The Etiology of Urolithiasis in HIV Infected Patients

Urolithiasis: Presentation and Surgical Outcome at a Tertiary Care Hospital in Ethiopia

Background

The prevalence of urolithiasis is on a rising trend in tropical and sub-Saharan African countries. The treatment options and data on the surgical outcome are limited in our country. This study was designed to assess the clinical presentation, surgical management and outcome of patients operated on for urolithiasis.

Patients and Materials

A retrospective study of all patients admitted and operated for urolithiasis at St. Paul’s hospital millennium medical college (SPHMMC) from July, 2016 to December, 2017 was conducted. Factors associated with surgical outcome were identified with binary logistic regression.

Results

Urolithiasis constituted 247 (30.0%) of 824 urologic admissions. Of these, 202 (Male:Female = 2:1) patients were investigated. The mean age was 37.1 ± 14.4 years (range, 10–85 years). The mean duration of illness was 16.7 ± 18.7 months and the commonest presenting symptom was isolated flank pain (97, 48.0%). A majority of the patients (186, 92.1%) had upper tract stones of which 96 (51.6%) were renal stones. More than two-thirds (164, 81.2%) of the patients had complications at presentation, and hydronephrosis (148, 73.3%) was the major one. Half of the patients (104, 51.5%) were treated with endoscopic procedures, 88 (43.6%) with open stone surgery and in 10 (4.9%) patients both were performed. Nephrectomy was done to 15 (7.4%) patients. Intraoperative and postoperative complications were noted in 16 (7.9%) and 26 (12.9%) patients, respectively. These complications were higher in patients with comorbid illness (AOR = 2.44; 95% CI 1.12–5.31; p = 0.024). Complete stone clearance was achieved in more than half of the clients (114, 61.0%). Multiple stones (AOR = 8.33; 95% CI 2.53–27.43; p < 0.0001) and endoscopic procedures (AOR = 4.17; 95% CI 1.57–10.71; p = 0.003) had significant association with incomplete stone clearance.

Conclusion

Patients’ presentation in this review was not different from studies elsewhere. Endoscopic procedures are emerging in our set up; however, it was significantly associated with incomplete stone clearance. Strategies to improve outcome (stone clearance) need to be implemented accordingly.

What a difference a delay makes! CT urogram: a pictorial essay

PURPOSE

The aim of this pictorial essay is to demonstrate several cases where the diagnosis would have been difficult or impossible without the excretory phase image of CT urography.

METHODS

A brief discussion of CT urography technique and dose reduction is followed by several cases illustrating the utility of CT urography.

RESULTS

CT urography has become the primary imaging modality for evaluation of hematuria, as well as in the staging and surveillance of urinary tract malignancies. CT urography includes a non-contrast phase and contrast-enhanced nephrographic and excretory (delayed) phases. While the three phases add to the diagnostic ability of CT urography, it also adds potential patient radiation dose. Several techniques including automatic exposure control, iterative reconstruction algorithms, higher noise tolerance, and split-bolus have been successfully used to mitigate dose. The excretory phase is timed such that the excreted contrast opacifies the urinary collecting system and allows for greater detection of filling defects or other abnormalities. Sixteen cases illustrating the utility of excretory phase imaging are reviewed.

CONCLUSIONS

Excretory phase imaging of CT urography can be an essential tool for detecting and appropriately characterizing urinary tract malignancies, renal papillary and medullary abnormalities, CT radiolucent stones, congenital abnormalities, certain chronic inflammatory conditions, and perinephric collections.

Protease Inhibitors for the Treatment of HIV/AIDS: Recent Advances and Future Challenges

Acquired Immunodeficiency Syndrome (AIDS) is a chronic disease characterized by multiple life-threatening illnesses caused by a retro-virus, Human Immunodeficiency Virus (HIV). HIV infection slowly destroys the immune system and increases the risk of various other infections and diseases. Although, there is no immediate cure for HIV infection/AIDS, several drugs targeting various cruxes of HIV infection are used to slow down the progress of the disease and to boost the immune system. One of the key therapeutic strategies is Highly Active Antiretroviral Therapy (HAART) or ' AIDS cocktail' in a general sense, which is a customized combination of anti-retroviral drugs designed to combat the HIV infection. Since HAART's inception in 1995, this treatment was found to be effective in improving the life expectancy of HIV patients over two decades. Among various classes of HAART treatment regimen, Protease Inhibitors (PIs) are known to be widely used as a major component and found to be effective in treating HIV infection/AIDS. For the past several years, a variety of protease inhibitors have been reported. This review outlines the drug design strategies of PIs, chemical and pharmacological characteristics of some mechanism-based inhibitors, summarizes the recent developments in small molecule based drug discovery with HIV protease as a drug target. Further discussed are the pharmacology, PI drug resistance on HIV PR, adverse effects of HIV PIs and challenges/impediments in the successful application of HIV PIs as an important class of drugs in HAART regimen for the effective treatment of AIDS.

[Nephrotoxicity of antiretrovirals other than tenofovir]

The remarkable improvement of the outcome of HIV infection came with the price of substantial toxicity of some antiretrovirals. The first molecules used to treat HIV included an important nephrotoxicity. Zalcitabine, stavudine and didanosine can induce severe lactic acidosis. Lactate production is enhanced and the renal capacity to regulate pH is overwhelmed. However, this side effect is not due to a direct dysfunction of the kidneys. Zalcitabine was withdrawn from the market because of this risk. Indinavir, a protease inhibitor, is soluble only in very acidic solutions. Consequently, the small fraction that is excreted in the urine precipitates and can be responsible for uro-nephrolithiasis, leukocyturia, cristalluria, obstructive acute kidney failure, and acute or chronic interstitial nephritis. This is the reason why indinavir is almost not prescribed nowadays, even if it is still marketed. In addition to the direct nephrotoxicity of some antiretrovirals, anti-HIV treatment also includes a toxicity which pathophysiology is not completely elucidated. This nephrotoxicity is the consequence of organ accelerated ageing and of an increased vascular risk. Kidney vascularization (from renal arteries to capillaries) is essential to kidney function and all cardiovascular risks are also renal risks. It is now clearly established that combined antiretroviral treatment increases the vascular risk. A better comprehension of the links between HIV infection, its treatment and very long-term kidney risk is needed to improve the complex management of patients who have now cumulated several decades of HIV infection and treatment with various toxicities.

Renal and urologic disorders in antiretroviral-treated patients with HIV infection or AIDS: spectrum of cross-sectional imaging findings

In the aging human immunodeficiency virus (HIV)-infected population with improved immune function under antiretroviral treatment, many different opportunistic disorders may be encountered, along with rare presentations or complicated forms of common diseases. Renal and urologic abnormalities observed in the setting of HIV infection or acquired immunodeficiency syndrome are reviewed with their imaging appearances, including renal dysfunction, urolithiasis, urinary tract infections and related complications, genitourinary tuberculosis, vascular lesions, urogenital tumors, and bladder abnormalities, with emphasis on characterization. In HIV-positive patients, early cross-sectional imaging is warranted to detect uncommon disorders and complications, with the aim to preserve renal function.

Characterization of a sulfadiazine-induced lithiasis calculus by physicochemical techniques

Currently available information on drug lithiasis usually describes the calculi based on the prescriptions given to the patient, but without a physicochemical characterization of the calculi themselves. We here have applied different, complementary, physicochemical techniques for a complete characterization of an unusual urolithiasis calculus. The calculus was characterized using powder X-ray diffraction, infrared spectroscopy, mass spectrometry, 1H-NMR spectroscopy, and scanning electron microscopy. The precise nature of the calculus was identified, being formed by N4-acetylsulfadiazine, so being related to the drugs prescribed to the patient. Analytical techniques widely used in laboratories of Materials Chemistry have proven to be useful tools for characterizing the chemical nature of unusual urolithiasis.

High incidence of renal stones among HIV-infected patients on ritonavir-boosted atazanavir than in those receiving other protease inhibitor-containing antiretroviral therapy

BACKGROUND

Little information is available on the incidence of renal stones with ritonavir-boosted atazanavir (ATV/r) use.

METHODS

In a single-center study, the incidence of renal stones was compared between human immunodeficiency virus (HIV)-infected patients who commenced ritonavir-boosted atazanavir (ATV/r)-containing antiretroviral (ARV) therapy (the ATV/r group) and those who were receiving other protease inhibitors (the other PIs group). The effects of ATV/r were estimated by univariate and multivariate Cox proportional hazards regression models. Other possible risk factors were evaluated by univariate analysis, and those found to be significant were entered into multivariate analysis.

RESULTS

Renal stones were diagnosed in 31 patients (23.7 cases per 1000 person-years) in the ATV/r group (n = 465) and 4 in patients (2.2 cases per 1000 person-years) in the other PIs group (n = 775). ATV/r use was significantly associated with renal stones, by univariate and multivariate analyses (adjusted hazard ratio, 10.44; 95% confidence interval [CI], 3.685-29.59; P < .001). ATV/r remained a significant risk factor for renal stones in all subgroups stratified by the median values of baseline variables. In the 31 patients receiving ATV/r who developed renal stones, the median time from commencement of ATV/r to diagnosis was 24.5 months (interquartile range, 14.7-34.6 months). Of the 18 patients who continued ATV/r despite the diagnosis of renal stones, 6 (33.3%) experienced recurrence. No patient who discontinued ATV/r experienced recurrence during the observation period (250.6 person-months).

CONCLUSIONS

The incidence of renal stones was substantially higher among patients in the ATV/r group, compared with patients in the other PIs group. Continuation of ATV/r after diagnosis of renal stones was associated with a high rate of recurrence. Switching ATV/r to other ARVs is warranted in patients who develop renal stones.

Prevalence of nephrolithiasis in human immunodeficiency virus infected patients on the highly active antiretroviral therapy

BACKGROUND AND PURPOSE

Protease inhibitors, specifically indinavir, have historically been implicated as a cause of nephrolithiasis in the human immunodeficiency virus (HIV) infected patients. There is a paucity of data, however, on stone disease with nonindinavir etiologies since the introduction of highly active antiretroviral therapy (HAART). We sought to describe the prevalence of nephrolithiasis in the HIV population since the use of HAART.

PATIENTS AND METHODS

We retrospectively reviewed HIV-positive patients currently receiving HAART treatment in whom image proven kidney and/or ureteral urolithiasis developed, between 1998 and 2010. A detailed analysis of patients' current treatment, surgical intervention, and metabolic studies was performed.

RESULTS

A total of 436 HIV-positive patients were included and 46 (11%) patients had nephrolithiasis. Each patient included in this study was receiving nonindinavir-based antiretroviral therapy. There were 41 men of whom 36 were Caucasian. Eleven (24%) patients underwent 24-hour urine collections with 11 metabolic abnormalities identified. Stone analysis was available for seven patients (four calcium oxalate monohydrate, one cystine, one uric acid, and one atazanavir).

CONCLUSIONS

We report the largest series of nephrolithiasis in an HIV population since the introduction of HAART and highlight not only the similar prevalence of nephrolithiasis to the non-HIV population but also the lack of consistent comprehensive metabolic evaluations in HIV patients with recurrent nephrolithiasis.

Approach to the Adult Kidney Stone Former

Nephrolithiasis is a prevalent and costly condition with high recurrence rate. A medical evaluation to identify abnormalities responsible for nephrolithiasis and guide subsequent therapy has been advocated to reduce the risk of stone recurrence. The evaluation of kidney stone formers generally comprises an extensive medical history to identify metabolic, environmental, dietary and/or genetic factors contributing to stone formation. Imaging studies are utilized to evaluate and follow stone burden. Laboratory studies including stone composition analysis and serum and urinary chemistries are commonly obtained to further assess for any underlying systemic disorders, to detect environmental and metabolic processes contributing to stone disease, and to guide initial and follow-up dietary and pharmacological therapy. The nature and extent of such an evaluation is discussed in this review article.

Current and Novel Inhibitors of HIV Protease

The design, development and clinical success of HIV protease inhibitors represent one of the most remarkable achievements of molecular medicine. This review describes all nine currently available FDA-approved protease inhibitors, discusses their pharmacokinetic properties, off-target activities, side-effects, and resistance profiles. The compounds in the various stages of clinical development are also introduced, as well as alternative approaches, aiming at other functional domains of HIV PR. The potential of these novel compounds to open new way to the rational drug design of human viruses is critically assessed.

[Kidney diseases in HIV-infected patients]

HIV infection has become a global disease, both in geographic terms, since it has spread worldwide, and at the individual level since it affects every organ of the human body. Antiretroviral treatments, in countries where they are easily available, have modified HIV infection into a systemic chronic disease, the life expectancy of which is yet to be determined precisely. Treatments have dramatically changed the pattern of the disease and clinicians now have to face a number of new challenges. Kidneys, like all the other organs, can be involved in a great number of diseases in HIV-infected patients. We have voluntarily chosen to present "kidney diseases in HIV-infected patients" in their wider meaning, with a discussion of renal diseases that are directly caused by the virus, nephropathies due to frequent viral co-infections in HIV-infected patients such as HCV and HBV, nephropathies induced by anti-HIV, HBV and HCV therapies. Physicians in charge of HIV-infected patients should be aware of the key role they have to play in the screening for kidney abnormalities. This participates not only in improving patients' kidney prognosis but also their long-term general outcome. Renal screening strategies must refer to simple routine laboratory tests. Enclosed at the end of this article are a few suggestions for the renal management of situations that frequently occur in HIV infected patients (kidney dysfunction screening, serum creatinine increase and discovery of a proteinuria).

Evaluation of the kidney stone patient

Kidney stones are one of the most common chronic disorders in industrialized countries. In patients with kidney stones, the goal of medical therapy is to prevent the formation of new kidney stones and to reduce growth of existing stones. The evaluation of the patient with kidney stones should identify dietary, environmental, and genetic factors that contribute to stone risk. Radiologic studies are required to identify the stone burden at the time of the initial evaluation and to follow up the patient over time to monitor success of the treatment program. For patients with a single stone an abbreviated laboratory evaluation to identify systemic disorders usually is sufficient. For patients with multiple kidney stones 24-hour urine chemistries need to be measured to identify abnormalities that predispose to kidney stones, which guides dietary and pharmacologic therapy to prevent future stone events.

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.

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.

HIV-associated renal disorders: recent insights into pathogenesis and treatment

Renal electrolyte disorders, acute renal failure, and a variety of chronic renal diseases are common in HIV-infected patients. Glomerular disorders include IgA nephropathy, cryoglobulinemia, amyloidosis, and a lupus-like immune complex glomerulopathy. The most attention has been focused on collapsing glomerulopathy associated with nephrotic syndrome and progressive renal failure, which appears to be unique for patients with HIV/AIDS, called HIV-associated nephropathy (HIVAN), and it occurs predominantly in African American patients. Investigations in humans and in a transgenic mouse model reveal direct infection of renal epithelial cells by HIV and toxic cellular and immunologic processes mediated by HIV glycoproteins as the principal pathophysiology of HIVAN. Highly active antiretroviral treatment may be associated with an improved renal outcome and even reversal of kidney disease in some patients. Treatment with angiotensin-converting enzyme inhibitors may avert progression of HIVAN to end-stage kidney disease and result in superior patient and kidney survival as compared with untreated patients.

Could reduced bone mineral densities in HIV be caused by nanobacteria?

From the observations of different research groups reporting on reduced bone mineral density (BMD) and on a pronounced tendency for kidney stone formation, both in HIV-infected patients, and from results achieved in the treatment of severest peripheral neuropathy with lasers, it is concluded that nanobacteria (NB) could actively contribute to the reduction of BMD. A reduced BMD could primarily stem from NB, extracting calcium and phosphate from blood, affecting the calcium and phosphate homeostasis in humans.

Suffocation of Nerve Fibers by Living Nanovesicles: A Model Simulation

A model using nanospheres to allow the simulation of the nonspecific interaction of nanobacteria (NB), one with another or with body tissues, is established. Depending primarily on their concentrations and stress levels, these apatite nanovesicles may nucleate thrombogenic conglomerates in blood, or self-assemble to dense nanoclay layers on surfaces in the body. Partial or total encapsulation of nerve fiber bundles by such mineral layers may interrupt the metabolic exchanges between the surrounded tissue and its immediate environment and may restrict signaling processes. The presented model could provide detailed insight into plaque formation triggered by NB, and the parameters encouraging it.