Chiari (kee-AR-ee) malformation (CM) includes a complex group of disorders characterized by herniation of the cerebellum through the large opening in the base of the skull (foramen magnum) into the spinal canal. The herniated tissue blocks the circulation of cerebrospinal fluid in the brain and can lead to the formation of a cavity (syrinx) within the spinal cord. There are three main types of CM. CM1, the simplest and most prevalent form, is generally considered to be a congenital malformation, although acquired cases are recognized. (See diagrams below.) It is rarely apparent at birth. CM2 and CM3 are more severe congenital malformations that are apparent at birth and associated with complex defects of the brain and spinal cord.
Patients with CM1 may experience no symptoms. When symptoms are present, they usually do not appear until adolescence or early adulthood, but can occasionally be seen in young children. The majority of patients complain of severe headache and neck pain. Other common symptoms are dizziness, vertigo, disequilibrium, visual disturbances, ringing in the ears, difficulty swallowing, palpitations, sleep apnea, muscle weakness, impaired fine motor skills, chronic fatigue and painful tingling of the hands and feet. Because of this complex symptomatology, patients with CM1 are frequently misdiagnosed.
With the development of the Hypothlamic Hamartoma Center by Dr. Harold Rekate in 2012, treatment for this rare disorder is now available. The hypothalamus is located at the base of the brain and controls many of the basic functions of life such as hunger, aggression, sexual drive, growth, hormonal development and body temperature. Hypothlamic hamartoma is a birth defect that results in rare tumors in a critical part of the brain directly above the optic nerves. These benign (non-cancerous) masses form in the third ventricle (fluid-filled cavity) at the base of the skull during the first months of embryonic development.
Classic symptoms of hypothalamic hamartoma include involuntary gelastic (laughing) seizures, precocious puberty, behavioral issues with episodes of severe rage, aggression and irritability and cognitive dysfunction.
Treatment for hypothalamic hamartoma includes:
- Open surgical removal of the mass
- Neuroendoscopy, a minimally invasive procedure in which the mass is removed either through the nose or mouth, or through small holes in the skull
- Gamma knife radiosurgery, in which minuscule beams of radiation target the mass, leaving healthy surrounding tissue
- Laser ablation, a minimally invasive treatment in which the mass is eliminated through laser pulses.
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