Background

Human T lymphotropic virus type 1 (HTLV-1) is a preventable sexually transmittable infection. Although in the majority it is asymptomatic, when it does manifest it causes significant morbidity and mortality. The association of HTLV-1 infection with myelopathy was described in Martinique in 1985 and Japan in 1986 (HTLV-1-associated myelopathy, HAM).1 2 HAM is characterised by slowly progressing weakness and/or spasticity of the lower limbs, bladder, bowel and sexual dysfunction, and pain. ‘Rapid progression’, arbitrarily defined as inability to walk within 2 years of the first symptoms, occurs occasionally.3 4 A 16% reduction in HAM cases in Japan 2 years after the introduction of blood donor HTLV-1 screening suggests that the interval between infection and the disease can be relatively short.5 This interval in non-iatrogenic infection is usually unknown. We describe rapid onset and rapid progression of HAM following sexually acquired HTLV-1 infection in a patient in whom the window of infection is determined, emphasising the rate and severity of disease that may follow this infection. We argue HTLV-1 should no longer be an ignored STI.

Presentation

A previously fit, Caribbean woman developed influenza-like symptoms, backache and lower limb numbness. Five weeks later numbness was ascending to the trunk with dual sphincter involvement. Mobility reduced over the next 2 weeks. Approximately 14 weeks after the first symptoms, she could no longer climb stairs without assistance, and 4 weeks later she was unable to walk due to spastic paraparesis. She had urinary hesitancy and retention as well as constipation. There followed a prolonged inpatient admission.

Investigations

Magnetic resonance scanning showed oedematous cord and extensive signal change from C2 to T10 with patchy enhancement. Cerebrospinal fluid (CSF) contained 0.106 x10⁹/L lymphocytes and 0.01 x10⁹/L polymorphs, a raised protein of 0.66 g/L, normal glucose (CSF glucose 3.3 mmol/L and blood glucose 6.1 mmol/L) and oligoclonal bands. PCR failed to amplify enteroviruses, varicella zoster virus and herpes simplex virus 1 and 2, while HIV, veneral disease research laboratory test (VDRL), antiaquaporin 4 and autoantibody (antinuclear antibodies, double-stranded DNA antibodies, extractable nuclear antigens, antineutrophil cytoplasmic antibodies, cardiolipin antibody, lupus screen) serology and tests for Borrelia, Brucella, Rickettsia, Flavivirus, Alphavirus and Phlebovirus were negative. Serum B₁₂, folate, ferritin, ACE, thyroid-stimulating hormone, immunoglobulins and electrophoresis were unremarkable. HTLV-1/2 antibodies were detected by enzyme immunoassay (sample/cut-off 145) and HTLV-1 infection confirmed by western blot, with antibodies to GD21, p19, p24 and rgp46-1 all strongly positive. Despite high-dose corticosteroids HTLV-1 proviral load was 0.3% in peripheral blood mononuclear cells and 16.2% in CSF, supporting the diagnosis of HAM.

All UK blood donors have been HTLV-1-screened since 2002. As the patient reported a donation 5 months prior to the onset of symptoms, the result was obtained from National Health Service Blood and Transplant. This, and another donation, tested negative for anti-HTLV-1 antibodies at the time of donation and on retest of the archived sera. The patient’s mother tested negative for HTLV-1, but her partner of 2 years tested positive. Sexual intercourse was reported to have taken place once during this period (due to the partner’s ill health).