HaNDL syndrome: transient headache and neurological deficits with cerebrospinal fluid lymphocytosis

We report the case of a 54-year-old woman with multiple presentations to the emergency department with severe headache, transient variable neurological deficits and normal investigations aside from CSF lymphocytosis. This represents a rare but under-diagnosed condition, transient headache and neurological deficits with cerebrospinal fluid lymphocytosis (HaNDL) syndrome. HaNDL is an important differential diagnosis for headache. We summarise the current knowledge about its clinical course, diagnosis and typical investigation findings.