[Zika virus infection and the nervous system]

Zika virus is an arbovirus from the family of flaviviruses, which is transmitted by the mosquito Aedes aegyptii and also by the Asian mosquito Aedes albopticus. The largest observed Zika virus epidemic is currently taking place in North and South America, in the Caribbean, southern USA and Southeast Asia. In most cases the infection is an unspecific, acute, febrile disease. Neurological manifestations consist mainly of microcephaly in newborns and Guillain-Barré syndrome but other rare manifestations have also become known in the meantime, such as meningoencephalitis and myelitis. Therefore, the Zika virus, similar to other flaviviruses, has neuropathogenic properties. In particular, the drastic increase in microcephaly cases in Brazil has induced great research activities. The virus is transmitted perinatally and can be detected in the amniotic fluid, placenta and brain tissue of the newborn. Vaccination or a causal therapy does not yet exist. The significant increase in Guillain-Barré syndrome induced by the Zika virus was observed during earlier outbreaks. In the meantime, scientifically clear connections between a Zika virus infection and these neurological manifestations have been shown. Long-term studies and animal models should be used for a better understanding of the pathomechanisms of this disease.

Mechanism- and experience-based strategies to optimize treatment response to the capsaicin 8% cutaneous patch in patients with localized neuropathic pain

The capsaicin 8% cutaneous patch is an emergent new treatment option for patients with peripheral neuropathic pain. In randomized controlled clinical studies relevant pain relief for 12 weeks was achieved in about one third of patients following a single application. The first part of this paper is a review of the pathophysiology, pharmacology, and published clinical trials with the capsaicin 8% cutaneous patch. The second part reports on outcomes of an interdisciplinary expert workshop, where new treatment results of three major German pain centers were presented and reviewed with the objectives of obtaining responder rates for different pain syndromes, assessing maintenance of effect under real-life conditions, and giving recommendations for practical care. The 12 week responder rates with pain relief of ≥ 30% were comparable in patients with mononeuropathies (37.9%) and postherpetic neuralgia (38.8%). Similar responder rates were seen in a subgroup of patients with cervical spine radiculopathy and back pain (46.7%). In HIV-associated neuropathy the responder rates were high (47.8%) but lower in patients with other polyneuropathies (17.6%). Response rates were nearly identical after 1 week (46.6%) and 4 weeks (43.3) and dropped only slightly at 12 weeks (37.4%). In a subgroup of 54 patients who underwent a second treatment, efficacy was maintained. Response rates in patients with or without lidocaine pretreatment were comparable. Treatment with the capsaicin 8% cutaneous patch was generally safe and well tolerated. The workshop panel recommended further investigation of opportunities to improve the application procedure and to perform studies on the skin penetration and distribution of capsaicin. A modified quantitative sensory testing (QST) should be developed for clinical practice in order to better understand the correlation of sensory profiles and response to capsaicin treatment.

Cognitive impairment in HIV infection is associated with MRI and CSF pattern of neurodegeneration

BACKGROUND AND PURPOSE

Biomarkers as indicators for the progression of human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) remain still elusive. We performed a cross-sectional study to analyze the correlation between cognitive impairment, abnormalities in magnetic resonance imaging (MRI), and cerebrospinal fluid (CSF) markers of neurodegeneration in HIV-infected patients.

METHODS

We enrolled 94 patients (82 men and 12 women; mean age 45 ± 10 years) with HIV infection, but without opportunistic infections of the CNS. All patients underwent MRI and CSF analysis. The global pattern of white matter signal intensity abnormalities, the index of atrophy, the severity of periventricular white matter abnormalities, and the severity of basal ganglia signal changes were analyzed. We measured CSF markers of neurodegeneration (total tau, phospho-tau, beta-amyloid). The findings of this evaluation were correlated with demographic and infection parameters of the patients in blood and CSF.

RESULTS

We found a highly significant correlation between the severity of global brain atrophy, basal ganglia signal changes, and cognitive impairment in HIV-infected patients. Furthermore, cognitive impairment was significantly correlated with total tau, but not with phospho-tau or A-beta-amyloid in CSF analysis.

CONCLUSIONS

Our results confirm the significant correlation between MRI changes and cognitive impairment in HIV infection. Furthermore, we could show that global brain atrophy and signal changes in basal ganglia are the typical MRI pattern in HAND. The correlation between cognitive impairment and total tau, but not phospho-tau, supports the hypothesis that HAND are not a subtype of Alzheimer's dementia.

[Neuro-AIDS in the cART era]

After the introduction of antiretroviral combination therapy for the treatment of HIV infection in 1996 (highly active antiretroviral therapy = HAART, nowadays called combination antiretroviral therapy = cART), a steady decline in infection associated complications had been expected, especially with respect to central and peripheral nervous system manifestations. Until the beginning of the new millenium this hope came in fact true, but since then there has been a slow, but constant rise in the prevalence, and later on also in the incidence of directly virus-associated neurological complications in HIV infected patients. HIV-associated diseases that neurologists might see in their routine work include HIV-associated dementia (HAD) and its precursor stages, HIV-associated myelopathy, HIV-associated polyneuropathies and myopathies as well as the opportunistic brain infections and immune reconstitution phenomena (IRIS). This article describes practical diagnostic procedures according to the guidelines of the German Neurological Society and the respective therapeutic options.

Increased dopaminergic neurotransmission in therapy-naïve asymptomatic HIV patients is not associated with adaptive changes at the dopaminergic synapses

Central dopaminergic (DA) systems are affected during human immunodeficiency virus (HIV) infection. So far, it is believed that they degenerate with progression of HIV disease because deterioration of DA systems is evident in advanced stages of infection. In this manuscript we found that (a) DA levels are increased and DA turnover is decreased in CSF of therapy-naïve HIV patients in asymptomatic infection, (b) DA increase does not modulate the availability of DA transporters and D2-receptors, (c) DA correlates inversely with CD4+ numbers in blood. These findings show activation of central DA systems without development of adaptive responses at DA synapses in asymptomatic HIV infection. It is probable that DA deterioration in advanced stages of HIV infection may derive from increased DA availability in early infection, resulting in DA neurotoxicity. Our findings provide a clue to the synergism between DA medication or drugs of abuse and HIV infection to exacerbate and accelerate HIV neuropsychiatric disease, a central issue in the neurobiology of HIV.

[Severe aseptic leucoencephalopathy. Manifested as immune reconstitution inflammatory syndrome in Caucasian and African patients]

BACKGROUND

We hypothesize that CNS immune reconstitution inflammatory syndrome (IRIS) after highly active antiretroviral therapy (HAART) in HIV-1-positive patients may become manifest without any opportunistic infection as an aseptic leucoencephalopathy. This opens a window of opportunity for successful treatment with corticosteroids.

DESIGN

We describe a case series of immunocompromised HIV-1-positive patients who were started on HAART. All of them had clinical laboratory follow-up tests and cerebral MRI in order to investigate the course and the underlying pathophysiology of this aseptic form of IRIS. One African patient died and we performed a neuropathological examination.

RESULTS

No infectious agent was detected before and during HAART. Three of four immunocompromised patients were successfully treated with corticosteroids while HAART was never interrupted and have survived up to now. One African patient died within 2 days despite intensive care due to cerebral oedema.

CONCLUSIONS

Starting HAART, HIV-1-positive patients may develop an aseptic type of IRIS of the CNS without any detectable opportunistic infection, a finding that has not yet been published. This makes them susceptible for successful treatment with corticosteroids. Perhaps IRIS has a higher incidence in African patients and the patients have a poorer outcome than Caucasians.

HIV or HIV-therapy? Causal attributions of symptoms and their impact on treatment decisions among women and men with HIV

OBJECTIVES

Among people with HIV, we examined symptom attribution to HIV or HIV-therapy, awareness of potential side effects and discontinuation of treatment, as well as sex/gender differences.

METHODS

HIV-patients (N=168, 46% female) completed a comprehensive symptom checklist (attributing each endorsed symptom to HIV, HIV-therapy, or other causes), reported reasons for treatment discontinuations and potential ART-related laboratory abnormalities.

RESULTS

Main symptom areas were fatigue/sleep/energy, depression/mood, lipodystrophy, and gastrointestinal, dermatological, and neurological problems. Top HIV-attributed symptoms were lack of stamina/energy in both genders, night sweats, depression, mood swings in women; and fatigue, lethargy, difficulties concentrating in men. Women attributed symptoms less frequently to HIV than men, particularly fatigue (p<.01). Top treatment-attributed symptoms were lipodystrophy and gastrointestinal problems in both genders. Symptom attribution to HIV-therapy did not differ between genders. Over the past six months, 22% switched/interrupted ART due to side effects. In women, side effect-related treatment decisions were more complex, involving more side effects and substances. Remarkably, women took predominantly protease inhibitor-sparing regimens (p=.05). Both genders reported only 15% of potential ART-related laboratory abnormalities but more than 50% had laboratory abnormalities. Notably, women had fewer elevated renal parameters (p<.01).

CONCLUSIONS

Men may attribute symptoms more often to HIV and maintain a treatment-regimen despite side effects, whereas women may be more prudent in avoiding treatment side effects. Lacking awareness of laboratory abnormalities in both genders potentially indicates gaps in physician-patient communication. Gender differences in causal attributions of symptoms/side effects may influence treatment decisions.

Substantia nigra hyperechogenicity and CSF dopamine depletion in HIV

Dopaminergic dysfunction is thought to play a pivotal role in human immunodeficiency virus (HIV)-related dementia. Decreased dopamine (DA) levels in the cerebrospinal fluid (CSF) and neuronal loss in the substantia nigra (SN) have been reported in HIV-infected patients, suggesting nigrostriatal damage. Structural changes detectable as hyperechogenicity in transcranial ultrasound (TCS) scans of the SN have been reported in patients with Parkinson's disease (PD) and other neurological conditions. In this study, we assessed the echomorphology of the SN in 40 HIV-positive patients compared to 40 age- and sex-matched healthy controls and correlated these findings with CSF levels of DA and the metabolites homovanillic acid (HVA) and 3,4-dihydroxy phenylacetic acid (DOPAC) and with neuropsychologic performance. We observed that the SN of HIV-infected patients was hyperechogenic relative to that of controls (0.07 +/- 0.05 vs. 0.04 +/- 0.07 cm(2); mean +/- SEM; P < 0.001) and that this SN hyperechogenicity was correlated with decreased DA levels in the CSF, decreased CD4 cell count, and an impaired performance in the psychopathology assessment scale (AMDP) subtest for drive and psychomobility. An association to CDC stage, duration of HIV infection, or presence of HIV dementia was not observed. Our results indicate changes in the nigrostriatal system in HIV-infected patients that are detectable as hyperechogenic SN precede prominent extrapyramidal symptoms and cognitive dysfunction.

Updated research nosology for HIV-associated neurocognitive disorders

In 1991, the AIDS Task Force of the American Academy of Neurology published nomenclature and research case definitions to guide the diagnosis of neurologic manifestations of HIV-1 infection. Now, 16 years later, the National Institute of Mental Health and the National Institute of Neurological Diseases and Stroke have charged a working group to critically review the adequacy and utility of these definitional criteria and to identify aspects that require updating. This report represents a majority view, and unanimity was not reached on all points. It reviews our collective experience with HIV-associated neurocognitive disorders (HAND), particularly since the advent of highly active antiretroviral treatment, and their definitional criteria; discusses the impact of comorbidities; and suggests inclusion of the term asymptomatic neurocognitive impairment to categorize individuals with subclinical impairment. An algorithm is proposed to assist in standardized diagnostic classification of HAND.

[Neurological manifestations of HIV-infection in the era of highly active antiretroviral therapy (HAART)]

After the introduction of highly active antiretroviral therapy (HAART) in 1996 the neurological manifestations of human immunodeficiency virus (HIV-1)-infection did not decline in incidence and prevalence like the other complications of immunodeficiency; in contrast, due to the longer survival times of HAART treated HIV-1-positive individuals, prevalence of virus associated neurological disease increased during the last years, as international studies underline. Therefore, clinicians and HIV-therapists should be able to diagnose HIV-1-associated neurological disease even in early stages. This article describes symptoms and signs, neuro-imaging and cerebrospinal fluid findings as well as therapy options in primary HIV-1-associated neurological disease like encephalo- and myelopathy and polyneuropathy. Furthermore, those opportunistic infections, caused by bacteria, viruses other than HIV and parasites emerging with manifest immunodeficiency and remaining to be relevant in the HAART era are presented from diagnostic, differential-diagnostic and therapeutic points of view. An extra paragraph describes the interaction of HAART with neurological/psychiatric standard therapies.

Recommendations for the classification of HIV associated neuromanifestations in the German DRG system

HIV associated neuromanifestations are of growing importance in the in-patient treatment of HIV infected patients. In Germany, all in-patients have to be coded according to the ICD-10 classification and the German DRG-system. We present recommendations how to code the different primary and secondary neuromanifestations of HIV infection. These recommendations are based on the commentary of the German DRG procedures and are aimed to establish uniform coding of neuromanifestations.

[Neurological manifestations of the HIV infection]

As a result of improved therapeutic possibilities with highly active antiretroviral therapy (HAART), an increasing prevalence of neurological complications of the HIV infection is observed. In particular, some authors now also describe a "morphogenesis" of the HIV-1-related encephalopathy. The current state of knowledge should be taken into account in the diagnostics and therapy of HIV-1-related encephalopathy, depression, progressive multifocal leukencephalopathy and polyneuropathy.

A placebo-controlled trial of gabapentin for painful HIV-associated sensory neuropathies

BACKGROUND

Painful HIV-associated sensory neuropathies (HIV-SN) are a common complication of HIV infection. The pathogenesis is unknown and the treatment very limited. Gabapentin (GBP) is effective in painful diabetic neuropathy and postherpetic neuralgia and its effectiveness on painful HIV-SN has been reported anecdotally.

DESIGN

Multicenter, prospective, randomised, double-blind, placebo-controlled study.

METHODS

Patients were followed for a 1-week screening, a 4-week double-blind and a 2-week open treatment phase. GBP was initiated at 400 mg/d, titrated over 2 weeks to 1200 mg/d, and then either maintained at this level or-if not beneficial-titrated to 2400 mg/d. After 4 weeks the medication was unblinded and the patient had the choice to begin, to maintain or to increase GBP to 3600 mg/d. The primary outcome measure was an improvement in median pain on the Visual Analogue Scale (VAS) from the screening week compared to the 4(th) treatment week. A secondary efficacy measure was the median sleep score (VAS).

RESULTS

15 patients received GBP and 11 placebo. In each group one patient dropped out during the doubleblind phase. Median pain (GBP 5.1; placebo 4.7) and sleep score (GBP 4.5; placebo 5.6) did not differ between both groups at baseline. In the GBP-group there was a significant decrease of the pain to 2.85 (-44.1 %) as well as of the sleep VAS to 2.3 (-48.9 %). No significant decrease in the pain (median VAS=3.3, -29.8 %) as well as in the sleep score (median VAS=4.95, -11.6 %) was observed in the placebo-group. GBP was generally well tolerated. The most frequent side effect was somnolence reported in 80% of GBP-treated patients.

CONCLUSIONS

GBP was more effective than placebo in reducing pain and sleep interference in patients with HIV-SN.

Vascular endothelial growth factor (VEGF) is increased in serum, but not in cerebrospinal fluid in HIV associated CNS diseases

Vascular endothelial growth factor (VEGF) is a potent angiogenic and mitogenic peptide, which also induces several mediators that may play a role in HIV induced CNS damage. VEGF levels were determined in cerebrospinal fluid (CSF) and serum samples from patients with (n = 8) and without (n = 19) directly HIV associated CNS disorders and HIV negative control patients (n = 18). VEGF serum but not CSF levels were significantly increased in HIV infected patients with (381.1 (78.9) pg/ml) HIV associated CNS diseases compared with those without (120.8 (13.1) pg/ml) and HIV negative control patients (133.1(14.8) pg/ml). Serum samples from patients with untreated HIV associated encephalopathy (HIVE, n = 3) contained the highest VEGF levels (583.9 (71.5) pg/ml). In two patients VEGF serum levels were reduced during antiretroviral therapy. However, regardless of effective viral suppression, patients with HIVE still had higher levels compared with HIV infected patients without HIVE. A relevant increase of serum VEGF was not observed in patients without HIVE though high HI viral load. We conclude that HIVE is associated with increased serum VEGF levels. Further studies are warranted to elucidate the role of VEGF in HIVE.

Potential c-fiber damage in Wilson's disease

OBJECTIVES

To find out about potential involvement of the peripheral and autonomic nervous system in Wilson's disease (WD).

MATERIAL AND METHODS

Seventeen patients with laboratory proven WD were examined with quantitative sensory testing (QST) (thermal, pain and vibratory sensation), pupillometric evaluation and electrophysiological testing of basal ganglia motor function [frequency of most rapid alternating movements (MRAM), reaction time (RT), contraction time (CT)]. Results were compared with those obtained in 20 healthy controls.

RESULTS

After correction for multiple comparisons, patients with WD showed significantly higher thresholds for warm sensation [sural and peroneal nerve, thermal sensory limen (TSL), unpaired t-test]. Individual results were pathological in eight (peroneal) and nine (sural nerve) patients, respectively. Pupil function was not altered. Patients with WD showed significant slowing of MRAM and prolongation of RT and CT. There was no significant correlation between RT and QST results.

CONCLUSIONS

These findings are compatible with a potential involvement of unmyelinated warm-specific C fibers in WD, independent from predominant basal ganglia motor dysfunction.

Delayed motor learning and psychomotor slowing in HIV-infected children

OBJECTIVE

To find out whether HIV-associated subclinical psychomotor slowing is present in HIV-infected children despite effective highly active antiretroviral therapy (HAART).

PATIENTS AND METHODS

An electrophysiological motor test battery shown to sensitively describe HIV-associated CNS disease in adults (tremor peak frequency []TPF], most rapid alternating movements [MRAM], reaction time [RT] and contraction time [CT]) was performed in 17 HIV seropositive (+) right-handed children. Results were compared to 16 HIV seronegative (-) children.

RESULTS

HIV (-) children showed slower frequencies (TPF, MRAM) and longer RT and CT than (-) adults. They showed a significant correlation (p = 0.0263) between RT (right = dominant hand) and age. HIV (+) children showed significant prolongations of RT (right hand) and CT (both hands) compared to HIV (-) children. RT right hand did not accelerate with age in HIV (+) children. CT were significantly prolonged in 10 children with detectable HIV plasma viral burden and normal in 7 children with no detectable HIV plasma viral load. There was no correlation between CT and CD 4 cell counts.

CONCLUSIONS

Despite effective HAART, electrophysiological motor testing in HIV (+) children reveals significant subclinical CNS dysfunction, especially in children with insufficient viral load suppression.

[Neurologic complications of HIV infection in the HAART era. Rapid and efficient diagnosis]

Despite the undisputable therapeutic success of highly active antiretroviral therapy (HAART), neurological complications of HIV-infection are still an unresolved problem. Most important are the directly HIV-associated complications, which comprise HIV-associated encephalopathy, myelopathy as well as peripheral neuropathies and muscle diseases. Among the nowadays relevant opportunistic infections are toxoplasma encephalitis and JC-virus related progressive multifocal leukencephalopathy, finally neurological complications are provoked by so called immune reconstitution phenomena. This reviews' aim is to provide a diagnostic manual leading to appropriate therapy by effective diagnostic procedures.