NORD gratefully acknowledges Laura Crandall, MA, Research Scientist and Orrin Devinsky, MD, Professor, Departments of Neurology, Neurosurgery and Psychiatry, Chief of Service, NYU Epilepsy Service, for assistance in the preparation of this report.
Nearly all children with SUDC were thought to be sleeping before becoming unresponsive. Most were born as full term singletons and their development was considered normal. Children were in their state of usual good health prior to death, or had mild symptoms of illness such as cold symptoms or fever. Some children with SUDC had a history of febrile seizures, or a family history of febrile seizures.
A febrile seizure is a convulsion in a child that may be caused by a spike in body temperature, often from an infection. Children aged 3 months to 5 or 6 years may have febrile seizures and they occur in 2% to 5% of all children. There is a slight tendency for them to run in families. If a child’s parents, brothers or sisters, or other close relatives have had febrile seizures, the child is a bit more likely to have them.
By definition, the cause(s) of SUDC are unknown. However, due to the lack of standardizations of death investigations, consideration of undiagnosed cases of cardiac disorders affecting the heart rhythm that are often due to genetic abnormalities, infections, and neurological conditions should be considered and ruled out.
The history of febrile seizures in some children with SUDC, and their family members, demonstrate a possible correlation to sudden unexpected death In epilepsy (SUDEP) defined as the sudden, unexpected, non-traumatic, non-drowning death in an individual with epilepsy, witnessed or unwitnessed, in which the postmortem examination does not reveal an anatomical or toxicological cause for the death. Most children with witnessed SUDEP are associated with a terminal convulsion, called a tonic-clonic seizure.
Examinations of the brains in a subset of children with febrile seizures reveal subtle abnormal development of an area deep in the temporal lobe. It is unknown whether these are a cause of seizures or a result of past seizures and whether they have a direct association with the death.
Children who die of SUDC are generally toddlers (60%), between 1 and 4 years of age, but older children can be affected. No particular ethnic group is affected. Nearly 90% are born full-term and nearly half are first born.
SUDC is not a diagnosis but a category of death. SUDC describes the sudden death of a child greater than 12 months of age that has undergone a thorough investigation and does not reveal evidence of an unnatural death. Death investigations also vary widely and therefore the extent to which known causes of death have been ruled should be reviewed.
Clinical Testing and Work Up
The investigation of the child’s death should be comprehensive including investigation of the scene where the child was found unresponsive, interviews with caregivers, a review of the child medical history and their family medical history, a complete autopsy with ancillary testing as clinically indicated.
SUDC is a multidisciplinary problem and requires coordination among the professionals involved to effectively investigate a case of SUDC and also provide appropriate communication and effective medical follow-up for family members. Families need effective communication in regards to the ramifications of the child’s final cause of death and what screening recommendations are appropriate to consider. Asking your primary care physician to collaborate with the medical examiner or coroner who performed the death investigation can be an excellent way to streamline communication in an emotionally traumatic and confusing situation.
Since genetic disorders affecting the heart’s conduction system or muscle can be inherited, other biological relatives may be at risk. Therefore, evaluation of family members for inherited heart arrhythmia or muscle conditions is valuable to confirm a family diagnosis and assess the risk in the living family members following an unexplained death. Clinical evaluation of family members following a sudden death may identify other affected members. First degree relatives (parents and siblings of the person who has died) should speak to their primary physician to obtain a referral to a cardiologist with expertise in electrophysiology and special training to evaluate genetic cardiac disorders.
SUDC is a category of death diagnosis of exclusion which means that it is only determined after the death and thorough investigation of the clinical history, scene of death and autopsy reveal no other cause. Because the determination of SUDC is made after death, there is no treatment.
SUDC Registry and Research Collaborative (SUDCRRC)
The purpose of the SUDCRRC is to increase the understanding of the characteristics, circumstances, medical histories and pathologies of children from ages 11 months through 18 years who have died suddenly and unexpectedly, and in some instances, without explanation. The SUDC Registry and Research Collaborative will analyze cases of sudden unexpected deaths in these children to understand risk factors and causes (including genetic studies on the child who died and both parents), and develop preventative measures. The SUDCRRC is available to review cases for evaluation through Dec 2019. For more information: https://sudc.org/research-and-medical-info/sudc-registry-research-collaborative
North American SUDEP Registry
NYU Comprehensive Epilepsy Center
223 East 34th St New York, NY 10016
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Ingrid A. Holm MD, MPH, Annapurna Poduri MD, MPH, Laura Crandall PT, MA, Elisabeth Haas MPH, Marjorie R. Grafe MD, PhD, Hannah C. Kinney MD, Henry F. Krous MD. Inheritance of febrile seizures in sudden unexplained death in toddlers. Pediatric Neurology 2012 Apr;46(4):235-9. doi: 10.1016/j.pediatrneurol.2012.02.007.
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Hannah C. Kinney, M.D., Amy E. Chadwick, B.A., Laura A. Crandall, M.A., Marjorie Grafe, M.D., Dawna L. Armstrong, M.D., William J. Kupsky, M.D., Felicia L. Trachtenberg, Ph.D., and Henry F. Krous, M.D. Sudden death, febrile seizures, and hippocampal and temporal lobe maldevelopment in toddlers: A new entity. Pediatr Dev Pathol 2009 Jul 16:1. Epub 2009 Jul 16
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