Evidence of Spinal Cord Damage in Human T Cell Lymphotropic Virus Type 1-Infected Subjects Without Motor Disability

Area of Science:

• Neurology
• Infectious Diseases
• Medical Imaging

Background:

• Human T cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy (HAM) is linked to spinal cord (SC) narrowing.
• It is unclear if central nervous system damage occurs in individuals with lower urinary tract symptoms (LUTSs) and probable HAM without motor deficits.

Purpose of the Study:

• To assess the utility of magnetic resonance imaging (MRI) with tractography in identifying SC abnormalities in HTLV-1-infected individuals presenting with LUTSs.

Main Methods:

• MRI with diffusion tensor imaging and tractography was used on patients with probable HAM (n=39), HTLV-1 carriers (HCs; n=41), and seronegative (SN) controls (n=12).
• Regions of interest were placed at T5 and T12-L1 to measure SC area, mean diffusivity, and fractional anisotropy (FA).

Main Results:

• Lumbar SC area was significantly smaller in probable HAM patients compared to HCs and SN controls.
• Median FA in the lumbar SC region was significantly lower in probable HAM patients.
• Thoracic SC area also showed a significant difference between groups, being smallest in probable HAM patients.

Conclusions:

• The study demonstrates SC narrowing in the lumbar region of patients with probable HAM, even in the absence of motor disability.
• MRI with tractography can detect SC abnormalities in HTLV-1-infected individuals with LUTSs and probable HAM.
• Urinary dysfunction is a key indicator of neurological involvement in probable HAM.