Central pontine and extrapontine myelinolysis in a pediatric patient following rapid correction of hypernatremia.

Central pontine and extrapontine myelinolysis are uncommon disorders characterized by distinctive clinical features and typical findings on neuroimaging. Only a few cases are reported in the pediatric age group. We describe the case of a leukemic, malnourished 14-year-old boy with a high serum sodium concentration that gradually increased to 170 mmol/L. During a septic shock episode, hydration with a low sodium concentration at the rate of 104 mL/h for 24 h was administered. A rapid correction of the high serum sodium occurred, exceeding 0.5 mmol/L/h. The following day the patient developed rapid and progressive neurological impairment with clinical features characteristic of central pontine and extrapontine myelinolysis. Magnetic resonance imaging confirmed the diagnosis 11 days later. The patient was treated with steroids and intravenous immunoglobulins. He achieved an almost full neurological recovery and radiological improvement. The reported case demonstrates that central pontine and extrapontine myelinolysis can occur after excessively rapid correction of hypernatremia.

Osmotic demyelination and hypertonic dehydration in a 9-year-old girl: changes in cerebrospinal fluid myelin basic protein.

A 9-year-old girl was admitted for the treatment of hyper-natremic dehydration. Her history was significant for psychogenic polydipsia, hyponatremia, and a renal concentrating defect. She presented with a 2-day history of altered mental status, ataxia, lethargy, fever, nausea, vomiting, and diarrhea. Meningitis was ruled out. Over the course of her illness, slow rehydration was maintained with a gradual decrease (10 mEq per 24 hours) of the serum sodium. Despite this care, she developed quadriparesis, and magnetic resonance imaging performed on day 6 of her illness was consistent with osmotic demyelination (central pontine myelinolysis). To rule out an excessively rapid correction of hypernatremia as the etiology of the problem, a myelin basic protein was measured in the cerebrospinal fluid that had been obtained on hospital day 1. The myelin basic protein was 649.50 ng/mL (normal, 0.07-4.10 ng/mL). The current literature is presented regarding the postulated pathogenesis of central pontine myelinolysis and suggested therapies, previous reports of central pontine myelinolysis in children are reviewed, and the potential role of myelin basic protein in its diagnosis is discussed.

Extrapontine myelinolysis with parkinsonism after rapid correction of hyponatremia: high cerebrospinal fluid level of homovanillic acid and successful dopaminergic treatment.

Extrapontine myelinolysis (EPM) is a demyelinating process of the brain. We report the case of an 11-year-old girl who developed EPM with parkinsonism. Magnetic resonance imaging revealed demyelinating patterns in the basal ganglia without central pontine lesions. The cerebrospinal fluid levels of homovanillic acid and 5-hydroxyindoleacetic acid were high at the time of onset and normalized upon complete recovery from extrapyramidal symptoms after a dopaminergic treatment. We speculated that demyelination of nerve fibers containing dopamine receptors in the striatum might be a main cause of these symptoms.