Biomedical subjects

D Wenzel

Publications and source records attributed to D Wenzel.

77 records · Page 5Linked to original sources

PubMedDate not supplied

[Functional disorder of the hypothalamic osmoreceptor as the cause of excessive hypernatremia in a girl with absence epilepsy].

BACKGROUND: Chronic hypernatremia is a rare disorder in childhood and normally results from impairment of the water homeostasis. In some cases, chronic hypernatremia is caused by decreased intake of water based on impaired thirst perception. CASE REPORT: We report a girl with microcephaly, partial agenesis of the corpus callosum, mild midface hypoplasia and absence seizures, who presented with severe hypernatremia (serum sodium concentration 189 mmol/l). Though serum osmolality was increased up to 382 mOsm/kg, the girl showed no signs of thirst. After normalization by intravenous fluid therapy, serum osmolality and serum sodium concentration remained in the normal range with an oral water intake of at least 1500 ml/d. Polyuria was never present, the ability to concentrate urine was preserved. CONCLUSIONS: In summary, we speculate that the chronic hypernatremia in our patient is caused by a selective hypothalamic osmoreceptor dysfunction associated with mild dysplasia of the midline structures. Only very few similar cases have been documented in the literature.

Agenesis of Corpus Callosum↗

PubMedDate not supplied

[Extra-cerebral intracranial fluid collections in childhood: differentiation between benign subarachnoid space enlargement and subdural effusion using color-coded duplex ultrasound].

BACKGROUND: Extracerebral fluid collections in infancy are a common diagnostic problem, because by noninvasive imaging studies (including cranial ultrasonography, CT and NMR), no definite differentiation between two distinct pathological conditions can be found until today: An enlargement of the subarachnoid spaces in children with macrocephaly is a frequent observation of mostly unknown etiology but is known to be associated with a good prognosis. If surgery is necessary in these patients, ventricular shunting is required. On the other hand subdural effusions are often of traumatic origin and require frequently neurosurgical intervention (subdural shunting). Most reports on extracerebral fluid collections in infancy have not differentiated between both pathological conditions and therefore reveal confusing results. Recent studies using magnetic resonance imaging have shown that vascular flow phenomena in the arachnoid space can be used to a reliable diagnosis, whereas previous noninvasive neuroimaging attempts including high resolution computerized tomography (CT) have been useless. PATIENTS AND METHODS: We investigated a cohort of 20 patients aged 4 mths to 30 mths (mean 10.5 +/- 6.6 months) 16 with the history of macrocephaly and normal neurological development and 4 patients after head trauma and symptoms of an elevated intracranial pressure. RESULTS: In all 16 patients with the clinical diagnosis of benign subarachnoid space enlargement colour coded Doppler sonography detected archnoid vessels within the fluid collection, furthermore high resolution ultrasound demonstrated the dural border of of the arachnoidea as an echogenic membrane, an observation useful as a further sign of the subarachnoid location of the fluid collection. In the 4 patients with subdural hematoma the fluid collection showed an increased echogenity, no vascular structures and no surrounding border. CONCLUSION: Out of these observations we conclude that high resolution ultrasound and colour-Doppler sonography are able to reliably differentiate between a subdural and a subarachnoid fluid collection. An NMR investigation with its higher risks (sedation, anesthesia) focused on this target only seems therefore to be not necessary in these patients.

Blood Flow Velocity↗

PubMedDate not supplied

[Heterotopic gray matter: MR findings and clinical aspects].

Heterotopias are conglomerates of neurons and glial cells in an abnormal location and belong to a group of malformations, which are the result of a disturbed migration of neurons during the embryonic development of the brain. The MRI-appearance and clinical symptoms of 14 patients with nodular or lamellar heterotopias are presented. Seizures were the leading symptom (12 of 14 patients), in children also a developmental deficit (4/10) with or without seizures. Most of the children (9/10) had further brain malformations especially of the corpus callosum or the cerebellar vermis. Nodular heterotopias without further malformations were found in 4 patients, two of them developing grand-mal seizures after childhood. On MRI heterotopias are characterized by a signal isointense to gray matter in all sequences. MRI-scans in at least 2 orientations are necessary to detect these anomalies reliably. MRI is the optimum method for the demonstration of these anomalies and should always be performed if seizures develop during childhood. At least in nodular heterotopias there is no definite correlation between the extent of the anomalies, the EEG-findings and the clinical symptoms. However there is a frequent combination of heterotopias with further cerebral malformations.

Adolescent↗

PubMedDate not supplied

[Click-evoked otoacoustic emissions and acoustic brain stem potentials in early detection of hearing disorders in premature and newborn infants after neonatal critical care].

Evoked otoacoustic emissions (EOAE) and brainstem acoustic evoked potentials (BAEP) were recorded from 78 children following neonatal intensive care. In 23% no EOAE could be obtained. Hearing impairment in the BAEP was found in 9%. In 22% negative EOAE were found in spite of normal BAEP. According to the latency-intensity function of waves I and V all children with abnormal BAEP were classified having a conductive hearing loss. In accordance in no case a narrowing of the emission spectrum could be found in the EOAE. In both methods the rate of hearing impairment was highest in children with birth weights of less than 1000 g. A screening of all infants after neonatal intensive care using EOAE is recommended. BAEP should be done additionally in cases with deficient EOAE.

Auditory Pathways↗

PubMedDate not supplied

Visuomotor coordination during focal and generalized EEG discharges.

A new computer-based method for continuous gauging of momentary, visuomotor coordination under simultaneous EEG control proved both effective and suitable for children. Thirty-eight patients (age 4-17 years) who had different types of hypersynchronous activity were examined: None of the patients with focal discharges showed significant impairment in the test performance. Slight losses were evident in less than 3-s generalized, irregular spike-wave paroxysms. Deterioration was particularly evident in the bilateral synchronous 3-Hz spike-wave series, which lasted greater than 3 s.

Adolescent↗