Cerebellar Fits in Children with Chiari I Malformation
Cerebellar Fits in Children with Chiari I Malformation
Object. The authors describe a series of children with Chiari I malformation who presented with fulminating symptoms of "cerebellar fits" characterized by drop attacks with or without deterioration of consciousness, opisthotonic posturing, and varying degrees of respiratory compromise.
Methods. A retrospective analysis was undertaken of the medical records of 47 consecutive patients undergoing surgery for symptomatic Chiari I malformations at Rainbow Babies and Children's Hospital.
Thirteen (28%) of the 47 patients presented with complaints consistent with cerebellar fits. Before the correct diagnosis was made, nine (69%) of the 13 children had previously undergone evaluation with electroencephalography and/or electrocardicography and Holter monitoring because of suspected cortical epilepsy or cardiogenic syncope. In each of the 13 children magnetic resonance imaging demonstrated pegged cerebellar tonsils herniated below the foramen magnum. A deep indentation or blanched discoloration of the cerebellar tonsils was noted in five (38%) of these 13 patients at the time of surgery. Of patients with symptomatic Chiari I malformations, the mean degree of tonsillar herniation was significantly less for those in whom cerebellar fits occurred than those in whom they were absent (8.8 mm and 13.9 mm, respectively; p = 0.007). In only one of the patients with cerebellar fits was a syrinx present, and this was a small focal lower thoracic collection. Spells resolved after surgery in all patients who presented with cerebellar fits.
Conclusions. Cerebellar fits may mimic other disorders such as cardiogenic syncope and epileptic seizures. The correct diagnosis may be delayed or the conditions may be misdiagnosed by those who fail to consider Chiari I malformation as a cause of drop attacks, abnormal extensor posturing, and apneic spells in children. The response to decompressive surgery in these patients is gratifying.
The Chiari I malformation is characterized by downward displacement of the cerebellar tonsils through the foramen magnum into the cervical spinal canal. Clinical manifestations are variable and are usually related to direct compression of neural structures and/or disturbance of cerebrospinal fluid circulation. The most common presenting symptom in patients with Chiari I malformation is pain, and the presenting signs are diverse and are usually related to brainstem or cranial nerve dysfunction, spinal cord dysfunction, or cerebellar dysfunction. With the widespread use of MR imaging, asymptomatic Chiari I malformation is being diagnosed with increased frequency.
Occasionally patients with Chiari I malformation present with fulminating symptoms. The present report concerns a group of children with Chiari I malformation who presented with drop attacks, extensor posturing, or varying degrees of respiratory compromise. This presentation bears similarity to the "cerebellar fits" first described by Jackson in 1871 and reported by him and others to occur as the result of mass effect from cerebellar tumors. Patients with Chiari I malformation by definition have chronic cerebellar tonsillar herniation, and fulminating presentations presumably reflect medullary compression as the result of crowding at the craniovertebral junction.
The relationship between cerebellar fits and Chiari I malformation has not been systematically investigated. In reviewing our series of pediatric patients with Chiari I malformation, we were surprised by the frequency of drop attacks as a presenting sign. The diagnosis of Chiari I malformation had often been overlooked in the initial evaluation, and children had frequently undergone EEG, ECG, and Holter monitoring for the detection of epileptic seizures or cardiogenic syncope. The purpose of the present study was to analyze the clinical and radiographic findings in a population of children presenting with cerebellar fits and Chiari I malformation and to discuss the outcome following decompressive surgery.
Object. The authors describe a series of children with Chiari I malformation who presented with fulminating symptoms of "cerebellar fits" characterized by drop attacks with or without deterioration of consciousness, opisthotonic posturing, and varying degrees of respiratory compromise.
Methods. A retrospective analysis was undertaken of the medical records of 47 consecutive patients undergoing surgery for symptomatic Chiari I malformations at Rainbow Babies and Children's Hospital.
Thirteen (28%) of the 47 patients presented with complaints consistent with cerebellar fits. Before the correct diagnosis was made, nine (69%) of the 13 children had previously undergone evaluation with electroencephalography and/or electrocardicography and Holter monitoring because of suspected cortical epilepsy or cardiogenic syncope. In each of the 13 children magnetic resonance imaging demonstrated pegged cerebellar tonsils herniated below the foramen magnum. A deep indentation or blanched discoloration of the cerebellar tonsils was noted in five (38%) of these 13 patients at the time of surgery. Of patients with symptomatic Chiari I malformations, the mean degree of tonsillar herniation was significantly less for those in whom cerebellar fits occurred than those in whom they were absent (8.8 mm and 13.9 mm, respectively; p = 0.007). In only one of the patients with cerebellar fits was a syrinx present, and this was a small focal lower thoracic collection. Spells resolved after surgery in all patients who presented with cerebellar fits.
Conclusions. Cerebellar fits may mimic other disorders such as cardiogenic syncope and epileptic seizures. The correct diagnosis may be delayed or the conditions may be misdiagnosed by those who fail to consider Chiari I malformation as a cause of drop attacks, abnormal extensor posturing, and apneic spells in children. The response to decompressive surgery in these patients is gratifying.
The Chiari I malformation is characterized by downward displacement of the cerebellar tonsils through the foramen magnum into the cervical spinal canal. Clinical manifestations are variable and are usually related to direct compression of neural structures and/or disturbance of cerebrospinal fluid circulation. The most common presenting symptom in patients with Chiari I malformation is pain, and the presenting signs are diverse and are usually related to brainstem or cranial nerve dysfunction, spinal cord dysfunction, or cerebellar dysfunction. With the widespread use of MR imaging, asymptomatic Chiari I malformation is being diagnosed with increased frequency.
Occasionally patients with Chiari I malformation present with fulminating symptoms. The present report concerns a group of children with Chiari I malformation who presented with drop attacks, extensor posturing, or varying degrees of respiratory compromise. This presentation bears similarity to the "cerebellar fits" first described by Jackson in 1871 and reported by him and others to occur as the result of mass effect from cerebellar tumors. Patients with Chiari I malformation by definition have chronic cerebellar tonsillar herniation, and fulminating presentations presumably reflect medullary compression as the result of crowding at the craniovertebral junction.
The relationship between cerebellar fits and Chiari I malformation has not been systematically investigated. In reviewing our series of pediatric patients with Chiari I malformation, we were surprised by the frequency of drop attacks as a presenting sign. The diagnosis of Chiari I malformation had often been overlooked in the initial evaluation, and children had frequently undergone EEG, ECG, and Holter monitoring for the detection of epileptic seizures or cardiogenic syncope. The purpose of the present study was to analyze the clinical and radiographic findings in a population of children presenting with cerebellar fits and Chiari I malformation and to discuss the outcome following decompressive surgery.
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