Chiari I malformation and syringomyelia may be associated with a wide spectrum of symptoms and signs in children. Clinical presentations vary based on patient age and relative frequency; some diagnoses represent incidental radiographic findings. Occipitocervical pain, propagated or intensified by Valsalva maneuvers (or generalized irritability in younger patients unable to communicate verbally), and syringomyelia with or without scoliosis are the most common clinical presentations. Cranial nerve or brainstem dysfunction also may be observed in younger patients, and is associated with more complex deformity that includes ventral compression secondary to basilar invagination, retroflexion of the dens, and/or craniocervical instability.
Key points
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Chiari I malformation (CM1) may present with varying symptoms depending on patient age, or may represent an incidental finding in asymptomatic patients.
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The most common clinical presentations of CM1 in children involve occipital headache or posterior cervical pain, syringomyelia, and/or scoliosis.
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The constellation of symptoms and signs in CM1 relate to brainstem or cervical spinal cord compression, lower cranial nerve dysfunction, and/or syringomyelia.
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Clinical examination signs in children with CM1 may include sensorimotor deficits, lower cranial nerve deficits, or signs of medullary dysfunction.
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In rare circumstances, children with CM1 may present with acute onset or rapidly progressive findings warranting urgent surgical consideration.
Introduction
Chiari I malformation (CM1) refers to abnormal cerebellar tonsillar descent below the foramen magnum, typically at least 5 mm below this level for a qualifying diagnosis. This form of hindbrain herniation may present with commonly recognized or rarely reported clinical symptoms, and also may be found incidentally. The frequency of radiographic findings consistent with CM1 among children undergoing brain and/or spine imaging for any indication has been estimated to be as high as 3% to 4%. Symptoms from CM1 generally exhibit the following characteristics :
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Clinical presentation (symptoms, signs) vary with respect to age; and
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Younger patients tend to present sooner, with shorter symptom duration, than adult patients.
As described more thoroughly in this article, tonsillar impaction within the foramen magnum causes compression of the cervicomedullary junction. The resulting compression and abnormal cerebrospinal fluid flow dynamics across the craniocervical junction result in a differential pressure gradient. Thus, the clinical presentation of CM1 in children may reflect a constellation of symptoms resulting from compression at the cervicomedullary junction and those related to syringomyelia and scoliosis. However, as with many neurosurgical conditions based partly on radiographic findings, CM1 may be discovered incidentally within asymptomatic patients or patients evaluated for nonspecific symptoms like headache or dizziness. Approximately 15% to 37% of pediatric patients with radiographic evidence of inferior cerebellar tonsillar ectopia may be asymptomatic, based on large retrospective reviews. Additionally, patients may develop acquired tonsillar descent owing to other causes (posterior fossa mass, lumbar cerebrospinal fluid drainage/leakage, etc).
The most common clinical presentations of CM1 involve headaches and/or neck pain and scoliosis (most commonly levoscoliosis; Table 1 ). Headaches represent a significant component of the clinical presentation in 27% to 70% of children with symptomatic CM1. Classically, headaches in adolescents and adults demonstrate an occipitocervical location and are provoked or intensified by Valsalva-type maneuvers, with relatively ephemeral duration. Various functions or activities that induce a Valsalva-type response, consistent with childhood behavior, include :
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Sneezing, coughing;
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Laughing, screaming;
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Defecation; and
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Running, repetitive jumping.
| Clinical Sign or Symptom | Reported Prevalence in Pediatric CM1 Population a |
|---|---|
| Headache, neck pain | 27%–70% |
| Scoliosis | 18%–50% |
| 6%–17% |
| Irritability (typically younger patients) | 12% |
| 4%–15% |
| Sleep apnea or bradycardia | 4%–13% |
| 6% |
| Frequent emesis | 1%–10% |
| Ataxia or gait impairment, decreased coordination | 4%–9% |
| Dysesthetic pain in C2 dermatomal distribution | 7% |
| Facial numbness (trigeminal nerve sensory deficits) | 7% |
| Auditory symptoms (tinnitus, hearing loss) | 2% |
| Respiratory difficulty, dyspnea, stridor | 1%–2% |
| Not reported |
a Prevalence estimates are based on frequencies reported in peer-reviewed publications, and likely represent upper estimates in most cases.
Younger patients (neonates, infants, toddlers) often may fail to demonstrate or adequately communicate these classic headache descriptors.
Characterized objectively by Cobb angles, scoliosis demonstrates strong association with syringomyelia in CM1. In general, the following rules apply :
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Most (but not all) pediatric CM1 patients with scoliosis have underlying syringomyelia; and
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Not all CM1 patients with syringomyelia have scoliosis.
Syringomyelia in CM1 demonstrates predilection for the following regions :
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Cervical spinal cord (15%–21%),
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Cervicothoracic spinal cord (12%–25%);
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Thoracic spinal cord (15%–16%);
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Lumbar spinal cord (3%–4%); and
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Holocord (39%–44%).
Less common but concerning symptoms of CM1 include those related to brainstem or upper cervical spinal cord compression. Medullary compression may adversely impact respiratory function and lead to sleep apnea, whereas similar brainstem or cervical spinal cord compression may cause sensorimotor deficits (hemiparesis, upper extremity paraparesis, quadriparesis), spasticity, or bladder dysfunction. Additionally, lower cranial nerve deficits may present in up to 10% of pediatric patients with CM1, causing dysphagia, absent gag reflex, dysarthria, vocal cord dysfunction, or abnormal extraocular motility (eg, esotropia owing to cranial nerve VI paresis). These symptoms occur with less frequency in the modern era likely owing to the advent of MRI offering earlier diagnosis, before neurologic disability occurs. Medullary compression symptoms are also seen more commonly in children with complex CM1 that includes basilar invagination and/or instability with ventral compression of the cervicomedullary junction. Up to 10% of patients with CM1 may also present with hydrocephalus owing to fourth ventricular outlet obstruction.
Introduction
Chiari I malformation (CM1) refers to abnormal cerebellar tonsillar descent below the foramen magnum, typically at least 5 mm below this level for a qualifying diagnosis. This form of hindbrain herniation may present with commonly recognized or rarely reported clinical symptoms, and also may be found incidentally. The frequency of radiographic findings consistent with CM1 among children undergoing brain and/or spine imaging for any indication has been estimated to be as high as 3% to 4%. Symptoms from CM1 generally exhibit the following characteristics :
- •
Clinical presentation (symptoms, signs) vary with respect to age; and
- •
Younger patients tend to present sooner, with shorter symptom duration, than adult patients.
As described more thoroughly in this article, tonsillar impaction within the foramen magnum causes compression of the cervicomedullary junction. The resulting compression and abnormal cerebrospinal fluid flow dynamics across the craniocervical junction result in a differential pressure gradient. Thus, the clinical presentation of CM1 in children may reflect a constellation of symptoms resulting from compression at the cervicomedullary junction and those related to syringomyelia and scoliosis. However, as with many neurosurgical conditions based partly on radiographic findings, CM1 may be discovered incidentally within asymptomatic patients or patients evaluated for nonspecific symptoms like headache or dizziness. Approximately 15% to 37% of pediatric patients with radiographic evidence of inferior cerebellar tonsillar ectopia may be asymptomatic, based on large retrospective reviews. Additionally, patients may develop acquired tonsillar descent owing to other causes (posterior fossa mass, lumbar cerebrospinal fluid drainage/leakage, etc).
The most common clinical presentations of CM1 involve headaches and/or neck pain and scoliosis (most commonly levoscoliosis; Table 1 ). Headaches represent a significant component of the clinical presentation in 27% to 70% of children with symptomatic CM1. Classically, headaches in adolescents and adults demonstrate an occipitocervical location and are provoked or intensified by Valsalva-type maneuvers, with relatively ephemeral duration. Various functions or activities that induce a Valsalva-type response, consistent with childhood behavior, include :
- •
Sneezing, coughing;
- •
Laughing, screaming;
- •
Defecation; and
- •
Running, repetitive jumping.
Related posts:
Definitions and Anatomic Considerations in Chiari I Malformation and Associated Syringomyelia
Pathogenesis and Cerebrospinal Fluid Hydrodynamics of the Chiari I Malformation
Prevalence of Chiari I Malformation and Syringomyelia
Surgical History of Sleep Apnea in Pediatric Patients with Chiari Type 1 Malformation
Craniovertebral Junction Instability in the Setting of Chiari I Malformation
Complex Chiari Malformations in Children
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