recovery images. Nevertheless, some patients without evidence of brain damage have been reported.[8] In sum, during hyperglycemia, a focal reduction in blood flow may occur with consequent focal seizures; however, there is no constant relationship between blood glucose levels and the frequency or severity of neurological symptoms. Also, focal seizures can be symptomatic of structural lesions within the brain.[2] Our patient had diabetes and also periventricular heterotopy. Even if there is T1DM in the focal seizure, should come to mind in structural anomalies of central nervous system.

In conclusion, we found a structural abnormality in a diabetic patient with focal seizure. Epilepsy can be a feature of diabetic patients. However, seizures should not be considered to be due solely to metabolic disorders of diabetes. In the presence of seizure, diabetic patients need a multidisciplinary approach that involves pediatric endocrinologists and neurologists to optimize therapeutic management and follow-up.

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