Arnold-Chiari malformation epidemiology and demographics

The prevalence of Arnold Chiari malformation is unknown since most of the cases are accidentally found. The mortality rate of Arnold Chiari malformation depends on the subtype but type 3 has the highest mortality rate as a result of respiratory failure in infancy. Arnold Chiari malformation commonly affects adolescence and adulthood, but also has been seen in younger children. There is no racial predilection to Arnold Chiari malformation.

• The prevalence of Arnold Chiari malformation is unknown since most of the cases are accidentally found.^[1]
• It is believed that approximate prevalence is 0.1 to 0.5 percent worldwide.

• The mortality rate of Arnold Chiari malformation depends on the subtype.
• Type 3 has the highest mortality rate as a result of respiratory failure in infancy.

• Arnold Chiari malformation commonly affects adolescence and adulthood, but also has been seen in younger children.

• There is no racial predilection to Arnold Chiari malformation.
• Arnold Chiari malformation usually presents with back pain in whites and lower extremity weakness in African-Americans.

• Women are more commonly affected by Arnold Chiari malformation than men. The women to men ratio is approximately 3 to 1.