Severe lactic acidosis in association with reverse transcriptase inhibitors with potential response to L-carnitine in a pediatric HIV-positive patient

Levocarnitine for the Treatment of Valproic Acid-Induced Hyperammonemic Encephalopathy in Children: The Experience of a Large, Tertiary Care Pediatric Hospital and a Poison Center

BACKGROUND

Although rare, symptomatic hyperammonemia is sometimes associated with valproic acid (VPA), especially in children. L-carnitine (levocarnitine), sometimes classified as an essential amino acid, is vital to mitochondrial utilization of fatty acids and can be helpful in treating this condition. The data supporting this, however, are limited.

STUDY QUESTION

The aim of the study was to illustrate the role of L-carnitine in the treatment of patients with VPA-induced hyperammonemic encephalopathy (VPE) at 2 different institutions.

METHODS

Medical records of affected patients were reviewed; data collected included exposure history, clinical manifestations, physical examination, and laboratory values.

RESULTS

There were 13 cases of VPE; 12 were associated with therapeutic dosing and 1 with an overdose. The maximum ammonia concentration was 557 μmol/L, and blood concentrations of VPA ranged from 68 to 600 μg/mL (therapeutic range 50-100 μg/mL). In all cases, liver function tests were normal or only mildly increased. In this study, 12 patients received a daily dose of L-carnitine 100 mg/kg, and 1 received 200 mg/kg (intravenous infusion over 30 minutes) divided every 8 hours until clinical improvement. All patients made a full recovery. None developed adverse effects or reactions, and no cases of toxicity were reported.

CONCLUSION

Our series suggests that intravenous L-carnitine, at a dose of 100 mg·kg·d in 3 divided doses each over 30 minutes until clinical improvement occurs, is a safe and effective treatment in the management of VPE in children.

Metabolic complications and treatment of perinatally HIV-infected children and adolescents

The benefits of long-term antiretroviral therapy (ART) are recognized all over the world with infected children maturing into adults and HIV infection becoming a chronic illness. However, the improved survival is associated with serious metabolic complications, including lipodystrophy (LD), dyslipidemia, insulin resistance, lactic acidosis and bone loss. In addition, the dyslipidemia mainly seen with protease inhibitors may increase the risk of cardiovascular disease in adulthood and potentially in children as they mature into adults. Nucleoside reverse transcriptase inhibitors, particularly stavudine, zidovudine and didanosine are linked to development of LD and lactic acidosis. Perinatally infected children initiate ART early in life; they require lifelong therapy with multiple drug regimens leading to varying toxicities, all potentially impacting their quality of life. LD has a significant impact on the mental health of older children and adolescents leading to poor self-image, depression and subsequent poor adherence to therapy. Reduced bone mineral density (BMD) is reported in both adults and children on ART with the potential for children to develop more serious bone complications than adults due to their rapid growth spurts and puberty. The role of vitamin D in HIV-associated osteopenia and osteoporosis is not clear and needs further study. Most resource-limited settings are unable to monitor lipid profiles or BMD, exposing infected children and adolescents to on-going toxicities with unclear long-term consequences. Improved interventions are urgently needed to prevent and manage these metabolic complications. Longitudinal cohort studies in this area should remain a priority, particularly in resource-limited settings where the majority of infected children reside.

Frequency of stavudine substitution due to toxicity in children receiving antiretroviral treatment in sub-Saharan Africa

INTRODUCTION

Stavudine is a commonly used drug in paediatric antiretroviral treatment (ART) regimens. Due to toxicity concerns, however, the drug abacavir has replaced stavudine in first-line paediatric regimens in many countries. We describe the frequency of stavudine toxicity in children receiving ART at a treatment clinic in Soweto, South Africa.

METHODS

Data on patient characteristics and outcomes of ART were collected from a cohort of 2222 HIV-infected children initiating ART between 2004 and 2008 when stavudine-containing regimens were routinely recommended. At several time-points after treatment initiation, we estimate the proportion of children where an attending clinician discontinued stavudine due to lipodystrophy, pancreatitis, lactic acidosis or peripheral neuropathy. Factors associated with stavudine-related toxicities were identified.

RESULTS

At ART initiation, most children had advanced disease. The majority initiated an efavirenz/lamivudine/stavudine regimen (n = 1422), and 76% of children remained on their initial ART regimen after a median 19.9 months of ART. Replacement of stavudine due to drug toxicity occurred at a rate of 28.8 per 1000 child years on treatment (95% confidence interval = 23.6-35.2). Rates of toxicity increased with treatment duration (in their first year of ART stavudine was replaced in 0.5% of children, but after 3 years stavudine had been changed to abacavir in 12.6% of children). Toxicity was more common in older children and in girls. Lipodystrophy accounted for 87 of 96 toxic events.

CONCLUSION

Stavudine-associated toxicity resulting in single-drug substitution was uncommon in this cohort, though its frequency increased steadily with ART duration, especially with lipodystrophy. Where drug options are limited, stavudine remains a relatively well tolerated and effective option for children.

Potential benefits of carnitine in HIV-positive patients

Carnitine is a nonessential amino acid that has a central role in lipid peroxidation and mitochondrial metabolism. Carnitine deficiency is rare in adult human subjects who have a normal diet and no underlying chronic diseases. Studies have shown that HIV-infected patients are at increased risk of carnitine deficiency due to decreased intake, increased metabolism, gastrointestinal problems, HIV infection itself, concomitant infections, underlying disease, concomitant drugs and antiretroviral therapy. Decreased serum and muscle carnitine content was reported following antiretroviral therapy in HIV-positive patients. The beneficial effects of carnitine on the human immune system, such as prevention of CD4 cell apoptosis, was reported in these patients. Additionally, polyneuropathy, myopathy, lactic acidosis, dyslipidemia and lipodystrophy are complications of antiretroviral therapy that have been proposed to potentially be related to carnitine deficiency and mitochondrial dysfunction. Carnitine may have a significant role in improving some aspects of mitochondrial toxicity induced by an antiretroviral regimen, such as lipodystrophy. Also, there are nearly sufficient data to support the beneficial effects of carnitine in improving the symptoms of lactic acidosis following antiretroviral therapy. According to available data, it is concluded that carnitine may have beneficial effects in the treatment of antiretroviral-induced neuropathy. Most of the evidence supports carnitine supplementation as a treatment strategy rather than prophylaxis for antiretroviralinduced complications. Several studies have shown the prevalence of carnitine deficiency and its role in different aspects of infection and antiretroviral-induced complications in HIV-positive patients, but the probable beneficial effects of carnitine supplementation are not clear in this population. In this review, we have collected and categorized available evidence regarding the potential benefits of carnitine supplementation in HIV-infected individuals.

Hypercalciuria is the main renal abnormality finding in Human Immunodeficiency Virus-infected children in Venezuela

Kidney involvement in children with Human Immunodeficiency Virus (HIV) infection is increasing in prevalence in parallel with the longer survival of HIV-infected patients and the side-effects of new antiretroviral drugs. However, there are only a few reports describing renal tubular disorders in HIV+ children. This is a cross-sectional, case series study evaluating kidney disease in 26 Venezuelan HIV-infected children. The study cohort consisted of 15 girls and 11 boys, with a median age of 5.9 years (25-75th percentile: 3.6-7.8), who had been treated with antiretrovirals for 2.8 +/- 0.4 years, Overall, the patients were short for their age and gender (Z-height: -3.1; 25-75th percentile: -4.94 to -1.98), and 15 showed signs of mild to moderate malnutrition. All of the children had a normal estimated glomerular filtration rate (136 +/- 22.6 ml/min/1.73 m2), and glomerular involvement was only observed in one patient with isolated proteinuria. None had nephromegaly. In contrast, tubular disorders were commonly found. Hypercalciuria was detected in 16 of the patients (UCa/Cr = 0.28; 25-75th percentile: 0.17-0.54 mg/mg), with five of these showing crystalluria. Eight children showed hyperchloremia, and three had frank metabolic acidosis. Kidney stones were absent in all, but one boy had bilateral medullary nephrocalcinosis. Conclusion, in Venezuelan children, HIV infection per se, or its specific treatment, was commonly associated with renal tubular dysfunction, especially hypercalciuria and acidosis, potentially leading to nephrocalcinosis and growth impairment. We recommend renal tubular evaluation during the follow-up of children with HIV infection.

Metabolic complications of antiretroviral therapy in HIV-infected children

The purpose of this review is to describe the metabolic complications associated with antiretroviral therapy in HIV-infected children. As a result of extensive research over the last 10 years, there is a greater awareness and understanding of these conditions. However, in resource-limited settings, where the majority of HIV-infected children live, the prevalence and risk factors of metabolic complications are largely unknown. Limited diagnostic resources contribute to this impediment. Therapies for these conditions are still under investigation, including prevention and optimal treatment of reduced bone mineral density, osteopaenia and osteoporosis. Future research goals should be directed towards closing the diagnostic and treatment gaps between rich and poor settings.

Management of antiretroviral treatment-related complications

Antiretroviral therapy for HIV restores immune function, controls viral replication, decreases opportunistic infections, and extends lifespan to near-normal for infected individuals. However, successful HIV therapy has been accompanied by the emergence of treatment-related complications, with an impact not yet fully understood. This article reviews six common complications of antiretroviral therapy, including hyperlactatemia/lactic acidosis, hypersensitivity reactions, abnormal glucose metabolism, dyslipidemia, body composition changes, and cardiovascular disease. A comprehensive approach to management of antiretroviral-related complications includes awareness of (1) risk factors for adverse reactions, (2) clinical syndromes suggestive of an evolving complication, and (3) evidence-based monitoring and treatment strategies. Fluency in options for preventing and managing complications can provide maximal opportunity to balance treatment effects with quality of life.

Carnitines and its congeners: a metabolic pathway to the regulation of immune response and inflammation

Carnitine and its congeners may regulate the immune networks, and their influence on functions of immune cells predominantly or exclusively relies on carnitine-dependent energy production from fatty acids. A reduced pool of carnitines has been demonstrated in either serum or tissues, or both, from patients with a wide spectrum of disorders characterized by unregulated or impaired immune responses ranging from sepsis syndrome to systemic sclerosis, infection with human immunodeficiency virus, and chronic fatigue syndrome. Furthermore, experimental studies have consistently reported that the deranged immune responses and the less efficient inflammation towards infectious organisms associated with aging may be enhanced or modulated by treatment with carnitines. There is also evidence that carnitine deprivation could adversely affect the course of the sepsis syndrome, at least in experimental models, and preliminary studies suggest that carnitine deficiency is ultimately implicated in the pathophysiology of endotoxin-mediated multiple organ failure. Several data indicate that carnitine deficiency is a contributing factor to the progression of infection with human immunodeficiency virus, and carnitine therapy in those patients could counteract the unregulated process of lymphocyte apoptosis and improve CD4 counts. Some case reports have suggested the use of carnitine for the treatment of the severe lactic acidosis that complicates in some patients the use of reverse transcriptase inhibitors.