Moderate to High Levels of Neurofilament Light in Two Patients with HaNDL

Acute confusional state in HaNDL syndrome

OBJECTIVE

To assess epidemiological, clinical and neuroimaging features of acute confusional state in the Headache and Neurological Deficits with cerebrospinal fluid Lymphocytosis (HaNDL) syndrome.

BACKGROUND

HaNDL is an increasingly recognized syndrome in which migraine-like headache episodes accompanied by hemiparaesthesia and/or hemiparesis and/or dysphasia are associated to CSF lymphocytic pleocytosis. The International Classification of Headache Disorders (ICHD-3) includes HaNDL syndrome in group 7 "headache attributed to non-vascular intracranial disorder" code 7.3.5, and lists the HaNDL-associated signs/symptoms that may be found less frequently. Confusional state is not mentioned in the 7.3.5-ICHD-3 "notes" or "comments" section as part of the HaNDL neurological spectrum. Moreover, the acute confusional state pathogenesis in HaNDL syndrome remains still uncertain and debated.

METHODS

Here, we report a 32-year-old male who complained episodes of migraine-like headache and left hemiparaesthesia complicated by confusional state which led to discovering CSF lymphocytosis. Since other workup to determine the cause of his symptoms was otherwise negative, he was diagnosed as having HaNDL syndrome. We also ascertained and reviewed all available reports of HaNDL to assess the significance of confusional state in this syndrome.

RESULTS

The search yielded 159 HaNDL cases among single reports and small/large series. Out of 159 patients who fulfilled the inclusion criteria for HaNDL according to the current ICHD at the time of diagnosis, 41 (25.7%) presented with acute confusional state. Among 41 HaNDL patients with confusional state, 16 (66.6%) out of 24 who underwent spinal tap had increased opening pressure.

CONCLUSION

We propose that a mention of acute confusional state may be included in the "comments" section of "7.3.5-syndrome of transient headache and neurological deficits with cerebrospinal fluid lymphocytosis (HaNDL)," when ICHD-3 diagnostic criteria will be updated. Moreover, we speculate that intracranial hypertension may play a role in the pathogenesis of the acute confusional state associated to HaNDL syndrome. Larger case series are needed to evaluate this hypothesis.

A Case of HaNDL with Low Cerebrospinal Fluid Level of Neurofilament Light Chain

Diagnosis of the syndrome of headache and neurological deficits with cerebrospinal fluid (CSF) lymphocytosis (HaNDL) is based on clinical features, and no diagnostic biomarkers are available. We present a case presenting with characteristic features of HaNDL and an MRI lesion in the splenium of corpus callosum. CSF neurofilament light chain (NFL) levels were assessed in this patient together with 7 additional HaNDL patients, 18 multiple sclerosis (MS) patients, and 15 primary headache patients. Both HaNDL and primary headache patients showed significantly lower NFL levels than MS patients. Our results suggest that increased CSF levels of NFL and neuroaxonal loss are not characteristic features of HaNDL. Neurological disorders mimicking HaNDL often present with increased levels of NFL, and thus CSF measurement of NFL might be useful in differential diagnosis of HaNDL.