Acute renal failure due to indinavir crystalluria and nephrolithiasis: report of two cases

Updates on HIV and Kidney Disease

PURPOSE OF REVIEW

With the advent of antiretroviral therapy, HIV infection has become a chronic disease in developed countries.

RECENT FINDINGS

Non-HIV-driven risk factors for kidney disease, such as APOL1 risk variants and other genetic and environmental factors, have been discovered and are better described. Consequently, the field of HIV-associated kidney disease has evolved with greater attention given to traditional risk factors of CKD and antiretroviral treatment's nephrotoxicity. In this review, we explore risk factors of HIV-associated kidney disease, diagnostic tools, kidney pathology in HIV-positive individuals, and antiretroviral therapy-associated nephrotoxicity.

Renal effects of non-tenofovir antiretroviral therapy in patients living with HIV

A review of literature published regarding non-tenofovir antiretroviral agents causing renal adverse effects was conducted. The literature involving renal adverse effects and antiretroviral therapy is most robust with protease inhibitors, specifically atazanavir and indinavir, and includes reports of crystalluria, leukocyturia, nephritis, nephrolithiasis, nephropathy and urolithiasis. Several case reports describe potential nephropathy (including Fanconi syndrome) secondary to administration of abacavir, didanosine, lamivudine and stavudine. Case reports documented renal events such as acute renal failure, nephritis, proteinuria and renal stones with efavirenz administration. Regarding rilpivirine, a small increase of serum creatinine levels (SCr) was found in clinical trials; however, the clinical significance and impact on actual renal function is unknown. The integrase strand transfer inhibitors and enfuvirtide have a relatively safe renal profile, although studies have shown dolutegravir and raltegravir cause mild elevations in SCr without an impact on actual renal function. This is similar to the reaction observed with cobicistat, the pharmacokinetic enhancer frequently given with elvitegravir.

Drug-Induced Kidney Stones and Crystalline Nephropathy: Pathophysiology, Prevention and Treatment

Drug-induced calculi represent 1-2% of all renal calculi. The drugs reported to produce calculi may be divided into two groups. The first one includes poorly soluble drugs with high urine excretion that favour crystallisation in the urine. Among them, drugs used for the treatment of patients with human immunodeficiency, namely atazanavir and other protease inhibitors, and sulphadiazine used for the treatment of cerebral toxoplasmosis, are the most frequent causes. Besides these drugs, about 20 other molecules may induce nephrolithiasis, such as ceftriaxone or ephedrine-containing preparations in subjects receiving high doses or long-term treatment. Calculi analysis by physical methods including infrared spectroscopy or X-ray diffraction is needed to demonstrate the presence of the drug or its metabolites within the calculi. Some drugs may also provoke heavy intra-tubular crystal precipitation causing acute renal failure. Here, the identification of crystalluria or crystals within the kidney tissue in the case of renal biopsy is of major diagnostic value. The second group includes drugs that provoke the formation of urinary calculi as a consequence of their metabolic effects on urinary pH and/or the excretion of calcium, phosphate, oxalate, citrate, uric acid or other purines. Among such metabolically induced calculi are those formed in patients taking uncontrolled calcium/vitamin D supplements, or being treated with carbonic anhydrase inhibitors such as acetazolamide or topiramate. Here, diagnosis relies on a careful clinical inquiry to differentiate between common calculi and metabolically induced calculi, of which the incidence is probably underestimated. Specific patient-dependent risk factors also exist in relation to urine pH, volume of diuresis and other factors, thus providing a basis for preventive or curative measures against stone formation.

Acute kidney injury in patients with human immunodeficiency virus infection

Acute kidney injury (AKI) is an important cause of hospitalization and morbidity in human immunodeficiency virus (HIV)-positive patients. However, the data on AKI in such patients is limited. The aim of the present study was to analyze the incidence, causes and outcome of AKI in HIV-positive patients from our antiretroviral therapy centre. All HIV-positive patients were evaluated for evidence of clinical AKI. AKI was noted in 138/3540 (3.9%) patients. Of 138 AKI patients, 96 (69.6%) had acquired immuno deficiency syndrome and 42 (30.4%) were HIV seropositive. Majority of AKI patients belonged to AKI network (AKIN) Stage II (42%) or III (48.5%) at presentation. Prerenal, intrinsic and postrenal AKI were noted in 53.6%, 44.2% and 2.2% of cases, respectively. Hypovolemia (44.2%) and sepsis (14.5%) contributed to AKI in vast majority of cases. AKI was multifactorial (volume depletion, sepsis and drugs) in 39% of patients. Acute tubular necrosis (ATN) was the most common intrinsic lesion. Acute interstitial nephritis and diffuse endocapillary proliferative glomerulonephritis were noted in five and two cases, respectively. In-hospital mortality was 24.64%. Lower CD4 count, decreased serum albumin level and Stage 4 WHO disease were associated with higher mortality. At 3 months or more follow-up complete recovery of renal function, chronic kidney disease Stage 3-5 and progression to end stage renal disease were noted in 58.69%, 14.5% and 2.2% of cases, respectively. Thus, prerenal factors and ischemic ATN were the most common cause of AKI in HIV-infected patients. Recovery of renal function was seen in 59% of cases, but AKI had high in-hospital mortality.

HIV medication-based urolithiasis

Drug-induced renal calculi represent 1–2% of all renal calculi. In the last decade, drugs used for the treatment of HIV-infected patients have become the most frequent cause of drug-containing urinary calculi. Among these agents, protease inhibitors (PIs) are well known to induce kidney stones, especially indinavir and atazanavir, and more recently darunavir. Urolithiasis attributable to other PIs has also been reported in clinical cases such as those during non-PI use. Antiretroviral drug-induced calculi deserve consideration because most of them are potentially preventable. This article summarizes the diagnosis, epidemiology, prevention and management of antiretroviral drug-induced urolithiasis.

Ritonavir-boosted protease inhibitors in HIV therapy

The advent of combination antiretroviral therapy has led to significant improvement in the care of HIV-infected patients. Originally designed as a protease inhibitor (PI), ritonavir is currently exclusively used as a pharmacokinetic enhancer of other protease inhibitors, predominantly due to ritonavir's potent inhibition of the cytochrome P450 3A4 isoenzyme. Ritonavir-boosting of PIs decrease pill burden and frequency of dosing. Boosted PIs are recommended for first-line therapy in treatment and play a key role in the management of treatment-experienced patients. Potential problems associated with PIs include metabolic abnormalities (e.g. dyslipidemia), increased cardiovascular risk, and drug interactions.

Immunodeficiency and renal impairment are risk factors for HIV-associated acute renal failure

OBJECTIVE

To identify risk factors for acute renal failure (ARF) in HIV-infected patients.

DESIGN

Observational cohort study of HIV-infected patients attending a South London HIV centre between January 1999 and December 2008.

METHODS

ARF was defined as a transient, more than 40% reduction in renal function as assessed by estimated glomerular filtration rate. Multivariate Poisson regression analysis was used to identify baseline and time-updated factors associated with ARF.

RESULTS

The incidence of ARF was 2.8 (95% confidence interval 2.41-3.24) episodes per 100 person-years. We observed a stepwise increase in ARF incidence with time accrued at lower CD4 cell count and at lower estimated glomerular filtration rate, with adjusted incidence rate ratios of 1 (reference), 1.56 (0.97-2.48), 2.08 (1.11-3.91), 6.38 (3.18-12.78) and 10.29 (5.11-20.98) for CD4 cell counts of more than 350, 201-350, 101-200, 51-100 and of 50/microl or less, and 1 (reference), 1.46 (0.86-2.51), 4.19 (2.37-7.42) and 27.00 (16.13-44.95) for estimated glomerular filtration rate more than 90, 75-89, 60-74 and less than 60 ml/min, respectively. Ethnicity, hepatitis B or C coinfection, exposure to combination antiretroviral therapy with or without indinavir, tenofovir or atazanavir and HIV viraemia were not associated with ARF.

CONCLUSION

Current levels of immunodeficiency and renal function were independent predictors of HIV-associated ARF.

Drug-induced Kidney Disease – Pathology and Current Concepts

The kidneys can be damaged by a large number of therapeutic agents. The aim of this article is to discuss the pathological features of drug-induced renal disease as diagnosed by kidney biopsy. The literature is reviewed and cases seen by the authors that have a known drug association are analysed. Mechanisms of injury are varied and all renal structures may be affected. The tubulointerstitial compartment is most frequently involved, but glomerular and vascular lesions are seen in a significant proportion of cases. Key words: Drug, Kidney, Nephrotoxicity, Pathology

HIV care and the incidence of acute renal failure

BACKGROUND

The clinical epidemiology of acute renal failure (ARF) in human immunodeficiency virus (HIV)-infected patients remains poorly defined.

METHODS

We conducted a retrospective analysis of patients who developed ARF while attending King's College Hospital (London, United Kingdom) during January 1998-December 2005. Serum creatinine level and estimated glomerular filtration rate were used to identify ARF. ARF episodes were classified as early onset if they occurred <3 months after initiation of HIV care and as late onset if they occurred > or =3 months after initiation of HIV care.

RESULTS

During the study period, 130 (5.7%) of 2274 patients developed 144 episodes of ARF. The incidences of early-onset and late-onset ARF were 19.3 episodes per 100 person-years (95% confidence interval [CI], 15.4-24.1 episodes per 100 person-years) and 1.1 episodes per 100 person-years (95% CI, 0.83-1.49 episodes per 100 person-years), respectively (rate ratio, 17.4; P<0.001). In multivariate analysis, nadir CD4 T cell count <100 x 10(9) cells/L (odds ratio [OR], 6.7; 95% CI, 2.5-18.3) and acquired immunodeficiency syndrome (OR, 6.7; 95% CI, 3.4-13.3) were associated with early-onset ARF, whereas injection drug use (OR, 4.8; 95% CI, 1.3-17.7), hepatitis C virus coinfection (OR, 3.4; 95% CI, 1.3-8.6), and nadir CD4 T cell count <100 x 10(9) cells/L (OR, 5.8; 95% CI, 2.5-13.4) were associated with late-onset ARF.

CONCLUSIONS

ARF was common and was associated with advanced immunodeficiency. The incidence of ARF decreased >10-fold in patients who had received HIV care for > or =3 months.

Drug-induced crystal nephropathy: an update

BACKGROUND

Several medications that are insoluble in human urine are known to precipitate within the renal tubules. Intratubular precipitation of either exogenously administered medications or endogenous crystals (induced by certain drugs) can promote chronic and acute kidney injury, termed crystal nephropathy. Clinical settings that enhance the risk of drug or endogenous crystal precipitation within the kidney tubules include true or effective intravascular volume depletion, underlying kidney disease, and certain metabolic disturbances that promote changes in urinary pH favoring crystal precipitation.

OBJECTIVE

Identify and review previously described and recently recognized medications that cause crystal nephropathy.

METHOD

A literature review was performed, using PubMed, Ovid, and Google Scholar, focusing on drugs (sulfadiazine, acyclovir, indinavir, triamterene, methotrexate (MTX), orlistat, oral sodium phosphate preparation, ciprofloxacin) that cause crystal nephropathy.

RESULTS/CONCLUSION

Sulfadiazine, acyclovir, indinavir, triamterene, and MTX are known to cause crystal nephropathy. Recently, several medications, including orlistat, ciprofloxacin, and oral sodium phosphate solution, along with underlying risk factors have been described as causing crystal nephropathy.

Indinavir/ritonavir remains an important component of HAART for the treatment of HIV/AIDS, particularly in resource-limited settings

For over a decade, indinavir has been approved for the treatment of HIV/AIDS; however, following the introduction of new protease inhibitors (PIs) with improved safety and pharmacologic profiles, its use in developed countries has become almost obsolete. In contrast, in resource-limited settings where the majority of people living with HIV/AIDS reside, indinavir is part of the most affordable PI-based highly active antiretroviral treatment regimen. A major drawback of indinavir use is renal toxicity, but low-dose indinavir plus ritonavir (400/100 mg) twice daily is both efficacious and tolerable. Similar low dosing levels in children have also proven successful, but data in pregnant women remains limited. Due to its low cost and proven efficacy indinavir remains a key component of HIV/AIDS treatment in resource-limited settings.

Microalbuminuria in HIV infection

OBJECTIVE

Microalbuminuria is associated with increased risk of cardiovascular disease and mortality. The objective of the study was to evaluate if HIV infection was an independent risk factor for microalbuminuria.

DESIGN

Cross sectional.

METHODS

The relationship between HIV infection and microalbuminuria was assessed using subjects enrolled in the study of Fat Redistribution and Metabolic Change in HIV Infection, which consists of HIV-positive and control men and women. Participants with proteinuria (dipstick >or= 1+) were excluded.

RESULTS

Microalbuminuria (urinary albumin/creatinine ratio, ACR > 30 mg/g) was present in 11% of HIV infected, and 2% of control participants (P < 0.001); a fivefold odds after multivariate adjustment (odds ratio, 5.11; 95% confidence interval, 1.97-13.31; P=0.0008). Several cardiovascular risk factors were associated with higher ACR in HIV participants: insulin resistance (HOMA > 4; 32%, P < 0.0001), systolic blood pressure (21%, P = 0.01 for 120-140 versus < 120 mmHg, and 43%, P = 0.06 for > 140 versus < 120 mmHg), and family history of hypertension (17%, P = 0.03). Higher CD4 cell count was associated with lower albumin/creatinine ratio (-24%, P = 0.009 for 200-400 versus < 200 cells/ml and -26%, P = 0.005 for > 400 versus < 200 cells/ml).

CONCLUSION

HIV infection had a strong and independent association with microalbuminuria, the severity of which was predicted by markers of insulin resistance, hypertension, and advanced HIV infection. These associations warrant further investigation, as the increased prevalence of microalbuminuria in HIV infection may be a harbinger of future risk of cardiovascular and kidney diseases.

Urological management of indinavir-associated acute renal failure in HIV-positive patients

INTRODUCTION

Indinavir, a protease inhibitor that is commonly used to treat HIV infection, may cause crystal formation within the renal tubules when urine pH is above 3.5. Crystallization in the urine may lead to intrarenal crystal deposition and acute renal failure (ARF).

AIM

To establish the beneficial urological management of acute renal failure caused by indinavir treatment of HIV/AIDS patients.

PATIENTS--METHODS

Five HIV positive patients (four men, one woman) with a mean age of 32 years (range 28-36 years) were referred to our Department of Urology from an AIDS outpatient Clinic, because of the development of postrenal acute renal failure with continuously elevated creatinine and urea plasma levels after indinavir therapy. Among the initial therapeutic maneuvers, indinavir administration was interrupted for 1 week while bilateral double-J ureteral stents were inserted in all the HIV/AIDS patients, during the first 24-72 h to secure upper-tract drainage. Concurrently urine has been acidified by oral administration of the amino acid L: -methionine and oral fluid intake was increased.

RESULTS

All the patients responded well to the treatment and their renal function was effortlessly restored to normal within a few days.

CONCLUSION

HIV-positive patients receiving indinavir therapy might be complicated by acute renal failure, mainly due to intrarenal crystal deposition (tubules) or urolithiasis (postrenal obstruction). This adverse effect may simply manage by the discontinuation of indinavir administration, urine acidification, as well as the possible early insertion of bilateral double-J ureteral stents.

Adverse effects of antiretroviral drugs on HIV-1-infected and -uninfected human monocyte-derived macrophages

Antiretroviral drugs approved for treatment of HIV-1 infection include nucleoside reverse transcriptase inhibitors (NRTIs) and protease inhibitors (PIs). Use of these drugs in combinations (highly active antiretroviral therapy) has delayed disease progression. However, long-term therapy is associated with potentially serious adverse effects. NRTIs are thought to contribute to these adverse effects via depletion of mtDNA. Inasmuch as macrophages (major targets for HIV-1) are highly metabolically active with large numbers of mitochondria, we investigated the effects of NRTIs (didanosine, stavudine, lamivudine, and zidovudine) on the viability and function of HIV-1-infected and -uninfected human monocyte-derived macrophages (MDMs). We demonstrate that the combinations didanosine/stavudine and lamivudine/zidovudine decrease mtDNA content in MDMs, with HIV-1-infected MDMs displaying a greater reduction than uninfected cells. This decrease correlated with decreased complement-mediated phagocytosis (C'MP) by MDMs, a process dependent on mitochondrial function. Inasmuch as PIs have previously been reported to interact with cellular proteases and given that cellular proteases are involved in the phagocytic process, we investigated the effects of the PI indinavir on C'MP. We demonstrate that indinavir augments C'MP by uninfected MDMs, but not HIV-1-infected MDMs. This study provides additional understanding on the effects of commonly used antiretroviral drugs on cellular immune function.

Lithiases médicamenteuses

Drug-induced renal calculi represent 1-2% of all renal calculi. They include two categories: those resulting from the urinary crystallisation of a highly excreted, poorly soluble drug or metabolite, and those due to the metabolic effects of a drug. Indinavir, used in HIV-infected patients, sulfonamides, especially sulfadiazine, and triamterene, which is less prescribed today, are the most frequent. Besides these drugs, about twenty other molecules, among them silicate-containing drugs and some antibiotics have been reported in patients receiving high doses or long-term treatments. Calculi analysis by physical methods such as infrared spectroscopy or x-ray diffraction can demonstrate the presence of the drug or its metabolites inside the calculi. In those calculi due to the metabolic effects of a drug, diagnosis relies on both stone analysis and clinical inquiry. Incidence of such calculi is probably underestimated, especially those due to calcium/vitamin D supplements or carbonic anhydrase inhibitors. Drug-induced calculi occur more often during high-dose or long term treatments, but there are also patient-related risk factors in relation to urine pH, urine output and other parameters, which can provide a basis for preventive treatment of such calculi. A better knowledge of these lithogenic complications of treatments and of solubility characteristics of drugs should reduce the incidence of drug-induced nephrolithiasis, especially in patients with identified risk factors.

Antiretroviral therapy and the kidney: balancing benefit and risk in patients with HIV infection

The widespread introduction of highly active antiretroviral therapy (HAART) has revolutionised the treatment and course of HIV infection, with complications of chronic HIV infection and HAART playing an increasingly important role in morbidity and mortality. Both HIV infection and HAART have been associated with the development of acute and chronic kidney disease. The incidence of HIV-associated nephropathy, the classic kidney disease of HIV, reached a plateau following the introduction of HAART, consistent with the pathogenic role of direct viral infection of the kidney. At the same time, antiretroviral agents and related therapies have demonstrated a range of nephrotoxic effects, including crystal-induced obstruction, lactic acidosis, tubular toxicity, interstitial nephritis and electrolyte abnormalities. This article reviews the impact of HAART on the epidemiology of HIV-related kidney disease, the potential nephrotoxicity of specific antiretroviral agents and related medications, and guidelines for monitoring kidney function in HAART-treated patients.

Highly active antiretroviral therapy and the kidney: an update on antiretroviral medications for nephrologists

Highly active antiretroviral therapy has dramatically altered the treatment and life expectancy of individuals who are infected with HIV. More than 20 antiretroviral drugs and drug combinations now are available in the United States. Nephrologists need to have an understanding of the pharmacokinetics of antiretroviral medications and the proper dosing of these medications in patients with impaired kidney function. It is also important for nephrologists to be aware of drug-drug interactions that can occur between antiretroviral medications and other medications that they may prescribe, including immunosuppressive medications that are used for renal transplantation, as this becomes more common in HIV-infected patients. Adverse reactions that affect the kidneys and cause fluid-electrolyte complications occur with certain antiretroviral agents, although most are relatively free of nephrotoxicity. This article reviews the clinical pharmacology and dosing modifications of the newer antiretroviral medications in patients with reduced kidney function; important drug-drug interactions involving these medications, particularly with other medications that are likely to be prescribed by nephrologists; and renal toxicities of antiretroviral agents.

Antiviral Drug-Induced Nephrotoxicity

Drug-induced kidney injury is a major side effect in clinical practice, frequently leading to acute renal failure (ARF). It accounts for more than 2% to 15% of cases of ARF in patients admitted to the hospital or in the intensive care unit, respectively. The exact frequency of nephrotoxicity induced by antiviral drugs is difficult to determine. Antiviral drugs cause renal failure through a variety of mechanisms. Direct renal tubular toxicity has been described with a number of new medications with unique effects on epithelial cells of the kidney. These include cidofovir, adefovir dipivoxil, and tenofovir, as well as acyclovir. Additionally, crystal deposition in the kidney may promote the development of renal failure. Several different drugs have been described to induce crystal nephropathy, including acyclovir and the protease inhibitor indinavir. Renal injury associated with antiviral drugs involves diverse processes having effects on the renal transporters, as well as on tubule cells. In this article, we review the pathogenesis of antiviral drug-induced kidney injury, common nephrotoxic renal syndromes, and strategies for preventing kidney injury.

Drug-induced renal failure: a focus on tubulointerstitial disease

Therapeutic agents induce acute renal failure (ARF) by promoting various types of injury to the kidney. Acute interstitial nephritis (AIN) develops from medications that incite an allergic reaction, leading to interstitial inflammation and tubular damage. Acute tubular necrosis (ATN) is a dose-dependent process that develops from direct toxicity on tubular epithelia, typically in the absence of inflammation. Additional, less common patterns of drug-induced renal injury include osmotic nephropathy, crystal nephropathy, and acute nephrocalcinosis. This review focuses on the multitude of patterns of drug-induced renal failure due to tubulointerstitial disease.

Drug-Induced Renal Failure in the ICU

Drug-induced renal failure is a frequent complication in the setting of ICU. Generally spoken pathomechanisms leading to drug-induced renal failure can be divided into hemodynamic effects, epithelial toxicity or crystalline nephropathy. The risk of drug-induced renal failure is increased by any form of hypovolemia (i.e. true hypovolemia or reduced effective circulating volume), older age, pre-existent renal impairment, and concomitant application of two or more nephrotoxins. This article reviews drugs most frequently responsible for renal failure in the ICU and discusses preventive measures. (Int J Artif Organs 2004; 27: 1034-42)

[Indinavir and renal lithiasis]

Indinavir is a new specific and potent drug that inhibits, like other antiretroviral agents, the protease of immune deficiency virus (HIV) or acquired immune deficiency syndrome (AIDS), an enzyme necessary to maduration and replication of the virus. Indinavir has the capacity to bind the active site causing a decrease in plasma of HIV1-RNA and an increase of T-CD4 helper lymphocytes. The aim of this work is to study in HIV and/or AIDS patients treated with indinavir the crystalluria and the formation of renal calculi due to the clearance of this drug. Two out of nine patients studied in this work presented abundant crystalluria and one of them presented spontaneously passed renal stone. Urinary crystals were studied under polarized-light microscopy and renal stone was analyzed by infrared spectroscopy.

Drug-induced renal failure: update on new medications and unique mechanisms of nephrotoxicity

Medications cause renal failure through a variety of mechanisms. Hemodynamic renal failure may result from drugs that reduce renal prostaglandins and hence renal blood flow and glomerular filtration rate. A relatively new group of drugs with this potential is the cyclooxygenase-2 selective inhibitors. Direct renal tubular toxicity has also been described with a number of new medications with unique effects on the epithelial cells of the kidney. These include the antiviral agents cidofovir, adefovir, and tenofovir as well as the bisphosphonate pamidronate. Additionally, crystal deposition in the kidney may promote the development of renal failure. Several different drugs have been described to induce crystal nephropathy, including the antiparasitic drug sulfadiazine, the antiviral agent acyclovir, and the protease inhibitor indinavir. Finally, an unusual form of renal failure characterized by swollen, vacuolated proximal tubular cells can develop from hyperosmolar substances. Agents recently described to induce an "osmotic nephrosis" include intravenous immunoglobulin and the plasma expander hydroxyethyl starch.

Persistent leukocyturia and loss of renal function in a prospectively monitored cohort of HIV-infected patients treated with indinavir

Symptomatic nephrotoxicity is a well-known complication of indinavir treatment. However, little is known about the relevance of other abnormalities, such as leukocyturia during use of indinavir. We determined the prevalence, risk factors, and consequences of persistent leukocyturia in a prospectively monitored cohort of indinavir users in three adult outpatient clinics. Patients were monitored for nephrotoxicity at regular visits (every 3 months) between August 1998 and September 2000. Monitoring involved urine dipstick analysis and microscopy for pH, erythrocytes, leukocytes, and indinavir crystals. The urine albumin concentration/creatinine concentration ratio and serum creatinine and indinavir plasma concentrations were measured, and urinary tract infection was excluded. Urologic symptoms were retrieved from medical records. Of 184 patients with at least one assessment, 35% had leukocyturia (i.e., >75 cells/microL) at least once during the study period, which coincided with mild increase in the serum albumin level, erythrocyturia, and crystalluria. Thirty-two (24%) of 134 patients with two or more assessments had persistent leukocyturia (i.e., on two or more occasions). Risk factors were indinavir plasma concentration of >9 mg/L, urine pH of >5.7, and crystalluria. Persistent leukocyturia was associated with a gradual loss of renal function but not with urologic symptoms. The data show that leukocyturia is a frequent finding and emphasize the need for monitoring renal function during indinavir treatment, even in the absence of urologic symptoms.

Renal Dysfunction in HIV-1-infected Patients

Improved therapy directed against opportunistic infection and HIV-1 itself has resulted in greatly enhanced patient survival in the past decade among patients infected with HIV-1. Since patients are living longer, HIV-1 infection is associated with a rising burden of kidney disease. Approximately 14% of black patients and 6% of white patients dying with HIV-1 infection in 1999 in the United States had renal disease. Overall, 10% of patients dying with HIV-1 infection had renal failure. The most common glomerular diseases are focal segmental glomerulosclerosis and immune complex glomerulonephritis. Appropriate therapy for focal segmental glomerulosclerosis includes effective antiretroviral therapy and angiotensin antagonist medication. Drug toxicity is also common, often manifesting as electrolyte abnormalities, acute renal failure, interstitial nephritis, or nephrolithiasis. In particular, indinavir is associated with crystalluria, nephrolithiasis, interstitial nephritis, and lower urinary tract inflammation. Appropriate screening for renal disease and appropriate intervention will likely reduce the morbidity and mortality associated with progressive renal disease.

Indinavir-associated interstitial nephritis and urothelial inflammation: clinical and cytologic findings

The objective of the present study was to characterize the genitourinary syndromes that accompany indinavir-associated pyuria. Of 23 indinavir-treated patients with persistent pyuria, 4 had isolated interstitial nephritis, 10 had both interstitial nephritis and urothelial inflammation, 7 had isolated urothelial inflammation, and 2 had pyuria with nonspecific urinary tract inflammation. A total of 21 patients had multinucleated histiocytes identified by cytologic testing of urine specimens. Urine abnormalities resolved in all 20 patients who stopped receiving indinavir therapy. Pyuria continued in the 3 patients who continued receiving indinavir. Six patients had elevated serum creatinine levels, which returned to baseline levels when indinavir was discontinued. In conclusion, indinavir-associated pyuria was frequently associated with evidence of interstitial nephritis and/or urothelial inflammation, multinucleated histiocytes were commonly present in urine specimens, and cessation of indinavir therapy was associated with prompt resolution of urine abnormalities.

Indinavir crystallization around the loop of Henle: experimental evidence

OBJECTIVE

To determine the probable site of the nephron and the plasma indinavir (IDV) concentration at which intrarenal IDV crystallization occurs.

DESIGN

We performed in vitro crystallization experiments in IDV solutions simulating conditions found in the nephron.

METHODS

To determine intrarenal IDV concentrations at which conditions in the nephron allow crystallization, several concentrations of IDV basic solutions (0-800 mM) were titrated from pH 4.0 to higher pH values until crystals formed within 1 minute. Based on the combination of pH and ionic strength at which crystals formed, we determined the site of the nephron at which this combination was first attained. Based on the capacity for concentration at that site, we were able to measure the corresponding plasma IDV concentration.

RESULTS

Under conditions normally found at the proximal tubule (i.e., pH 6.7 and ionic strength of 200 mM), IDV crystallized at 200 mg/L. Under conditions applying to the loop of Henle, pH 7.4 and ionic strength of 200 mM, IDV crystallized at 125 mg/L, which would correspond to a plasma IDV concentration of 8 mg/L.

CONCLUSIONS

IDV crystallization is most likely in the loop of Henle and may already start at plasma IDV concentrations as low as 8 mg/L. Increasing hydration does not reduce the risk of IDV crystallization in the loop of Henle but instead prevents IDV crystallization and aggregation in the lower urinary tract. It remains to be confirmed whether prevention of high IDV plasma concentrations will reduce the risk of IDV crystallization in the loop of Henle.

The management of the clinical complications of antiretroviral therapy

In clinical practice, combination antiretroviral therapy is frequently complicated by adverse reactions and drug-related toxicities. The incidence, presentation, differential diagnosis, and management of the most frequent and severe of these complications are discussed. The recently described spectrum of metabolic complications, including hyperlipidemia, fat redistribution, and lactic acidosis, are covered in detail. The management of nephrotoxicity, pancreatitis, bone marrow suppression, peripheral neuropathy, and hypersensitivity reactions related to antiretroviral therapy is also discussed.

Prospective study of urinalysis abnormalities in HIV-positive individuals treated with indinavir

Indinavir is a potent protease inhibitor widely used in combination with reverse-transcriptase inhibitors to treat human immunodeficiency virus (HIV) disease. Individuals treated with indinavir are prone to develop urinary complications, including renal colic, renal calculi, lower urinary tract symptoms, and indinavir crystalluria. Although renal stones secondary to indinavir have been described and characterized, little is known about the onset, frequency, and significance of the crystalluria. To document the longitudinal characteristics of indinavir crystalluria and associated urine abnormalities, 54 asymptomatic indinavir-naive HIV-positive individuals had urinalysis testing initially weekly and then monthly during the first year of indinavir treatment. Six hundred eight urinalyses were performed (11 +/- 2 urinalysis/subject), including 579 microscopy examinations performed by a nephrologist (10 +/- 2 examinations/subject). Baseline urinalysis results were essentially normal. After the start of treatment, indinavir crystalluria was frequently observed (67% of subjects). After the first 2 weeks, indinavir crystalluria remained constant at a frequency of approximately 25% of urine sediments examined at each test point. Other urine abnormalities, principally leukocytes (>/=10/high-power field) and casts, were observed in 39% of subjects. These abnormalities were more severe in five subjects, with concomitant increasing serum creatinine levels in three of them. Additional urine findings include the predominance of low pH (</=5. 5 in 72% of urinalyses) and high specific gravity (>/=1.025 in 66% of urinalyses). In conclusion, abnormal urinalysis results were noted frequently during the first year of treatment with indinavir. The main findings were the high proportion of subjects with crystalluria and the relatively high frequency of crystalluria observed consistently throughout. These findings may occasionally be associated with other urine abnormalities, presumably secondary to indinavir crystalluria.

Renal toxicity of protease inhibitors

Introduction of several classes of antiviral agents for the treatment of immunodeficiency virus has led to increased survival and improved quality of life for patients with HIV infection. Protease inhibitors have become the mainstays of current therapy in patient with AIDS. Renal intolerance of indinavir is a rare but important complication in HIV positive patients. The renal function of patients receiving indinavir should be closely monitored. Benign and asymptomatic crystalluria occurs in 4-13% of HIV positive patients. Several cases of acute renal failure, renal atrophy and interstitial nephritis have also been reported. A hydration protocol consisting of one to two liters of fluid should be initiated three hours after each indinavir dose. If significant renal insufficiency persists, temporary indinavir withdrawal or switching to another protease inhibitor should be considered.

Acute renal failure in HIV-infected patients: a brief review of common causes

Acute renal failure is a well-described renal syndrome observed in patients infected with the human immunodeficiency virus (HIV). Underlying glomerular disease and disturbances in renal tubular function predispose these patients to a number of hemodynamic and nephrotoxic insults. Prerenal azotemia from both "true" and "effective" depletion of intravascular volume is the most common cause of acute renal insufficiency in patients infected with HIV. Direct damage to the renal tubules from both nephrotoxic medications and prolonged ischemic processes occurs frequently in hospitalized patients. Injury to the tubulointerstitium of the kidney may also result from allergic reactions to medications prescribed to patients. Deposition of crystals in the tubular lumens, and rarely in the glomerular capillaries, will cause acute renal failure in the setting of tumor lysis syndrome or during therapy with medications associated with crystal nephropathy. Finally, obstruction of the urinary system will rarely cause postrenal azotemia in patients infected with HIV.

Acute tubulointerstitial nephritis attributable to indinavir therapy

Indinavir sulfate has been reported to cause asymptomatic crystalluria and nephrolithiasis in patients with human immunodeficiency virus (HIV) infection. Patients taking indinavir may present with asymptomatic crystalluria, nephrolithiasis with frank renal colic and obstruction, flank pain in the absence of nephrolithiasis, and dysuria or urgency. Asymptomatic crystalluria has been described as benign. Discontinuation of the drug has not been recommended in the absence of nephrolithiasis. We report two HIV-positive patients receiving indinavir who developed acute interstitial nephritis with foreign body giant cell reaction on renal biopsies. Both patients had asymptomatic crystalluria, although crystals were associated with clumps of white blood cells (WBCs) on urinalysis in one patient. Both cases show that the inflammatory response was significant enough to lead to tubular injury and acute renal impairment. Our findings suggest that asymptomatic crystalluria attributable to indinavir may illicit an inflammatory response with acute renal insufficiency, warranting monitoring of renal function, especially in patients with crystalluria.

[Renal colic and lithiasis in HIV(+)-patients treated with protease inhibitors]

INTRODUCTION

Protease inhibitors, mainly Indinavir, are widely used drugs for the treatment of patients infected by the human immunodeficiency virus (HIV) and are related to renal colic and urinary obstruction. These conditions are the result of urine excretion of these drugs which favours the formation of small calculi (crystalluria and lithiasis).

MATERIAL AND METHODS

Five PI treated HIV(+) patients; four males, one female, have recently been seen for renal colic at the Lithiasis Unit, Fundación Jiménez Díaz (FJD). All five patients had renal colic, one bilateral and one renal obstruction and fever. Small lithiasic concretions of null or minor radiological calcium density were identified by urinary X-ray and UIV. The patients had haematuria, crystalluria and urinary pH 5.0-6.0. Treatment was symptomatic, pharmacologic, emergency in situ extracorporeal shock-wave lithotrity (ESWL), or ureteral catheterisation, as appropriate.

RESULTS

Patients had been treated with these antiviral agents for several months. They all required urologic care: pharmacologic, ureteral catheterisation, or ESWL, with good results. No stones were obtained for mineralogic analysis, but crystalluria was identified as being due to Indinavir and calcium oxalate.

CONCLUSIONS

Renal excretion and urinary elimination of PIs (or their metabolites) results in asymptomatic crystalluria in HIV(+) patients treated with this class of drugs. Other cases present genuine calcium oxalate calculi with sings of renal colic and urinary obstruction requiring urologic care.

Detection of indinavir crystals in urine: dependence on method of analysis

OBJECTIVES

To determine the frequency of crystalluria in patients treated with the human immunodeficiency virus protease inhibitor indinavir and to compare methods of detecting crystalluria.

METHODS

A total of 308 freshly voided urine specimens from 168 patients treated with indinavir were evaluated by manual microscopy of sediment and microscopy with an automated workstation and by dipstick analysis.

RESULTS

Crystals were detected in 22%, 31%, or 32% of specimens using, respectively, an automated workstation, manual microscopy, or both methods. Proteinuria or hemoglobinuria occurred significantly more often in specimens with (28%) than without (18%) crystals. Frequency of crystalluria was unrelated to specific gravity, but it increased at higher pH. Crystals were detected in 21% of specimens with pH less than 6 and 42% of specimens with pH of 6 or higher.

CONCLUSIONS

Crystalluria occurs in more than 30% of urine specimens from patients treated with indinavir, but detection rates vary substantially with method of analysis. Manual microscopy detected crystalluria 41% more often than did an automated workstation.

Intravenous cidofovir for compassionate use in AIDS patients with cytomegalovirus retinitis. Spanish Cidofovir Study Group

We report the compassionate use of intravenous cidofovir for the treatment of cytomegalovirus retinitis in 51 patients with AIDS who were receiving highly active antiretroviral therapy (HAART). After a median of 9 doses, 49 patients showed no retinitis activity. However, treatment was stopped in 17 patients because of adverse reactions and in 5 patients for other reasons. Two deaths were considered related to the drug. Iritis developed in 21 patients (41.2%), a frequency higher than that reported during the pre-HAART era. Patients with iritis had median CD4 cell counts-both at nadir and at the initiation of cidofovir therapy-approximately 3 times higher than those for patients without iritis (P=.003 and P=.05, respectively). Our study confirms the efficacy of cidofovir therapy for AIDS-associated cytomegalovirus retinitis. Our data suggest that the risk of iritis may be higher for patients with better immunological status, probably because of their enhanced ability to mount an inflammatory response.

Increased Incidence of Indinavir Nephrolithiasis in Patients with Hepatitis B or C Virus Infection

Materials and Methods

A HIV-1 patient database was scanned in March 1998, and 750 patients were identified who had received HAART including indinavir. Of these, 28 cases had nephrolithiasis; and 85 asymptomatic indinavir-treated patients were randomly selected as controls. The characteristics of cases and controls were compared by analysis of variance for quantitative parameters and by Fisher's exact test for classes.

Results

We observed a significant increase in the incidence of nephrolithiasis in patients co-infected with HIV-1 and either hepatitis C virus (HCV) (HCV RNA-positive) or hepatitis B virus (HBV) (HBs antigen-positive) (odds ratio and 95% confidence intervals: 2.8 and 1.1–7.7), whereas no significant differences were demonstrated between cases and controls with regard to age (42.4±8.0 versus 39.8±9.8 years), sex (male patients 70.4 versus 74.1%), duration of HIV-1 infection (8.6±3.1 versus 7.7±4.0 years), duration of indinavir treatment (16.1±5.8 versus 14.1±5.4 months), AST increase ≥1.25 of normal (29.6 versus 25.9%), or ALT increase ≥1.25 of normal (33.3 versus 22.4%). In co-infected patients, ALT increase (≥1.25 of normal), but not AST increase, at the time of indinavir initiation was statistically related to the occurrence of nephrolithiasis.

Conclusions

We found a significant increase of nephrolithiasis incidence in patients co-infected with HIV-1 and HCV or HBV, which suggests that underlying multifactorial hepatic damage may limit liver catabolism of indinavir, and consequently increase its renal excretion and the risk of nephrolithiasis. Caution is therefore advised when initiating indinavir treatment in HIV patients with evidence of HBV or HCV infection.

The use of antiretroviral agents in patients with renal insufficiency

Current guidelines for the dosing of antiretroviral agents in HIV-positive patients with renal insufficiency including those requiring dialysis are limited, as revealed by a literature search performed using Health Knowledge Network MEDLINE and HealthSTAR. Pharmacokinetic and chemical aspects were taken into consideration to develop further recommendations. Results showed reverse transcriptase inhibitor dosage adjustment guidelines are available, but for patients receiving dialysis, guidelines are limited to zidovudine and didanosine. There are limited clinical data on dosage adjustments required for the use of protease inhibitors or non-nucleoside reverse transcriptase inhibitors (NNRTIs). Indinavir appears to require no dose modification. For nelfinavir, ritonavir and saquinavir, the chemical and pharmacokinetic characteristics along with the pathophysiology of renal dysfunction and dialysis suggest that these agents can likely be given at usual doses with close monitoring for toxicities. More data is required to make recommendations for use of NNRTIs in renal insufficiency. Combining the information from previous dosing guidelines and the pharmacokinetic data of antiretroviral agents allows for preliminary recommendations to be made until confirmed by definitive clinical data.

New developments in the treatment of HIV disease: An overview

The management of HIV disease has evolved into a complicated and sophisticated subspecialty in recent years. Fourteen drugs, in various combinations, are being used in increasingly complex treatment regimens. The side effects of some of these drugs, as well as certain drug-drug interactions may mimic signs and symptoms of HIV disease itself. Therefore it is imperative for the emergency physician to be knowledgeable about the new medications as well as about selected adverse effect and drug interaction profiles in order to be able to take care of the increasing numbers of HIV-positive patients presenting to emergency departments. This article aims to provide a focused review of these topics. In addition, health care workers with significant exposures to HIV-infected body fluids may present to the emergency department for initial evaluation. This presents a situation whereby emergency physicians may have to prescribe appropriate combinations of antiretroviral agents themselves. Thus familiarity with the basic principles of post-exposure prophylaxis is desirable and current Centers for Disease Control and Prevention guidelines are briefly reviewed.

A risk-benefit assessment of HIV protease inhibitors

The use of triple regimens, often called highly active antiretroviral therapy (HAART), generally involving 2 nucleoside analogues and an HIV protease inhibitor, have been endorsed as the standard of care for persons with HIV initiating therapy by a number of sets of international guidelines. The widespread availability of protease inhibitor-containing regimens has been associated with a dramatic drop in the incidence of new AIDS events and mortality throughout the developed world. Use of HAART regimens, particularly in treatment-naïve individuals, is also associated with dramatic reductions in HIV RNA load, rises in CD4+ cell numbers and improvements in some aspects of immune function. However, protease inhibitor therapy is associated with a range of adverse effects, which varies between agents, and regimens frequently involve inconvenient administration schedules and disruption to patient's lives. Thus, the undoubted benefits of antiretroviral therapy come at some cost in terms of both physical and psychological morbidity to the recipient. In assessing an individual for therapy, consideration of the risk of disease events and the benefit of therapy in reducing or preventing these events must be weighed against the potential of therapy to cause morbidity. Using these criteria, we suggest that an individual with a 3 year risk of disease progression of less than 10% (based on CD4+ cell count and HIV RNA load) is more likely to a experience a morbidity if treated with HAART than if left untreated and monitored. For individuals with higher risks of HIV progression the risk versus benefit of initiating therapy may, in many cases, still be in favour of no therapy and continued observation. This will vary depending on the individuals risks (such as family and past medical history) and on the choice of agents in the regimen, some regimens having greater risks than others.

Crystal-induced acute renal failure

Several medications--notably acyclovir, sulfonamides, methotrexate, indinavir, and triamterene--are associated with the production of crystals that are insoluble in human urine. Intratubular precipitation of these crystals can lead to acute renal insufficiency. Many patients who require treatment with these medications have additional risk factors, such as true or effective intravascular volume depletion and underlying renal insufficiency, that increase the likelihood of drug-induced intrarenal crystal deposition. Acute renal failure in this setting may be preventable if it is anticipated by appropriate drug dosing, volume expansion with high urinary flow, and alkalinization of the urine when appropriate. Renal failure may be reversible if the drug is discontinued, and by volume repletion and alkalinization of the urine when appropriate. Management of established renal insufficiency includes volume repletion, dialytic support if necessary, adjustment of drug doses, and avoidance of further exposure to nephrotoxins.

Persistent flank pain, low-grade fever, and malaise in a woman treated with indinavir

This case report describes a 32-year-old woman treated with indinavir who developed mild to moderate flank pain, malaise, and low-grade fever. Sterile pyuria preceded increased serum creatinine levels. Workup revealed persistent pyuria, normal-sized kidneys, a normal intravenous pyelography, and negative urinary cultures. Renal biopsy showed interstitial nephritis and chronic inflammation. Collecting ducts contained crystals. Two months after treatment with indinavir was discontinued, serum creatinine levels returned to normal and pyuria disappeared. Sterile pyuria in patients taking indinavir may help to identify patients at risk for renal dysfunction and interstitial nephritis. Markedly increasing the fluid intake above the recommended dosage may ameliorate or even reverse the process of tubulointerstitial disease.

Evaluation of urinary markers in acute renal failure

Acute renal failure continues to be a difficult clinical problem despite developments in dialysis and critical care. Diagnosis of the etiology frequently determines treatment. Urinalysis remains an essential diagnostic tool in the approach to acute renal failure, particularly with the current emphasis on cost-containment and evidence-based medicine. This review focuses on some of the characteristic features in the urinalysis found in different forms of acute renal failure, current developments into the molecular basis for these urinary abnormalities, and new markers on the horizon.