Beyond Headache: HaNDL Syndrome Unveiled by Seizures. A Case Report
Barbara Malaga Espinoza1, Marcelo Bedoya Sommerkamp2, Jesús Medina Ranilla2, Victor Chau Rodríguez2, Alejandro Escalaya2, Jorge Burneo3
1Internal Medicine, The University of Texas Rio Grande Valley, 2Neurology, Universidad Peruana Cayetano Heredia, Alberto Hurtado Faculty of Medicine, 3Neurology, University of Western Ontario
Objective:
To describe an atypical presentation of Headache and Neurologic Deficits with cerebrospinal fluid Lymphocytosis syndrome (HaNDL), emphasizing the occurrence of seizures and neuropsychiatric symptoms, and to highlight diagnostic considerations in a complex clinical scenario.
Background:

HaNDL syndrome is a rare, self-limited disorder characterized by recurrent headaches, transient neurologic deficits, and cerebrospinal fluid (CSF) lymphocytosis. Typical manifestations include hemiparesis, hemiparesthesia, and aphasia. Seizures and behavioral changes are uncommon, posing a diagnostic challenge and often leading to extensive evaluation for infectious, autoimmune, or vascular etiologies. We report a case of a 35 year-old male patient with multiple episodes of headaches with a variety a focal neurological symptoms, including tonic-clonic seizures.

Design/Methods:

A 35-year-old man with a family history of migraine presented with recurrent episodes of severe headache accompanied by transient unilateral paresthesias, dysarthria, and later, confusion, agitation, and visual hallucinations. CSF analysis revealed lymphocytic pleocytosis with elevated protein and normal infectious and autoimmune studies. During hospitalization, he developed a bilateral tonic-clonic seizure with postictal focal weakness. Brain MRI and vascular imaging remained unremarkable; EEG demonstrated frontal intermittent rhythmic delta activity (FIRDA). Supportive management and discontinuation of empiric antivirals and antiepileptics were followed by clinical recovery. No further episodes occurred during 18 months of follow-up.

Results:
This case represents a rare HaNDL presentation involving seizures and neurobehavioral disturbances, expanding the clinical spectrum beyond classical focal deficits. The absence of structural lesions and transient EEG abnormalities support a diffuse cortical dysfunction rather than focal pathology. Only one previous case of HaNDL with seizures has been reported, underscoring its exceptional nature. Recognition of atypical features is essential to avoid misdiagnosis and unnecessary interventions.
Conclusions:

HaNDL syndrome should be considered in a patient with headaches, CSF lymphocytosis and unusual neurological findings (seizures, confusion, behavioral changes, abnormal EEG findings), when common and uncommon etiologies have been ruled out.

10.1212/WNL.0000000000216957
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