[Delayed diagnosis of phenylketonuria as the cause of mental retardation in an adolescent]. / Diagnóstico tardío de fenilcetonuria como causa de retraso mental en un adolescente.

INTRODUCTION: The hyperphenylalaninemias (HFA) form a diverse group of recessive autosomic disorders. They are caused by defects in the hepatic system for hydroxylation of the amino acid phenylalamine to tyrosine. The estimated incidence is approximately 10 cases per 100,000 live births. Children with this metabolic disorder may present with varied neurological symptoms. Control of plasma levels, so that they are more normal as soon as possible after birth, significantly prevents mental retardation and other neuropsychological dysfunction. For this reason HFA has been included in neonatal screening. However, some patients are not detected on screening. When they are adults, these patients pose problems of diagnosis for neurologists who attend adults. CLINICAL CASE: We describe an adolescent with mental and linguistic retardation, in whom neonatal screening to rule out metabolic defects was normal. At the age of 15, the phenylalanine in blood and urine were found to be raised. On cerebral magnetic resonance changes typical of pheynylketonuria (PKU) were seen. CONCLUSIONS: The HFA should be considered as causes of cerebral dysfunction in adults, since in spite of neonatal screening, false negatives may occur. We describe a clinical case and consider different forms of hyperphenylaleninemias. Their diagnosis and treatment.

[Familial paroxysmal ataxia: a new case]. / Ataxia paroxística familiar: a propósito de un caso.

Over the last years several families affected of a clinical syndrome characterized by sudden ataxia, related to physical or mental stress, and lasting a few days have been described. Intercritical exploration is otherwise normal. We describe a new case which presents the clinical, laboratory and neuroradiological data characteristic of periodic familial ataxia. The patient is a 34 year old male who from his 23 has suffered three crisis of gait inestability, ataxia of trunk and limbs and spontaneous nystagmus in every direction, which increased in association with head movement. These episodes were always in relation with fatigue and stress and have decreased in severity. Mean duration of crisis has been 4 to 6 days. After starting treatment with acetazolamide there have no new crisis. In this case we have found no family history of the disease as it was the rule in previous description.

Thallium poisoning presenting with abdominal colic, paresthesia, and irritability.

A case of acute thallium poisoning presenting with sudden abdominal pain, paraesthesiae and irritability is described. The peripheral nervous system was later affected along with loss of hair and the development of streaks (Mee's lines) on the nails of the hands and feet. The diagnosis was established by thallium assays of blood and urine. Thallium was undetectable in the blood by day 70. The manifestations cleared in six months with symptomatic treatment only. We review the characteristics and differential diagnosis of thallium poisoning and stress the importance of a high index of clinical suspicion.