Case of syndrome of headache with neurological deficits and cerebrospinal fluid lymphocytosis (HaNDL) with focal slowing on electroencephalogram

We describe a case of headache and neurological deficits with cerebrospinal fluid (CSF) lymphocytosis in a patient presenting with a 3-week history of recurrent severe headaches associated with negative sensory symptoms and dysphasia. The patient had no cardiovascular risk factors and no family history of migraines. Neurological examination was unremarkable. Cerebral magnetic resonance imaging was unremarkable. CSF analysis revealed lymphocytosis (leucocytes 84 × 10⁶/L, 100% lymphocytes). Extensive laboratory investigations of CSF and serum did not reveal an infectious, autoimmune or metabolic cause. Visual evoked potentials were normal. Awake electroencephalogram revealed intermittent 3-5Hz generalised slowing and frontal intermittent rhythmic delta activity, without epileptiform discharges. Repeat CSF analysis showed marked reduction of the total leucocyte count and remained negative for infectious aetiology. Propranolol was commenced, and no recurrence of headache or neurological symptoms was observed at follow-up. An extensive literature review on the topic is discussed.