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Biomedical subjects

R Korobkin

Publications and source records attributed to R Korobkin.

15 recordsLinked to original sources

Near-miss sudden infant death syndrome in eight infants with sleep apnea-related cardiac arrhythmias.

Eight full-term infants between 3 and 8 weeks of age, who had had 24 to 48 hours of vague problems involving a congested upper airway and/or irritability, had a life-threatening respiratory episode at home, called a near-miss for sudden infant death syndrome event. Polygraphically monitored mixed apneas occurred in clusters during non-rapid eye movement (NREM) sleep with significant cardiac arrhythmias, predominantly sinus arrest. The cardiorespiratory problems continued during sleep in the following 8 to 12 weeks but did not recur after that time, and there were no long-term sequelae when the children were studied again 4 to 7 years later.

Arrhythmias, Cardiac

Five cases of near-miss sudden infant death syndrome and development of obstructive sleep apnea syndrome.

Five full-term infants were referred for "near miss" sudden infant death syndrome events, which occurred between 3 and 12 weeks of age. After a complete pediatric evaluation and 24-hour polygraphic monitoring, each infant was monitored at home with a cardiorespiratory monitor. Each was followed regularly (with repeat polygraphic recordings) up to 4 years of age. All five infants developed heavy snoring at night and symptoms of obstructive sleep apnea syndrome. The diagnosis of obstructive sleep apnea syndrome was confirmed by polygraphic recordings; surgery was recommended. Four of the five children underwent adenoidectomies between 3 and 4 years of age, and this significantly improved their condition. These five cases are the first polygraphically documented histories of the development of obstructive sleep apnea syndrome.

Adenoidectomy

'Near-miss' for sudden infant death syndrome infants: a clinical problem.

Three hundred six infants were referred for evaluation of "near-miss" sudden infant death syndrome (SIDS) from 1973 to 1980. Following the hospitalization and medical evaluation, there were 156 infants (115 term and 41 preterm) for whom there was no explanation for the presenting event and who were considered near-miss infants; 88% of these infants were seen during the first 3 months of life. A repeat near-miss event was reported in 63% (term) and 83% (preterm) infants. Twelve percent of term infants and 17% of the preterm infants had ten or more repeat events. A home apnea/cardiac monitor was prescribed for 88% of the infants for an average duration of 5.6 months in term infants and 3.5 months in preterm infants. Monitoring had been discontinued in 69% of the infants by 7 months of age. One full-term infant was later a SIDS victim. The risk of a repeat near-miss event is concluded to be sufficiently great to demand immediate hospitalization, medical evaluation, home monitoring when there is no specific treatment, and close clinical follow-up. Follow-up studies are needed to determine whether there is any long-term morbidity for infants who have had near miss events.

Age Factors

Children and nocturnal snoring: evaluation of the effects of sleep related respiratory resistive load and daytime functioning.

Twenty-five children, age range 2 to 14 years (mean age = 7), were referred to the Stanford University Sleep Disorders Clinic for various clinical symptoms, including excessive daytime somnolence, heavy nocturnal snoring, and abnormal daytime behavior. All children (10 girls and 15 boys) were polygraphically monitored during sleep. No sleep apnea syndrome or oxygen desaturation was revealed. However, each child presented significant respiratory resistive load during sleep associated with electrocardiographic R-R interval and endoesophageal pressure swings. The most laborious breathing occurred during REM sleep. Second degree atrioventricular blocks were also noted. Tonsillectomy and/or adenoidectomy was performed in every case and resulted in a complete disappearance or substantial amelioration of the reported symptoms. Objective evaluation by Multiple Sleep Latency Test and Wilkinson Addition Test confirmed the beneficial effect of surgery.

Adenoidectomy

Congenital central alveolar hypoventilation syndrome in six infants.

Six infants with congenital alveolar hypoventilation syndrome (CCHS) were seen and observed over several years. Two had an association of CCHS with Hirchsprung's disease. All infants were treated by tracheostomy and mechanical ventilation. Three infants have survived (including one with CCHS and Hirchsprung's disease). However, all survivors have required frequent rehospitalization. The infant with the longest survival (now 4 years of age) has developed significant daytime problems involving the "behavioral control" of ventilation. One infant was considered as a "near miss for sudden infant death syndrome" and became significantly symptomatic after establishment of delta (stage 3-4 non-rapid eye movement) sleep, which normally develops between 2 and 4 months of age. CCHS involves autonomic nervous system dysfunction, and the question of a defect involving the integration of chemoreceptor information more than a direct defect of the central chemoreceptor is discussed.

Chemoreceptor Cells

Sleep parameters and respiratory variables in "near miss' sudden infant death syndrome infants.

Twenty-nine near miss for sudden infant death syndrome and thirty normal infants between the ages of 3 weeks and 6 months were monitored polygraphically for 24 hours. The distribution of sleep and abnormal respiratory events were analyzed for both groups. On the basis of mixed and obstructive apnea, 12-hour nocturnal segments (8 PM to 8 AM) consistently distinguished near miss from normal infant groups between the ages of 3 weeks and 4.5 months. Daytime naps do not provide statistical differences sufficient to differentiate between the two groups. During sleep, abnormal respiratory events are more likely to occur between 1 AM and 6 AM, at least 40 minutes after sleep onset. Respiratory pauses show a significant increase just prior to waking (a strong respiratory stimulus). Any impairment of the arousal threshold during sleep will place near miss infants at increased risk.

Monitoring, Physiologic

Mixed and obstructive sleep apnea and near miss for sudden infant death syndrome: 2. Comparison of near miss and normal control infants by age.

Twenty-nine full-term near miss for sudden infant death syndrome (SIDS) and 30 normal control infants underwent 24-hour polygraphic monitoring. Several types of respiratory events during sleep (eg, central, mixed, and obstructive apnea, periodic breathing) were defined and tabulated. Analysis of these respiratory variables and comparison of groups of near miss and control infants indicated that between 3 weeks and 4 1/2 months of age only one variable was consistently different at a statistically significant level: the number of mixed and obstructive apnea greater than 3 seconds during total sleep time. This study also showed an increase in mixed and obstructive respiratory events during sleep at 6 weeks of age in control as well as in near miss infants.

Female

Neurologic abnormalities in near miss for sudden infant death syndrome infants.

As part of the Sudden Death Research Project at Stanford University School of Medicine, we have performed systematic neurologic examination of 41 near miss infants, 7 normal siblings of babies who died a sudden infant death, and 21 normal control infants. Many infants were examined longitudinally until 2 years of age. We found that near miss infants under 3 months of age had consistent abnormalities of muscle tone, particularly shoulder hypotonia. These abnormalities disappeared with maturation, but only 60% of older infants who had suffered near miss episodes of neurologically and developmentally normal. In addition, only one of the seven apparently normal siblings had an entirely normal neurologic examination when first seen. Thus, infants who present with near miss episodes may have an underlying central nervous system abnormality or may acquire some abnormality as a result of the episode.

California

Neck extensor hypertonia: a clinical sign of insult to the central nervous system of the newborn.

Abnormal hypertonia of the neck extensor muscles in newborns may be appreciated by observing spontaneous posture, evaluating resistance to repeated passive flexion of the head, and eliciting the head straightening reflexes. This sign correlates well with other signs of insult to the central nervous system. Of 1743 newborns over 37 wk gestational age, 17 appeared to have signs of cerebral insult according to the classical criteria of abnormal state of consciousness, tone, and reflexes. Of these 17, 12 (70%) had neck extensor hypertonia. 38 newborns appeared to have mild signs of cerebral insult with abnormalities of tone and excitability. Of these 38, 14 (37%) had neck extensor hypertonia. Only 12 (0.7%) of 1655 newborns with otherwise normal neurological examination had neck extensor hypertonia. Further studies are necessary to evaluate the prognostic value of neck extensor hypertonia in the neonatal period.

Central Nervous System Diseases

Glue-sniffing neuropathy.

Although industrial exposure to n-hexane is known to cause neuropathy, it is less well recognized that inhalation of n-hexane present in the vapors of some commercial contact cements is also neurotoxic to peripheral nerves. A young man with a long history of addictive glue-sniffing developed severe distal symmetrical polyneuropathy several months after switching to a cement containing n-hexane and gradually improved several months after switching to another cement containing no n-hexane. Fascicular biopsy of radial cutaneous nerve showed striking segmental distention of axons by neurofilamentous masses with secondary thinning of myelin sheath, paranodal myelin retraction, and widening velocities were correspondingly slow. We conclude that n-hexane used as a solvent in some contact cements may be neurotoxic when inhaled to excess and, further, that the neuropathy has characteristic electrophysiological and pathological features.

Acetates

The relationship between head circumference and the development of communicating hydrocephalus in infants following intraventricular hemmorrhage.

Rapidly enlarging head circumference is a standard clinical sign of progressive hydrocephalus in an infant. Six neonates 29 to 36 weeks gestational age, with intraventricular hemorrhage, confirmed by ventricular tap, had head circumferences measured at intervals from birth. The sudden appearance of rapidly expanding head size, not associated with changing clinical status, occurred 9 to 20 days after the estimated time of hemorrhage in all of the infants. Air ventriculography within three days of abnormal acceleration of head circumference growth demonstrated moderately to severely dilated ventricles. The ventricles were probably enlarging slowing from the time of hemorrhage because there was no associated clinical deterioration in the infants coincident with the rapid increase in head circumference. After intraventricular hemorrhage, enlarging head circumference appears to be an insensitive sign of hydrocephalus in premature infants.

Cephalometry