Chiari Malformation and Ehlers-Danlos Syndrome (EDS)

Chiari Malformation Type I (CMI) is a structural abnormality affecting the brainstem and spinal canal that has been increasingly linked with Ehlers-Danlos Syndrome (EDS) and Hypermobility Spectrum Disorders (HSD). Chiari malformations occur when the cerebellum, the part of the brain at the back of the skull, descends through the foramen magnum (the opening at the base of the skull), resulting in compression of surrounding tissues and disrupted cerebrospinal fluid (CSF) flow. While Chiari can occur independently of other conditions, it is frequently seen in people with connective tissue disorders like EDS.

Understanding Chiari Malformation Type I (CMI)

In Chiari I, the brain tissue—specifically the cerebellar tonsils—descends at least 4mm into the spinal canal, leading to the compression of nerves, interference with the flow of cerebrospinal fluid (CSF), and often, various neurological symptoms. Symptoms of Chiari malformation can range from mild to severe and may include:

• Severe neck and head pain, often described as a sharp occipital headache
• Balance problems and dizziness
• Visual disturbances, such as blurred or double vision
• Loss of muscle strength, especially in the upper body
• Hypersensitivity to bright lights
• Loss of pain and temperature sensation in the upper torso and arms
• Spasticity and abnormal muscle contractions

In the context of EDS, Chiari malformations often occur in individuals with the hypermobile form of EDS (hEDS), where joint and tissue laxity, a hallmark of the condition, plays a significant role in exacerbating neurological symptoms.

The Connection Between EDS and Chiari Malformation

People with EDS, especially the hypermobile type, often exhibit weakened connective tissues, including the ligaments that support the skull and cervical spine. This weakness can contribute to a variety of craniocervical instabilities such as Chiari malformation and other related conditions like atlantoaxial instability and craniocervical instability (CCI). These conditions can further complicate the management of Chiari because the cervical spine’s ligaments, responsible for holding the head and neck in place, are prone to excessive stretching and instability​​.

In EDS, this connective tissue fragility may not only contribute to the development of Chiari but also make surgical treatment more challenging. Surgical interventions like posterior fossa decompression (a common procedure for Chiari I malformation) aim to relieve pressure at the base of the skull, but in EDS patients, the risks of complications—such as cerebrospinal fluid leaks—are higher due to the fragility of tissues​.

Symptoms and Impact on Quality of Life

The symptoms of Chiari in people with EDS can significantly impact daily functioning, often requiring careful, multidisciplinary management. One study found that individuals with EDS and Chiari malformation are more likely to present with symptoms earlier than the general population diagnosed with Chiari​. Additionally, the fluid obstruction in Chiari can lead to further complications, such as:

• Flattening of the pituitary gland, leading to hormonal changes.
• Syringomyelia, a condition where a fluid-filled cyst (syrinx) forms within the spinal cord, adding further to neurological impairments​.

Treatment and Management

Managing Chiari malformation in patients with EDS requires a nuanced approach due to the multisystem involvement of EDS. Surgery, when recommended, aims to alleviate symptoms by decompressing the cerebellum to restore the normal flow of cerebrospinal fluid and relieve pressure on the brain and spinal cord. However, not all patients with Chiari malformation require surgery, and some may experience symptom improvement with non-invasive interventions, such as physical therapy and pain management​​.

Non-surgical treatment options might include:

• Physical therapy to improve neck stability and manage pain.
• Medications to address chronic pain or manage specific symptoms such as headaches and dizziness.
• Lifestyle modifications, including avoiding activities that worsen symptoms, such as heavy lifting or sustained head tilting​​.

When surgery is necessary, a team approach involving neurosurgeons familiar with EDS and Chiari malformation is crucial to optimize outcomes and minimize risks. Post-surgery, ongoing care is needed to monitor for complications such as cerebrospinal fluid leaks and recurrent symptoms​​.

The Importance of Early Diagnosis

Timely diagnosis of Chiari malformation in patients with EDS is critical to improving their quality of life and preventing irreversible damage. Given that the neurological symptoms of Chiari can overlap with other complications of EDS, including dysautonomia and gastrointestinal issues​, comprehensive evaluations by specialists in neurology, rheumatology, and pain management are essential. Diagnostic imaging, such as MRI, plays a key role in identifying Chiari malformation and guiding treatment decisions​.

Conclusion

Chiari malformation is a challenging condition to manage in patients with EDS due to the connective tissue fragility inherent to the disorder. A multidisciplinary, individualized approach to care, often including both surgical and non-surgical strategies, is essential to ensure the best possible outcomes. As research into the link between Chiari and EDS progresses, it will provide more tailored treatment protocols for this unique patient population.

References

• Rock, Mitchell B et al. "Neurosurgical Management of Patients with Ehlers-Danlos Syndrome: A Descriptive Case Series." Journal of Craniovertebral Junction & Spine, vol. 14, no. 1, 2023, pp. 24-34. doi:10.4103/jcvjs.jcvjs_127_22
• Henderson Sr., FC, et al. "Neurological and Spinal Manifestations of the Ehlers-Danlos Syndromes." American Journal of Medical Genetics Part C: Seminars in Medical Genetics, vol. 175C, 2017, pp. 195–211. https://pubmed.ncbi.nlm.nih.gov/28220607/

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