Cerebellar ectopia is a brain condition where the lobes at the base of the cerebellum, known as the cerebellar tonsils, push through the hole at the base of the skull. This structure, called the foramen magnum, is designed to accommodate the base of the brain stem and spinal cord. When the cerebellar tonsils herniate through this opening, the patient can experience medical complications, which can vary in severity depending on the extent of the protrusion.
Severe herniation is known as a Chiari malformation, while cerebellar ectopia involves lesser protrusions that do not quite meet the guidelines for a Chiari diagnosis. Some patients may not experience symptoms until adulthood, while in other cases, neurological problems develop in infancy and may become more apparent with time. Treatment may be available through a neurosurgeon.
Patients with cerebellar ectopia sometimes have balance problems and may experience symptoms like headaches, blurred vision, and giddiness. Compression can occur along the cerebellum and brainstem and may create variable symptoms from patient to patient. These symptoms may grow worse over time in response to buildups of pressure.
A medical imaging study can show the position of the cerebellum and may reveal the telltale protrusion of the cerebellar tonsils through the foramen magnum. A radiologist can determine the extent of the condition to help a doctor arrive at an accurate diagnosis. In some cases, a wait-and-see approach may be advised, while in others, surgery can be considered as an option. During surgery, it may be possible to relieve pressure and make the patient more comfortable.
The origins of cerebellar ectopia are not well understood. The condition is congenital in nature and is progressive over the patient’s lifetime as the brain grows and shifts inside the skull, although in mild cases it may not be apparent until adolescence or adulthood. Medications can help with the management of cases primarily characterized by pain and discomfort, while more aggressive options might need to be considered if a patient experiences substantial hardship because of the condition.
Cerebellar ectopia support groups, as well as organizations dedicated to Chiari information, often have information for patients and families. This information can help people make informed decisions about their medical care. It may also connect patients with care providers and clinical trials who might provide a wider spectrum of treatment options than could be available through a neurologist who does not specifically focus on the management of this condition.