Severe lactic acidosis induced by nucleoside analogues in an HIV-infected man

Metabolic acidosis in AIDS patients

BACKGROUND AND AIMS

Metabolic acidosis (MA) is a frequent and serious complication in HIV-infected patients. The aim of the study is to compare patients with and without MA associated with HIV.

METHODS

Patients were retrospectively studied involving all HIV-infected patients with blood gas analysis performed during hospital stay admitted to a single hospital between April 2004 and July 2006. Statistical analysis was performed using SPSS 10.0 for Windows.

RESULTS

Included in the study were 159 HIV patients, 72 cases (45.3%) with MA and 87 cases (54.7%) without. The comparison of both groups showed a mean arterial pH of 7.24 +/- 0.08 vs. 7.44 +/- 0.05, HCO(3) 12 +/- 5.7 vs. 21 +/- 5.1 mEq/L, serum urea 81 +/- 68 mg/dL vs. 39 +/- 46 mg/dL and serum creatinine 2.7 +/- 2.6 mg/dL vs. 1.2 +/- 1.9 mg/dL in MA-HIV and non-MA-HIV, respectively (p <0.05). Antiretroviral therapy (ART) was being administered to 38 subjects (52.8%) in MA-HIV group and 45 (51.7%) in non-MA-HIV group (p = 0.57). There was no association between the use of ART and MA. Mortality was higher in patients with acidosis (52.7 vs. 17.2%, p <0.0001).

CONCLUSIONS

In the present study, MA was associated with acute kidney injury and increased mortality. There was no association between the use of ART and MA.

Myositis in infiltrative lymphocytosis syndrome: clinicopathological observations and treatment

Diffuse infiltrative lymphocytosis syndrome (DILS) is characterized by the presence of persistent circulating CD8 lymphocytosis and visceral CD8 lymphocytic infiltration, predominantly in the salivary glands and lungs in a subset of human immunodeficiency virus (HIV) patients. Myositis has been rarely documented in DILS. We report here the histopathological abnormalities and treatment response of an HIV patient with DILS associated myositis. Muscle biopsy revealed features of polymyositis but electron microscopy study showed intranuclear filamentous inclusions of 18 nm diameter, without intracytoplasmic inclusion. Treatment with intravenous immunoglobuline was useful.

Lactic acidosis related to nucleoside therapy in HIV-infected patients

The incidence of nucleoside analogue-related lactic acidosis has been estimated in 0.57 - 8.5 cases/1000 person years of antiretroviral therapy. The onset of lactic acidosis is usually insidious and patients complain of nausea, vomiting, abdominal pain, fatigue and weight loss. When lactate levels are high enough, a catastropic clinical situation develops, resulting in multiorgan failure. The mortality rate of patients with lactic acidosis related to nucleoside therapy is very high, 33 - 60%. Although all nucleoside analogues have been implicated in lactic acidosis, most cases are associated with stavudine. At present, there are no controlled trials to evaluate the treatment of nucleoside-induced lactic acidosis. Therapy is based on supportive measures and discontinuation of all antiretroviral drugs. Administration of essential vitamin coenzymes, electron acceptors and L-carnitine may be useful in some cases.

Bench-to-bedside review: severe lactic acidosis in HIV patients treated with nucleoside analogue reverse transcriptase inhibitors

Nucleoside reverse transcriptase inhibitors (NRTIs) are effective antiretroviral therapy for the treatment of HIV-infected patients. NRTIs can induce mitochondrial impairment that leads to a number of adverse events, including symptomatic lactic acidosis. In the present review, we describe the underlying mechanism of NRTI-induced toxicity and the main clinical features of this infrequent, but severe, emerging complication. We also summarise experimental data and clinical observations that support the use of L-carnitine supplementation to reverse NRTI-induced mitochondrial impairment.

Metabolic acidosis and hepatic steatosis in two HIV-infected patients on stavudine (d4T) treatment

Nucleoside analog reverse transcriptase inhibitors (NRTI) have been used to treat HIV-infected patients for >10 years. Some severe adverse events have been attributed to mitochondrial dysfunction. Since 1991, cases of severe lactic acidosis have been reported in association with nucleoside therapy. Our objective was to report two cases of metabolic acidosis and hepatic steatosis in patients receiving stavudine (d4T) and to review the literature. A male and a female, 47 and 45 years of age, respectively, presented with abdominal pain, nausea, vomiting, and weakness after 9 and 6 months, respectively, of treatment with stavudine. At presentation, both patients had severe metabolic acidosis and liver failure. Ultrasonography showed hepatic steatosis (confirmed by biopsy in one case). All antiretroviral drugs were withdrawn and patients were treated with bicarbonate. Both patients developed fulminant liver dysfunction and multiple organ failure. We reviewed the literature and found 75 cases of lactic acidosis and hepatic steatosis associated with use of NRTI; 57 of these patients received d4T (76%). Of all cases reported in association with nucleoside therapy, 63% were females and mortality was 47%. General weakness, hepatic enzyme elevation, and liver steatosis are data that should alert physicians to this serious adverse event and to respond with prompt interruption of antiretroviral drugs and measurement of lactic acid in plasma. It is important to report serious adverse events in commercially released drugs to know prevalence in an exposed population. Physicians should be aware of risk and early signs of this serious adverse event.

Severe nucleoside-associated lactic acidosis in human immunodeficiency virus-infected patients: report of 12 cases and review of the literature

Lactic acidosis is a rare but often fatal complication reported in some human immunodeficiency virus (HIV)-infected patients treated with nucleoside-analogue reverse-transcriptase inhibitors. We report a series of 12 patients with HIV infection treated with nucleoside analogues who developed unexplained metabolic acidosis. We have also reviewed 60 additional published cases. The aim of the present study is to describe the clinical picture, prognostic factors, and final outcome for nucleoside-associated lactic acidosis. The mortality rate is high: 33% for our patients, and 57% for the patients described in the literature. In the multivariate analysis, a lactate serum level of >10 mM (odds ratio [OR], 13.23; 95% confidence interval [CI], 2.96-59.25) was the only factor associated with higher mortality. The administration of specific therapy with cofactors against acidosis was associated with a lower mortality (OR, 0.17; 95% CI, 0.04-0.73). We conclude that specific therapy with cofactors may improve the outcome for patients with this syndrome.

Symptomatic elevations of lactic acid and their response to treatment manipulation in human immunodeficiency virus-infected persons: a case series

Symptomatic lactic acidemia was seen in 5 human immunodeficiency virus-positive patients receiving combination therapy that included stavudine and > or =1 other nucleoside. Peak venous lactic acid levels of 3.1-7.4 mmol/L (normal range, 0.5-2.1 mmol/L) were associated with fatigue and rapid weight loss, whereas withdrawal of antiretrovirals led to normalization of venous lactic acid levels, symptomatic improvement, and weight gain. Resumption of an altered therapeutic regimen, which did not include stavudine but did include other nucleosides in 4 of 5 cases, did not result in recurrence of the syndrome after up to 126 days.

Emerging role of riboflavin in the treatment of nucleoside analogue-induced type B lactic acidosis

Type B lactic acidosis is a rare and often fatal complication seen in patients receiving the nucleotide analogues zidovudine, stavudine, didanosine, and lamivudine. We describe a case of a 51-year-old human immunodeficiency virus (HIV)-positive woman receiving three nucleotide analogues. She presented with nausea, vomiting, abdominal pain, and hepatic steatosis. Signs of mitochondrial toxicity were demonstrated by diffuse myopathy and pancreatitis. Serum riboflavin levels documented a deficiency that was treated with 50 mg of riboflavin daily. Immediately after treatment, serum blood urea nitrogen level, lactic acid levels, and arterial blood pH all returned to normal values. Her signs of mitochondrial toxicity also improved after treatment with riboflavin. Successful reversal of the patient's type B lactic acidosis after riboflavin therapy suggested that riboflavin deficiency plays a direct role in the development of nucleotide analogue-induced lactic acidosis. It is impossible to predict which patients are predisposed to the development of this syndrome. For this reason, it may be important to screen and treat riboflavin deficiency in patients on nucleoside analogues.

Metabolic Syndromes Associated With HIV: Mitigating the Side Effects of Drug Therapy

HIV infection and highly active antiretroviral therapy (HAART) are associated with a variety of metabolic disorders such as AIDS wasting syndrome, cachexia, sarcopenia, metabolic dysregulation, lipodystrophy, abnormalities of serum lipids, and lactic acidosis. Adjunctive therapies (eg, diet, antilipid therapy), risk-factor modification (eg, smoking cessation, blood pressure control), aerobic exercise, and anabolic treatments can be used to mitigate the effects of HIV infection and the adverse effects of HAART, thereby improving long-term health in individuals infected with HIV.

Mitochondrial DNA depletion, near-fatal metabolic acidosis, and liver failure in an HIV-infected child treated with combination antiretroviral therapy

A child with controlled human immunodeficiency virus infection presented with neurologic deterioration, lactic acidosis, and organic aciduria. Muscle biopsy revealed abnormal mitochondrial (mt) morphology, reduced mt enzyme activities, and mtDNA depletion. After adjustment of antiretroviral therapy to a regimen free of nucleoside analogs, marked improvement was seen in clinical status and mt abnormalities.

Significant Toxicities Associated with Antiretroviral Therapy

Use of at least three potent antiretroviral agents has become the standard of care in the management of HIV infection. The potential toxicities associated with highly active antiretroviral therapy (HAART) however, may limit a patient’s ability to adhere to and tolerate these agents. Although a comprehensive discussion of all toxicities associated with HAART is beyond the scope of this article, selected short-term and long-term significant toxicities will be reviewed. Short-term toxicities that will be discussed include abacavir-induced hypersensitivity reactions, efavirenz-associated central nervous system side effects and rash associated with the non-nucleoside reverse transcriptase inhibitors (NNRTIs) and the protease inhibitor (PI) amprenavir. Several long-term toxicities associated with the nucleoside reverse transcriptase inhibitors (NRTIs) are hypothesized to be due to mitochondrial toxicity. These toxicities include myositis and lactic acidosis with hepatic steatosis, pancreatitis and peripheral neuropathy. Some experts also hypothesize that mitochondrial toxicity is responsible for the lipodystrophy syndrome, which includes hyperglycemia, abnormal fat redistribution and dyslipidemia. Finally, indinavir-associated nephrolithiasis, which may present with either short term or long term use will be discussed. This article will provide the practicing pharmacist with a review of these significant toxicities, the implicated agents, incidence, usual clinical presentation, and recommendations for management.

Lactic acidosis associated with nucleoside reverse transcriptase inhibitors

Limitations on antiretroviral therapies as a result of resistance and adverse events have been described in the literature. Lactic acidosis has been reported in patients on nucleoside reverse transcriptase inhibitors on rare occasions. Successful assessment and treatment of lactic acidosis is dependent on the nurse's role in the recognition of this condition. This article provides an overview of the clinical presentation, diagnosis, treatment strategies and nursing management of lactic acidosis in patients with HIV/AIDS.

Mechanisms of exercise limitation in HIV+ individuals

Cardiopulmonary exercise testing (CPX) is an important diagnostic tool for both clinical and research purposes in HIV positive (HIV+) individuals. Important information can be obtained from the gas exchange responses that can elucidate heart, lung, peripheral vascular, pulmonary vascular, and muscle abnormalities in this population. A large percentage of these patients are deconditioned, respond well to exercise training, and have no intrinsic limitation to exercise. Results of a progressively increasing CPX can be used to: 1) design an exercise prescription for aerobic training in HIV+ individuals; 2) identify and refer patients with subtle abnormalities of gas exchange for further diagnostic studies to exclude early infectious complications: and 3) evaluate the improvements in maximal oxygen uptake, lactic acidosis threshold, and gas exchange kinetics as result from an aerobic exercise training program. Gas exchange kinetic analysis of constant work rate tests can provide similar information in a nonmaximal, reproducible, readily obtainable format. Both progressively increasing and constant work rate CPX tests provide important information on the changes in oxygen flow from the environment to the exercising muscle that occur with aerobic exercise training. Finally, a case study involving the exercise prescription for HIV+ individuals is reviewed as well as the risk of transmission of HIV during competitive sports competition events.

Acute liver failure

Worldwide, viral infection is responsible for the majority of cases of acute liver failure, and the presence of co-existing chronic viral hepatitis may increase its severity. The newly described hepatotrophic viruses, hepatitis G virus and transfusion-transmitted virus, are unlikely to be major aetiological agents. In the USA and western Europe drug-induced hepatotoxicity is the most common cause, and most frequently results from acetaminophen. Hepatotoxicity caused by Ecstasy is increasingly important, particularly in young adults. Hepatic encephalopathy and cerebral oedema remain important and life-threatening complications, and their pathogenesis is not completely understood. The effects of the cerebral metabolism of the high levels of ammonia that circulate in hepatic failure appear to be important. Induced hypothermia is a promising modality of treatment for refractory cerebral oedema, but the only form of treatment known to improve survival is emergency liver transplantation. Living donor and auxiliary liver transplantation are likely to improve survival rates further and reduce the number of patients requiring long-term post-transplant immunosuppression.