Acute paraparesis in HIV-infected patient after initiation of highly active antiretroviral therapy.

Neurological syndromes occur in around 40-70% of HIV-infected people. Direct central nervous system involvement by the virus usually manifests as HIV encephalitis, HIV leucoencephalopathy, vacuolar leucoencephalopathy or vacuolar myelopathy. Indirect involvement is usually associated with neurotropic opportunistic infections which include tuberculosis, toxoplasmosis, cryptococcosis and viral encephalitis such as herpes simplex, varicella-zoster, cytomegalovirus and Human polyomavirus 2. We report a case of transverse myelitis in a recently diagnosed HIV patient who was otherwise asymptomatic initially and developed paraparesis after 1 month of initiation of antiretroviral therapy. After ruling out opportunistic infections and other causes of compressive and non-compressive myelopathy, development of transverse myelitis was attributed to immune reconstitution inflammatory syndrome in view of baseline low CD4 count and their improvement after HAART initiation. Prompt treatment with corticosteroids successfully reversed the symptoms.

Delayed-onset paraparesis in Lassa fever: A case report.

Lassa fever (LF) is an endemic viral hemorrhagic fever in West Africa. Among the serious complications of the disease are neurological manifestations whose spectrum is incompletely known. Here we report the case of a 61-year-old man who developed a delayed-onset paraparesis a few weeks after getting infected with Lassa virus, thereby suggesting a possible association between LF and spinal cord disorders.

Acute myelitis associated with dengue infection.

OBJECTIVES: To present a rare neurological complication of dengue fever. PATIENTS AND METHODS: A 24-year-old female presented with acute myelitis seven days after dengue fever onset. RESULTS: The patient presented with intense fever. The day-7 examination revealed a paraparesis, T2 sensory level, and urinary retention. The patient complained of electric discharges in the four limbs. The sitting and standing positions were impossible. An MRI of the spinal cord performed on day 8 revealed diffuse medullar hyper intense lesions on T2-weighted sequences at the cervical and thoracic levels, with enhancement of the thoracic lesion after gadolinium injection. Laboratory tests revealed positive dengue antigen on day 5 and positive IgM/IgG on day 8. Treatment with intravenous pulse methylprednisolone was initiated. CONCLUSION: Dengue virus has not often been reported as a cause of myelitis. Physicians must be aware of this rare complication in patients living in or coming from endemic areas.

Cytomegalovirus infection with MRI signal abnormalities affecting the optic nerves, optic chiasm, and optic tracts.

A 49-year-old woman who had been immunosuppressed after a renal transplant developed bilateral severe visual loss. Visual acuities were finger counting and hand movements in the two eyes. Both optic nerves were pale. There were no other ophthalmic abnormalities. Brain MRI disclosed marked signal abnormalities involving the optic nerves, optic chiasm, and optic tracts. Cerebrospinal fluid polymerase chain reaction (PCR) was positive for cytomegalovirus. Treatment did not restore vision. Such extensive clinical and imaging involvement of the anterior visual pathway, which has been previously reported with other herpes viruses, illustrates the propensity for this family of viruses to track along axons.

Paraparesis in a polar bear (Ursus maritimus) associated with West Nile virus infection.

A polar bear (Ursus maritimus) housed at the Toronto Zoo presented with acute-onset, nonambulatory paraparesis. Physical examination 24 hr after onset was otherwise unremarkable, spinal radiographs looked normal, and blood tests indicated mild dehydration. With continued deterioration in its general condition, euthanasia was elected a day later. Necropsy did not reveal a cause for the major presenting clinical signs. Serum collected at the time of initial examination was positive for West Nile virus (WNV) antibodies in a serum neutralization assay and at the time of euthanasia was positive in both a competitive enzyme-linked immunosorbent assay and in a plaque reduction neutralization assay. The major microscopic finding was a mild-to-moderate nonsuppurative meningoencephalomyelitis. WNV was not detected by immunohistochemistry in brain or spinal cord or by real-time reverse transcription-polymerase chain reaction (RT-PCR) and cell culture of brain and kidney, but it was isolated and identified by RT-PCR in second passage cell culture of spleen. Retrospective immunohistochemistry on spleen revealed rare antigen-positive cells, probably macrophages. Prevention of exposure to potentially WNV-infected mosquitoes or vaccination of captive bears against WNV should be considered.

A patient with leg weakness.

The present case was typical in many respects for neuroinvasive WNV infection. The differential diagnosis considered was appropriately comprehensive. The present case also reminds us that little or no abnormalities will be seen on imaging in many cases, and that initial serology may be negative and should be repeated beyond the acute phase ante- or postmortem. Fortunately, specific antibodies are also now available for identification of viral proteins in tissue although sensitivity of the latter may be affected by the stage of infection and sampling of areas bearing a higher viral load. West Nile Virus, along with other emerging infections, serves notice of the health care implications of humanity's globalization of ecosystems.

Passage of human T-cell leukemia virus type-1 during progression to cutaneous T-cell lymphoma results in myelopathic disease in an HTLV-1 infection model.

Studies comparing functional differences in human T-cell leukemia virus type 1 (HTLV-1) clones that mediate distinct outcomes in experimentally infected rabbits, resulted in a dermatopathic smoldering adult T-cell leukemia/lymphoma following chronic infection with HTLV-1 strain RH/K34. During the 3.5 years' follow-up, HTLV-1 skin disease progressed to cutaneous T-cell lymphoma. When infection was passed to several naive rabbits, progressive paraparesis due to myelopathic neurodegeneration, analogous to HTLV-associated myelopathy, resulted in one of 4 transfusion recipients. Similar proviral loads were detected in the two diseases, regardless of stage of progression or tissue compartment of infection. Complete proviral sequences obtained from the donor and affected recipient aligned identically with each other and with the inoculated virus clone. Existence of disparate pathogenic outcomes following infectious transmission further extends the analogy of using rabbits to model human infection and disease. Although the experimental outcomes shown are limited by numbers of animals affected, they mimic the infrequency of HTLV-1 disease and authenticate epidemiological evidence of virus sequence stability regardless of disease phenotype. The findings suggest that further investigation of a possible role for HTLV-1 in some forms of cutaneous T-cell lymphoma is warranted.