Chiari Malformation and hEDS
Chiari I malformation is empirically more prevalent in individuals with hypermobile Ehlers-Danlos syndrome (hEDS) than in the general population. It involves the downward displacement of the cerebellar tonsils through the foramen magnum at the base of the skull, potentially compressing the brainstem and disrupting cerebrospinal fluid (CSF) flow.
The Relationship Between hEDS and Chiari I
In hEDS, connective tissue laxity can lead to craniocervical instability (looseness at the joint between the skull and spine), allowing the cerebellar tonsils (lower part of the brain at the back) to descend and crowd the foramen magnum (the opening at the base of the skull where the spinal cord passes through).
Ligamentous laxity at the craniocervical junction and altered neuraxial biomechanics (changes in the movement and alignment of the brain, spine, and spinal cord) may contribute to the development or worsening of Chiari malformation.
Many individuals with hEDS and Chiari show features of cervical instability (looseness or excessive movement in the neck vertebrae), CSF flow (cerebrospinal fluid) disruption, or tethered cord syndrome (a condition where the spinal cord is abnormally attached, limiting its movement), further complicating diagnosis and treatment.
The presence of Chiari in hEDS may worsen functional impairment and complicate the management of coexisting comorbidities such as hearing loss, mitral valve prolapse (a heart valve that doesn’t close properly), and autonomic dysfunction (problems with the part of the nervous system that controls things like heart rate and blood pressure), all of which can lower activity tolerance.
Common Symptoms in hEDS with Chiari I
Symptoms frequently overlap with general hEDS symptoms, making diagnosis more complex.
Common signs include
Occipital headaches (pain at the back of the head), especially worsened by coughing, straining, or positional changes (Valsalva maneuvers)
Neck pain and stiffness
Dizziness, vertigo, and balance issues
Syncope (fainting), often linked to dysautonomia
Neurological deficits (numbness, tingling, weakness, blurred vision)
Fatigue and headache that may be misattributed to hEDS alone
These symptoms can be mistaken for migraines, postural orthostatic tachycardia syndrome (POTS), or tension headaches, and often flare with exertion or posture changes, reinforcing the need for individualized pacing strategies.
Diagnosis and Evaluation
MRI of the brain and cervical spine is the standard imaging tool to assess cerebellar tonsil descent and evaluate CSF flow.
Cine MRI studies may be used to visualize dynamic CSF flow and guide treatment decisions.
Evaluation should include screening for craniocervical instability, tethered cord, or syringomyelia—a fluid-filled cyst within the spinal cord—when symptoms are complex or severe.
Management Strategies
Management is typically multidisciplinary, involving neurology, neurosurgery, genetics (to identify underlying syndromes such as Marfan syndrome, which may involve cardiovascular issues), physical therapy, and pain specialists familiar with connective tissue disorders.
Risks of Misdiagnosis or Inadequate Management
Failure to identify and treat Chiari malformation in the context of hEDS may lead to
Ongoing or worsening neurological symptoms
Increased pain and disability
Reduced quality of life
Delayed access to supportive therapies or surgical intervention
The presence of Chiari necessitates customized pacing and energy management strategies, as overexertion or poor posture can worsen symptoms or delay recovery.
Summary
Chiari I malformation occurs more frequently in individuals with hEDS and is thought to result from connective tissue laxity and craniocervical instability. Symptoms often overlap with those of hEDS itself, including headaches, dizziness, and neurological complaints, and may be difficult to distinguish without targeted imaging. Management should be multidisciplinary and cautious, with conservative care as the first step and surgery reserved for severe cases. Due to the complexity and multisystem involvement in hEDS, individualized pacing and careful monitoring are essential for preserving function and quality of life.
