Petrous bone fractures in children: risk of meningitis, and indication for early Cochlear implant?

The case of a 5 year old boy who had a right petrous bone fracture with right CSF otorrhea and deafness is reported. This child presented, three years after the trauma, a right side otitis media, complicated by meningitis and pneumococcal sepsis, which might have as consequence a left side deafness. The bilateral deafness and the early possibility for cochlear ossification made us decide rapidly on a cochlear implant. Benjamin was then operated for a left side cochlear implant 40 days after contracting meningitis. Two months later, this boy was able to understand a speech without lip reading. Current concepts in the management of petrous bone fractures with CSF otorrhea are reviewed in this report. We also discussed prophylactic attitudes to adopt to reduce the risk of post temporal bone fracture meningitis.

[Hearing impairment in low birth weight infants: warning signs, diagnosis and rehabilitation program]. / Déficience auditive et prématurité: signes d'alerte, diagnostic et suivi.

The incidence of deafness is high in children born prematurely as compared with the general population of children. Early start of the rehabilitation being an important prognosis factor the detection of deafness must be made as early as possible. Therefore a careful attention must be paid to any early signs of possible hearing imparment; parents concerns in particular must always be considered seriously. Diagnosis of deafness rests on behavioural tests and electrophysiological technics.

Reinduction of hyponatremia improves survival in rats with myelinolysis-related neurologic symptoms.

Brain myelinolysis occurs after excessive correction (delta SNa > 20 mEq/1/24 hours) of chronic hyponatremia. However, we showed recently that the mechanisms leading to brain myelinolysis remain reversible. Indeed, reinduction of the hyponatremia by water administration despite 12 hours of sustained excessive correction could prevent the development of demyelination in rats still asymptomatic at that time. Whether this therapeutic maneuver could be also beneficial to rats with preexisting myelinolysis-related neurologic symptoms is unknown. Therefore we evaluated here the effect of reinduction of the hyponatremia on the survival and on brain damage in rats presenting obvious neurologic symptoms after excessive correction of hyponatremia. After 3 days of severe hyponatremia induced by 2.5 D-glucose in water and continuous infusion of AVP, rats were submitted to a large correction (delta SNa approximately 30 mEq/l) by 2 i.p. injections of hypertonic saline given over 24 hours. In group I (n = 15) the rats developing neurologic symptoms during the first 24 hours of correction received one i.p. injection of distilled water which rapidly decreased the natremia to a final correction gradient <20 mEq/l/24 hour. In group II (n = 13, controls) the symptomatic rats were left permanently overcorrected. In group I, after water administration, the neurological manifestations were generally attenuated or disappeared. Seven of the 15 rats (47%) in this group survived up to day 10 with a mean survival time of 7.5 +/- 2 days, an outcome clearly improved as compared to group II (controls): only 1 of the 13 rats (7%, p < 0.03) was still alive on day 10 and the mean survival time was 3.3 +/- 2 days (p < 0.001) in this group II. The duration of the symptoms also influences the prognosis. In group I, in 9 rats the water administration was performed 4 hours after symptoms onset. These rats had a better outcome than the 6 rats with more sustained (8-10 hours) neurologic symptoms before water loading. Brain analysis in the 7 surviving rats of group I demonstrated demyelinating lesions in only 2 of them, suggesting the reversibility of the process even when neurologic manifestation developed. In conclusion, after exposure to an excessive correction of chronic hyponatremia, even when rats have developed myelinolysis-related neurologic symptoms, hypotonic fluids administration could improve survival and could prevent the subsequent development of brain myelinolysis.

Brain myelinolysis following hypernatremia in rats.

Brain myelinolysis could develop after excessive correction (delta SNa > 20-25 mEq/1/24 hour [h]) of chronic hyponatremia; however, this neurological event is not recognized as a complication of hypernatremia when arising from a normonatremic baseline. Previous animal studies were unable to reproduce these brain lesions in hypernatremia after acute increase of serum sodium to moderately hypernatremic levels. We hypothesize that to produce brain dehydration and myelinolysis from normonatremic baseline requires a more important osmotic gradient than when starting from hyponatremic state. Rapid and sustained hypernatremia (at least > 6 to 12 h) was induced in male rats by i.p. administration of NaCl 2 M (3 injections at 6 h intervals). The NaCl doses were determined to define two groups of hypernatremic rats (moderate and severe hypernatremia) for further analysis of the neurological outcome. In group 1 (moderate hypernatremia, n = 26) 8 rats died early (< 12 h) after the beginning of the NaCl administration without specific neurologic manifestations. All the surviving rats fared well and were asymptomatic at time of death (day 8). They were submitted for at least 6 to 12 h to a serum sodium gradient of 28 +/- 6 mEq/l. Brain analysis was normal in all of them without brain demyelinating lesions. In group 2 (n = 51), 24 rats also died rapidly (< 12 h). The surviving rats developed severe neurologic symptoms as typically encountered in hyponatremic rats with myelinolysis. The majority of them died before day 8. The hypernatremic gradient in this group was significantly higher than rats in group 1 that completely recovered (mean delta SNa: 39 +/- 8 mEq/l, p < 0.001). In the 7 surviving rats (mean delta SNa: 33 +/- 3 mEq/l) brain analysis demonstrated severe demyelinating lesions similar to the histologic changes observed in hyponatremia-related myelinolysis. We demonstrated for the first time that high and sustained levels of hypernatremia could induce brain myelinolysis and that the osmotic gradient necessary to produce brain lesions is higher for normonatremic than for hyponatremic rats.

Prevention of brain demyelination in rats after excessive correction of chronic hyponatremia by serum sodium lowering.

Brain myelinolysis occurs after correction of chronic hyponatremia in rats when the magnitude of increase in serum sodium (delta SNa) exceeds 20 to 25 mEq/liter/24 hr (the critical threshold for brain). We tested the hypothesis that after a sustained excessive correction, brain lesions (BL) could be prevented by subsequently decreasing the serum sodium below the critical threshold for brain through the administration of hypotonic fluids. After three days of severe (< 115 mEq/liter) chronic (3 days) hyponatremia, 55 rats were submitted to an excessive correction (delta SNa > 25 mEq/liter) by a single i.p. infusion of hypertonic saline (NaCl). This osmotic stress was maintained during 12 hours before the serum sodium decrease was initiated. Thirty-two rats reached the twelfth post-correction hour without symptoms. In group 1 after a large (delta SNa 32 mEq/liter) and sustained (12 hr) osmotic stress, the natremia was rapidly (2 hr) decreased by the administration of oral tap water and, at the end of the first 24 hours, the magnitude of correction was maintained below 20 mEq/liter/24 hr. All the rats fared well in this group and were free of neurologic symptoms. Mild BL were noticed in only 20% of them. On the contrary, in controls (no hypotonic fluids administration at the twelfth hour) whose serum sodium was left overcorrected, all the rats became symptomatic and 57% of them died rapidly. Brain damage developed in 100% of the surviving rats. In group 2, despite hypotonic fluids administration, the serum sodium decreased insufficiently and the correction was > 20 mEq/liter at the end of the first 24 hours (delta SNa 25 mEq/liter).(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of chronic hyponatremia in rats by intravenous saline: comparison of rate versus magnitude of correction.

The role of the rate of correction in the development of demyelinating brain lesions after correction of chronic severe hyponatremia is controversial. It has been recently suggested in rats treated by intravenous (i.v.) hypertonic saline (NaCl) that both the rate and the absolute change in serum sodium represent critical risk factors. However, we previously demonstrated in rats treated by intraperitoneal (i.p.) injections of NaCl that below a threshold of serum sodium rise of 20 mEq/liter/24 hr, only 5% of the brain lesions were recorded, even in rats submitted to a rapid (1 hr) serum sodium increment following the i.p. injection. Working below this threshold (serum sodium rise less than 20 mEq/liter/24 hr) in the present work, allowed us to independently determine the role of the rate in the outcome of the correction. This was done by submitting the rats to a rapid (1 hr) intravenous infusion of NaCl. As a difference between the i.p. and i.v. route in the degree of volume expansion produced by the NaCl administration could also play a role in the pathogenesis of the brain lesions, rats treated with rapid i.v. infusion of NaCl (associated with volume expansion) were compared to a group of rats treated with water restriction (associated to volume contraction) to evaluate the role of volemia on the incidence of neurological damage. Hyponatremia was induced over three days with d-glucose in water and vasopressin. The group 1 was corrected by intravenous (i.v.) infusion of hypertonic saline over one hour.(ABSTRACT TRUNCATED AT 250 WORDS)

Limits of brain tolerance to daily increments in serum sodium in chronically hyponatraemic rats treated with hypertonic saline or urea: advantages of urea.

1. At present there is no consensus about the optimal management of hyponatraemia to prevent demyelinating brain lesions. We have evaluated in a large series of rats (n = 136) the protective role of urea for the brain in the treatment of severe chronic hyponatraemia. Urea (group I, n = 51) was compared with hypertonic saline in boluses (group II, n = 46) and with hypertonic saline in divided doses (group III, n = 39). Treatment was administered intraperitoneally over 48 h. The severity of brain lesions was assessed by histological scoring. 2. For 95% of the injured animals treated with hypertonic saline, brain lesions appeared for an absolute increment in serum Na+ concentration (delta SNa+) of 20 mmol day-1 l-1. Above this limit neurological injuries gradually worsened, and beyond a transition zone (delta SNa+ greater than or equal to 20 less than or equal to 23 mmol day-1 l-1) 89% (group III) to 100% (group II) of the animals were injured. This limit can be reached rapidly, as attested by the comparable severity of brain lesions observed in group II (mean delta SNa+ 1 h after a bolus injection, 19 mmol/l) and in group III (mean delta SNa+ 1 h after an injection, 2 mmol/l), both groups achieving similar daily delta SNa+. 3. A correction above the threshold of 20 mmol day-1 l-1 is as toxic during the first 24 h as during the second day of the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

[The child with defective hearing. Medical, educational, sociological and psychological aspects]. / L'enfant à audition déficiente. Aspects médicaux, éducatifs, sociologiques et psychologiques.

Hearing impairment in children is considered in its various aspects: medical, sociological, psychological, and educational. After a review of the aetiologies, the biological consequences of early auditory deprivation are underlined. The necessity of avoiding or reducing them justifies the efforts made to insure early diagnosis and adequate intervention. Screening and diagnostic techniques are described and illustrated by current results. The particular features of deafness, which stands out among other physical handicaps by the fact that it has given birth to a language, sign language, are stressed and the resulting socio-cultural implications are described. The relationships between deafness and psychology are treated so as to point out that there are no psychological features which characterize deafness, but that it can lead to several cognitive and behavioural consequences. The multiple interventions requested by a child's hearing impairment are detailed, emphasizing that medical or surgical actions must be part of a team work. The physician is called upon to play an essential part in this work, which he can correctly fulfill only by taking into account the sociological, cultural, psychological, educational and prosthetic aspects. The principles of prosthetic adaptation and the different types of prosthetic devices are presented, with special mention of recent and prospective developments. After a historical survey of deaf education, the evolution of ideas and methods from 1972 to 1987 is related, and the presently utilized methods are described and discussed. The different educational structures and their respective merits are outlined, as well as the action in favour of deaf children and their families of social services and parental cooperation.

[Rehabilitation programs for patients with cochlear implants as a function of acquired experience in logopedics for deaf children]. / Réflexions sur les programmes de réadaptation des patients porteurs d'implants cochléaires, en fonction de l'expérience acquise en logopédie d'enfants sourds.

Rehabilitation of patients after cochlear implant surgery should be planified along the same basic principles as those that have been envolved for the adaptation of patients to a classical hearing aid or acoustic prosthesis. When this is adapted to a patient with a sensorineural hearing loss, the quality of hearing differs from that of normal hearing because the pathological inner ear introduces distorsions. The patient therefore has to be trained to equate the new auditory sensations with those he had previously, which is basically the same situation as with a cochlear implant. Some profoundly or totally deaf patients are fitted with vibro-tactile aids and they also have to be trained to make use of these new sensations in a meaningful way for an aid to speech understanding. For the above reasons the term "cochlear prosthesis" is considered particularly adequate. It also has the advantage of playing down the surgical aspect of this new technique, often overemphasized by the media and creating exaggerated emotional involvement of the patients. If the above facts are recognized, one should entrust the rehabilitation of patients fitted with cochlear prostheses to logopeds (speech therapists) well trained in the habilitation and prosthetic adaptation of profoundly deaf children. Only they have the expertise necessary to devise and apply a program founded upon experience. This will help avoid the pitfalls into which several surgically directed cochlear implant teams are currently falling. One of these is to design a training program in function of the tests meant to measure the patients' new capacities.(ABSTRACT TRUNCATED AT 250 WORDS)

[A rapid technic for preparing the temporal bone for histologic study]. / Une technique rapide de préparation du rocher pour I'étude histologique.

The authors describe a new technique for the preparation of the temporal bone for histological studies. A serious advantage of this technique is its quickest realization allowing to obtain histological serial sections of the cochlea in 6 or 8 weeks.

Consequences of auditory deprivation in animals and humans.

An electron microscopic study of the cerebral cortex of mutant deaf mice (Deol's dn gene) has shown differences in synaptic organisation between these mice and normally hearing ones. In the auditory cortex of the deaf mice, there are fewer synapses and these are larger than in the normally hearing, whereas there is no difference between these two categories in the visual cortex. These results are the reverse of those observed by other authors in the occipital cortex of rats raised in an enriched or impoverished environment. In humans, the functional consequences of early hearing loss have been investigated on moderately to severely deaf (60-80 db mean loss) youngsters, who have been tested for their capacity of categorical perception, auditory discrimination, and production of significant contrasts between stop consonants. Categorical perception was absent in all but one subject. Auditory discrimination was poor for both the voiced-voiceless contrast and the place of articulation contrast. In the production experiments, the subjects had greater difficulty in producing the voiced-voiceless than the place of articulation contrasts. The possible relevance of these animal and human studies to cochlear implantation is discussed.

Clinicopathological study of the visual pathways, eyes, and cerebral hemispheres in 32 cases of disseminated sclerosis.

The pathological study of the cerebral hemispheres and visual pathways in 32 cases of disseminated sclerosis, including 15 cases in which the retinal structures were investigated, lead us to point out: 1) the high frequency of histological lesions of the optic nerves, tracts and radiations; 2) the lack of correlation between the extent of demyelination of the optic nerves and the impairment of visual acuity that is mainly related to axonal lesions; 3) the relative high frequency of pathological sheathing of retinal veins; and 4) the high proportion of shadow plaques in the cerebral hemispheres in cases with clear-cut relapses and remissions.

Temporal lobe oligodendroglioma developing from infancy into adulthood.

Clinical, radiological, surgical, and histological features are reported for a patient with a temporal lobe oligodendroglioma that had developed in infancy and was diagnosed and partially resected at age 10. The patient is presently 24 years old and still well. To the best of our knowledge this is the first report of an oligodendroglioma with probable onset at 5 months of life and satisfactory course over 24 years.

[Diagnosis of perceptive type hearing deficiency in children by determination of stapes reflex thresholds]. / A propos du diagnostic de la déficience auditive de type perception chez lenfant par la recherche des seuils de réflexe stapédien

The article reports on the limits regarding the study of the stapes reflex thresholds as a diagnostic method with profoundly deaf young children. A number of 30 children and adolescents have been tested at high intensities and the findings indicate stapedian reflexes at 250 and 500 Hx (all the patients) 1000 Hz (the majority of patients) and 1500 Hz (some patients).