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Biomedical subjects

R D Sheth

Publications and source records attributed to R D Sheth.

At least 55 records · Page 3Linked to original sources
PubMed1996

Bone mineral density in geographically diverse adolescent populations.

OBJECTIVE: Measure bone mineral density (BMD) in healthy Newfoundland adolescents and determine whether BMD is comparable in geographically diverse adolescent populations. STUDY DESIGN: Lumbar spine BMD was measured by dual-energy radiograph absorptiometry in 26 healthy adolescents between ages 8 and 20 years. The age and gender of these subjects were used to predict BMD from equations derived from normative BMD data in six geographically diverse populations. The actual BMD value obtained for each subject was then compared with each of the six predicted BMD values for that adolescent using the Wilcoxon signed-ranks test. RESULTS: Actual lumbar spine BMD in Newfoundland adolescents was not significantly different from that predicted by age and gender if they were from California, Finland, France, North Carolina, and Switzerland. Only the prediction based on the Spanish population resulted in a 4% greater BMD than was actually measured in the Newfoundland adolescents. CONCLUSIONS: Lumbar spine BMD measurements for most healthy adolescent populations, as in adults, are comparable despite geographic diversity. Thus, generation of institution-specific normative BMD data may not be necessary for most adolescent populations.

Adolescent↗
PubMed1995

Longitudinal head growth in developmentally normal preterm infants.

OBJECTIVE: To determine growth in head circumference from birth to 18 months of age in normal infants with low birth weight. METHODS: Healthy, appropriate-for-gestational-age, singleton, white infants weighing less than or equal to 2500 g at birth and with normal development at 18 months of age were included in this study. Serial measurements of head circumference (corrected for gestational age) from 450 eligible infants were compared with reference data for head circumference. RESULTS: Longitudinal measurements of head circumference for infants weighing more than 1000 g at birth were similar to reference data for term infants. Head measurements for infants weighing less than or equal to 1000 g at birth were notably smaller than the measurements in the reference data. A cubic spline curve drawn through the head circumference measurements between birth and age 18 months (corrected for gestational age) for infants weighing less than or equal to 1000 g at birth was significantly (P < .001) below the curve for infants weighing more than 1000 g at birth. At age 18 months, the mean difference in head circumference between the group weighing less than or equal to 1000 g at birth and the weights in the reference data was 1.6 cm (P < .01). (Data were analyzed with Wilcoxon's signed rank test.) CONCLUSIONS: These data show that head circumference grids are appropriate for observing head growth in infants with a birth weight more than 1000 g. However, head circumference growth for normal infants with birth weight less than or equal to 1000 g does not "catch up" with that of larger premature infants or term infants.

Birth Weight↗
PubMed1995

Acute confusional migraine: variant of transient global amnesia.

Acute confusional migraine in children and transient global amnesia in adults share a number of similar clinical manifestations. Acute confusional migraine in 6 children (mean age: 11.7 years; range: 7.5-17 years) was characterized by transient episodes of amnesia and acute confusion lasting 1-12 hours. Episodes were preceded by headache and vomiting in 4 patients. In 2 patients acute confusional migraine was the initial symptom. A history of preceding trivial head injury was reported in 3 patients and migraine in 4. Urine and serum drug screens were negative. Cerebral imaging studies and interictal electroencephalograms were normal. Ictal electroencephalograms in 3 patients revealed diffuse or bioccipital delta wave slowing. Recurrent episodes of acute confusional migraine occurred in 2 children during 1-3 years of follow-up. The clinical manifestations of acute confusional migraine in this series of children are similar to those reported in transient global amnesia. The similarity of the clinical manifestations of acute confusional migraine in children and transient global amnesia in adults suggests that these disorders may share a common pathophysiology.

Acute Disease↗
PubMed1995

Progressive neurologic impairment from an arteriovenous malformation vascular steal.

Approximately 15% of all cerebral arteriovenous malformations (AVMs) present with progressive neurologic deficits, the pathogenic mechanism of which has not been established. One suggestion is that AVMs by expanding over time compress normal surrounding cerebral parenchyma and thereby cause progressive neurologic impairment. Alternatively, a vascular steal results in progressive ischemia of normal cerebral tissue. Because the area occupied by the AVM and the area of observed blood flow reductions in all reported patients have overlapped, delineating the relative contribution of local compression from that of vascular steal has not been possible. We present a 7-month-old girl and a 7-year-old boy with AVMs restricted to the diencephalon who had progressive cognitive impairment and dystrophic cerebral hemispheral calcification (in the 7-month-old girl) indicating diffuse cerebral cortical involvement remote from the AVM. These patients provide evidence for vascular steal, and not local compression, as the primary mechanism underlying a progressive neurologic course associated with some AVMs.

Brain Ischemia↗
PubMed1995

Effect of carbamazepine and valproate on bone mineral density.

OBJECTIVE: To examine the effect of carbamazepine and valproate monotherapy on bone mineral density in children. METHODS: Axial (second, third, and fourth lumbar vertebrae) and appendicular (distal third of radius) bone mineral density was measured by dual-energy x-ray absorptiometry in 27 healthy children and 26 children with uncomplicated idiopathic epilepsy treated with either carbamazepine (n = 13) or valproate (n = 13) for more than 18 months. Control subjects and patients were similar with respect to age, race (all white), and geographic area, and had no dietary restrictions, neurologic impairment, or physical handicaps. RESULTS: Subjects were seizure-free for more than 6 months on a regimen of carbamazepine or valproate therapy, and had mean serum trough levels of 6.88 +/- 2 micrograms/ml and 72.04 +/- 45.6 micrograms/ml, respectively. Dietary calcium intake was similar in control and treated groups. After correction for gender and age, children treated with valproate had a 14% (p = 0.003) and 10% (p = 0.005) reduction in bone mineral density at the axial and appendicular sites, respectively. The reduction in bone mineral density increased with the duration of valproate therapy. Carbamazepine did not significantly reduce bone mineral density. CONCLUSION: Valproate montherapy, but not carbamazepine therapy, significantly reduces axial and appendicular bone mineral density in children with idiopathic epilepsy and may increase their risk of osteoporotic fractures.

Absorptiometry, Photon↗
PubMed1995

Critical illness neuromuscular disease in children manifested as ventilatory dependence.

Four children with prolonged dependency on a ventilator were found to have reversible quadriparesis, muscle wasting, and hyporeflexia after 8 to 20 days of assisted ventilation for life-threatening sepsis or respiratory failure. Critical illness neuromuscular disease, which was recently recognized as a distinct clinical syndrome in adults, may also be manifested in children by prolonged ventilatory dependency.

Adolescent↗
PubMed1995

Clobazam for intractable pediatric epilepsy.

We report our experience with add-on clobazam therapy over a 5-year period in 63 children with refractory epilepsy. The mean duration of epilepsy was 6.7 years. Children were followed for 15 to 64 months. Of 63 children, 57 were developmentally delayed, and 54 had a symptomatic/cryptogenic epilepsy. Forty-one percent became either seizure free or had a greater than 90% reduction in seizure frequency. Seizure frequency was reduced 50% to 90% in another 24%. The average daily dose of clobazam was 0.8 mg/kg. Thirty-five percent had the medication withdrawn for persistent or unacceptable side effects or the development of tolerance (seven patients). Side effects included severe aggressive outbursts, hyperactivity, insomnia, and depression with suicidal ideation. Clobazam is a useful add-on medication for 65% of children with epilepsy. Clinical utility may be limited by behavioral side effects in some patients.

Adolescent↗
PubMed1995

Opsoclonus myoclonus syndrome secondary to Epstein-Barr virus infection.

We report the first two children to have the "opsoclonus myoclonus syndrome" after a serologically confirmed acute Epstein-Barr virus infection. Although opsoclonus was absent in one patient, both patients had all other features typical of this syndrome. Patients without opsoclonus have been described as having an isolated postinfectious myoclonus syndrome but probably lie within the spectrum of opsoclonus myoclonus syndrome. The prognosis for the opsoclonus myoclonus syndrome in children with Epstein-Barr virus infection and without evidence for a neuroblastoma appears to be better than in those patients where a cause cannot be identified.

Antibodies, Viral↗
PubMed1995

Neuromuscular complications of sepsis in children.

Sepsis occurs frequently in the pediatric intensive care unit and is a significant cause of morbidity and mortality. Multiple organ systems are adversely affected by sepsis. Approximately 70% of adult patients with sepsis have peripheral nervous system dysfunction on electrophysiologic studies, of whom 30% are symptomatic. Neuromuscular dysfunction in children with sepsis is increasingly reported; however, the incidence remains undefined. Flaccid quadriplegia with the inability to wean from ventilatory support despite full cardiopulmonary recovery is the typical presentation. However, lesser degrees of weakness may be demonstrated with careful evaluation. Electrophysiologic studies often demonstrate the presence of axonal polyneuropathies, abnormalities of neuromuscular transmission, or acute myopathies. Identifiable neuromuscular syndromes in children with sepsis include critical illness polyneuropathy, pure motor polyneuropathy, thick-filament myopathy, and necrotizing myopathy. The common underlying pathogenic process in these syndromes appears to be sepsis, which may be accentuated by the administration of steroids or neuromuscular blocking agents. Recovery in strength usually occurs over a period of weeks to months.

Adult↗
PubMed1995

Differential involvement of the brain in neonatal asphyxia: a pathogenic explanation.

Multiple cystic lesions in brain parenchyma supplied by the anterior cerebral circulation is a recognized pattern of cerebral injury associated with hypoxic-ischemic encephalopathy in the term infant. This report presents a series of seven infants (gestational age, 39.3 +/- 2.8 weeks; range, 36 to 44 weeks) who developed multicystic encephalomalacia in the distribution of the anterior cerebral circulation after severe neonatal asphyxia. Cerebral imaging and pathologic studies demonstrate relative preservation of the cerebellum, brain stem, and cerebral structures supplied by the vertebrobasilar circulation. Compared to the vertebrobasilar vasculature, the anterior cerebral vessels in the term infant have dense sympathetic innervation. Asphyxia, a potent sympathetic stimulator, may induce vasoconstriction in the anterior circulation and differentially accentuate the effects of hypoxia/ischemia on cerebral tissue.

Asphyxia Neonatorum↗
PubMed1994

Episodic spontaneous hypothermia with hyperhidrosis: implications for pathogenesis.

Unprovoked hypothermia is an unusual presenting sign. When occurring with diaphoresis it has been referred to as episodic spontaneous hypothermia with hyperhidrosis. Earlier reports described episodic, spontaneous hypothermia with hyperhidrosis in patients with agenesis of the corpus callosum and postulated a midline congenital malformation of the central nervous system. Since then, various endocrine, electrolyte, autonomic, and sleep disturbances have been described but the etiology remains undetermined. Three unrelated children are reported each of whom had an intact corpus callosum and normal endocrine function. Shivering was consistently absent despite marked symptomatic hypothermia. One child had spontaneous resolution of episodic spontaneous hypothermia with hyperhidrosis and two children responded to the antiserotonergic, cyproheptadine. It is hypothesized that specific serotonergic dysfunction in the anterior hypothalamic extrapyramidal shivering mechanism is central in the pathogenesis of this condition.

Body Temperature Regulation↗
PubMed1994

Aggression in children treated with clobazam for epilepsy.

Seven of 63 children (11%) treated with clobazam (CLB) for refractory epilepsy developed a severe behavior disorder. This disorder was characterized by aggressive agitation, self injurious behavior, insomnia, and incessant motor activity occurring between 10 and 55 days after initiation of drug therapy. The affected children were relatively young (mean age 6.4 years) and developmentally disabled (four were autistic and two had isolated mental retardation). The disorder occurred with a short latency after initiation of therapy and at a relatively low dosage of CLB. Serum levels of other coadministered antiepileptic drugs were unchanged by the administration of CLB. One child was taking CLB monotherapy. This behavioral deterioration required the discontinuation of CLB, after which patients returned to their previous behavior within 3 weeks. After > 3 years of follow-up all children continue to require multiple antiepileptic drugs but have not had a recurrence of this aggressive agitation. The mechanism of the behavioral change is unclear.

Aggression↗
PubMed1994

Effective utilization of home-video recordings for the evaluation of paroxysmal events in pediatrics.

In young children, differentiating seizures from nonepileptic "spells" by history alone can be difficult, even for the specialist. Nonepileptic spells may be psychogenic (rare in the young child) or physiologic in origin. Physiologic spells misidentified as epileptic may be treated with antiepileptic medication where none is needed. Recording spells on video provides a potentially valuable supplement to the clinical history in arriving at a correct diagnosis. In practice, however, most home-video recordings prove difficult to interpret. Simple instructions to parents on the manner in which spells should be recorded will greatly increase the usefulness of home-video recordings. A systemic analysis of precipitating factors and the evolution and resolution of the spell will very often exclude seizures. The widespread availability of home-video recordings provides the pediatrician with an opportunity to visually examine a child's spells, often avoiding unnecessary investigations and referrals and allowing the physician to more confidently offer reassurance to the parents.

Anticonvulsants↗
PubMed1994

Cerebral dysgenesis. An overview.

A significant portion of patients with neurodevelopmental abnormalities (mental retardation, learning disabilities, and so forth) have no definable cause for these problems. Mounting evidence suggests a substantial number of these idiopathic conditions have subtle abnormalities of brain development (cerebral dysgenesis) as the inherent pathophysiologic event. In this article the authors summarize normal and abnormal brain development, the diagnostic approach to idiopathic neurodevelopmental anomalies, and the new molecular genetic insights into the underlying causes of brain malformations.

Brain↗
PubMed1993

The focal encephalopathies associated with mycoplasma pneumoniae.

Five patients with evidence of focal encephalopathy are reported. In each case, evidence of mycoplasma pneumoniae infection was detected. No patient improved with conventional antibiotic therapy, but in three subjects, rapid and complete recovery did occur contemporaneously with the administration of high dose steroid therapy. It is suggested that focal as well as diffuse cerebral or cerebellar lesions may occur as manifestations of auto-immune disease complicating mycoplasmal infections in young people and that this illness may be designated as acute mycoplasma-associated encephalopathy.

Adolescent↗
PubMed1991

A multi-centre comparative study of diclofenac sodium and a dipyrone/spasmolytic combination, and a single-centre comparative study of diclofenac sodium and pethidine in renal colic patients in India.

A single-blind, randomized clinical trial was carried out to compare the analgesic effectiveness in patients with renal colic of single intramuscular doses of diclofenac sodium (75 mg) versus a dipyrone (1 g)/spasmolytics combination, and diclofenac sodium (75 mg) versus pethidine (75 mg). The first study involved three centres, the second study one centre. In total, 107 patients were treated with diclofenac sodium, 85 with dipyrone/spasmolytics, and 25 with pethidine. Assessments were made during the first hour after drug administration of the degree of pain relief, the severity of pain using a visual analogue scale, and the duration of analgesia. A global assessment of treatment efficacy was made by the participating physicians at the end of the study period. Patients treated with diclofenac sodium showed an earlier onset of analgesia and a higher incidence of total pain relief compared to those treated with dipyrone/spasmolytics or pethidine. Although the mean duration of analgesia was only slightly greater in the diclofenac sodium group than in the dipyrone/spasmolytics group, a significantly longer effect was seen when diclofenac sodium was compared with pethidine (p less than 0.01). Pain severity assessments revealed that diclofenac sodium caused a significantly greater improvement in pain after 60 minutes compared to dipyrone/spasmolytics (p less than 0.05) and after 30 minutes compared to pethidine (p less than 0.05). Global efficacy assessments by the physician rated diclofenac sodium as significantly superior to dipyrone/spasmolytics (p less than 0.01) and pethidine (p less than 0.001). Moreover, diclofenac sodium was better tolerated than either of the comparative treatments. The results indicate that intramuscular diclofenac sodium is a useful alternative to the drugs commonly used in India in the treatment of renal colic.

Adolescent↗