Chiari malformation type 2

Chiari malformation type 2 usually occurs sporadically (in people with no family history of the condition). However, the exact cause is not known. Genes may play a role in predisposing a person to the condition, but environmental factors (such as lack of proper vitamins or nutrients in the maternal diet during pregnancy) may also contribute to the condition.

There have been reports in the medical literature of families in which more than one family member had a Chiari malformation. However, limited information specific to familial cases of Chiari malformation type 2 is available.

The long-term outlook depends on the nature of the malformation and the symptoms present in each person. Although some people experience a reduction of symptoms, there is no guarantee that surgery will help every person. Nerve damage that has already occurred usually cannot be reversed with surgery, and pain from nerve damage can be difficult to treat. Some people may need repeat surgeries.

People with Chiari malformation type II are typically treated with surgery. Surgery may include closure of open neural tube defects shortly after birth, treatment for hydrocephalus (most often by use of a shunt), and posterior fossa decompression (creating more space for the cerebellum and relieving pressure on the spinal cord). Medical issues may involve management of neurogenic bowel and bladder, neonatal feeding difficulties, respiratory failure, and apnea.

As with any form of surgery, there are risks associated with surgery to treat Chiari malformations. Sometimes, surgery leads to no improvement or even worsening of symptoms. For example, if nerve injury in the spinal canal has already occurred, surgery will not reverse the damage. However, most people who have surgery have improvement of symptoms afterwards. Even if symptoms do not improve significantly, surgery might prevent existing symptoms from worsening.