Quantitative assessment of subclinical spasticity in human T-cell lymphotropic virus type I infection.
OBJECTIVE
To compare human T-cell lymphotrophic virus type I (HTLV-I) seropositive and seronegative women for symptoms and signs of spasticity.


BACKGROUND
Infection with HTLV-I causes tropical spastic paraparesis/ HTLV-I-associated myelopathy (TSP/HAM). Certain populations, including female commercial sex workers (FSW), are at increased risk of developing this infection. Fewer than 5% of HTLV-I-seropositive persons develop TSP/HAM, which is typically associated with spasticity.


METHODS
Cross-sectional study of 255 registered FSW in Callao, Perú, involving a questionnaire detailing demographics and neurologic symptoms, standard neurologic examination, quantitative assessment of spasticity (QSA) of muscle tone, and serologic testing for HTLV-I. Participants and examiners were blinded to serology results.


RESULTS
On the questionnaire and neurologic examination, none of the 32 HTLV-I-seropositive or 223 seronegative women had signs or symptoms of spasticity. However, mean values on QSA were significantly higher among seropositive women (27.1 Newton-meters/radian [N-m/r]) than among seronegative women (21.6 N-m/r, p = 0.01), indicating a subclinical increase in lower extremity tone. With values of QSA divided into tertiles, and the first tertile serving as the comparison group, the odds ratio for seropositivity was 1.4 (95% confidence interval [CI] 1.0 to 2.0) in the second and 3.1 (95% CI 2.2 to 4.3) in the third tertile, after adjusting for age and place of birth.


CONCLUSIONS
Although a standard neurologic evaluation could not distinguish between women with and without HTLV-I infection, QSA indicated significantly increased lower extremity tone in those with infection. Long-term follow-up will determine whether these subclinical findings in asymptomatic women progress to overt TSP/HAM.
Zunt
J R
JR
Department of Neurology, Center for AIDS and STD, University of Washington School of Medicine, Seattle, USA. jzunt@u.washington.edu
Alarcón
J O
JO
Montano
S
S
Longstreth
W T
WT
Price
R
R
Holmes
K K
KK
D000328:Adult; D005260:Female; D015490:HTLV-I Infections / Q000097:blood / Q000503:physiopathology*; D015368:Human T-lymphotropic virus 1 / Q000302:isolation & purification; D006801:Humans; D009128:Muscle Spasticity / Q000503:physiopathology*; D016017:Odds Ratio; D010568:Peru