Key words: HaNDL, cerebrospinal fluid lymphocytosis, inflammation, neurofilament light protein, EEG.

Here we describe two cases of HaNDL (Headache with Neurological Deficits and cerebrospinal fluid Lymphocytosis). A thirty year old man with episodes of headache with lateralizing symptoms and confusion and a 41 year old man with headache, aphasia and right hemiparesis. Symptoms resolved completely in both patients. Considerable cerebrospinal fluid lymphocytosis was present but no signs of CNS infection and MRIs of the brain were normal. Although the cause of HaNDL is unknown, it is thought to be triggered by a viral infection by some. The prognosis is excellent and symptoms normally resolve within 1-3 weeks. It is important to rule out more serious etiologies like stroke, subarachnoid hemorrhage or central nervous system infections.