Introduction Pyridoxine deficiency is a metabolic disorder with recessive autosomical inheritance. It should be suspected in the presence of intractable neonatal seizures. It is believed that there is a glutamate decarboxilase failure (which promotes the GABA production), then high pyridoxine levels are necessary for its adequate working. More rarely, the problem takes root in the production of the active form of pyridoxine (piridoxal phosphate). Usually, the confirmation of pyridoxine deficiency is clinical improvement after pyridoxine administration, because metabolic exams do not show abnormal results.

Case report This report describes a newborn, whose perinatal antecedents were a caesarean section birth with normal Apgar scores. At birth, he showed respiratory distress, macrocephaly, prominent front, erratic movements and hyperreflexia. Because of severe neurological impairment, mechanical ventilation was necessary, and intractable seizures started. EEG showed a slow focal activity in the left temporal lobe, and MRI a non-specific alteration of the supratentorial white matter of both brain hemispheres. An inborn disorder of metabolism was suspected, so extensive metabolic workup was performed, with PA elevated on plasma and CSF. This finding is consistent with pyridoxine deficiency. After treatment with pyridoxine, progressive neurological improvement and disappearance of seizures were observed.

Comments Our case has a characteristic elevation of the PA levels in plasma and CSF. This fact has a good correlation with the diagnosis of pyridoxine deficiency, being more probable as the PA-LCR/PA-p ratio is higher. At present, the origin of this finding and its implication in the production of seizure is unknown.