Longitudinally Extensive Transverse Myelitis in Autoimmune Connective Tissue Diseases: A Comprehensive Review

Longitudinally extensive transverse myelitis (LETM) is a severe inflammatory disorder of the spinal cord characterised by lesions extending across three or more vertebral segments and is associated with significant neurological morbidity. Autoimmune connective tissue diseases constitute an important noninfectious cause of this entity, reflecting complex immune-mediated and vascular mechanisms that result in extensive spinal cord injury. Despite increasing recognition, clinical presentation is heterogeneous, diagnostic differentiation remains challenging, and management strategies lack standardisation. The objective of this review is to synthesise current evidence on LETM occurring in the context of autoimmune connective tissue diseases, with emphasis on epidemiology, immunopathogenesis, clinical features, diagnostic evaluation, therapeutic approaches, and prognostic factors. A narrative literature search was conducted in PubMed/MEDLINE, Scopus, Web of Science, and Google Scholar covering studies published between 2000 and 2025 using predefined keywords related to LETM and autoimmune connective tissue diseases. Relevant studies were selected based on predefined thematic relevance and were narratively synthesised across clinical, radiological, laboratory, and therapeutic domains. The review highlights systemic lupus erythematosus as the most frequently associated disease, followed by Sjögren's syndrome, systemic sclerosis, overlap syndromes, and antiphospholipid syndrome. Neuroimaging and serological evaluation play central roles in diagnosis, and early aggressive immunotherapy is consistently associated with improved neurological outcomes. LETM represents a rare but high-impact neurological manifestation of autoimmune connective tissue diseases. Improved awareness, timely diagnosis, and integrated multidisciplinary management are essential to optimise outcomes and reduce long-term disability.