Spinal tract pathology in AIDS: postmortem MRI correlation with neuropathology

The neurological sequelae of pandemics and epidemics

Neurological manifestations in pandemics frequently cause short and long-term consequences which are frequently overlooked. Despite advances in the treatment of infectious diseases, nervous system involvement remains a challenge, with limited treatments often available. The under-recognition of neurological manifestations may lead to an increase in the burden of acute disease as well as secondary complications with long-term consequences. Nervous system infection or dysfunction during pandemics is common and its enduring consequences, especially among vulnerable populations, are frequently forgotten. An improved understanding the possible mechanisms of neurological damage during epidemics, and increased recognition of the possible manifestations is fundamental to bring insights when dealing with future outbreaks. To reverse this gap in knowledge, we reviewed all the pandemics, large and important epidemics of human history in which neurological manifestations are evident, and described the possible physiological processes that leads to the adverse sequelae caused or triggered by those pathogens.

Longitudinally extensive transverse myelitis and Hepatitis C-a case report and literature review

Tractopathy lesions in the spinal cord associated with HCV infection, which normalized on MRI after antiviral treatment, are described. These specific MRI findings can be used in the diagnosis and treatment of secondary causes of transverse myelitis.

HIV-associated neurocognitive disorder and HIV-associated myelopathy in a patient with a preserved CD4, but high viral load-a rarely reported phenomenon: a case report and literature review

BACKGROUND

Despite widespread use of combination antiretroviral therapy (cART), HIV-associated neurocognitive disorder (HAND) and HIV-associated myelopathy (HAM) are not showing significant reduction in there occurrence. The HAM is a progressive myelopathy that often occur synchronously with severe form of the HAND in patients' having advanced immunosuppression. However, co-existence of less severe form of the HAND and HAM in patient with relatively preserved CD4 cells is rarely reported clinical entity in post cART era.

CASE PRESENTATION

We report a 16-year old male, acquired HIV infection vertically, was on second line regimen because of virological failure since 3 years. His current CD4 lymphocyte count is 835 cells/uL with viral RNA level of 33,008 copies/mL. Currently presented with progressive forgetfulness, gait imbalance, and a frequent staring episodes without loss of postural tone. Neurological examination was pertinent for cognitive dysfunction with score of 6 on International HIV Dementia Scale (motor speed = 3, psychomotor speed = 2, and memory recall = 1). Lower limbs power is 4^-/5, increased deep tendon reflexes, and unsteady gait. Brain MRI revealed diffuse both cortical and white matter T2 and FLAIR hyperintense lesions. Thoracic MRI showed abnormal T2 signal prolongation spanning from mid thoracic cord to conus. Electroencephalography study showed severe generalized slowing with evidence of focal dysrhythmia in bilateral frontotemporal regions. Unremarkable serum vitamin B 12 level (286 ng/mL). Virological failure with the HAND, HAM and seizure was considered. Dolutegravir +3TC + ATV/r regimen and valproate for seizure disorder was started. On 6 months follow up evaluation, he is clinically stable with significant improvement of his symptoms related to seizure disorders and modest improvement of his cognitive dysfunction, as he is now attending his school regularly. However, less improvement was observed reading his gait abnormality.

CONCLUSION

This case supports the current understanding regarding the persistent occurrence of HIV-associated neurocognitive disorder and HIV-associated myelopathy even decades after introduction of cART. Therefore, it's important to screen HIV+ patients for the HAND and HAM even if they have relatively preserved immunity. Because patient can be easily shifted to ART drugs with better CNS penetrating potential to achieve acceptable virological suppression level, to observe sound clinical improvement.

HIV-Associated Vacuolar Myelopathy and HIV-Associated Dementia as the Initial Manifestation of HIV/AIDS

HIV-associated vacuolar myelopathy (HIV-VM) is the most common cause of spinal disease in HIV/AIDS. HIV-VM causes progressive spastic paraparesis, sensory ataxia, and autonomic dysfunction. It is a progressive myelopathy that shares features with subacute combined degeneration seen in vitamin B12 deficiency as well as other neurological diseases and can occur synchronously with HIV-associated dementia (HAD). Here, we describe a rare case in which a patient's initial presentation of HIV/AIDS was both HIV-VM and HAD. A fifty-three-year-old man presented with a six-month history of numerous falls due to progressive gait instability with associated memory loss, tremor, urinary retention, and impotence. His exam was significant for hyperreflexia and weakness in bilateral lower extremities, upgoing plantar reflex, dysmetria, and ataxic gait. MRI-brain was notable for nonspecific volume loss and diffusely increased T2 signal throughout the supratentorial white matter. Lumbar puncture showed isolated lymphocytic pleocytosis with all other CSF testing unremarkable. He ultimately tested positive for HIV-1, with a CD4 count of 157 cells/mm³ and a viral load of 874,000 copies/mL. He was diagnosed with HIV-VM and HAD which improved after several months of antiretroviral therapy. This case highlights the importance of considering HIV testing in a patient with a sensory neuropathy and/or progressive cognitive impairment.

Neuroinflammation and virus replication in the spinal cord of simian immunodeficiency virus-infected macaques

Studies of neurologic diseases induced by simian immunodeficiency virus (SIV) in Asian macaques have contributed greatly to the current understanding of human immunodeficiency virus pathogenesis in the brain and peripheral nervous system. Detailed investigations into SIV-induced alterations in the spinal cord, a critical sensorimotor relay point between the brain and the peripheral nervous system, have yet to be reported. In this study, lumbar spinal cords from SIV-infected pigtailed macaques were examined to quantify SIV replication and associated neuroinflammation. In untreated SIV-infected animals, there was a strong correlation between amount of SIV RNA in the spinal cord and expression of the macrophage marker CD68 and the key proinflammatory mediators tumor necrosis factor and CCL2. We also found a significant correlation between SIV-induced alterations in the spinal cord and the degree of distal epidermal nerve fiber loss among untreated animals. Spinal cord changes (including elevated glial fibrillary acidic protein immunostaining and enhanced CCL2 gene expression) also were present in SIV-infected antiretroviral drug-treated animals despite SIV suppression. A fuller understanding of the complex virus and host factor dynamics in the spinal cord during human immunodeficiency virus infection will be critical in the development of new treatments for human immunodeficiency virus-associated sensory neuropathies and studies aimed at eradicating the virus from the central nervous system.

MRI in transverse myelitis

Transverse myelitis is an acute inflammatory disease of the spinal cord, characterized by rapid onset of bilateral neurological symptoms. Weakness, sensory disturbance, and autonomic dysfunction evolve over hours or days, most progressing to maximal clinical severity within 10 days of onset. At maximal clinical severity, half will have a paraparesis, and almost all patients have sensory disturbance and bladder dysfunction. Residual disability is divided equally between severe, moderate and minimal or none. The causes of transverse myelitis are diverse; etiologies implicated include demyelinating conditions, collagen vascular disease, and parainfectious causes, however, despite extensive diagnostic work-up many cases are considered idiopathic. Due to heterogeneity in pathogenesis, and the similarity of its clinical presentation with those of various noninflammatory myelopathies, transverse myelitis has frequently been viewed as a diagnostic dilemma. However, as targeted therapies to optimize patient outcome develop, timely identification of the underlying etiology is becoming increasingly important. In this review, we describe the imaging and clinical features of idiopathic and disease-associated transverse myelitis and its major differentials, with discussion of how MR imaging features assist in the identification of various sub-types of transverse myelitis. We will also discuss the potential for advanced MR techniques to contribute to diagnosis and prognostication.

Spine MR imaging features of subacute combined degeneration patients

BACKGROUND AND PURPOSE

Subacute combined degeneration (SCD) is a potentially reversible neurological complication of a vitamin B12 deficiency; therefore, timely diagnosis and appropriate treatment are of great importance. The study was to evaluate the spine MR imaging features of SCD in a series of patients.

MATERIALS AND METHODS

Eight patients diagnosed with SCD from 2008 to 2010 comprised the study population. Spine MRIs were available for all eight patients, and three of them had follow-up MRIs after vitamin B12 treatment. Two radiologists evaluated the prevalence of signal intensity abnormality of spinal cord and analyzed the distribution and pattern of the signal change in consensus. And they also evaluated post-treatment MRI to find interval change.

RESULTS

Seven of eight patients showed abnormal hyperintensity within posterior aspect of spinal cord on T2-weighted images. The spinal cord abnormalities were seen at cervical spine in five patients (62.5 %) and at thoracic spine in the other two patients (25 %). For patients with cervical spinal cord abnormalities, axial T2-weighted images showed symmetric linear T2-hyperintensity as an "inverted V" at cervical spinal cord. For patients with thoracic spinal cord abnormalities, the abnormal signal intensity looked bilateral paired nodular T2-hyperintensity as "dumbbell" or "binoculars" at thoracic spinal cord. Follow-up MRIs after vitamin B12 treatment showed interval resolution of the areas of abnormal T2-hyperintensity in all.

CONCLUSION

Symmetric T2-hyperintensity within dorsal column of spinal cord is commonly seen in SCD patients with a linear pattern in the cervical spine and a nodular pattern in the thoracic spine.

Spinal MR imaging in Vitamin B12 deficiency: Case series; differential diagnosis of symmetrical posterior spinal cord lesions

We report three cases of Vitamin B12 deficiency with symmetrical posterior spinal cord lesions and discuss the differential diagnosis, some of which are not well known. Because the degree of resolution of the clinical symptoms in subacute combined degeneration depends on early detection, MRI findings should not be missed.

Neuroimaging in acute transverse myelitis

Transverse myelitis is an acute inflammatory condition. A relatively rare condition, the diversity of causes makes it an important diagnostic challenge. An approach to the classification and work-up standardizes diagnostic criteria and terminology to facilitate clinical research, and forms a useful tool in the clinical work-up for patients at presentation. Its pathogenesis can be grouped into four categories. Imaging appearances can be nonspecific; however, the morphology of cord involvement, enhancement pattern, and presence of coexistent abnormalities on MR imaging can provide clues as to the causes. Neuroimaging is important in identifying subgroups that may benefit from specific treatment.

Progressive vacuolar myelopathy and leukoencephalopathy in childhood acute lymphoblastic leukemia and transient improvement with vitamin B12

Vacuolar myelopathy (VM) in leukemia is rare. We report a boy with leukemia who developed isolated central nervous system (CNS) relapse during reinduction therapy. 5 months after cranial radiotherapy, he gradually developed quadriparesis. Magnetic resonance imaging revealed an intramedullary lesion which extended through the cervical spine. Serum vitamin B12, folic acid, cerebrospinal fluid methyl malonic acid were normal. Viral screening by ELISA was negative. He had lymphopenia, and reduced immunoglobulins, from a cardiac arrest. Biopsy revealed VM. He responded to weekly vitamin B12 treatment but on the 6th week of the therapy he died after developing periventricular, gliotic, hyperintense lesions in the brain.

Spinal cord pathology and viral burden in homosexuals and drug users with AIDS

Unless treated with effective antiretroviral therapy many AIDS patients develop a characteristic vacuolar myelopathy of the spinal cord associated with moderate clinical disability. Opinion is divided as to whether vacuolar myelopathy is causally linked to HIV myelitis. To investigate this further, spinal cord pathology was assessed in 41 drug users, 33 homosexual men and 16 other patients, all with AIDS. Previous work has shown that HIV encephalitis is more common in Edinburgh drug users than in homosexual men. In the present study HIV myelitis (10% overall) was more common in drug users (17%) than in homosexual men (3%) (P = 0.05), whereas the incidence of opportunistic infections (7% v. 9%) and lymphomas (2% v. 6%) was comparable in the two groups, but with a slight trend in the reverse direction, reflecting similar findings in the brain. However, moderate or severe vacuolar myelopathy was equally represented in both groups (20% of drug users and 21% of homosexual men). The HIV proviral load, assessed by polymerase chain reaction in frozen samples of thoracic spinal cord in 37 cases, correlated closely with the presence of giant cells and/or with immunocytochemical evidence of productive HIV infection. In 13 cases, the proviral load was measured in cervical, thoracic and lumbar samples and proved to be uniformly high or low in individual cases. This study provides no evidence for direct involvement of HIV, cytomegalovirus, papovavirus or human foamy virus in the pathogenesis of vacuolar myelopathy.

Direct detection of eae-positive bacteria in human and veterinary colorectal specimens by PCR

A PCR test based on the amplification of an eae-specific sequence was designed and evaluated for its ability to directly detect homologous sequences in enteropathogenic Escherichia coli and Citrobacter spp. (amplification of eae open reading frame, 178 bp) in sections of the intestines of humans and animals with colonic lesions. Positive PCR results were observed with eae-positive reference strains of E. coli and Citrobacter rodentium (Citrobacter freundii biotype 4280). Known eae-negative reference strains of E. coli and other laboratory strains of enteric bacteria were negative by the amplification test. The sensitivity of the PCR for detection of eae-positive E. coli and C. rodentium was between 1 and 2 CFU. To detect these sequences directly from sections of fixed colon from human and veterinary sources, PCR conditions were modified by the addition of 0.1 mM 8-methoxypsoralen to eliminate extraneous bacterial DNA from the PCR amplification cocktail without added template. Sections of colon from three pigs experimentally affected with colon lesions due to enteropathogenic (attaching and effacing) E. coli were PCR positive for bacterial eae genome. Sections from control animals were negative. Sections of colon from one of 18 biopsies from confirmed AIDS patients and from 22 of 35 colorectal cancer patients were PCR positive for bacterial eae genome. The PCR test was a simple and quick method of detecting bacterial eae genome in human and veterinary clinical specimens. This method may remove the need for initial culture and detection of the gene by DNA probing from potential associated lesions. The clear relationship of bacteria containing the eae gene with colonic lesions in the pigs and mice indicates that a similar relationship is possible for human patients having similar lesions.

AIDS-associated vacuolar myelopathy

AIDS-associated vacuolar myelopathy (VM) is a common neurologic complication of AIDS. Pathologically, VM is characterized by vacuolization in the lateral and posterior columns of the thoracic spinal cord and has a striking similarity with the myelopathy of vitamin B12 deficiency. In autopsy series, 20% to 55% of patients with AIDS have evidence of spinal cord disease consistent with VM. The myelopathy usually manifests late in the course of HIV infection, with slowly progressive weakness of the lower extremities, gait disorder, sensory abnormalities in the legs, impotence in men, and urinary frequency and urgency. Its course is invariably progressive and leads to severe paralysis of the lower limbs, with loss of the ability to walk and of sphincter control. The differential diagnosis is extensive and includes metabolic, infective, and neoplastic spinal cord diseases. The diagnosis is based on the clinical observation and the exclusion of other causes of myelopathy via serologic, radiographic, and cerebrospinal fluid studies. The pathogenesis of VM is unknown. Attempts to detect HIV in the spinal cord have not yielded significant results, and there is no evidence of a relationship between the presence of HIV and the development of myelopathy. A metabolic disorder of the vitamin B12-dependent transmethylation pathway, induced by HIV or cytokine activation, is considered the possible cause of VM associated with AIDS. There is no known treatment for AIDS myelopathy and there is no evidence that antiretroviral drugs can improve the symptoms or slow the progression of VM. The symptomatic treatment includes antispasticity agents, management of sphincter dysfunction, and physical therapy. Experimental treatments are being tested in clinical trials.

Magnetic resonance imaging of the corticospinal tracts in amyotrophic lateral sclerosis

In 13 patients with amyotrophic lateral sclerosis (ALS), corticospinal tract lesions on spinal cord, brain and brain stem were examined by MR imaging. In 9 patients, areas of high signal intensity located in the dorsolateral columns coinciding with the lateral corticospinal tracts, were detected on axial T2*-weighted MR imaging of the cervical spinal cord using a gradient echo technique. In two patients, these spinal cord MR abnormalities corresponded well to the postmortem pathological findings of lateral corticospinal tract degeneration. T2-weighted abnormal MR signals along the corticospinal tract at the brain and brain stem were detected in 4 patients, all of whom also showed abnormal signals on cervical cord MR imaging. Four of 13 patients did not show any abnormal signals on brain and brain stem or spinal cord MR imaging. Spinal cord MR imaging provides a useful information regarding upper motor neuron lesions in ALS.