Anti-Hu-associated brainstem encephalitis

Abstract

Objective: We review a series of patients with anti-Hu-associated brainstem encephalitis to better define the clinical presentation and to improve its recognition. Methods: We collected data from 14 patients diagnosed by members of the Paraneoplastic Neurological Syndromes Euronetwork, and eight patients from the literature who presented with isolated brainstem encephalitis and had antiHu antibodies. Results: The median age of the 22 patients was 64 years (range 42-83) and 50% were men. All patients developed a subacute neurological syndrome, in days or weeks. Brain MRI was always normal. Mild CSF pleocytosis was reported in only two patients. The following syndromes were identified on admission: A medullary syndrome was seen in 11 (50%) patients. Seven of them presented with dysphagia, dysarthria and central hypoventilation. The other four in addition of bulbar symptoms, without central hypoventilation, presented pontine manifestations. Six (27%) patients developed a pontine syndrome with paresis of the VI or VII cranial nerves, nystagmus, usually vertical, and gait ataxia. There was a rapid downward progression to the medulla in all patients. Five (23%) patients presented a ponto-mesencephalic syndrome with uni or bilateral palsy of the III and VI cranial nerves and gait ataxia, but rapidly progressed to complete gaze paresis and medullary dysfunction. Conclusions: The study confirms the predominant medullary involvement but also shows that half of the patients present with linical features that indicate an upper, mainly pontine, dysfunction before downward progression.