LAUSR

Background Transient lesions in the splenium of the corpus callosum have been identified in many clinical cases, and often correspond to a metabolic insult to the brain. The syndrome of transient headache and neurological deficits with cerebrospinal fluid lymphocytosis (HaNDL syndrome) is a rare but under-recognised headache syndrome. Case A 47-year-old man presented to our hospital with a 2-week history of intermittent headache, and acute right sided hemisensory deficit. A CSF lymphocytosis was found and a diagnosis of HaNDL was made. A lesion in the splenium of the corpus callosum was identified on MRI. CSF lymphocytosis and the splenial lesion resolved on follow up 4 weeks later. Conclusion These two entities are uncommon but increasingly recognised. The co-incidence in this patient raises the possibility of similar underlying pathological mechanisms, including vasomotor changes in blood vessels, cortical spreading depression and glutamate excitotoxicity leading to intra-myelinic oedema. Awareness of these entities will allow prompt diagnosis, preventing unnecessary tests and treatment, and allow appropriate patient management.