Utility of fractional excretion of urea in acute kidney injury with comparison to fractional excretion of sodium: A systematic review and meta-analysis.

BACKGROUND: Differentiating between intrinsic and prerenal acute kidney injury (AKI) presents a challenge. Here, we assessed the performance of the fractional excretion of urea (FEUrea) and compared it to the fractional excretion of sodium (FENa) in distinguishing intrinsic from prerenal AKI. METHODS: A thorough search was conducted in several databases until January 16, 2024. We included studies evaluating FEUrea, with or without FENa, for differentiating AKI etiologies in adults. We assessed the methodological quality using the QUADAS-2 and QUADAS-C tools. We performed a meta-analysis using the bivariate random effects model, with subgroup analyses to explore the impact of diuretic therapy on FEUrea, and direct statistical comparisons between FEUrea and FENa involving the subgroups with and without diuretics. RESULTS: We included 11 studies with 1108 hospitalized patients. Among eight studies (915 patients) evaluating FEUrea >35% for distinguishing intrinsic from prerenal AKI, the pooled sensitivity and specificity were 66% (95% CI, 49%-79%) and 75% (95% CI, 60%-85%), respectively. In a subset of six studies (302 patients) comparing FEUrea at 35% to FENa at 1% in patients not receiving diuretics, there were no significant differences in sensitivity (77% versus 89%, P = 0.410) or specificity (80% versus 79%, P = 0.956). In four studies, 244 patients on diuretics, FEUrea demonstrated lower sensitivity (52% versus 92%, P < 0.001) but higher specificity (82% versus 44%, P < 0.001) compared to FENa for the diagnosis of intrinsic AKI. CONCLUSIONS: FEUrea has limited utility in differentiating intrinsic from prerenal AKI. FEUrea does not provide a superior alternative to FENa, even in patients receiving diuretics.

Acute Severe Hyponatremia following Hysteroscopic Procedure in a Young Patient: A Case Report and Review of the Literature.

BACKGROUND: Hysteroscopic surgery is a minimally invasive procedure used to diagnose and treat intrauterine pathologies. It requires distension of the uterine cavity for the adequate visualization of the operative field. Glycine (1.5%) is one of the most commonly used solutions because it is nonconductive and also has good optical properties. However, acute hyponatremia is a critical complication that can develop after the absorption of a sufficient amount of the irrigation medium. Case Presentation. We report a case of a 43-year-old female patient who developed acute symptomatic hyponatremia (104 mEq/L) and pulmonary edema secondary to hysteroscopic resection of leiomyoma and hastily approached with rapid sodium correction measures. CONCLUSION: Multiple strategies can be taken to reduce the risk of fluid absorption and subsequent hyponatremia. Moreover, attention should be paid to the treatment approach for patients with acute hyponatremia following hysteroscopic procedures; rapid correction of acute hyponatremia for such patients might be safe, although there is no consensus in the literature, and further trials are needed.

Predialysis nephrology care amongst Palestinian hemodialysis patients and its impact on initial vascular access type.

Referral time for end-stage renal disease (ESRD) patients to nephrologists and initial vascular access method are considered significant factors that impact health outcomes at the time of hemodialysis (HD) initiation. Native arteriovenous fistula (AVF) is strongly recommended as initial access. However, little is known about the referral rate among ESRD receiving HD in Palestine and its correlation with AVF creation. In Ramallah Hemodialysis Center, we investigated the pre-dialysis nephrology care and AVF usage in 156 patients. Type of access at HD initiation was temporary central venous catheter (CVC) in 114 (73%), tunneled hemodialysis catheter (TDC) in 21 (13%) and AVF in 21 (13%). Out of all participants, 120 (77%) were seen by nephrologist prior to dialysis. Of the participants who initiated dialysis with a CVC, 36 (31%) had not received prior nephrology care. All participants who initiated dialysis with functional AVF had received prior nephrology care. Patients who were not seen by a nephrologist prior to HD initiation had no chance at starting HD with AVF, whereas 17% of those who had nephrology care >12 months started with AVF. In conclusion, a relatively large percentage of Palestinian HD patients who were maintained on HD did not have any predialysis nephrology care. In addition, patients who received predialysis nephrology care were significantly more likely to start their HD through AVF whereas all those without predialysis nephrology care started through CVC. More in-depth national studies focusing on improving nephrology referral in ESRD patients are needed to increase AVF utilization.

Perceived barriers and attitudes toward arteriovenous fistula creation and use in hemodialysis patients in Palestine.

In the dialysis center in Ramallah, we investigated the attitudes and perceived barriers to having arteriovenous fistula (AVF) in 156 patients. The current method of HD access was AVF in 52% and central venous catheter in 47%. Perceived causes of no or delayed AVF were: patient's refusal of AVF in 54.5%, late referral to a surgical evaluation in 31.3% and too long to surgical appointments in 14.2%. Among those who refused AVF, reasons were: concern about the surgical procedure in 42.5%, poor understanding of disease/access in 23.3%, fear of needles in 15.1%, denial of disease or need for HD in 17.8%, and cosmetic reasons in 1.4%. Forty six percent of patients believed they received education about AVF prior to the creation of HD access, and 73.7% would recommend AVF as the method of access due to the lower risk of infection (96%), easier to care for (16%), easier showering (14%), and better-associated hygiene (3%). In conclusion, the majority would recommend an AVF as the mode of vascular access for HD. The most common barrier to having an AVF was patient's refusal to undergo AVF creation because of their concern about the surgical procedure. A systematic evaluation of the process that precedes the creation of AVF may allow for better utilization.

Cystatin C Predicts Renal Recovery Earlier Than Creatinine Among Patients With Acute Kidney Injury.

INTRODUCTION: Serum cystatin C increases earlier than creatinine during acute kidney injury. However, whether cystatin C decreases earlier during recovery is unknown. This retrospective study aimed to determine the temporal trend between creatinine and cystatin C in acute kidney injury. METHODS: We identified hospitalized patients with nonoliguric acute kidney injury who had serial creatinine and cystatin C values measured between May 2015 and May 2016. Demographic and laboratory data, causes of acute kidney injury, and relevant comorbidity data were collected through chart review. RESULTS: For the 63 identified patients, mean (SD) age was 58.7 (13.9) years; male sex, 62%; white race/ethnicity, 95%. Baseline median (range) creatinine was 1.1 (0.5-3.0) mg/dl; 13% were kidney transplant recipients and 37% received corticosteroids. Comorbidities included malignancy (38%), diabetes mellitus (33%), heart failure (19%), and thyroid disorder (16%). The cause of kidney injury was acute tubular necrosis in 71%, 61% had acute kidney injury stage III, and 33% required dialysis. Cystatin C began to decrease before creatinine in 68% of patients: 1 day earlier, 46%; 2 days earlier, 16%; and 3 days earlier, 6%. In 24% of cases, both began decreasing on the same day; in only 8%, cystatin C decreased after creatinine. Overall, cystatin C mean (95% confidence interval) decrease was 0.92 (0.65-1.18) days before creatinine (P < 0.001). CONCLUSION: In summary, cystatin C decreases before creatinine in most hospitalized patients with acute kidney injury. If confirmed in large prospective studies, these findings may have important management implications, possibly shortening hospital stay and reducing costs.

Impairment of Thyroid Function in Critically Ill Patients in the Intensive Care Units.

Unexplained hypotension in the intensive care unit is commonly attributed to volume depletion, cardiorespiratory failure, sepsis, or relative adrenal insufficiency. In these acute conditions, thyroid hormone levels measured in blood, serum or plasma are often altered and solely attributed to critical illness. We report a series of 3 critically ill patients with prolonged respiratory failure, suppressed mental status and unexplained hypotension. Thyroid stimulating hormone levels ranged from normal to mildly elevated (2.36-7.65IU/mL; normal: 0.27-4.20), but free thyroxin was markedly suppressed (0.239-0.66ng/dL; normal: 0.93-1.70). After initiation of intravenous levothyroxine (75-100µg/day), the patients could be weaned off vasopressors and were successfully extubated shortly thereafter. These cases demonstrate that hypothyroid intensive care unit patients may exhibit even seemingly normal or mildly abnormal thyroid stimulating hormone values. Early recognition and treatment of a hypothyroid state superimposed on critical illness may contribute to recovery from hypotension or the need for mechanical ventilation.

Targeted surgical parathyroidectomy in end-stage renal disease patients and long-term metabolic control: A single-center experience in the current era.

BACKGROUND: The long-term results of surgical parathyroidectomy (PTX) in end-stage renal disease (ESRD) patients are less well known in the modern era of newer activated vitamin-D analogs, calcimimetics and intraoperative monitoring of parathyroid hormone (PTH). METHODS: We performed a retrospective chart review of all ESRD patients undergoing PTX at the University of Mississippi Medical Center between January 2005 and August 2011, with follow-up data as available up to 4 years. All PTXs were performed with intraoperative second-generation PTH monitoring and targeted gland size reduction. RESULTS: The cohort (N = 37) was relatively young with a mean (±SD) age of 48.4 ± 13.9. 94.6% of the subjects were African American and 59.5% female. Preoperatively, 45.9% received cinacalcet (CNC) at a mean dose of 63.5 ± 20.9 mg. The size of the largest removed glands measured 1.7 ± 0.8 cm and almost all (94.6%) glands had hyperplasia on histology. The mean length of inpatient stay was 5.5 ± 2.4 days. Preoperative calcium/phosphorus measured 9.6 ± 1.2/6.6 ± 1.7 mg/dL with PTH concentrations of 1589 ± 827 pg/mL. Postoperative PTH values measured 145.4 ± 119.2 pg/mL. Preoperative PTH strongly correlated (P < 0.0001) with both alkaline phosphatase (ALP) levels (r: 0.596) and the number of inpatient days (r: 0.545), but not with CNC administration. Independent predictors for the duration of hospitalization were preoperative ALP (beta 0.469; P = 0.001) and age (beta -0.401; P = 0.005) (R2 0.45); for postoperative hypocalcemia, age (beta: -0.321; P = 0.006) and preoperative PTH (beta: 0.431; P = 0.036) were significant in linear regression models with stepwise selection. CONCLUSION: Gland-sparing PTX achieved acceptable control of ESRD-associated hyperparathyroidism in most patients from a socioeconomically challenged, underserved population of the United States.

The Rate of Acute Kidney Injury After Total Hip Arthroplasty Is Low but Increases Significantly in Patients with Specific Comorbidities.

BACKGROUND: The purpose of this study was to investigate the rate and risk factors associated with the development of acute kidney injury after total hip arthroplasty, including the perioperative use of nonsteroidal anti-inflammatory drugs (NSAIDs). METHODS: We retrospectively collected the demographic and comorbidity data of all patients who underwent total hip arthroplasty between 2004 and 2014 at our institution (n = 8,949). We conducted analyses of the entire cohort and a nested case-control subset. Subjects who developed acute kidney injury were matched by age, sex, and year of surgical procedure to subjects without acute kidney injury. Variables associated with acute kidney injury were determined using univariate and multivariate logistic regressions. RESULTS: The mean patient age (and standard deviation) was 64.6 ± 13.8 years, 48.6% of patients were male, and 114 cases (1.1%) developed acute kidney injury, mostly stage 1 (79%). Variables associated with acute kidney injury included older age (odds ratio [OR], 1.4 per decade; p < 0.001), male sex (OR, 1.78; p = 0.005), chronic kidney disease (OR, 4.6; p < 0.001), heart failure (OR, 4.5; p < 0.001), diabetes (OR, 2.1; p < 0.001), and hypertension (OR, 2.1; p = 0.007). The results were consistent in the case-control analysis. NSAIDs were not associated with acute kidney injury (OR, 1.26; p = 0.36), but were avoided in subjects at risk, making any interpretation difficult because of confounding. A risk model for acute kidney injury after total hip arthroplasty was developed for clinical use and had good discrimination (area under the curve, 0.82; p < 0.001). CONCLUSIONS: The rate of acute kidney injury after total hip arthroplasty is low, but increases significantly, from <1% to >20%, in those with several independent risk factors present preoperatively. Increasing awareness of these risk factors may help to decrease the risk of acute kidney injury after total hip arthroplasty. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Coadministration of Liposomal Amphotericin B and Contrast Medium Does Not Increase Risk of Kidney Injury.

Intravenous radiographic contrast medium and amphotericin B are commonly required in the care of patients with fungal infections. Both interventions have proposed nephrotoxicity through similar mechanisms. We systematically examined patients who received coadministration of liposomal amphotericin B (AmBisome; GE Healthcare) and intravenous contrast medium within a 24-h period and compared the results for those patients with the results for patients who underwent non-contrast medium studies. We found 114 cases and 85 controls during our study period. Overall, no increased risk of renal injury was seen with coadministration of these 2 agents. Adjustment for age, baseline kidney function, and other clinical factors through propensity score adjustment did not change this result. Our observations suggest that, when clinically indicated, coadministration of contrast medium and liposomal amphotericin B does not present excess risk compared with that from the administration of liposomal amphotericin B alone.

Comparison of Blood Pressure Control Rates Among Recommended Drug Selection Strategies for Initial Therapy of Hypertension.

BACKGROUND: Several approaches to initiation of antihypertensive therapy have been suggested. These include thiazide diuretics (TDs) as the first drug in all patients, initial drug selection based on age and race criteria, or therapy selection based on measures of plasma renin activity (PRA). It is uncertain which of these strategies achieves the highest control rate with monotherapy in Stage-I hypertension. We sought to compare control rates among these strategies. METHODS: We used data from the Pharmacogenomic Evaluation of Antihypertensive Responses study (PEAR) to estimate control rates for each strategy: (i) TD for all, (ii) age- and race-based strategy: Hydrochlorothiazide (HCTZ) for all blacks and for whites ≥50 years and a renin-angiotensin system inhibitor (atenolol) for whites <50 years) or (iii) a PRA based strategy: HCTZ for suppressed PRA (<0.6ng/ml/h) and atenolol for non-suppressed PRA (≥0.6ng/ml/h) despite age or race. Hypertension was confirmed prior to treatment with HCTZ (148 blacks and 218 whites) or with atenolol (146 blacks and 221 whites). RESULTS: In the overall sample, using clinic blood pressure (BP) response, the renin-based strategy was associated with the greatest control rate (48.9% vs. 40.8% with the age and race-based strategy (P = 0.0004) and 31.7% with the TD for all strategy (P < 0.0001)). The findings were similar using home or by 24-hour ambulatory BP responses and within each racial subgroup. CONCLUSIONS: A strategy for selection of initial antihypertensive drug therapy based on PRA was associated with greater BP control rates compared to a thiazide-for-all or an age and race-based strategy.

Tunneled Hemodialysis Catheter Removals by Non-Interventional Nephrologists: The University of Mississippi Experience.

Bedside removal of tunneled hemodialysis catheters (TDC) by noninterventional Nephrologists has not been frequently performed or studied. We performed a retrospective review of bedside TDC removal at the University of Mississippi Medical Center between January, 2010 and June, 2013. We collected data on multiple patients and procedure-related variables, success, and complications rates. Of the 138 subjects, mean age was 50 (±15.9) years, 49.3% were female, 88.2% African American and 41% diabetics. Site of removal was the right internal jugular (IJ) in 76.8%, the left IJ in 15.2%, and the femoral vein in 8% of patients. Exactly 44.9% of removals took place in the outpatient setting. Main indications for the removal were proven bacteremia in 30.4%, sepsis or clinical concerns for infection in 15.2% of the cases, while TDC was no longer necessary in 52.2% of patients. All removals were technically successful and well tolerated, but we observed Dacron "cuff" separation and subcutaneous retention in 6.5% of the cases. There was a significant association between outpatient removal and cuff retention (p = 0.007), but not with the site of removal or operator experience. In this relatively large mixed cohort of inpatients and outpatients, bedside TDC removal was well tolerated with a minimal complication rate.

Risk factors, complication and measures to prevent or reverse catastrophic sodium overcorrection in chronic hyponatremia.

Hyponatremia is the most common electrolyte disorder encountered in clinical practice. Patients who develop this condition for more than 48 hours are at risk for severe neurological sequelae if correction of the serum sodium occurs too rapidly. Certain medical disorders are known to place patients at an increased risk for rapid correction of serum sodium concentration. Large-volume polyuria in this setting is an ominous sign. For these patients, early identification of risk factors, close monitoring of serum sodium correction and the use of 5% dextrose with or without desmopressin to prevent or reverse overcorrection are important components of treatment.

Psoas muscle infiltration masquerading distant adenocarcinoma.

Malignant metastasis to the psoas muscle is rare. We report a case that clinically mimicked psoas abscess that was subsequently proven to be from metastatic disease secondary to adenocarcinoma of the duodenum. A 62-year-old male presented with a seven-month history of right lower quadrant abdominal pain and progressive dysphagia. CT scan of abdomen-pelvis revealed a right psoas infiltration not amenable to surgical drainage. Patient was treated with two courses of oral antibiotics without improvement. Repeated CT scan showed ill-defined low-density area with inflammatory changes involving the right psoas muscle. Using CT guidance, a fine needle aspiration biopsy of the right psoas was performed that reported metastatic undifferentiated adenocarcinoma. Patient underwent upper endoscopy, which showed a duodenal mass that was biopsied which also reported poorly differentiated adenocarcinoma. In this case, unresponsiveness to medical therapy or lack of improvement in imaging studies warrants consideration of differential diagnosis such as malignancy. Iliopsoas metastases have shown to mimic psoas abscess on their clinical presentation and in imaging studies. To facilitate early diagnosis and improve prognosis, patients who embody strong risk factors and symptoms compatible with underlying malignancies who present with psoas imaging concerning for abscess should have further investigations.

Desmopression is an effective adjunct treatment for reversing excessive hyponatremia overcorrection.

We report a case of a 50-year-old malnourished African American male with hiccups, nausea and vomiting who was brought to the Emergency Department after repeated seizures at home. Laboratory evaluations revealed sodium (Na(+)) 107 mmol/L, unmeasurably low potassium, chloride < 60 mmol/L, bicarbonate of 38 mmol/L and serum osmolality 217 mOsm/kg. Seizures were controlled with 3% saline IV. Once nausea was controlled with iv antiemetics, he developed large volume free water diuresis with 6 L of dilute urine in 8 h (urine osmolality 40-60 mOsm/kg) and serum sodium rapidly rose to 126 mmol/L in 12 h. Both intravenous desmopressin and 5% dextrose in water was given to achieve a concentrated urine and to temporarily reverse the acute rise of sodium, respectively. Serum Na(+) was gradually re-corrected in 2-3 mmol/L daily increments from 118 mmol/L until 130 mmol/L. Hypokalemia was slowly corrected with resultant auto-correction of metabolic alkalosis. The patient discharged home with no neurologic sequaele on the 11(th) hospital day. In euvolemic hyponatremic patients, controlling nausea may contribute to unpredictable free water diuresis. The addition of an antidiuretic hormone analog, such as desmopressin can limit urine output and prevent an unpredictable rise of the serum sodium.

The safety and efficacy of bedside removal of tunneled hemodialysis catheters by nephrology trainees.

BACKGROUND: Some nephrologists remove tunneled hemodialysis catheters (TDC) at the bedside, but this practice has never been formally studied. Our hypothesis was that bedside removal of TDC is a safe and effective procedure affording prompt removal, including in cases of suspected infection. METHODS: We reviewed our consecutive 3-year experience (2007-2009) with bedside TDC removal at the University of Mississippi Renal Fellowship Program. Data were collected on multiple patients and procedure-related variables, success and complication rates. Association between clinical characteristics and biomarkers of inflammation and myocardial damage was examined using correlation coefficients. RESULTS: Of 55 inpatient TDC removals (90.9% from internal jugular location), 50 (90.9%) were completed without hands-on assistance from faculty. Indications at the time of removal included bacteremia, fever or clinical sepsis with hemodynamic instability or respiratory failure. All procedures were successful, with no cuff retention noted; one patient experienced prolonged bleeding which was controlled with local pressure. Peak C-reactive protein (available in 63.6% of cohort) was 12.9 ± 8.4 mg/dL (reference range: <0.49) and median troponin-I (34% available) was 0.534 ng/mL (IQR 0.03-0.9) (reference range: <0.034) and they did not correlate with each other. Abnormal troponin-I was associated with proven bacteremia (p < 0.05) but not with systolic and diastolic BP or clinical sepsis. CONCLUSION: Our results suggest that bedside removal of TDC remains a safe and effective procedure regardless of site or indications. Accordingly, TDC removal should be an integral part of competent Nephrology training.