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Biomedical subjects

A Rodríguez-Núñez

Publications and source records attributed to A Rodríguez-Núñez.

At least 19 recordsLinked to original sources
PubMed2001

Usefulness of the head-upright tilt test for distinguishing syncope and epilepsy in children.

PURPOSE: Episodic loss of consciousness in children, whether or not associated with hypertonia or short-duration clonic movements, presents a diagnostic challenge to the pediatrician and child neurologist. We provide some evidence of the usefulness of the head-upright tilt test for investigating the causes of transient loss of consciousness in children, and for distinguishing between syncope, convulsive syncope, and epilepsy. METHODS: We studied nine children previously diagnosed as epileptic on the basis of compatible clinical events and epileptiform findings in routine EEGs who were treated over the long term with antiepileptic drugs, but whose clinical records suggested syncope or convulsive syncope rather than epilepsy on reevaluation. All subjects underwent head-upright tilt testing. RESULTS: The tilt-test result was positive in all nine cases, with the patients reporting the same symptoms as in the previously considered epileptic attacks. CONCLUSIONS: Inadequate histories and misuse/overinterpretation of EEG results often lead to misdiagnosis of epilepsy in children. The head-upright tilt test is a useful and reliable diagnostic technique, allowing syncopal events to be induced and evaluated under controlled conditions. In a subset of patients, it may help to distinguish epilepsy from simple or convulsive syncope.

Adolescent↗
PubMed2001

The relation between hyperventilation and pediatric syncope.

OBJECTIVE: The objective was to evaluate prospectively the role of hyperventilation in the development of neurocardiogenic syncope in children during head-upright tilt testing (HUTT). STUDY DESIGN: Tilt testing was performed in 34 children (mean age 10.6 years) with clinical suspicion of syncope. Respiratory rate and end-tidal carbon dioxide pressure were continuously monitored during HUTT. RESULTS: Tilt test was negative in 12 cases; 3 (25%) patients of this group exhibited hyperventilation any time during the test. In the remaining 22 cases the HUTT was positive, and 15 (68.2%) patients of this group exhibited hyperventilation at the onset of clinical symptoms and during syncope. In the positive HUTT group, the mean time elapsed from the tilt to the onset of syncope and the mean time elapsed from the onset of clinical symptoms to syncope (latency time) were significantly longer for patients who hyperventilated than for those who did not hyperventilate, (21.8 vs 11.5 minutes) (P =.002) and (78 vs 51 seconds) (P =.04), respectively. CONCLUSIONS: Spontaneous hyperventilation could play a relevant role in the pathophysiology of pediatric neurocardiogenic syncope, and it could point out a specific subtype of response to orthostatic stress in susceptible patients. We suggest the inclusion of capnography in tilt-test protocols could improve the assessment of syncope in children.

Adolescent↗
PubMed2001

Concentrations of nucleotides, nucleosides, purine bases, oxypurines, uric acid, and neuron-specific enolase in the cerebrospinal fluid of children with sepsis.

To determine the effects of sepsis on cerebral energy metabolism, the cerebrospinal fluid adenosine monophosphate, inosine monophosphate, inosine, adenosine, guanosine, hypoxanthine, xanthine, and urate concentrations were determined by high-performance liquid chromatography and the neuron-specific enolase levels by means of an enzyme immunoassay method in 32 children with sepsis, without meningitis, aged between 2 months and 13 years, and in 160 age-matched controls. The septic group had significantly higher cerebrospinal fluid concentrations of inosine, adenosine, xanthine, and urate than controls. These results suggest that sepsis could provoke some degree of neuronal hypoxia and significant alterations of cerebral energy metabolism homeostasis.

Adolescent↗
PubMed2000

Cerebral syncope in children.

We report a child with recurrent syncopal episodes who underwent head-up tilt testing according to a protocol that includes continuous and noninvasive measurement of brain oxygen saturation. We demonstrated significant cerebral hypoxemia during syncope without concomitant systemic hemodynamic disturbances. This response to head-up tilt test suggested the diagnosis of cerebral syncope.

Blood Pressure Determination↗
PubMed2000

Cerebrospinal fluid purine metabolite and neuron-specific enolase concentrations after febrile seizures.

If febrile seizures cause significant compromise of neuronal metabolism (whether permanent or reversible), this should be reflected in an increase in the cerebrospinal fluid concentrations of neuron-specific enolase (NSE) and/or adenosine triphosphate (ATP) breakdown products. In the present study, AMP, IMP, inosine, adenosine, guanosine, adenine, guanine, hypoxanthine, xanthine, uric acid and NSE concentrations were determined in the cerebrospinal fluid of 90 children 1 h after febrile seizure (73 simple febrile seizures (SFS); 17 complex febrile seizures (CFS)), and in a control group of 160 children. There was no statistically significant difference between the SFS group and the control group for any of the substances determined, suggesting that SFS neither significantly depletes neuronal ATP concentration, nor significantly increases NSE concentration; thus, SFS do not appear to constitute a threat to neuronal integrity. However, patients with CFS showed significantly lower IMP concentrations and significantly higher adenine concentrations than controls, and significantly higher AMP concentrations than SFS patients; these results suggest that CFS may affect energy metabolism in the brain. However, NSE concentrations were normal in the cerebrospinal fluid of both SFS and CFS patients, suggesting that neither type of seizure causes significant neuronal damage, at least early after the seizure.

Adenosine Monophosphate↗
PubMed2000

Unexpected sudden death from coronary sinus thrombosis. An unusual complication of central venous catheterization.

Coronary sinus thrombosis is an unusual but potentially serious complication of the use of central venous devices. We report a fatal case of coronary sinus thrombosis in relation to a malpositioned central venous catheter. The death occurred very soon following the beginning of symptoms and the cause could not be suspected. Direct trauma of the catheter on the coronary sinus endothelium seems the most probable cause of the thrombosis.

Cardiac Tamponade↗
PubMed1999

Neuron-specific enolase levels in the cerebrospinal fluid of neurologically healthy children.

Levels of neuron-specific enolase (NSE) levels in the cerebrospinal fluid (CSF) of children without neurological disease were assessed. CSF samples were obtained from 37 subjects aged between 1 month and 13 years. All subjects had undergone lumbar puncture for diagnostic purposes, and were subsequently shown not to be suffering any form of neurological disease. NSE levels in CSF were determined by an enzyme immunoassay method. NSE level ranged from below the detection limit to 4.8 ng/ml (1.52+/-1.01 ng/ml). The present results may be useful as a basis for defining reference levels of NSE in CSF in post-neonatal children.

Adolescent↗
PubMed1993

Indicators of hypoxia in cerebrospinal fluid of hydrocephalic children with suspected shunt malfunction.

We used high performance liquid chromatography to determine the concentration of purine metabolites in the cerebrospinal fluid of three hydrocephalic children with a history of shunt malfunction. Hypoxanthine and xanthine levels were high in comparison with controls. We consider these purines to be valuable indicators of disturbance of neuronal metabolism following the sustained rise in intracranial pressure caused by shunt valve malfunction.

Adolescent↗
PubMed1993

Concentrations of nucleotides, nucleosides, purine bases and urate in cerebrospinal fluid of children with meningitis.

The release of agents mediating inflammation in meningitis may bring about neuronal hypoxia, under which circumstances ATP concentrations decrease and its degradation products increase and are released into the cerebrospinal fluid. In this study of alterations in neuronal energy metabolism in meningitis, AMP, IMP, inosine, adenosine, guanosine, adenine, guanine, hypoxanthine, xanthine and urate were determined by high performance liquid chromatography in the cerebrospinal fluid of 54 children aged between 1 month and 13 years suffering from meningitis (25 viral, 24 bacterial and 5 tuberculous cases) and 63 controls. Compared to the controls, patients with viral meningitis exhibited high concentrations of IMP, adenosine, guanosine, adenine, guanine and xanthine; patients with bacterial meningitis exhibited high concentrations of IMP, inosine, guanosine, adenosine, hypoxanthine, xanthine and urate; and patients with tuberculous meningitis exhibited high concentrations of AMP, guanosine, xanthine and urate. Viral and bacterial cases did not differ significantly for any of the metabolites studied. AMP and urate concentrations were significantly higher in patients with tuberculous cases compared with viral or bacterial meningitis cases.

Adenosine Monophosphate↗
PubMed1992

Concentrations of purine nucleotides and purine and pyrimidine bases in cerebrospinal fluid of neurologically healthy children.

The concentrations of the nucleotides AMP and IMP, the nucleosides adenosine, guanosine and inosine, the purine bases adenine, guanine, hypoxanthine and xanthine, urate, and the pyrimidine bases cytosine, thymine and uracil were determined by high performance liquid chromatography in the cerebrospinal fluid of 63 children aged between 1 month and 13 years who showed no sign of neurological disease. The results are compared with those of other authors, and used to establish reference ranges for the above metabolites in the cerebrospinal fluid of children.

Adolescent↗
PubMed1991

Purine metabolites and pyrimidine bases in cerebrospinal fluid of children with simple febrile seizures.

Adenosine monophosphate, inosine monophosphate, inosine, adenosine, guanosine, adenine, guanine, hypoxanthine, xanthine, uric acid and pyrimidine bases were determined in the CSF of 18 children after simple febrile seizures and in a control group. There was no statistically significant difference between the two groups for any of these metabolites. This suggests that simple febrile seizures neither significantly disturb the metabolism of nucleotides, nucleosides or bases, nor significantly deplete neuron adenosine triphosphate ATP levels.

Adenine↗
PubMed1989

[Rett syndrome. A frequent cause of progressive mental retardation in girls].

We report 6 cases of Rett syndrome, a disorder that occurs only in girls and is characterized by slowly progressive deterioration of higher brain function, with dementia and autistic behavior, loss of purposeful use of the hands and deceleration of head growth. We consider interesting this report because Rett syndrome would be an important cause of mental retardation in girls, which has been overlooked until few years ago.

Adolescent↗