The risk of sudden death in persons with the Chiari I malformation is unknown. A search of PubMed identified 7 reports describing 9 cases since 1984. Excluded were reports in which sudden death may have been due to other pathology.
Case Reports
Case 1: In 1984, Tomaszek et al. reported a 3-year-old child with Chiari-I who died 48 hours after an a fall down a flight of stairs. There was no loss of consciousness and neurological evaluation in the emergency department was normal. Twelve hours later her returned for irritability, vomiting and “two unexplained falls while walking”. Exam was normal except for an oral temperature of 38.4 C and a cerebellar gait. He was diagnosed with “viral upper respiratory illness” and allowed to go home. He was “restless and irritable” through the night.
“When awakened in the morning he was lethargic and confused. He became unresponsive and then apneic 45 minutes later. He was brought to the emergency department in cardiorespiratory arrest and could not be resuscitated.”
Autopsy revealed synostosis of the sagittal and lambdoid sutures. The cerebellar tonsils were “prolapsed through the foramen magnum into the upper cervical spinal canal ”. There was “slight brain swelling”, “focal cerebellar cortical atrophy” and “gliosis where the tonsils had been chronically compressed by the edge of the foramen magnum.”
Case 2: In 1985, Iwabuci et al. reported 30-year-old female “sudden-death case of Arnold-Chiari malformation (type 1) accompanied with spina bifida and closed meningomyelocele.” (Today, this would be considered a Chiari type II malformation.)
Cases 3 & 4: In 1993, Martinot et al. reported “the first two fatal cases of sudden unprovoked cardiorespiratory arrest in children with previously undiagnosed Arnold-Chiari type 1 malformation.”
Cases 5 & 6: In 1998, Wolf et al. reported a 71-year-old individual and in a 22-year-old individual who died following minor trauma.
“In both cases, postmortem examination revealed prominent cerebellar tonsillar herniation. One had associated tonsillar sclerosis and hydrocephalus.”
Case 7: In 1999, Zeigler and Mallonee reported a ... with Chiari malformation and syringomyelia who died “after repeated attacks of headache and syncope that had been diagnosed as basilar migraine”.
Case 8: In 2003, James reported a 25-year-old man with Chiari I malformation and syringomyelia ”who collapsed and died following a blow to the face”.
Case 9: In 2003, Goral et al. reported a 25-year-old man with sudden death found to have CM-I.
Summary: Sudden death from Chiari I can occur at any age; in these abstracts, age ranges from 3 to 71 years. Approximately half (4 of 9) of the sudden death cases were related to trauma. Another died after attacks of headache and syncope. Two children died with “sudden unprovoked cardiorespiratory arrest”. One patient had cerebellar symptoms and another sleep apnea before sudden death.
How common is sudden death in CM-I?
A survey by the American Association of Neurological Surgeons revealed that their 2,511 board-certified members performed 3,566 Chiari decompressions in 1999. Now, 9 years following the report, and in view of increasing recognition of the condition, it is reasonable to estimate at least 4,000 persons undergo surgical treatment for Chiari-I in the US each year.
If we assume 1 out of 3 patients presenting with the Chiari-I malformation undergo surgical treatment, then 12,000 persons seek medical attention in the US each year.
Of the 9 cases of sudden death from Chiari-I reported in the literature since 1984, 4 occurred in the US. If we assume only 1 out of 10 Chiari-related sudden death cases are reported in the literature, then there could have been 40 sudden death cases in 24 years in the US.
With 12,000 cases reaching medical attention each year, there would be 40 sudden deaths out of 288,000 cases in the past 24 years, or 1 sudden death per 7,200 cases. If we assume only 1 in 100 Chiari-related sudden death cases are reported, then the risk is 1 out of 720 per year.
Conclusion: Sudden death from the Chiari I malformation does occur, but seems to be very rare. About 1/2 of cases are related to mild or moderate trauma. The most likely cause if trauma or dysfunction of the medullary cardiac and respiratory centers.
Please send comments, corrections, or additions to chiaritimes@mac.com or post your comment below.
Posted by John Oro’, MD
The risk of sudden death in persons with the Chiari I malformation is unknown. A search of PubMed identified 7 reports describing 9 cases since 1984. Excluded were reports in which sudden death may have been due to other pathology.
Case Reports
Case 1: In 1984, Tomaszek et al. reported a 3-year-old child with Chiari-I who died 48 hours after an a fall down a flight of stairs. There was no loss of consciousness and neurological evaluation in the emergency department was normal. Twelve hours later her returned for irritability, vomiting and “two unexplained falls while walking”. Exam was normal except for an oral temperature of 38.4 C and a cerebellar gait. He was diagnosed with “viral upper respiratory illness” and allowed to go home. He was “restless and irritable” through the night.
“When awakened in the morning he was lethargic and confused. He became unresponsive and then apneic 45 minutes later. He was brought to the emergency department in cardiorespiratory arrest and could not be resuscitated.”
Autopsy revealed synostosis of the sagittal and lambdoid sutures. The cerebellar tonsils were “prolapsed through the foramen magnum into the upper cervical spinal canal ”. There was “slight brain swelling”, “focal cerebellar cortical atrophy” and “gliosis where the tonsils had been chronically compressed by the edge of the foramen magnum.”
Case 2: In 1985, Iwabuci et al. reported 30-year-old female “sudden-death case of Arnold-Chiari malformation (type 1) accompanied with spina bifida and closed meningomyelocele.” (Today, this would be considered a Chiari type II malformation.)
Cases 3 & 4: In 1993, Martinot et al. reported “the first two fatal cases of sudden unprovoked cardiorespiratory arrest in children with previously undiagnosed Arnold-Chiari type 1 malformation.”
Cases 5 & 6: In 1998, Wolf et al. reported a 71-year-old individual and in a 22-year-old individual who died following minor trauma.
“In both cases, postmortem examination revealed prominent cerebellar tonsillar herniation. One had associated tonsillar sclerosis and hydrocephalus.”
Case 7: In 1999, Zeigler and Mallonee reported a ... with Chiari malformation and syringomyelia who died “after repeated attacks of headache and syncope that had been diagnosed as basilar migraine”.
Case 8: In 2003, James reported a 25-year-old man with Chiari I malformation and syringomyelia ”who collapsed and died following a blow to the face”.
Case 9: In 2003, Goral et al. reported a 25-year-old man with sudden death found to have CM-I.
Summary: Sudden death from Chiari I can occur at any age; in these abstracts, age ranges from 3 to 71 years. Approximately half (4 of 9) of the sudden death cases were related to trauma. Another died after attacks of headache and syncope. Two children died with “sudden unprovoked cardiorespiratory arrest”. One patient had cerebellar symptoms and another sleep apnea before sudden death.
How common is sudden death in CM-I?
A survey by the American Association of Neurological Surgeons revealed that their 2,511 board-certified members performed 3,566 Chiari decompressions in 1999. Now, 9 years following the report, and in view of increasing recognition of the condition, it is reasonable to estimate at least 4,000 persons undergo surgical treatment for Chiari-I in the US each year.
If we assume 1 out of 3 patients presenting with the Chiari-I malformation undergo surgical treatment, then 12,000 persons seek medical attention in the US each year.
Of the 9 cases of sudden death from Chiari-I reported in the literature since 1984, 4 occurred in the US. If we assume only 1 out of 10 Chiari-related sudden death cases are reported in the literature, then there could have been 40 sudden death cases in 24 years in the US.
With 12,000 cases reaching medical attention each year, there would be 40 sudden deaths out of 288,000 cases in the past 24 years, or 1 sudden death per 7,200 cases. If we assume only 1 in 100 Chiari-related sudden death cases are reported, then the risk is 1 out of 720 per year.
Conclusion: Sudden death from the Chiari I malformation does occur, but seems to be very rare. About 1/2 of cases are related to mild or moderate trauma. The most likely cause if trauma or dysfunction of the medullary cardiac and respiratory centers.
Please send comments, corrections, or additions to chiaritimes@mac.com or post your comment below.
Posted by John Oro’, MD