Resumo:
Introduction: The primary neurological manifestation of definitive HTLV-1-associated myelopathy (HAM) is spastic paraparesis, but it occurs in only 5% of patients. In contrast, approximately 40% of individuals infected with HTLV-1 present symptoms of urinary dysfunction, including nocturia, urgency, and incontinence, which may progress to an inability to urinate. Since these patients do not exhibit motor dysfunction, they are classified as probable HAM. Thoracic spinal cord (SC) atrophy is the main abnormality observed in magnetic resonance imaging (MRI) in patients with definitive HAM, but SC damage has not been reported in patients with probable HAM. Objective: To describe spinal cord features in individuals infected with HTLV-1 through magnetic resonance imaging (MRI). Methods: HTLV-1 infection was diagnosed by Western blot, and MRI was performed using a 1.5 Tesla scanner. Atrophy was defined when the SC area was less than 25% of the intrathecal area. Results: We observed a progressive reduction in all SC area segments among HTLV-1 carriers, patients with probable HAM, and definitive HAM. Notably, 48.3% of patients with probable HAM exhibited lumbar region atrophy. Conclusion: This study demonstrates, using MRI metrics, atrophy of the lumbar SC segments in patients presenting urinary symptoms associated with HTLV-1 but without motor dysfunction. Our findings suggest that spinal cord evaluation through MRI should be considered in clinical practice for the early monitoring of HTLV-1-infected patients, especially those with probable HAM. Early detection of SC atrophy may enable timely therapeutic interventions, potentially slowing disease progression and improving clinical outcomes. The impact of SC atrophy on functionality and quality of life highlights the need for more precise diagnosis and systematic follow-up.
