Epidemiology and clinical features of HIV-1 associated neuropathies

Anti-neurofascin 155 Antibody-positive Neuropathy in a Human Immunodeficiency Virus-infected Patient

Human immunodeficiency virus (HIV)-associated neuropathy is a common complication of HIV infection and has several clinical subtypes. HIV-associated chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a demyelinating neuropathy whose clinical features are known to differ from those of CIDP in the HIV-uninfected population. We herein report a case of CIDP in an HIV-infected patient who was finally diagnosed with anti-neurofascin 155 (NF155) antibody-positive neuropathy. The clinical features, including clinical findings and therapeutic responses, were typical of paranodal antibody-mediated neuropathy. To our knowledge, this is the first case of anti-NF155 antibody-associated neuropathy in an HIV-infected patient.

Dual ankyrinG and subpial autoantibodies in a man with well-controlled HIV infection with steroid-responsive meningoencephalitis: A case report

Neuroinvasive infection is the most common cause of meningoencephalitis in people living with human immunodeficiency virus (HIV), but autoimmune etiologies have been reported. We present the case of a 51-year-old man living with HIV infection with steroid-responsive meningoencephalitis whose comprehensive pathogen testing was non-diagnostic. Subsequent tissue-based immunofluorescence with acute-phase cerebrospinal fluid revealed anti-neural antibodies localizing to the axon initial segment (AIS), the node of Ranvier (NoR), and the subpial space. Phage display immunoprecipitation sequencing identified ankyrinG (AnkG) as the leading candidate autoantigen. A synthetic blocking peptide encoding the PhIP-Seq-identified AnkG epitope neutralized CSF IgG binding to the AIS and NoR, thereby confirming a monoepitopic AnkG antibody response. However, subpial immunostaining persisted, indicating the presence of additional autoantibodies. Review of archival tissue-based staining identified candidate AnkG autoantibodies in a 60-year-old woman with metastatic ovarian cancer and seizures that were subsequently validated by cell-based assay. AnkG antibodies were not detected by tissue-based assay and/or PhIP-Seq in control CSF (N = 39), HIV CSF (N = 79), or other suspected and confirmed neuroinflammatory CSF cases (N = 1,236). Therefore, AnkG autoantibodies in CSF are rare but extend the catalog of AIS and NoR autoantibodies associated with neurological autoimmunity.

Paraparesis in a patient with advanced HIV infection: a diagnostic conundrum

In patients with HIV infection, lower limb weakness is a result of the pathological involvement of the brain, spinal cord or peripheral nervous system. The pathological process can be opportunistic infections, nutrient deficiencies, neoplastic infiltration or HIV itself. Here, we present the case of a 50-year-old manual labourer who presented with gradually progressive lower limb weakness, sensory disturbances, impotence and urinary urgency. He was diagnosed with HIV during evaluation. Based on the presentation and other supportive laboratory and radiological evidence, the following differentials were considered: vacuolar myelopathy, amyotrophic lateral sclerosis and myeloradiculopathy. The patient was initiated on antiretroviral therapy, and he showed significant improvement of symptoms on follow-up. We report this case to discuss the diagnostic puzzle.

Evidence for a novel subcortical mechanism for posterior cingulate cortex atrophy in HIV peripheral neuropathy

We previously reported that neuropathic pain was associated with smaller posterior cingulate cortical (PCC) volumes, suggesting that a smaller/dysfunctional PCC may contribute to development of pain via impaired mind wandering. A gap in our previous report was lack of evidence for a mechanism for the genesis of PCC atrophy in HIV peripheral neuropathy. Here we investigate if volumetric differences in the subcortex for those with neuropathic paresthesia may contribute to smaller PCC volumes, potentially through deafferentation of ascending white matter tracts resulting from peripheral nerve damage in HIV neuropathy. Since neuropathic pain and paresthesia are highly correlated, statistical decomposition was used to separate pain and paresthesia symptoms to determine which regions of brain atrophy are associated with both pain and paresthesia and which are associated separately with pain or paresthesia. HIV+ individuals (N = 233) with and without paresthesia in a multisite study underwent structural brain magnetic resonance imaging. Voxel-based morphometry and a segmentation/registration tool were used to investigate regional brain volume changes associated with paresthesia. Analysis of decomposed variables found that smaller midbrain and thalamus volumes were associated with paresthesia rather than pain. However, atrophy in the PCC was related to both pain and paresthesia. Peak thalamic atrophy (p = 0.004; MNI x = - 14, y = - 24, z = - 2) for more severe paresthesia was in a region with reciprocal connections with the PCC. This provides initial evidence that smaller PCC volumes in HIV peripheral neuropathy are related to ascending white matter deafferentation caused by small fiber damage observed in HIV peripheral neuropathy.

Biology of the human blood-nerve barrier in health and disease

A highly regulated endoneurial microenvironment is required for normal axonal function in peripheral nerves and nerve roots, which structurally consist of an outer collagenous epineurium, inner perineurium consisting of multiple concentric layers of specialized epithelioid myofibroblasts that surround the innermost endoneurium, which consists of myelinated and unmyelinated axons embedded in a looser mesh of collagen fibers. Endoneurial homeostasis is achieved by tight junction-forming endoneurial microvessels that control ion, solute, water, nutrient, macromolecule and leukocyte influx and efflux between the bloodstream and endoneurium, and the innermost layers of the perineurium that control interstitial fluid component flux between the freely permeable epineurium and endoneurium. Strictly speaking, endoneurial microvascular endothelium should be considered the blood-nerve barrier (BNB) due to direct communication with circulating blood. The mammalian BNB is considered the second most restrictive vascular system after the blood-brain barrier (BBB) based on classic in situ permeability studies. Structural alterations in endoneurial microvessels or interactions with hematogenous leukocytes have been described in several human peripheral neuropathies; however major advances in BNB biology in health and disease have been limited over the past 50 years. Guided by transcriptome and proteome studies of normal and pathologic human peripheral nerves, purified primary and immortalized human endoneurial endothelial cells that form the BNB and leukocytes from patients with well-characterized peripheral neuropathies, validated by in situ or ex vivo protein expression studies, data are emerging on the molecular and functional characteristics of the human BNB in health and in specific peripheral neuropathies, as well as chronic neuropathic pain. These early advancements have the potential to not only increase our understanding of how the BNB works and adapts or fails to adapt to varying insult, but provide insights relevant to pathogenic leukocyte trafficking, with translational potential and specific therapeutic application for chronic peripheral neuropathies and neuropathic pain.

51-year old man with tingling, burning and progressive limb weakness

Peripheral neuropathy is a common reason for referral to neurology. Chronic acquired demyelinating neuropathies are an important and varied group with overlapping presentations, and may have an immune-mediated cause. Their correct diagnosis is important as they respond to different treatments; timely intervention can prevent irreversible axonal degeneration. We present a case that highlights the approach to an adult presenting with a chronic demyelinating neuropathy.

Mitochondrial dysfunction in HIV-induced peripheral neuropathy

Mitochondria play an essential role in cellular energy production and calcium homeostasis. Abnormalities in mitochondrial homeostasis and function are seen in several acquired as well as genetic neuropathies, emphasizing their prominent role in neuronal cell activities. Chronic infection with HIV, even when appropriately treated, is a risk factor for developing peripheral neuropathy. In this chapter, we discuss the way in which HIV infection, the resultant toxic viral products that are generated, and some of the viral inhibitors used in its treatment may lead to abnormal mitochondrial function. Of importance are the effects on mitochondrial DNA replication and the neurotoxic effects of the viral gp120 protein. One aspect of mitochondrial dysfunction that remains unexplored is the role of the interaction between mitochondria and the endoplasmic reticulum as a possible target of disruption in HIV neuropathy.

Clinical electrophysiology of axonal polyneuropathies

Axonal neuropathies encompass a wide range of acquired and inherited disorders with electrophysiologic characteristics that arise from the unique neurophysiology of the axon. Accurate interpretation of nerve conduction studies and electromyography requires an in-depth understanding of the pathophysiology of the axon. Here we review the unique neurophysiologic properties of the axon and how they relate to clinical electrodiagnostic features. We review the length-dependent Wallerian or "dying-back" processes as well as the emerging body of literature from acquired axonal neuropathies that highlights the importance of axonal disease at the nodes of Ranvier. Neurophysiologic features of individual inherited and acquired axonal diseases, including primary nerve disease as well as systemic immune mediated, metabolic, and toxic diseases involving the peripheral nerve, are reviewed. This comprehensive review of electrodiagnostic findings coupled with the current understanding of pathophysiology will aid the clinician in the evaluation of axonal polyneuropathies.

Peripheral nerve abnormality in HIV leprosy patients

BACKGROUND

The geographical overlap of HIV (human immunodeficiency virus) and leprosy infection has become increasingly frequent and worrying, bringing many clinical issues. Peripheral neuropathy is very frequent in leprosy because of the predilection of its etiologic agent by Schwann cells of the peripheral nervous system, and it also affects individuals with HIV as one of the most common neurological manifestations.

METHODOLOGY/PRINCIPAL FINDINGS

The present study compared a cohort of 63 patients diagnosed with leprosy and coinfected with HIV with a cohort of 64 patients with leprosy alone, who were followed at the outpatient clinic of the Nucleus of Tropical Medicine of the Federal University of Pará, Brazil. We observed that HIV-coinfected leprosy patients presented greater odds of overall peripheral nerve damage (nerve function impairment-NFI) than patients with leprosy alone. More sensitive damage was observed, especially in patients coinfected with multibacillary forms. Leprosy patients coinfected with HIV presented higher chances of motor damage with improvement over time using multidrug therapy (MDT) and highly active antiretroviral therapy (HAART), along with a greater extent of damage and occurrence of neuritis. The data suggest that in addition to patients presenting possible damage caused by leprosy, they also had a greater damage gradient attributable to HIV disease, but not related to HAART because most of these patients had been on the treatment for less than a year. Neuritis was treated with prednisone at doses recommended by the WHO, and coinfected patients had the highest rate of clinical improvement in the first 60 days.

CONCLUSIONS/SIGNIFICANCE

The clinical characteristics of the two diseases should be considered in leprosy patients coinfected with HIV for better diagnosis and treatment of peripheral neuropathy. We suggest that new simplified assessment tools that allow the evaluation of the NFI of these patients be developed for use in the service.

Cerebrospinal fluid findings in Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathies

The classic immunologic alteration of the cerebrospinal fluid (CSF) in Guillain-Barré syndrome (GBS), albuminocytologic dissociation, has been known since the original paper by Guillain, Barré, and Strohl. Albuminocytologic dissociation has been also described in other forms of the GBS spectrum, such as axonal motor or motor-sensory forms (AMAN, AMSAN), the anti-GQ1b spectrum of Miller Fisher syndrome, and Bickerstaff brainstem encephalitis. Cytokines, chemokines, antibodies, complement components, and molecules with a putative neuroprotective role or indicating axonal damage have also been examined using different methods. Besides these candidate approaches, proteomics has been recently applied to discover potential biomarkers. The overall results support the immunopathogenesis of GBS, but albuminocytologic dissociation remained the only consistent CSF biomarker supporting the diagnosis of GBS. Chronic inflammatory neuropathies also comprise a heterogeneous group of diseases. Increased protein in the CSF is a supportive factor of chronic inflammatory demyelinating polyneuropathy, especially in the absence of definite electrophysiologic criteria. A number of other markers have also been investigated in the CSF of patients with chronic inflammatory neuropathies, similar to GBS. However, none has been used in supporting diagnosis, differentiating among syndromes, or predicting the clinical course and treatment responses.

Neuropathic pain: treatment guidelines and updates

PURPOSE OF REVIEW

The purpose of this review is to provide an update on the diagnosis, treatment, and prevention of neuropathic pain.

RECENT FINDINGS

Neuropathic pain can be debilitating, leading to poor quality of life and functional status. Neuropathic pain results from numerous mechanisms of nerve injury including infectious diseases, complication of medical diseases, and mechanical damage. As a result of the lack of class I evidence for the treatment of numerous neuropathic pain conditions, those diseases without such evidence are often managed, as though neuropathic pain is a singular condition. In diseases such as diabetes, HIV, and herpes infections, the resultant neuropathic pain is often modifiable with prevention strategies. In one of the more prevalent neuropathic pain conditions, radiculopathy, the commonly used treatments lack sufficient evidence to explain their widespread use.

SUMMARY

The literature reveals that neuropathic pain is underdiagnosed and often undertreated or treated with ineffective or untested modalities. Evolving definitions of neuropathic pain has broadened the range of therapeutic approaches and brought current treatment paradigms under increased scrutiny. The lack of a mechanism-based approach to treatment may be responsible for the lackluster responses seen in most neuropathic pain conditions.

Cachexia & debility diagnoses in hospitalized children and adolescents with complex chronic conditions: evidence from the Kids' Inpatient Database

Objective:

To characterize the frequency, cost, and hospital-reported outcomes of cachexia and debility in children and adolescents with complex chronic conditions (CCCs).

Methods:

We identified children and adolescents (aged ≤20 years) with CCCs, cachexia, and debility in the Kids’ Inpatient Database [Healthcare Cost and Utilization Project, Agency for Healthcare Research & Quality]. We then compared the characteristics of patients and hospitalizations, including cost and duration of stay, for CCCs with and without cachexia and/or debility. We examined factors that predict risk of inpatient mortality in children and adolescents with CCCs using a logistic regression model. We examined factors that impact duration of stay and cost in children and adolescents with CCCs using negative binomial regression models. All costs are reported in US dollars in 2014 using Consumer Price Index inflation adjustment.

Results:

We estimated the incidence of hospitalization of cachexia in children and adolescents with CCCs at 1,395 discharges during the sample period, which ranged from 277 discharges in 2003 to 473 discharges in 2012. We estimated the incidence of hospitalization due to debility in children and adolescents with CCCs at 421 discharges during the sample period, which ranged from 39 discharges in 2003 to 217 discharges in 2012. Cachexia was associated with a 60% increase in the risk of inpatient mortality, whereas debility was associated with a 40% decrease in the risk of mortality. Cachexia and debility increased duration of stay in hospital (17% and 39% longer stays, respectively). Median cost of hospitalization was $15,441.59 and $23,796.16 for children and adolescents with cachexia and debility, respectively.

Conclusions:

Incidence of hospitalization for cachexia in children and adolescents with CCCs is less than that for adults but the frequency of cachexia diagnoses increased over time. Estimates of the incidence of hospitalization with debility in children and adolescents with CCCs have not been reported, but our study demonstrates that the frequency of these discharges is also increasing.

NGX-4010, a capsaicin 8% dermal patch, for the treatment of painful HIV-associated distal sensory polyneuropathy: results of a 52-week open-label study

OBJECTIVES

To evaluate the efficacy, safety, and tolerability of repeated NGX-4010 treatments in the open-label extension phase of a 52-week study in patients with neuropathic pain due to HIV-associated distal sensory polyneuropathy (HIV-DSP).

METHODS

Patients completing the 12-week, randomized, double-blind phase of the study could enter a 40-week, open-label phase, and receive up to 3, 60-minute NGX-4010 treatments. Patients recorded their "average pain for the past 24 hours" daily using the Numeric Pain Rating Scale (NPRS). Efficacy assessment included the percentage NPRS score reduction from baseline to weeks 2 to 12 after the final treatment, and Patient Global Impression of Change (PGIC) and Clinician Global Impression of Change (CGIC) questionnaires at study termination.

RESULTS

Of 307 patients randomized, 272 entered the open-label phase; 81, 90, 55, and 46 received 0, 1, 2, and 3 retreatments, respectively. The mean percentage decrease in NPRS score from baseline to weeks 2 to 12 after the final treatment was similar in patients receiving single or multiple NGX-4010 treatments (-25.8%, -27.1%, -24.6%, and -22.7% for 1, 2, 3, and 4 NGX-4010 treatments, respectively). PGIC and CGIC results demonstrated a benefit of NGX-4010 treatment through to the end of the study regardless of the number of treatments received. Transient local application site reactions were the most frequently reported adverse events, and were mainly mild to moderate, nonserious, and did not increase with repeated treatment.

DISCUSSION

Repeated NGX-4010 treatments were generally well tolerated and resulted in consistent reductions in HIV-DSP-associated pain and improvement in patient-reported outcomes.

Over-reported peripheral neuropathy symptoms in a cohort of HIV infected and uninfected Rwandan women: the need for validated locally appropriate questionnaires

BACKGROUND

Peripheral neuropathy symptoms (PNS) are commonly manifested in HIV-infected (HIV+) individuals, although data are limited on the prevalence and predictors of PNS in HIV+ patients from sub-Saharan Africa.

OBJECTIVE

To determine the prevalence and predictors of PNS in HIV+ and HIV-uninfected (HIV-) Rwandan women.

METHODS

Data were analysed from 936 (710 HIV+ and 226 HIV-) women from the Rwanda Women Interassociation Study and Assessment (RWISA), an observational prospective cohort study investigating the effectiveness and toxicity of ART in HIV+ women.

RESULTS

Of 936 enrolled, 920 (98.3%) were included in this analysis with 44% of HIV- and 52% of the HIV+ women reporting PNS (p=0.06). CD4+ count was not associated with PNS, although there was a non-significant trend towards higher prevalence in those with lower CD4+ counts. For the HIV- women, only alcohol and co-trimoxazole use were independently associated with PNS. WHO HIV stage IV illness and albumin ≤ 3.5 were associated with PNS in HIV+ women.

CONCLUSIONS

The rate of peripheral neuropathy symptoms reported in this cohort of HIV-infected African women seems implausible, and rather suggests that the screening tool for peripheral neuropathy in culturally diverse African settings be locally validated.

Animal models of HIV peripheral neuropathy

The use of animal models in the study of HIV and AIDS has advanced our understanding of the underlying pathophysiologic mechanisms of infection. Of the multitude of HIV disease manifestations, peripheral neuropathy remains one of the most common long-term side effects. Several of the most important causes of peripheral neuropathy in AIDS patients include direct association with HIV infection with or without antiretroviral medication and infection with opportunistic agents. Because the pathogeneses of these diseases are difficult to study in human patients, animal models have allowed for significant advancement in the understanding of the role of viral infection and the immune system in disease genesis. This review focuses on rodent, rabbit, feline and rhesus models used to study HIV-associated peripheral neuropathies, focusing specifically on sensory neuropathy and antiretroviral-associated neuropathies.

Infectious and noninfectious triggers in Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is the commonest cause of acquired flaccid paralysis in the world and regarded by many as the prototype for postinfectious autoimmunity. Here the authors consider both infectious and noninfectious triggers of GBS and determine where possible what immunological mechanisms may account for this association. In approximately two-thirds of cases, an infectious trigger is reported in the weeks that lead up to disease onset, indicating that the host's response to infection must play an important role in disease pathogenesis. The most frequently identified bacteria, Campylobacter jejuni, through a process known as molecular mimicry, has been shown to induce cross-reactive anti-ganglioside antibodies, which can lead to the development of axonal-type GBS in some patients. Whether this paradigm can be extended to other infectious organisms or vaccines remains an important area of research and has public health implications. GBS has also been reported rarely in patients with underlying systemic diseases and immunocompromised states and although the exact mechanism is yet to be established, increased susceptibility to known infectious triggers should be considered most likely.

The Molecular and Pharmacological Mechanisms of HIV-Related Neuropathic Pain

Infection of the nervous system with the human immunodeficiency virus (HIV-1) can lead to cognitive, motor and sensory disorders. HIV-related sensory neuropathy (HIV-SN) mainly contains the HIV infection-related distal sensory polyneuropathy (DSP) and antiretroviral toxic neuropathies (ATN). The main pathological features that characterize DSP and ATN include retrograde ("dying back") axonal degeneration of long axons in distal regions of legs or arms, loss of unmyelinated fibers, and variable degree of macrophage infiltration in peripheral nerves and dorsal root ganglia (DRG). One of the most common complaints of HIV-DSP is pain. Unfortunately, many conventional agents utilized as pharmacologic therapy for neuropathic pain are not effective for providing satisfactory analgesia in painful HIV-related distal sensory polyneuropathy, because the molecular mechanisms of the painful HIV-SDP are not clear in detail. The HIV envelope glycoprotein, gp120, appears to contribute to this painful neuropathy. Recently, preclinical studies have shown that glia activation in the spinal cord and DRG has become an attractive target for attenuating chronic pain. Cytokines/chemokines have been implicated in a variety of painful neurological diseases and in animal models of HIV-related neuropathic pain. Mitochondria injured by ATN and/or gp120 may be also involved in the development of HIV-neuropathic pain. This review discusses the neurochemical and pharmacological mechanisms of HIV-related neuropathic pain based on the recent advance in the preclinical studies, providing insights into novel pharmacological targets for future therapy.

The reliability of the modified lower extremity functional scale among adults living with HIV on antiretroviral therapy, in Rwanda, Africa

Peripheral neuropathy (PN) is common among people living with HIV (PLHIV) on antiretroviral therapy (ART), and affects their daily functional ability and quality of life. Lower extremity functional ability, which is most commonly compromised in patients with PN, has not been clearly evaluated in an African setting, with regard to functional limitations. The lower extremity functional scale (LEFS) was originally developed and validated among elderly people in the USA, where the environment and activities of daily life are very different from those in Rwanda. The purpose of this study was to adapt and establish the reliability of LEFS, among adults living with HIV on ART, in a Rwandan environment. The study translated LEFS from English to Kinyarwanda, the local language spoken in Rwanda, the LEFS was then modified accordingly, and tested for test-retest reliability among 50 adult PLHIV on ART. An average Spearman rank order correlation coefficient, ρ ≥ 0.7, was considered optimal for reliability. Prior to the modification of the LEFS and in the initial testing of the translated LEFS, none of the activities was strongly correlated (ρ ≥ 0.8); most of the activities (90%, 18/20) were moderately correlated (ρ ≥ 0.5) and 10% (2/20) were weakly correlated (ρ ≤ 0.5). The ρ of most of the functional activities improved after modification by an expert group to ρ ≥ 0.7, establishing reliability and validity of LEFS among PLHIV on ART with lower extremity functional limitations, in this environment. In conclusion, this study demonstrated the importance of modifying and establishing test - retest reliability of tools derived from developed world contexts to local conditions in developing countries, such as in Rwanda. The modified LEFS in this study can be used in Rwanda by clinicians, specifically at ART clinics to screen and identify people with functional limitations at an early stage of the limitations, for treatment, rehabilitation and/or referral to appropriate health care services.

Inadequate pain relief in ambulatory patients with human immunodeficiency virus disease in Port Harcourt

OBJECTIVES

To estimate the prevalence of pain in ambulatory patients with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) in Port Harcourt and to determine the type, site, severity, and adequacy of the treatment of pain in these patients.

MATERIALS AND METHODS

A cross-sectional survey was carried out at two antiretroviral therapy centers in Port Harcourt, Nigeria. A data sheet, the brief pain inventory, and the short form of the McGill pain questionnaire were used and 157 patients in various stages of HIV/AIDS participated in the study.

RESULTS

About 83.7% (129/157) of the ambulatory patients with HIV/AIDS complained of pains. Of the patients who reported pain 61.24% (79/129) reported nociceptive pain while 38.76% (50/129) reported neuropathic pain. Chest pain was the most frequent site of pain followed by headache. About 82% (106/129) of those who complained of pain received some form of analgesic, but only 23.58% (25/106) of these obtained adequate pain relief. The majority of the participants had significant impairment of their quality of life due to the severity of their pain.

CONCLUSION

Pain associated with significant impairment of quality of life is common in ambulatory patients with HIV/AIDS in Port Harcourt. Whereas the majority of the patients used various pain relief methods, analgesia was inadequate.

Uses of skin biopsy for sensory and autonomic nerve assessment

Skin biopsy is a valuable diagnostic tool for small-fiber-predominant neuropathy by the quantification of intraepidermal nerve fiber density (IENFD). It has the unique advantage of being a minimally invasive procedure with the potential for longitudinal evaluation of both sensory and autonomic fibers. Unmyelinated small fibers are not otherwise quantified objectively with such a level of sensitivity as has been reported with IENFD. Recent advances include an expansion of the skin punch biopsy technique to evaluate larger myelinated fibers and mechanoreceptors, and recent work has also focused on additional methods of quantifying dermal fibers and densely innervated autonomic structures. This review discusses current work using skin biopsy for the pathologic analysis of peripheral nerve fibers in neuropathy of various causes as well as its use in clinical trials.

Herpes virus infection of the peripheral nervous system

Among the human herpes viruses, three are neurotropic and capable of producing severe neurological abnormalities: herpes simplex virus type 1 and 2 (HSV-1 and HSV-2) and varicella-zoster virus (VZV). Both the acute, primary infection and the reactivation from the site of latent infection, the dorsal sensory ganglia, are associated with severe human morbidity and mortality. The peripheral nervous system is one of the major loci affected by these viruses. The present review details the virology and molecular biology underlying the human infection. This is followed by detailed description of the symtomatology, clinical presentation, diagnosis, course, therapy, and prognosis of disorders of the peripheral nervous system caused by these viruses.

A randomized, double-blind, controlled study of NGX-4010, a capsaicin 8% dermal patch, for the treatment of painful HIV-associated distal sensory polyneuropathy

INTRODUCTION

Effective treatment of HIV-associated distal sensory polyneuropathy remains a significant unmet therapeutic need.

METHODS

In this randomized, double-blind, controlled study, patients with pain due to HIV-associated distal sensory polyneuropathy received a single 30-minute or 60-minute application of NGX-4010--a capsaicin 8% patch (n = 332)--or a low-dose capsaicin (0.04%) control patch (n = 162). The primary endpoint was the mean percent change from baseline in Numeric Pain Rating Scale score to weeks 2-12. Secondary endpoints included patient global impression of change at week 12.

RESULTS

Pain reduction was not significantly different between the total NGX-4010 group (-29.5%) and the total control group (-24.5%; P = 0.097). Greater pain reduction in the 60-minute (-30.0%) versus the 30-minute control group (-19.1%) prevented intended pooling of the control groups to test individual NGX-4010 treatment groups. No significant pain reduction was observed for the 30-minute NGX-4010 group compared with 30-minute control (-26.2% vs.-19.1%, respectively, P = 0.103). Pain reductions in the 60-minute NGX-4010 and control groups were comparable (-32.8% vs. -30.0%, respectively; P = 0.488). Posthoc nonparametric testing demonstrated significant differences favoring the total (P = 0.044) and 30-minute NGX-4010 groups (P = 0.035). Significantly, more patients in the total and 30-minute NGX-4010 group felt improved on the patient global impression of change versus control (67% vs. 55%, P = 0.011 and 65% vs. 45%, P = 0.006, respectively). Mild to moderate transient application site pain and erythema were the most common adverse events.

CONCLUSIONS

Although the primary endpoint analyses were not significant, trends toward pain improvement were observed after a single 30-minute NGX-4010 treatment.

Dorsal root ganglia damage in SIV-infected rhesus macaques: an animal model of HIV-induced sensory neuropathy

HIV-associated sensory neuropathy (HIV-SN) is currently the most common neurological complication of chronic HIV infection and continues to substantially affect patient quality of life. Mechanisms underlying the neuronal damage and loss observed in sensory ganglia of HIV-infected individuals have not been sufficiently studied. The present study aimed to develop and characterize a model of HIV-SN using SIV-infected CD8 T-lymphocyte-depleted rhesus macaques (Macaca mulatta). Uninfected controls (n = 5), SIV-infected CD8-depleted (n = 4), and SIV-infected non-CD8-depleted (n = 6) animals were used. Of the six non-CD8-depleted animals, three were conventional progressors (progressing to AIDS >1 year after infection) and three were rapid progressors (AIDS within 6 months). Dorsal root ganglia (DRG) were examined for histological hallmarks of HIV-SN, including satellitosis, presence of Nageotte nodules, and neuronophagia, as well as increased numbers of CD68(+) macrophages and abundant viral replication. In contrast to non-CD8-depleted animals, which had mild to moderate DRG pathology, the CD8-depleted SIV-infected animals had moderate to severe DRG damage, with increased numbers of CD68(+) satellite cells. Additionally, there was marked active viral replication in the affected DRG. These findings confirm that many features of HIV-SN can be recapitulated in the CD8-depleted SIV-infected rhesus macaque model within a short time frame and illustrate the importance of this model for study of sensory neuropathy.

Lipodystrophy and adrenal insufficiency: potential mediators of peripheral neuropathy in HIV infection?

The mechanisms behind certain co-morbid conditions associated with chronic HIV disease still remain elusive. HIV-associated peripheral neuropathy is one among those rarely studied manifestations in HIV-1 infection. Numerous underlying factors associated with peripheral neuropathy have been described in HIV disease. Herein, we hypothesized certain heretofore undescribed potential mechanisms that lead to HIV associated neuropathy. Being a multifactoral manifestation, HIV-associated neuropathy is presumed to have an association with physiological factors namely, adrenal inadequacy/steroid resistance and lipodystrophy-induced cushion-effect loss in peripheral nerves. Therefore, management of the adrenals with steroids at the time-point of high inflammatory burden thereby preventing lipodystrophy by selecting the optimum treatment regimen could markedly alleviate the severity of HIV-associated neuropathic manifestations.

Clinical characteristics and pain management among patients with painful peripheral neuropathic disorders in general practice settings

Alleviating chronic pain is a global healthcare priority. Understanding the medical profile and current treatment patterns in patients with painful neuropathic disorders (PNDs) is crucial to the development of effective pain management strategies. Thus, our objective was to describe the demographic and clinical characteristics of persons with PNDs and their use of pain medications. Using the general practice research database, we categorized PNDs in two ways: Pure PNDs (which include diabetic neuropathy, postherpetic neuralgia, etc.; N=16,690) and Mixed PNDs (which include back/neck pain with neuropathic involvement; N=14,309). On average, PND patients were 55 years old (Pure, 55.4 [SD=16.9] years; Mixed, 54.3 [SD=16.4] years). Over a third had other chronic pain-related (Pure, 37.5%; Mixed, 37.1%) and nearly a quarter had non-pain related (Pure, 28.1%; Mixed, 24.1%) comorbidities. Use of medications with clinically demonstrated efficacy in PNDs was higher among patients with Pure PNDs (tricyclic antidepressants [Pure, 16.6%; Mixed, 10.1%]; 2nd generation antidepressants [Pure, 11.0%; Mixed, 9.7%]; and antiepileptics [Pure, 12.2%; Mixed, 2.6%]), whereas use of NSAIDs (Pure, 43.1%; Mixed, 65.2%) and opioids (Pure, 8.5%; Mixed, 14.3%) was higher among patients with Mixed PNDs. Average daily doses of select neuropathic pain-related medications among PND patients (Pure and Mixed) were lower than those recommended for neuropathic pain. Among both Pure and Mixed PND patients, use and doses of evidenced-based neuropathic pain-related medications was low, and lower than the use of NSAIDs (a medication class with no proven efficacy for PNDs) in each group, suggesting possible sub-optimal neuropathic pain management among these patients.

Neurological diseases and pain

Chronic pain is a frequent component of many neurological disorders, affecting 20-40% of patients for many primary neurological diseases. These diseases result from a wide range of pathophysiologies including traumatic injury to the central nervous system, neurodegeneration and neuroinflammation, and exploring the aetiology of pain in these disorders is an opportunity to achieve new insight into pain processing. Whether pain originates in the central or peripheral nervous system, it frequently becomes centralized through maladaptive responses within the central nervous system that can profoundly alter brain systems and thereby behaviour (e.g. depression). Chronic pain should thus be considered a brain disease in which alterations in neural networks affect multiple aspects of brain function, structure and chemistry. The study and treatment of this disease is greatly complicated by the lack of objective measures for either the symptoms or the underlying mechanisms of chronic pain. In pain associated with neurological disease, it is sometimes difficult to obtain even a subjective evaluation of pain, as is the case for patients in a vegetative state or end-stage Alzheimer's disease. It is critical that neurologists become more involved in chronic pain treatment and research (already significant in the fields of migraine and peripheral neuropathies). To achieve this goal, greater efforts are needed to enhance training for neurologists in pain treatment and promote greater interest in the field. This review describes examples of pain in different neurological diseases including primary neurological pain conditions, discusses the therapeutic potential of brain-targeted therapies and highlights the need for objective measures of pain.

Functional recovery of untreated human immunodeficiency virus-associated Guillain-Barré syndrome: a case report

HIV-associated Guillain-Barré syndrome is a well-documented phenomenon, typically occurring at seroconversion. GBS may result in functional impairment treated with a combination of medications, plasmapheresis, and rehabilitation. The quantified functional recovery of HIV-associated GBS with or without HIV treatment is not well described. Utilizing serial FIM scoring, we describe a patient's recovery from HIV-associated GBS after treatment with IVIg and acute inpatient rehabilitation without HIV treatment.

Relationship of depression and catastrophizing to pain, disability, and medication adherence in patients with HIV-associated sensory neuropathy

Few studies have examined how patients with chronic HIV infection cope with pain and how pain relates to medication adherence. Pain coping strategies such as catastrophizing are often associated with increased pain and disability and may also influence adherence to medications. The goal of our study is to assess the relationship of catastrophizing and depression to pain, disability, and medication adherence through questionnaires administered to a cross-section of patients with HIV-associated sensory neuropathy. In our study, 46 HIV-seropositive subjects completed questionnaires evaluating neuropathic pain severity, pain catastrophizing, pain-related disability, depressive symptoms, severity of antiretroviral therapy (ART) side effects, and common reasons for medication nonadherence. Hierarchical regression analysis indicated that pain catastrophizing correlated with severity of neuropathic pain independent of depressive symptoms. Furthermore, depressive symptoms were not associated with multiple factors independent of pain catastrophizing such as severity of neuropathic pain and pain-related disability. Pain catastrophizing, but not depressive symptoms, correlated with increased pain disability even after controlling for the effects of age and neuropathic pain. We also found that poor adherence attributed to fear of side effects or forgetfulness was associated with increased severity of neuropathic pain, while depressive symptoms but not catastrophizing correlated with ART side effects. These findings suggest that both catastrophizing and depressive symptoms are important factors to consider in the management of pain from HIV neuropathy and adherence to ART.

Entzündliche Erkrankungen

Unter einer Meningitis versteht man eine Entzündung von Pia mater und Arachnoidea. Das Erregerspektrum ist weit und reicht von Bakterien, die hämatogen-metastatisch, fortgeleitet oder durch offene Hirnverletzung zur eitrigen Meningitis führen, über Viren zu Pilzen und Parasiten. Insbesondere bei den unbehandelt häufig letal verlaufenden eitrigen Meningitiden ist eine rasche Diagnose mit Erregernachweis notwendig. Unverzüglich ist daraufhin eine spezifische, der regionalen Resistenzentwicklung angepasste Therapie einzuleiten. Die meningeale Affektion im Rahmen einer Listeriose oder Tuberkulose verdient aufgrund des klinischen Bildes, des Verlaufs und der spezifischen Therapie besondere Beachtung. Die fungalen Infektionen werden, da klinisch häufig als Meningoenzephalitis imponierend, in Abschn. 33.3 abgehandelt.

Tumour necrosis factor haplotypes associated with sensory neuropathy in Asian and Caucasian human immunodeficiency virus patients

In human immunodeficiency virus (HIV) patients, neuropathy is a common adverse side effect to some antiretroviral treatments, particularly stavudine. As stavudine is cheap, it is widely used in Asia and Africa. We showed that increasing age and height moderately predict the development of neuropathy. This was improved by the inclusion of tumour necrosis factor (TNF)-1031 (rs1799964). To investigate this association, Malay (n = 64), Chinese (n = 74) and Caucasian patients (n = 37) exposed to stavudine were screened for neuropathy. DNA samples were genotyped for polymorphisms in the central major histocompatibility complex (MHC) near TNF, and haplotypes were derived. The haplotype group FVa6,7,8 (incorporating TNF-1031) was found to be associated with neuropathy in Chinese patients in bivariate analyses (P = 0.03), and in Malays and Chinese in a multivariate analysis correcting for age and height (P = 0.02, P = 0.03, respectively). This trend was also confirmed in Caucasians.

[HIV-associated neuropathies]

Human immunodeficiency virus (HIV)-associated polyneuropathy has become the most common neurological complication of HIV infection and is one of the main risk factors for development of a neuropathy worldwide. Therefore HIV should always be considered as an underlying cause in patients with neuropathy. Many types of peripheral neuropathies are seen in HIV infection depending on the stage of infection. The inflammatory demyelinating neuropathies both acute (Guillain-Barré syndrome, GBS) and chronic (chronic inflammatory demyelinating neuropathy, CIDP) occur mainly at the time of seroconversion or early in the course of the disease while syndromes associated with opportunistic infections like CMV (i.e. polyradiculoneuropathy) occur in the late phase of HIV infection and are related to the loss of immune function. Distal symmetrical polyneuropathy (DSP) is the most common neuropathy in HIV-infected patients. We review the clinical manifestations, epidemiology, clinical diagnostics, pathophysiology and management strategies for HIV-associated polyneuropathies.

Long-term safety of NGX-4010, a high-concentration capsaicin patch, in patients with peripheral neuropathic pain

CONTEXT

Postherpetic neuralgia (PHN) and painful human immunodeficiency virus-associated distal sensory polyneuropathy (HIV-DSP) are peripheral neuropathic pain syndromes that are difficult to treat. Current treatment options are often limited by poor tolerability.

OBJECTIVES

The objective of the current open-label study was to assess the safety of repeated applications of NGX-4010, a high-concentration capsaicin patch (capsaicin 8%), over one year, in patients with moderate to severe PHN or HIV-DSP.

METHODS

Patients had successfully completed a previous NGX-4010 study and had a pain level appropriate for further treatment. Eligible patients had not been treated with NGX-4010 within 12 weeks of study initiation. Patients received pretreatment with a topical local anesthetic (lidocaine 4%) for 60 minutes followed by either a 60-minute (PHN and HIV-DSP patients) or a 90-minute (HIV-DSP patients) treatment with NGX-4010. Patients could receive up to three additional treatments at intervals of > or = 12 weeks. Regardless of the number of treatments received, all patients were followed up for 48 weeks except for those withdrawing early.

RESULTS

A total of 106 patients were enrolled and received a total of 293 NGX-4010 treatments. The most frequently reported treatment-emergent adverse events were transient, mild-to-moderate application site erythema, pain, edema, and papules. Small, transient pain-related increases in blood pressure during and immediately after NGX-4010 application were observed. There was no evidence of an increased incidence of adverse events, dermal irritation, intolerability, or impaired neurological function with repeated treatments.

CONCLUSION

It is concluded that repeated treatments with NGX-4010 administered over a one-year period are generally safe and well tolerated.

Pregabalin for painful HIV neuropathy: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

Pregabalin is effective in several neuropathic pain syndromes. This trial evaluated its efficacy, safety, and tolerability for treatment of painful HIV-associated neuropathy.

METHODS

This randomized, double-blind, placebo-controlled, parallel-group trial included a 2-week double-blind dose-adjustment (150-600 mg/day BID) phase, a 12-week double-blind maintenance phase, and an optional 3-month open label extension phase. The primary efficacy measure was the mean Numeric Pain Rating Scale (NPRS) score, an 11-point numeric rating scale. Secondary measures included Patient Global Impression of Change (PGIC) and sleep measurements.

RESULTS

Baseline mean NPRS score was 6.93 for patients randomized to pregabalin (n = 151) and 6.72 for those to placebo (n = 151). Pregabalin average daily dosage (SD) was 385.7 (160.3) mg/d. At endpoint, pregabalin and placebo showed substantial reductions in mean NPRS score from baseline: -2.88 vs -2.63, p = 0.3941. Pregabalin had greater improvements in NPRS score relative to placebo at weeks 1 (-1.14 vs -0.69, p = 0.0131) and 2 (-1.92 vs -1.43, p = 0.0393), and at weeks 7 (-3.22 vs -2.53 p = 0.0307) and 8 (-3.33 vs -2.53, p = 0.0156). At all other time points, differences between groups were not significant. Sleep measurements and 7-item PGIC did not differ among treatment groups; however, collapsed PGIC scores showed 82.8% of pregabalin and 66.7% of placebo patients rated themselves in 1 of the 3 "improved" categories (p = 0.0077). Somnolence and dizziness were the most common adverse events with pregabalin.

CONCLUSIONS

Pregabalin was well-tolerated, but not superior to placebo in the treatment of painful HIV neuropathy. Factors predicting analgesic response in HIV neuropathy warrant additional research.

CLASSIFICATION OF EVIDENCE

This Class II trial showed that pregabalin is not more effective than placebo in treatment of painful HIV neuropathy.

Neurologic presentations of AIDS

The human immunodeficiency virus (HIV), the cause of AIDS, has infected an estimated 33 million individuals worldwide. HIV is associated with immunodeficiency, neoplasia, and neurologic disease. The continuing evolution of the HIV epidemic has spurred an intense interest in a hitherto neglected area of medicine, neuroinfectious diseases and their consequences. This work has broad applications for the study of central nervous system (CNS) tumors, dementias, neuropathies, and CNS disease in other immunosuppressed individuals. HIV is neuroinvasive (can enter the CNS), neurotrophic (can live in neural tissues), and neurovirulent (causes disease of the nervous system). This article reviews the HIV-associated neurologic syndromes, which can be classified as primary HIV neurologic disease (in which HIV is both necessary and sufficient to cause the illness), secondary or opportunistic neurologic disease (in which HIV interacts with other pathogens, resulting in opportunistic infections and tumors), and treatment-related neurologic disease (such as immune reconstitution inflammatory syndrome).

Genome-wide screen identifies drug-induced regulation of the gene giant axonal neuropathy (Gan) in a mouse model of antiretroviral-induced painful peripheral neuropathy

Painful peripheral neuropathy is a debilitating complication of the treatment of HIV with nucleoside reverse transcriptase inhibitors (NRTIs). Patients are living longer with these drugs; however many develop excruciating, unremitting, and often treatment-limiting neuropathy that is resistant to conventional pain management therapies. Improving patient comfort and quality of life is paramount and depends on a clearer understanding of this devastating side effect. The mechanisms underlying the development of NRTI-induced neuropathy, however, remain unclear. Using a mouse model of NRTI-induced neuropathy, the authors conducted an unbiased whole-genome microarray screen to identify molecular targets in the spinal dorsal horn, which is the location where integration of ascending sensory transmission and descending modulatory effects occur. Analysis of the microarray data identified a change in the gene giant axonal neuropathy 1 (Gan1). Mutation of this gene has been linked to the development of giant axonal neuropathy (GAN), a rare autosomal recessive condition characterized by a progressive sensorimotor neuropathy. Gan1 has not been previously linked to nerve pathologies in other populations. In this study, downregulation of the Gan1 gene and the gene protein product, gigaxonin, was validated via quantitative polymerase chain reaction ([qPCR] gene expression) and Western blot analyses (protein level). Our report is the first to suggest that Gan1 might be a novel molecular target in the development of NRTI-induced peripheral neuropathy with implications for new therapeutic approaches to preventing or reducing a significant side effect of HIV treatment.

[Treatment of neuropathic pain in HIV-infected patients]

Neuropathic pain of various etiologies is a frequent symptom in HIV-infected patients that is underdiagnosed and inadequately treated. It requires a multidisciplinary pain approach based on psychosocial factors, diet and exercise, etiologic treatment whenever possible, symptomatic medical treatment, and sometimes, interventional techniques. Medical treatment should be individualized and introduced gradually, with a mind to potential drug interactions. Neuropathic pain responds poorly to conventional analgesics, such as nonsteroidal antiinflammatory drugs and opiates; tricyclic antidepressants and anticonvulsants are the drugs of choice. Before establishing an analgesic treatment, possible drug interactions should be ruled out, mainly those occurring with antiretroviral agents.

A review of the epidemiology of painful diabetic peripheral neuropathy, postherpetic neuralgia, and less commonly studied neuropathic pain conditions

Although the burden of neuropathic pain is well-recognized, the descriptive epidemiology of specific neuropathic pain conditions has not been well-described. While painful diabetic peripheral neuropathy and postherpetic neuralgia have been widely evaluated, many other peripheral and central neuropathic pain syndromes have been less frequently studied. This review summarizes incidence and/or prevalence information about two relatively frequent neuropathic pain conditions-painful diabetic peripheral neuropathy and postherpetic neuralgia-and similarly summarizes the more limited epidemiologic information available for other peripheral and central neuropathic pain conditions. The data suggest that while our knowledge is still incomplete, the high frequency of several of these conditions in specific populations should be considered an important impetus for further studies designed to evaluate their contribution to the overall burden of neuropathic pain.

Disseminated sporotrichosis presenting with granulomatous inflammatory multiple mononeuropathies

We describe a case of sporotrichosis that disseminated to involve multiple nerves after initiation of immunosuppressive therapy and then precipitously worsened after withdrawal of therapy. This case illustrates that multiple mononeuropathies are not always caused by vasculitis, and a correct pathological diagnosis should be established before treatment. Based on clinical and pathological features, the mechanism of neuropathy may have been due to either direct nerve infection or a bystander effect of inflammatory/immune damage or, perhaps more likely, to both mechanisms.

Central activation, muscle performance, and physical function in men infected with human immunodeficiency virus

Loss of muscle mass and limitations in activity have been reported in persons infected with human immunodeficiency virus (HIV), even those who are otherwise asymptomatic. The extent to which factors other than muscle atrophy impair muscle performance has not been addressed in depth. The purpose of this study was to determine the extent of neuromuscular activation of the knee extensors and ankle dorsiflexors of 27 men infected with HIV receiving antiretroviral therapy and its relationship to muscle performance. The central activation ratio (CAR) was determined using superimposed electrical stimulation during maximum voluntary contractions. In addition to force and power measurements, muscle cross-sectional area and composition was evaluated using computed tomography. Aerobic capacity was determined from treadmill exercise testing. Eleven of the subjects had an impaired ability to activate the knee extensors (CAR = 0.72 +/- 0.12) that was associated with weakness and decreased specific force. The reduced central activation was not associated with muscle area, body composition, aerobic capacity, CD4 count, or medication regimen. Those individuals with low central activation had higher HIV-1 viral loads and were more likely to have a history of AIDS-defining illness. These results suggest the possibility of a different mechanism contributing to muscle impairment in the current treatment era that is associated with impairment of central motor function rather than atrophy. Further investigation is warranted in a larger, more diverse population before more definitive claims are made.

Neurotoxicity caused by didanosine on cultured dorsal root ganglion neurons

The purpose of the present study was to investigate whether didanosine (ddI) directly causes morphological and ultrastructural abnormalities of dorsal root ganglion (DRG) neurons in vitro. Dissociated DRG cells and organotypic DRG explants from embryonic 15-day-old Wistar rats were cultured for 3 days and then exposed to ddI (1 microg/ml, 5 microg/ml, 10 microg/ml, and 20 microg/ml) for another 3 days and 6 days, respectively. Neurons cultured continuously in medium served as normal controls. The diameter of the neuronal cell body and neurite length were measured in dissociated DRG cell cultures. Neuronal ultrastructural changes were observed in both culture models. ddI induced dose-dependent decreases in neurite number, length of the longest neurite in each neuron, and total neurite length per neuron in dissociated DRG cell cultures with 3 days treatment. There were no morphological changes seen in organotypic DRG cultures even with longer exposure time (6 days). But ddI induced ultrastructural changes in both culture models. Ultrastructural abnormalities included loss of cristae in mitochondria, clustering of microtubules and neurofilaments, accumulation of glycogen-like granules, and emergence of large dense particles between neurites or microtubules. Lysosome-like large particles emerged inconstantly in neurites. ddI induced a neurite retraction or neurite loss in a dose-dependent manner in dissociated DRG neurons, suggesting that ddI may partially contribute to developing peripheral neuropathy. Cytoskeletal rearrangement and ultrastructural abnormalities caused by ddI in both culture models may have a key role in neurite degeneration.

Central action of prosaptide TX14(A) against gp120-induced allodynia in rats

We investigated the effect of the prosaposin-derived peptide prosaptide TX14(A) on tactile allodynia in rats following intraplantar injection of the HIV envelope glycoprotein gp120. Systemic administration of TX14(A) dose-dependently prevented onset of tactile allodynia following intraplantar injection of gp120 and also transiently alleviated established allodynia in the same model. TX14(A) did not prevent tactile allodynia when injected directly into the foot pad whereas intrathecal administration of TX14(A) both prevented and alleviated gp120-induced tactile allodynia. Nerve and spinal cord levels of TNFalpha protein were unchanged in intraplantar gp120 injected rats that displayed allodynia. These results indicate that TX14(A) has anti-allodynic properties in a rat model of gp120-induced tactile allodynia and that the mechanism of action of TX14(A) may include modulation of spinal nociceptive processing.

Specific neurologic complications of human immunodeficiency virus type 1 (HIV-1) infection in children

Pediatric human immunodeficiency virus type 1 (HIV-1) infection is endemic throughout southern Africa. Neurologic complications are described in 20% to 60% of published series, mostly related to HIV-1 encephalopathy. With increasing HIV prevalence, more atypical cases are presenting. We present, as illustrative cases, seven children (three girls) with unusual neurologic sequelae as a consequence of HIV-1 infection. The median age at presentation was 33 months (range 7 months-6 years). Five of the seven children were developmentally normal before presentation. They presented with progressive multifocal leukoencephalopathy, myelopathy, intractable seizures, acute vasculitis and blindness, hemiplegia, peripheral neuropathy, and paraspinal lymphoma. Neuroimaging of the brain was performed in five patients, of whom one had basal ganglia calcification. All children had poor outcome with incomplete recovery or continued deterioration. In conclusion, children with HIV-1 infection who survive beyond the first year of life can present with a wide variety of neurologic complications. A similar spectrum of neurologic manifestations is likely to occur in other sub-Saharan African countries, characterized by high HIV prevalence. The case histories demonstrate that the neurologic features of pediatric HIV infection do not easily fit into a simplified classification system.

Degenerative and inflammatory lesions in sympathetic ganglia: further morphological evidence for an autonomic neuropathy in AIDS

There is accumulating evidence that autonomic dysfunction occurs in HIV infection. While many studies have demonstrated autonomic abnormalities on clinical basis, only one has studied the morphology of sympathetic ganglia. The superior sympathetic ganglia of 12 randomly selected AIDS patients and those of 6 controls were examined morphologically in order to determine the frequency and severity of their involvement. Although they had not been investigated for autonomic dysfunction, 5 had suffered from non-infectious diarrhoea, one showed bilateral ptosis and another had non-specified visual problems. All cases showed clusters, and perivascular mononuclear inflammatory cells, occasionally infiltrating vessel walls, some evidence of nerve cell degeneration, and proliferation of capsule cells. Immunostainings showed T lymphocytes and an increased number of macrophages. HIV antigens were detected in macrophages, in 6 cases (50%). This study provides further morphological support for the autonomic dysfunction in association with HIV infection. As for the mechanism of this dysfunction, it has been postulated a direct infection, the virus entering the ganglia through macrophages and acting as a reservoir for HIV, and an autoimmune pathogenesis. Since HIV antigens were not detected in 50% of the cases in this and in a previous study, despite the existence of morphological lesions, it is possible that, as in HIV-related sensory-motor peripheral neuropathies, an autoimmune mechanism may also play a role in the development of the autonomic lesions.

HIV peripheral neuropathy: pathophysiology and clinical implications

One of the most debilitating neurological complications of human immunodeficiency virus (HIV), affecting nearly one in three patients, is painful peripheral neuropathy. Although HIV infection can cause distal sensory polyneuropathy (DSP), the advent of highly active antiretroviral therapy (HAART) to treat HIV infection has resulted in a significant number of patients developing a clinically indistinguishable form of toxic neuropathy. The predominant symptom, regardless of etiology, is excruciating unremitting pain, resistant to pharmacological treatments, that leads to a reduction in the ability to conduct activities of daily living and, eventually, inability to ambulate. Since withdrawal from nucleoside therapy is not typically recommended, a more thorough understanding of the etiology and pathophysiology underlying nucleoside-induced peripheral neuropathy, through basic and clinical research endeavors, will aid in the development of new therapeutic treatments aimed at alleviating or ameliorating pain. This article provides the latest information regarding the pathophysiology and clinical implications of HIV peripheral neuropathy.

CD8+ lymphocyte-mediated injury of dorsal root ganglion neurons during lentivirus infection: CD154-dependent cell contact neurotoxicity

Neuronal damage in dorsal root ganglia (DRGs) with accompanying axonal injury is a key feature of human immunodeficiency virus (HIV)-related distal sensory polyneuropathy (DSP). In a model of HIV-related DSP, we observed numerous CD3+ T lymphocytes (p < 0.05) in DRGs from feline immunodeficiency virus (FIV)-infected animals, which also exhibited low CD4+ and high CD8+ lymphocyte levels in blood accompanied by a selective loss of small-diameter sural nerve axons (p < 0.05). FIV-infected lymphocytes cocultured with syngeneic DRGs caused neuronal damage, indicated by neurite retraction, neuronal soma atrophy, and loss (p < 0.05). In contrast, supernatants from FIV-infected or uninfected lymphocytes were minimally neurotoxic, despite high FIV virion levels. Among lymphocyte subsets cocultured with DRG cultures, CD8+ T cells from both FIV-infected and uninfected lymphocytes selectively caused DRG neuronal injury (p < 0.05). FIV-infected CD8+ T cells showed markedly increased CD154 expression (p < 0.05), whereas neurons were the predominant cells expressing CD40 in DRGs. Blocking CD154 on activated CD8+ T cells protected DRG neurons (p < 0.05). These findings indicated that CD8+ T cells were principal effectors of DRG neuronal injury after FIV infection through a CD40-CD154 interaction in a cell contact-dependent manner.