Evaluation of Metabolite Changes in the Occipital Cortex of Patients with Idiopathic Infantile Nystagmus or Bilateral Ametropic Amblyopia by Magnetic Resonance Spectroscopy

PURPOSE: To evaluate the effects of idiopathic infantile nystagmus (IN) and bilateral ametropic amblyopia on metabolites in the occipital cortex by magnetic resonance spectroscopy. METHODS: The children included in this prospective study were divided into three groups. Group 1 consisted of 11 patients with idiopathic IN, group 2 consisted of 10 patients with bilateral ametropic amblyopia and group 3 consisted of nine normal children. A single-voxel magnetic resonance spectroscopy examination was performed by placing a region of interest on the occipital cortex of each participant. N-acetyl aspartate (NAA), creatine (Cr) and choline (Cho) concentrations were measured in the occipital cortex. This was followed by calculating and comparing the NAA/Cr and Cho/Cr ratios between the three groups. The Kruskal-Wallis test, Mann-Whitney U-test, and chi-square test were used for statistical analysis. RESULTS: There was no statistically significant difference in NAA/Cr ratios between patients with idiopathic IN and normal children, but there was a statistically significant difference between these groups when Cho/Cr ratios were compared; the ratio was higher in the idiopathic IN group. There were no statistically significant differences in NAA/Cr or Cho/Cr ratios between patients with bilateral ametropic amblyopia and normal children. CONCLUSIONS: Our findings suggest that the neurochemical profile of the occipital cortex is partially affected by idiopathic IN, but not by bilateral ametropic amblyopia.

patient with cystinosis presenting like bartter syndrome and review of literature

Nephropathic cystinosis is an autosomal recessively inherited metabolic disorder presenting with metabolic acidosis, Fanconi syndrome and renal failure. We present a 6-year-old girl with severe growth failure, hyponatremia and hypokalemia. Her parents were 4th degree relatives. Two relatives were diagnosed as end stage renal failure. She also had persistant hypokalemic hypochloremic metabolic alkalosis. Her renal function was normal at presentation. She was thought to have Bartter syndrome with supporting findings of elevated levels of renin and aldosterone with normal blood pressure, and hyperplasia of juxtaglomerular apparatus. Her metabolic alkalosis did not resolve despite supportive treatment. At 6[th] month of follow-up proteinuria, glucosuria and deterioration of renal function developed. Diagnosis of cystinosis was made with slit lamp examination and leukocyte cystine levels. At 12[th] month of follow-up her metabolic alkalosis has converted to metabolic acidosis. In children presenting with persistant metabolic alkalosis, with family history of renal failure, and parental consanguinity, cystinosis should always be kept in mind as this disease is an important cause of end stage renal failure which may have features mimmicking Bartter syndrome