Joan L. Venes

Ventriculopleural Shunting in the Management of Hydrocephalus

6 cases of ventriculopleural shunting for control of hydrocephalus are presented. In the other child and adult, drainage of cerebrospinal fluid into the pleural cavity seems to be well tolerated in exceptional circumstances where other shunt procedures, including intracranial shunts, are contraindicated. In the infant and young child, accumulation of fluid in the pleural space is enchanced by a poorly understood immune-related mechanism and may lead to significant pulmonary dysfunction. On the basis of our experience, this procedure appears contraindicated in this age-group.

Multiple Cranial Nerve Palsies in an Infant with Arnold‐Chiari Malformation

A case of Arnold‐Chiari malformation associated with cranial nerve palsies and proving refractory to adequate management of hydrocephalus is reported. This complication of the Arnold‐Chiari malformation in infancy and the rôle of posterior fossa decompression as treatment are discussed.

Reye syndrome Monoamine metabolites in ventricular fluid

Concentrations of homovanillic acid (HVA) were markedly elevated in the ventricular fluid of 15 children with Reye syndrome (median, 887 ng per milliliter) compared to 7 controls (median, 282 ng per milliliter), but 5-hydroxyindoleacetic acid (5-HIAA) values were comparable (medians of 198 and 189 ng per milliliter, respectively). The ratio of 5-HIAA to HVA was significantly lower in patients with Reye syndrome (0.26) than in controls (0.51). Serial samples demonstrated wide fluctuations in HVA concentration, but not in that of 5-HIAA. Monoamine metabolite concentrations were not correlated with serum ammonia, increased intracranial pressure, morbidity, or mortality. Increased HVA in Reye syndrome may reflect cerebral ischemia and release of vasoactive amines (particularly dopamine) into the brain and cerebrospinal fluid (CSF).

B Waves – a Reflection of Cardiorespiratory or Cerebral Nervous Systems Rhythm?

A review of 92 consecutive shunt revisions is presented in an attempt to assess the contribution of computerized axial tomography to the long-term management of the child with shunted hydrocephalus. 20-22 percent of all cases of acute shunt malfunction presented with small ventricles, indicating that absence of ventricular enlargement should not be interpreted as demonstrating adequate shunt function. The single most useful application of computerized axial tomography in our hands is the detection of indolent shunt malfunction associated with ventriculomegaly and decline of cognitive function in the older child.

Evoked cerebral cortical activity from small peripheral nerve fibers in cat.

Abstract In 19 cats anesthetized with 75% nitrous oxide/25% oxygen, two types of cortical activity have been demonstrated to respond to repetitive stimulation of small myelinated and unmyelinated peripheral nerve fibers. One is a rhythmic 3–4 c/sec high voltage activity seen most prominently in the cortical association areas. The other is a 20–40 c/sec small amplitude train of brief discharges appearing most prominently in the primary somatosensory area. This latter response is related to the activity of smaller peripheral nerve fibers. The two responses differ in that the 20–40 c/sec activity is not evoked by epinephrine, appears shortly after the stimulus, and has a shorter duration of activity than the higher voltage 3–4 c/sec theta activity. The slow rhythm is evoked by epinephrine, is delayed in onset and outlasts an evoking stimulus train. Neither response is evoked by optic stimulation or by stimulation of the larger peripheral afferent fibers. Both varieties of cortical activity are suppressed by intravenous phenobarbital.

ELEVATED CONCENTRATIONS OF CSF HOMOVANILLIC ACID IN REYE SYNDROME-A POSSIBLE RELATION TO CEREBRAL HYPOPERFUSION

Recent investigations suggest a relationship between braindopamine release and subsequent hypoperfusion. Such an association has important therapeutic implications since abundant pharmacological agents are available that could be utilized to modify central monoaminergic mechanisms. We have examined cerebral ventricular fluid concentrations of homovanillic acid(HVA) and 5-hydroxyindoleacetic acid (5-HIAA), the principal metabolites of dopamine and serotonin respectively, in 7 children with Reye syndrome. In these children, CSF was obtained during continuous intracranial pressure (ICP) monitoring and compared with ventricular CSF from 6 children with communicating hydrocephalus. Maximum HVA (ng/ml, mean ± SEM) was significantly elevated in Reye syndrome averaging 1140 ± 313 compared to 267 ± 64.5 in controls (p < 0.005) while 5-HIAA was similar, averaging 232 ± 32.5 and 187 ± 33.9 in Reye syndrome and controls respectively (p > 0.10). Peak HVA concentration occurred 1-2 days after the maximum blood NH3; however, there was no significant correiation between the maximum CSF concentration of either HVA or 5-HIAA and maximum blood NH3. ICP was increased in all children with Reye syndrome but there was no consistent pattern between HVA concentration and degree of ICP elevation. Our findings suggest a sequence of dopamine release (as reflected by elevations in HVA), cerebral vasoconstriction, and a resultant hypoperfusion in Reye syndrome.