Chiari malformation
| Chiari | |
|---|---|
 |
|
| A sagittal FLAIR MRI scan, from a patient with an Arnold-Chiari malformation, demonstrating tonsillar herniation of 7 mm | |
| Classification and external resources | |
| Specialty | Neurosurgery |
| ICD-10 | Q07.0 |
| ICD-9-CM | 348.4,741.0 |
| OMIM | 207950 |
| DiseasesDB | 899 |
| eMedicine | article/1483583 |
| Patient UK | Arnold–Chiari malformation |
| MeSH | D001139 |
Chiari malformation, Type II is also known as Arnold–Chiari malformation after the surgeons that initially described it, is a malformation of the skull. It consists of a downward displacement of the cerebellar tonsils through the foramen magnum (the opening at the base of the skull), sometimes causing non-communicating hydrocephalus as a result of obstruction of cerebrospinal fluid (CSF) outflow. The cerebrospinal fluid outflow is caused by phase difference in outflow and influx of blood in the vasculature of the brain. It can cause headaches, difficulty focusing, concentrating, and thinking, as well as difficulty coping (with what most consider and experience as normal, everyday life), fatigue, muscle weakness, difficulty swallowing (sometimes accompanied by gagging), choking and vomiting, dizziness, nausea, tinnitus, impaired coordination, neck pain, unsteady gait (problems with balance), poor hand coordination (fine motor skills), numbness and tingling of the hands and feet, and speech problems (such as hoarseness).
Less often, people with Chiari malformation may experience ringing or buzzing in the ears (tinnitus), weakness, slow heart rhythm, or fast heart rhythm, curvature of the spine (scoliosis) related to spinal cord impairment, abnormal breathing, such as central sleep apnea, characterized by periods of breathing cessation during sleep, and, in severe cases, paralysis.
The blockage of cerebrospinal fluid (CSF) flow may also cause a syrinx to form, eventually leading to syringomyelia. Central cord symptoms such as hand weakness, dissociated sensory loss, and, in severe cases, paralysis may occur.
Syringomyelia is a chronic progressive degenerative disorder characterized by a fluid-filled cyst located in the spinal cord. Its symptoms include pain, weakness, numbness, and stiffness in the back, shoulders, arms or legs. Other symptoms include headaches, the inability to feel changes in the temperature, sweating, sexual dysfunction, and loss of bowel and bladder control. It is usually seen in the cervical region but can extend into the medulla oblongata and pons or it can reach downward into the thoracic or lumbar segments. Syringomyelia is often associated with Chiari malformation type I and is commonly seen between the C-4 and C-6 levels. The exact development of syringomyelia is unknown but many theories suggest that the herniated tonsils in Chiari malformation type I form a "plug" which does not allow an outlet of CSF from the brain to the spinal canal. Syringomyelia is present in 25% of patients with Chiari malformation.
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