Primary Lateral Sclerosis: An Overview.

Primary lateral sclerosis (PLS) is a rare neurodegenerative disorder which causes the selective deterioration of the upper motor neurons (UMNs), sparing the lower motor neuron (LMN) system. The clinical course is defined by a progressive motor disability due to muscle spasticity which typically involves lower extremities and bulbar muscles. Although classically considered a sporadic disease, some familiar cases and possible causative genes have been reported. Despite it having been recognized as a rare but distinct entity, whether it actually represents an extreme end of the motor neuron diseases continuum is still an open issue. The main knowledge gap is the lack of specific biomarkers to improve the clinical diagnostic accuracy. Indeed, the diagnostic imprecision, together with some uncertainty about overlap with UMN-predominant ALS and Hereditary Spastic Paraplegia (HSP), has become an obstacle to the development of specific therapeutic trials. In this study, we provided a comprehensive analysis of the existing literature, including neuropathological, clinical, neuroimaging, and neurophysiological features of the disease, and highlighting the controversies still unsolved in the differential diagnoses and the current diagnostic criteria. We also discussed the current knowledge gaps still present in both diagnostic and therapeutic fields when approaching this rare condition.

Bibrachial amyotrophy as a rare manifestation of intraspinal fluid collection: a case report and systematic review.

INTRODUCTION: Intraspinal cerebrospinal fluid (CSF) collection has been reported as a rare cause of lower motor neuron (LMN) disorder. We report a case of bibrachial diplegia associated with intraspinal CSF collection and perform a systematic literature review. PATIENT AND METHODS: A 52-year-old man developed a bibrachial amyotrophy over 6 years, confirmed by the presence of cervical subacute neurogenic changes at electromyography (EMG). Brain magnetic resonance imaging (MRI) revealed cerebral siderosis, while spine MRI showed a ventral longitudinal intraspinal fluid collection (VLISFC) from C2 to L2. No CSF leakage was localized at myelography; a conservative treatment was chosen. We searched for all published cases until 30th April 2023 and extrapolated data of 44 patients reported in 27 publications. RESULTS: We observed a male predominance, a younger disease onset compared to amyotrophic lateral sclerosis, and a quite long disease duration, highlighting a slow disease progression. LMN signs were more frequently bilateral, mostly involving C5-C6 myotomes. Around 61% of patients presented additional symptoms, but only three referred to a history of headache. Accordingly, CSF opening pressure was mostly normal. Spinal MRI revealed the presence of VLISFC and in some cases myelomalacia. EMG patterns displayed both chronic and subacute neurogenic change in the cervical region. The disease course mainly depended on the treatment choice, which was mostly represented by a surgical approach when a specific dural defect was detected by imaging. CONCLUSION: Bibrachial diplegia due to VLISFC can be a treatable cause of focal amyotrophy and presents some clinical and radiological "red flags" which cannot be missed by a clinical neurologist.