S Fernández-Cebrián | PubMed Health

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↗

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↗

PubMedDate not supplied

[Early mitochondrial encephalomyopathy due to complex IV deficiency consistent with Alpers-Huttenlocher syndrome: report of two cases].

INTRODUCTION: Complex IV or cytochrome c oxidase (COX) deficiency is the most common disorder involving complexes of the respiratory chain in the pediatric age. Exceptionally, it has been reported in association with Alpers syndrome or Alpers disease, and with its variant named progressive neuronal degeneration with liver disease or Alpers-Huttenlocher syndrome. OBJECTIVE: To report the cases of two infants with mitochondrial encephalomyopathy due to COX deficiency in whom the clinical, biochemical, neurophysiologic and neuroimaging characterization suggested an associated Alpers-Huttenlocher syndrome. CLINICAL CASES: Two no-related males, one with noncontributory family history and the other with third-grade consanguineous parents developed refractory seizures from age 20 and 60 days, respectively. Additionally, myoclonic fits accounted on evolution of the condition. In the first case, serial EEG recordings showed low amplitude polyspikes, polyspike waves and very slow waves of high amplitude alternating with a trace of burst-suppression activity. In the second case, a right preponderant but also bilateral low amplitude polyspikes, polyspike waves and occasional desynchronization of basal trace were recorded. In both, a rapidly progressive cerebral atrophy, neurological deterioration with pyramidal signs, and tendency to microcephaly, ensued. Accompanying to this clinical picture, minor hepatic dysfunction, elevated protein levels in the CSF, lactic acidosis and COX deficiency in muscle homogenate were demonstrated. In the first case, moreover, cortical blindness and severe hepatic failure occurred while receiving valproate, in spite of concomitant L-carnitine therapy. CONCLUSIONS: We believe that the reported cases are consisted with Alpers-Huttenlocher syndrome associated with mitochondrial encephalomyopathy due to COX deficiency. Nevertheless, early myoclonic encephalopathy, a condition related in same cases with poliodistrophy, must be keep in mind as a possible diagnosis in case 1.

Anticonvulsants↗