Diagnosing and treating HIV-associated sensory neuropathy: a global perspective

Neuropathy in Human Immunodeficiency Virus: A Review of the Underlying Pathogenesis and Treatment

This article explores the various causes of the human immunodeficiency virus (HIV), and its associated neuropathy, including the effects of HIV on the nervous system and the long-standing therapy that is often provided to patients with HIV. Several studies regarding the neurotoxic effects of combined antiretroviral therapy (cART) and HIV were reviewed and various hypotheses were discussed. Furthermore, we present the nature of HIV-sensory neuropathy (HIV-SN) among different demographic populations and their subsequent risk factors predisposing them to this condition. It was observed that the incidence of the disease increases in increased survival of the patients as well as in males. Finally, the current approach to HIV-SN and its overlapping features with other causes of peripheral neuropathy have been discussed which demonstrates that a clinical examination is the most important clue for a healthcare professional to suspect the disease. Our main aim was to study the current perspectives and guidelines for diagnosing and managing a patient with HIV-SN to reduce disease prevalence and bring about a more aware frame of mind when following up with an HIV patient.

Magnetic Resonance Imaging as a Biomarker in Diabetic and HIV-Associated Peripheral Neuropathy: A Systematic Review-Based Narrative

Background: Peripheral neuropathy can be caused by diabetes mellitus and HIV infection, and often leaves patients with treatment-resistant neuropathic pain. To better treat this condition, we need greater understanding of the pathogenesis, as well as objective biomarkers to predict treatment response. Magnetic resonance imaging (MRI) has a firm place as a biomarker for diseases of the central nervous system (CNS), but until recently has had little role for disease of the peripheral nervous system. Objectives: To review the current state-of-the-art of peripheral nerve MRI in diabetic and HIV symmetrical polyneuropathy. We used systematic literature search methods to identify all studies currently published, using this as a basis for a narrative review to discuss major findings in the literature. We also assessed risk of bias, as well as technical aspects of MRI and statistical analysis. Methods: Protocol was pre-registered on NIHR PROSPERO database. MEDLINE, Web of Science and EMBASE databases were searched from 1946 to 15th August 2020 for all studies investigating either diabetic or HIV neuropathy and MRI, focusing exclusively on studies investigating symmetrical polyneuropathy. The NIH quality assessment tool for observational and cross-sectional cohort studies was used for risk of bias assessment. Results: The search resulted in 18 papers eligible for review, 18 for diabetic neuropathy and 0 for HIV neuropathy. Risk of bias assessment demonstrated that studies generally lacked explicit sample size justifications, and some may be underpowered. Whilst most studies made efforts to balance groups for confounding variables (age, gender, BMI, disease duration), there was lack of consistency between studies. Overall, the literature provides convincing evidence that DPN is associated with larger nerve cross sectional area, T2-weighted hyperintense and hypointense lesions, evidence of nerve oedema on Dixon imaging, decreased fractional anisotropy and increased apparent diffusion coefficient compared with controls. Analysis to date is largely restricted to the sciatic nerve or its branches. Conclusions: There is emerging evidence that various structural MR metrics may be useful as biomarkers in diabetic polyneuropathy, and areas for future direction are discussed. Expanding this technique to other forms of peripheral neuropathy, including HIV neuropathy, would be of value. Systematic Review Registration: (identifier: CRD 42020167322) https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=167322.

Novel RET agonist for the treatment of experimental neuropathies

The glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs) alleviate symptoms of experimental neuropathy, protect and stimulate regeneration of sensory neurons in animal models of neuropathic pain, and restore their functional activity. However, clinical development of GFL proteins is complicated by their poor pharmacokinetic properties and multiple effects mediated by several receptors. Previously, we have identified a small molecule that selectively activates the major signal transduction unit of the GFL receptor complex, receptor tyrosine kinase RET, as an alternative to GFLs, for the treatment of neuropathic pain. We then introduced a series of chemical changes to improve the biological activity of these compounds and tested an optimized compound named BT44 in a panel of biological assays. BT44 efficiently and selectively stimulated the GFL receptor RET and activated the intracellular mitogene-activated protein kinase/extracellular signal-regulated kinase pathway in immortalized cells. In cultured sensory neurons, BT44 stimulated neurite outgrowth with an efficacy comparable to that of GFLs. BT44 alleviated mechanical hypersensitivity in surgery- and diabetes-induced rat models of neuropathic pain. In addition, BT44 normalized, to a certain degree, the expression of nociception-related neuronal markers which were altered by spinal nerve ligation, the neuropathy model used in this study. Our results suggest that the GFL mimetic BT44 is a promising new lead for the development of novel disease-modifying agents for the treatment of neuropathy and neuropathic pain.

Alcohol-Induced Neuropathy in Chronic Alcoholism: Causes, Pathophysiology, Diagnosis, and Treatment Options

Purpose of the Review

Alcohol abuse causes a wide range of disorders that affect the nervous system. These include confusion, cerebellar ataxia, peripheral neuropathy, and cognitive impairment. Chronic and excessive alcohol consumption is the primary cause of peripheral neuropathy. It is worth noting that peripheral neuropathy has no reliable treatment due to the poor understanding of its pathology.

Recent Findings

Coasting is a major feature of alcoholic neuropathy, largely due to chronic alcohol abuse. Its major features are hyperalgesia, allodynia, and burning pain. Even though much research was done in this area, still we do not have a full understanding of the mechanism of alcoholic neuropathy. However, some theories have been proposed. These include direct or indirect effects of alcohol metabolites, impaired axonal transport, suppressed excitatory nerve pathway activity, or imbalance in neurotransmitters. Activation of spinal cord microglia, mGlu5 spinal cord receptors, and hypothalamic-pituitary-adrenal axis also seem to be implicated in the pathophysiology of this alcoholic neuropathy. The goal of treatment is to impede further damage to the peripheral nerves while also restoring their normal physiology. Alcohol abstinence, intake of balanced diets, and treatment with medications are suggested including benfotiamine, alpha-lipoic acid, acetyl-l-carnitine, vitamin E, methylcobalamin, myo-inositol, N-acetylcysteine, capsaicin, tricyclic antidepressants, or antiepileptic drugs.

Summary

This review focuses on the many pathways that play a role in the onset and development of alcohol-induced neuropathy, as well as present the possible treatment strategies of this disorder, providing insights into a further search of new treatment modalities.

Higher iron stores and the HFE 187C>G variant delay onset of peripheral neuropathy during combination antiretroviral therapy

OBJECTIVE

People with HIV (PWH) continue to experience sensory neuropathy and neuropathic pain in the combination antiretroviral therapy (cART) era for unclear reasons. This study evaluated the role of iron in a previously reported association of iron-loading hemochromatosis (HFE) gene variants with reduced risk of neuropathy in PWH who received more neurotoxic cART, since an iron-related mechanism also might be relevant to neuropathic symptoms in PWH living in low-resource settings today.

DESIGN

This time-to-event analysis addressed the impact of systemic iron levels on the rapidity of neuropathy onset in PWH who initiated cART.

METHODS

Soluble transferrin receptor (sTFR), the sTFR-ferritin index of iron stores, and high-sensitivity C-reactive protein (hsCRP) levels were determined in stored baseline sera from participants of known HFE genotype from AIDS Clinical Trials Group (ACTG) Study 384, a multicenter randomized clinical trial that evaluated cART strategies. Associations with incident neuropathy were evaluated in proportional-hazards, time-to-event regression models, adjusting for potential confounders.

RESULTS

Of 151 eligible participants with stored serum who were included in the original genetic study, 43 had cART-associated neuropathy; 108 had sufficient serum for analysis, including 30 neuropathy cases. Carriers of HFE variants had higher systemic iron (lower sTFR and sTFR-ferritin index) and lower hsCRP levels than non-carriers (all p<0.05). Higher sTFR or iron stores, the HFE 187C>G variant, and lower baseline hsCRP were associated with significantly delayed neuropathy in self-reported whites (n = 28; all p-values<0.05), independent of age, CD4+ T-cell count, plasma HIV RNA, and cART regimen.

CONCLUSIONS

Higher iron stores, the HFE 187C>G variant, and lower hsCRP predicted delayed onset of neuropathy among self-reported white individuals initating cART. These findings require confirmation but may have implications for cART in HIV+ populations in areas with high endemic iron deficiency, especially those PWH in whom older, more neurotoxic antiretroviral drugs are occasionally still used.

Assessment and Management of HIV Distal Sensory Peripheral Neuropathy: Understanding the Symptoms

Distal sensory peripheral neuropathy (HIV-DSP) affects upwards of 50% of people living with HIV. Causing often debilitating symptoms of tingling, numbness and burning, HIV-DSP can result in disability, unemployment and low quality of life. Comorbidities further complicate nursing care, heightening risk of polypharmacy and symptom exacerbation. Therefore, a neurological sensory assessment, combined with the patient's self-report of symptoms, can help nurse practitioners visualize, quantify and understand symptoms. Common pharmacological interventions include antiepileptics, antidepressants, analgesics and medical marijuana. The complexity of care for individuals with HIV-DSP merits a comprehensive approach. Implications for practice include interdisciplinary management with neurologists, podiatrists, mental health providers, and nurse-led counseling inclusive of patient safety teaching.

The molecular mechanisms that underpin the biological benefits of full-spectrum cannabis extract in the treatment of neuropathic pain and inflammation

Cannabis has been shown to be beneficial in the treatment of pain and inflammatory diseases. The biological effect of cannabis is mainly attributed to two major cannabinoids, tetrahydrocannabinol and cannabidiol. In the majority of studies to-date, a purified tetrahydrocannabinol and cannabidiol alone or in combination have been extensively examined in many studies for the treatment of numerous disorders including pain and inflammation. However, few studies have investigated the biological benefits of full-spectrum cannabis plant extract. Given that cannabis is known to generate a large number of cannabinoids along with numerous other biologically relevant products including terpenes, studies involving purified tetrahydrocannabinol and/or cannabidiol do not consider the potential biological benefits of the full-spectrum cannabis extracts. This may be especially true in the case of cannabis as a potential treatment of pain and inflammation. Herein, we review the pre-clinical physiological and molecular mechanisms in biological systems that are affected by cannabis.

Peripheral neuropathy in patients with human immunodeficiency viral infection at a tertiary hospital in Ghana

Peripheral neuropathy (PN) is the most frequent neurological complication in people living with HIV/AIDS. Neurological damage was identified to not only be caused by the viral infection itself but also through neurotoxic antiretroviral therapy (ART). PN is associated with a variety of risk factors; however, detailed knowledge is scarce for sub-Saharan African populations, bearing among the highest HIV/AIDS infection burden.

In a cross-sectional study, we assessed the prevalence of PN in 525 adult outpatients suffering from HIV/AIDS and admitted to the largest tertiary hospital in Ghana. Through a detailed questionnaire and clinical examination including neurologic assessment and laboratory blood sample testing, this study investigated associations of PN with demographic and health determinants and identified risk factors associated with sensory neuropathy.

The prevalence of PN in the Ghanaian cohort was 17.7% and increased odd ratios (OR) when patients were taller (> 1.57 m; OR = 3.84; 95% CI 1.38–10.66) or reached the age > 34 years (p = 0.124). Respondents with longer education duration had significantly less PN (≥ 9 years of education; OR = 0.49; 95% CI 0.26–0.92). The study also identified significant association of PN to both waist and hip girth and neutrophil counts. Curiously, higher adjusted odd ratios (aOR) of PN of patients under ART treatment were observed when CD4 lymphocytes were elevated (aOR = 0.81; 95% CI 0.36–1.83 and aOR = 2.17; 95% CI 0.93–5.05, for 300 and 600 counts, respectively). For patients on ART, an increase of 10 CD4 cell count units increased their chance of developing PN by 1% (aOR = 1.01; 95% CI 1.00 to 1.03).

Despite current drug application regulations, prevalence of PN is still unacceptably high in sub-Saharan African populations. Reduction in chronic morbidity through a health system with routine monitoring, early diagnosis and prompt intervention, and effective case management can improve people living with HIV/AIDS’ quality of life.

Pain in people living with HIV and its association with healthcare resource use, well being and functional status

OBJECTIVE

We describe the prevalence of pain and its associations with healthcare resource utilization and quality-of-life.

DESIGN

The POPPY Study recruited three cohorts: older people living with HIV (PLWH; ≥50 years, n = 699), younger demographically/lifestyle similar PLWH (less than 50 years, n = 374) and older demographically/lifestyle similar HIV-negative (≥50 years, n = 304) people from April 2013 to February 2016.

METHODS

Current pain and pain-related healthcare use was collected via a self-reported questionnaire. Logistic regression assessed between-group differences in the prevalence of pain in the past month and current pain after controlling for potential confounders. Associations between current pain and healthcare resource use, reported joint problems, depressive symptoms, quality-of-life and functional status were assessed in PLWH using Mann-Whitney U and chi-squared tests.

RESULTS

Pain in the past month was reported by 473 out of 676 (70.0%) older PLWH, 224 out of 357 (62.7%) younger PLWH and 188 out of 295 (63.7%) older HIV-negative controls (P = 0.03), with current pain reported in 330 (48.8%), 134 (37.5%) and 116 (39.3%), respectively (P = 0.0007). Older PLWH were more likely to experience current pain, even after adjustment for confounders. Of those with pain in the past month, 56 out of 412 (13.6%) had missed days of work or study due to pain, and 520 (59%) had seen a doctor about their pain. PLWH experiencing current pain had more depressive symptoms, poorer quality-of-life on all domains and greater functional impairment, regardless of age group.

CONCLUSION

Even in the effective antiretroviral therapy era, pain remains common in PLWH and has a major impact on quality-of-life and associated healthcare and societal costs. Interventions are required to assist clinicians and PLWH to proactively manage pain.

Racial and socioeconomic disparities in the symptom reporting of persons living with HIV

Persons living with HIV (PLWH) today can survive decades with the disease, making the symptom experience much more relevant to their lifestyle and health outcomes. The goal of the research reported here was to assess the symptom reporting of PLWH in the Unites States (US) in the combined antiretroviral therapy (cART) age of the epidemic. We conducted an anonymous online survey of symptomatic PLWH in the US and asked participants to report the frequency and intensity of 28 frequently occurring symptoms in the past 30 days. The relationship between symptom reporting and demographic factors was investigated using the adaptive least absolute shrinkage and selection operator (LASSO) method. Fatigue was the most frequently reported symptom in our study population. Those with the lowest income were more likely to report more burdensome symptoms. In comparison to other racial and ethnic groups, Black non-Hispanic participants were significantly more likely to report a lower symptom burden score for fatigue, depression, muscle aches, anxiety, difficulties with memory and concentration. There were no racial/ ethnic differences in the burden of the symptoms related to sleep or neuropathy. Findings from this study present new evidence on the symptom reporting of PLWH in the US. Neuropathy continues to be a pervasive neurological symptom with no difference noted between racial/ ethnic groups.

A qualitative exploration of chronic pain and opioid treatment among HIV patients with drug use disorders

OBJECTIVE

The study explored high-risk participants' experiences with pain management regarding clinical access to and use of prescription opioids.

DESIGN

Qualitative semistructured interviews and focus groups.

SETTING

Data were collected August 2014 to May 2015 at an urban community-based research facility in Baltimore City, MD.

PARTICIPANTS

HIV participants with chronic pain and a history of illicit drug use.

METHODS

Qualitative coding and analysis used an iterative, inductive, and thematic approach and coders achieved inter-coder consistency.

RESULTS

The authors identified two major themes. First, participants had positive and negative interactions with healthcare providers regarding chronic pain treatment. Participants perceived that providers lacked empathy for their pain and/or were not adequately managing their pain. These interactions resulted in participants seeking new providers or mistrusting the medical system. Further, providers' surveillance of participants' pain treatment regimen contributed to distress surrounding pain management. The second theme centered on participants' pain management experiences with prescribed opioid analgesics. Participants felt they were receiving dosages and classes of analgesics that did not sufficiently address their pain, and consequently modified their dosages or rationed prescription opioids. Other participants were reluctant to take analgesics due to their history of illicit drug use. Some participants relapsed to illicit drug use when they felt their prescription opioids did not adequately address their pain needs.

CONCLUSIONS

Participant struggles with receiving and managing prescribed opioid analgesics suggest a need for: therapies beyond these medications; guidelines for providers specific to this population; and harm reduction trainings for providers.

Genetics of HIV-associated sensory neuropathy and related pain in Africans

Despite the use of safer antiretroviral medications, the rate of HIV-associated sensory neuropathy (HIV-SN), the most common neurological complication of HIV, remains high. This condition is often painful and has a negative effect on quality of life. Up to 90% of those with HIV-SN experience pain for which there is no effective analgesic treatment. Genetic factors are implicated, but there is a lack of a comprehensive body of research for African populations. This knowledge gap is even more pertinent as Africans are most affected by HIV. However, recent studies performed in Southern African populations have identified genes displaying potential as genetic markers for HIV-SN and HIV-SN-associated pain in Africans. Here, we review the published studies to describe current knowledge of genetic risk factors for this disease in Africa.

Treatment of human immunodeficiency virus-related peripheral neuropathy with Scrambler Therapy: a case report

Peripheral neuropathy is one of the most common neurological complications of HIV infection with a 30-60% lifetime prevalence. Newer HIV drugs cause less peripheral neuropathy, but patients are now living long enough to develop concomitant diabetes-related, vascular-related, and chemotherapy-related neuropathy so it continues as a major debilitating issue. Recent national CDC guidelines have stressed the importance of non-opioid therapies, especially in this population that may have had drug abuse problems. We treated a 52-year-old man who had severe disabling classic peripheral neuropathy since 1998 with Scrambler Therapy (Calmare), an FDA-cleared peripheral non-invasive neuromodulation device. His pain rapidly improved, as did his motor and sensory function, with just four 45-min treatments, and he was able to come off opioids for the first time in years. When his pain returned six months later, only two treatments were needed to resolve it. This represents the first published use of this novel, inexpensive, and non-invasive pain modality in HIV peripheral neuropathy, and should engender further trials.