An adolescent with pseudomigraine, transient headache, neurological deficits, and lymphocytic pleocytosis (HaNDL Syndrome): case report and review of the literature.

We report a 16-year-old adolescent with 2 episodes of focal neurological deficits, pseudomigrainous headache, and lymphocytic pleocytosis due to the syndrome of transient headache and neurological deficits with cerebrospinal fluid (CSF) lymphocytosis (HaNDL), also known as pseudomigraine with CSF pleocytosis. Review of the literature identifies 13 additional cases of HaNDL in the pediatric population. These cases are reviewed and evidence for possible etiopathogenesis is discussed. This syndrome may mimic much more common conditions such as complicated or hemiplegic migraine, aseptic meningitis, meningoencephalitis, or stroke. However, HaNDL differs from complicated or hemiplegic migraine and stroke since CSF pleocytosis is uniformly present. There are many infectious conditions that can present with neurological deficits, headache, and CSF pleocytosis, but the transient nature of the deficits and lack of a consistently identifiable infectious etiology despite extensive evaluations typify HaNDL. This clinical syndrome is underrecognized and underreported. HaNDL remains a diagnosis of exclusion.