Wheels within wheels: multifocal autoimmune myelitis in a woman with Huntington’s disease

Abstract

Hungtington’s disease (HD) is an autosomal dominant inherited genetic/neurodegenerative disorder. Early clinical manifestation varies widely, including cognitive and behavioural abnormalities. In later stages, the full clinical picture of HD is not limited to choreiform movements, but may comprise various other symptoms and eventually imitate other neurologic disorders, e.g., rigidity in juvenile HD and even signs of motor neuron disease [1, 2]. Besides clinical examination and family history, if available, diagnosis consists of CAG repeats in the huntingtin gene, with CAG [ 39 certainly predicting HD. Despite current research efforts, the only available consensus surrogate marker for age of onset and disease progression, though limited in sensitivity, is the number of CAG repeats [3, 4]. A 47-year-old female patient was transferred to us from the psychiatric clinic for further clarification of dyskinesia and walking inability. She had previously been treated in an outpatient clinic after being found in her apartment in a cachectic and disoriented state unable to walk. She had been divorced for about 10 years and ever since without social contacts, accounting for the scarce medical and family history. After exclusion of apparent somatic deficits she had been referred to the psychiatric clinic suspecting a psychotic disorder, which was excluded, and she was referred to us. On admission she demonstrated a reduced cognitive performance, responding inadequately, and was unable to summarise her symptoms in an organised chronological order. On neurological examination she had mild distal choreiform hyperkinesias in the upper limbs and mild dysarthria, which in combination with behavioural abnormalities supported clinically manifest Huntington’s disease (HD). No further clinical HD signs were evident. Furthermore, she had severe spastic paraparesis [2/5 for the hip flexors on the Medical Research Council (MRC) scale] with brisk reflexes of the lower limbs and positive leftsided Babinski sign. No paresis or reflex abnormalities were present in the upper limbs. On genetic testing, 44 CAG repeats on one huntingtin allele and 17 on the other were detected. Total motor score on Unified Huntington’s Disease Rating Scale was 16 (range 0–124). As to the spastic paraparesis, external cranial MRI scans a week prior to admission had not revealed any abnormalities in terms of neuroinflammation, generalised or focal cortical/subcortical atrophy, or any neoplastic changes or neurovascular events. In addition, we performed electrophysiology (motor evoked potentials) showing prolonged central latencies (M. peroneus), cerebrospinal fluid (CSF) sampling demonstrating oligoclonal bands (OCB), and spinal MRI showing several increased T2-weighted signals in the cervical (C3/ 4, C6/7; Fig. 1a, b) and thoracic spine (Th2, Th4; Fig. 1c) with a gadolinium-enhancing lesion (C6/7; Fig. 1d). Further serological and CSF analyses excluded infectious, paraneoplastic or other autoimmune entities as neuromyelitis optica spectrum diseases (antibodies against A. Haghikia and B.F. Decard contributed equally to this case presentation.