Simple whiplash?

We describe a case of type-I Arnold-Chiari malformation in a 27-year-old woman who presented on two separate occasions with an apparent whiplash injury. She developed debilitating symptoms after two apparently low velocity vehicle collisions. MRI revealed a type-I Arnold-Chiari malformation. She was referred for consideration of neurosurgical decompression. Type-I Arnold-Chiari malformation is the downward herniation of the cerebellar tonsils through the foramen magnum. It is usually asymptomatic but may present after apparently insignificant trauma with a wide range of possible symptoms. The protean nature of its presentation and the similarity of the symptoms to those of a whiplash injury mean that it is easily overlooked. It is, however, important that it is detected early.