Microscopic hematuria diagnosis and management

Glomerular isolated microscopic hematuria: urinary features and long term follow-up of a selected cohort of patients

BACKGROUND

Isolated microscopic hematuria is a condition characterized by the presence in the urine of an "abnormal" number of erythrocytes in the absence of proteinuria. Several studies have been published on this condition, but with heterogeneous inclusion criteria and variable outcomes at follow-up. In this retrospective study, we describe a selected and homogenous cohort of patients who presented with isolated microscopic hematuria of glomerular origin.

METHODS

We included in the study patients with isolated microscopic hematuria of glomerular origin (> 1 erythrocyte/high power field at 400× and ≥ 40% dysmorphic erythrocytes and/or ≥ 5% acanthocytes and proteinuria ≤ 150 mg/24 h) with a follow-up of > 60 months from the first documentation of microscopic hematuria.

RESULTS

Forty-two patients (M 12, F 30, age at presentation 14-68 years, eGFR < 60 ml/min/1.73 m²: 1 patient) were included. During a medium term follow-up, microscopic hematuria was persistent in 25 patients (59.5%), transiently absent in 17 (40.5%), always glomerular in 16 patients (38.1%), and occasionally non-glomerular in 26 (61.9%); proteinuria, observed in 16 patients (38.1%), was always transient and < 500 mg/24 h. At the end of a follow-up of 181.8 ± 97.9 (median 168) months, only 2 patients (4.8%) had eGFR < 60 ml/min/1.73 m², one of whom had reduced eGFR already at presentation.

CONCLUSIONS

This study on a small but selected and homogeneous cohort of patients with isolated microscopic hematuria of glomerular origin demonstrates that urinary features can transiently change over time and that the renal outcome is good.

Urine erythrocyte morphology in patients with microscopic haematuria caused by a glomerulopathy

The evaluation of urinary erythrocyte morphology (UEM) has been proposed for patients with isolated microscopic haematuria (IMH) to early orientate the diagnosis towards a glomerular or a nonglomerular disease. However, to date, the role of this test in patients with IMH has very rarely been investigated. Sixteen patients (ten children, six adults) with persistent IMH classified as glomerular on the basis of repeated UEM evaluations (55 urine samples, two to eight per patient) were submitted to renal biopsy. This showed a glomerular disease in 14/16 patients (87.5%) (nine thin basement membrane disease; three Alport syndrome; two other), whereas in two patients, no abnormalities were found. Of four microscopic criteria investigated to define a IMH as glomerular, >80% dysmorphic erythrocytes were not found in any sample, >or=40% dysmorphic erythrocytes alone were seen in seven samples (12.7%), >or=5% acanthocytes alone in 15 samples (27.3%) and erythrocytic casts in six samples (10.9%). There was >or=40% dysmorphic erythrocytes associated with >or=5% acanthocytes in 25 samples (45.5%). Sensitivity and positive predictive values in diagnosing a glomerular haematuria were 59.2% and 90.6%, respectively, for >or=40% dysmorphic erythrocytes, 69.4% and 85% for >or=5% acanthocytes/G1 cells and 12.2% and 100% for erythrocytic casts. Our findings demonstrate that the evaluation of UEM is useful to identify patients with an IMH of glomerular origin.

Haematuria 1: risk factors, clinical evaluation and laboratory investigations

Haematuria is a common complaint presenting to doctors in both community and acute centres. It can be a sign of underlying urinary tract malignancy. Appropriate investigation and management should follow evidence-based practice and recognized guidelines, and subsequently lead to a rapid diagnosis.

Haematuria 2: Imaging investigations, management and follow up

Haematuria is a common complaint presenting to doctors in both primary and secondary care. It can be a sign of underlying urinary tract malignancy. Appropriate investigation and management should follow evidence-based practice and recognized guidelines, and subsequently lead to a rapid diagnosis.

Risk factors associated to kidney stones in primary hyperparathyroidism

Nephrolithiasis is the most important clinical manifestation of primary hyperparathyroidism (PHPT), although nowadays this disorder is often asymptomatic. Clinical or biochemical differences between PHPT patients with and without nephrolithiasis have not been clearly identified in most of the previous studies. The aim of the study was to investigate clinical and biochemical parameters in kidney stone former (SF) and non-stone former (NSF) patients with PHPT in order to identify potential risk factors. Serum and plasma samples from 55 consecutive patients (43 females, 12 males) with PHPT were collected after overnight fasting; 24-h urine collection and a fresh sample of urine for sediment analysis were obtained from all patients. Clinical data were recorded in all. Out of 55 patients, 22 had kidney stones, which were symptomatic in 73%. SFs showed circulating PTH, total and ionized calcium, 1,25 dihydroxyvitamin D3, urinary calcium excretion and 24-h urine oxalate levels significantly higher than NSFs. Hypercalciuria was often concomitant with massive quantities of calcium oxalate crystals in urine sediment. Hypercalciuria and relatively high oxaluria were associated with stone formation with an odds ratio (OR) of 4.0 and 7.0, respectively, which rose to 33.5 when they coexisted. Hypomagnesuria and hypocitraturia were common in at least one third of all PHPT patients, but they were not associated to an increased OR. As expected, they were positively correlated with urine calcium excretion, suggesting that calcium, magnesium and citrate are commonly regulated at renal level. In conclusion, hypercalciuria, higher oxalate excretion and severe PHPT are associated with kidney stones in PHPT.

Evaluation of the patient with hematuria

There is little controversy regarding whether gross or visible hematuria requires complete upper and lower urinary tract evaluation. With regard to microscopic hematuria, investigators have disagreed on precisely which patients require a complete work-up. Most agree that older patients (> 40 years), patients with a history of cigarette use, and those with occupational exposure or history of chronic phenacetin use should absolutely undergo upper tract imaging, cystourethroscopy, and cytologic examination of the urine in addition to a thorough history and physical examination. A multidisciplinary group of oncologists, radiologists, urologists, and internists has published its recommendations as part of the American Urological Association best practice policy. The formal guidelines, which were distributed, rereviewed, and modified following a nationwide survey of clinicians, recommend complete urologic evaluation for all patients with microscopic hematuria who are over 40 years of age, and younger patients with a history suspicious for urologic disease. This identifies those at highest risk for malignancy while minimizing the number of evaluations in patients unlikely harboring significant disease.

Kidney transplantation in patients with IgA mesangial glomerulonephritis

BACKGROUND

Strategies for treating IgA glomerulonephritis (IgAGN) are controversial, particularly with regards to the long-term results of kidney transplantation, including the risk of recurrence of IgAGN post-transplant and the impact of this recurrence on graft survival.

METHODS

The outcomes of 106 adults transplanted because of a biopsy-proven IgAGN and of 212 patients without IgAGN transplanted during the same period were analyzed. To evaluate the risk of recurrence, patients with hematuria, proteinuria, or an increase in plasma creatinine were submitted to allograft biopsy. Factors influencing recurrence and the impact of recurrence on graft survival were analyzed.

RESULTS

The ten-year patient (0.93 vs. 0.92) and graft survival (0.75 vs. 0.82) probabilities were not significantly different between IgAGN patients and controls. Only plasma creatinine and proteinuria at six months were associated with an increased relative risk (RR) of graft failure (RR 2.79 and 5.94, respectively). Histological recurrence of IgA glomerulonephritis was diagnosed in 37 patients. Younger age (RR 2.63), increased plasma creatinine (RR 2.39), and proteinuria (RR 6.02) at six months were associated with the risk of recurrence. If proteinuria and plasma creatinine at six months were considered in the Cox model, IgA recurrence per se was not associated with an increased risk of graft failure (P = 0.181). The main causes of graft failure were glomerulonephritis in patients with recurrence of IgAGN and chronic rejection in patients without recurrence.

CONCLUSIONS

The ten-year graft survival rate was similar in patients with IgAGN or other renal diseases. At least 35% IgAGN patients had biopsy-proven recurrence, and younger patients were more prone to the risk of recurrence. Recurrence did not affect the ten-year graft survival.

Familial microscopic hematuria caused by hypercalciuria and hyperuricosuria

We report 12 patients belonging to five different families in whom persistent isolated microhematuria was associated with hypercalciuria and/or hyperuricosuria. Four patients had episodes of gross hematuria, three patients had passed renal stones, and a history of nephrolithiasis was obtained in four of the families (80%). Calcium oxalate and uric acid crystals were commonly observed in the urine sediments. Urinary erythrocytes had a normal appearance on phase-microscopic examination. Reduction of calciuria and uricosuria by thiazide diuretics, allopurinol, forced fluid intake, and dietetic measures led to a persistent normalization of urine sediment with complete disappearance of hematuria. Determination of calcium and uric acid urinary excretions should be included in the study of familial hematuria.

Reexamining the value of hematuria testing in patients with acute flank pain

PURPOSE

Hematuria testing is routinely performed in patients with acute flank pain to screen for ureterolithiasis and to help determine the need for excretory urography. Unenhanced helical computerized tomography (CT) has recently been shown to be superior to excretory urography in diagnosing ureteral obstruction and can evaluate many other causes of flank pain. Given the speed, accuracy and safety of CT the value of hematuria testing for acute flank pain should be reexamined.

MATERIALS AND METHODS

We reviewed the medical records of 267 consecutive patients with acute flank pain referred for unenhanced helical CT. Microscopic and dipstick urinalysis data were obtained in 195 patients. Using helical CT as the gold standard, we calculated the sensitivity, specificity, predictive value and accuracy of hematuria for diagnosing ureterolithiasis.

RESULTS

Of the patients with ureterolithiasis 33% had 5 or less, 19% had 1 or less and 11% had no red blood cells (RBCs) per high power field. Of the patients without ureterolithiasis 24% had greater than 5 and 51% had greater than 1 RBC per high power field. Of the patients with ureterolithiasis 14% had a negative dipstick test and 1 RBC or less per high power field. There were 25 patients without ureterolithiasis who had CT abnormalities unrelated to the urinary tract, of whom 8 had greater than 1 RBC per high power field.

CONCLUSIONS

Absence of hematuria in the setting of acute flank pain cannot exclude a diagnosis of ureterolithiasis and should not obviate other diagnostic testing. Even when strongly positive on microscopy, hematuria has insufficient positive predictive value for diagnosing ureterolithiasis and may be misleading as other serious conditions resulting in acute flank pain may yield a positive test.

The value of comparative volumetric analysis of urinary and blood erythrocytes to localize the source of hematuria

PURPOSE

We evaluate comparative volumetric analysis of blood and urinary red blood cells (RBCs) to identify the source of hematuria. Comparative volumetric analysis is defined as the difference between mean corpuscular erythrocyte volume in peripheral blood (MCVB) diluted in urine supernatant after centrifugation and mean corpuscular volume of urinary erythrocytes (MCVU). The potential of MCVB-MCVU to distinguish the origin of hematuria is compared to MCVU alone. The fundamental hypothesis is that RBCs that can go through the glomerulus will be smaller than those from the collecting system or lower urinary tract, thus having a smaller MCVU and larger difference between MCVB and MCVU.

MATERIALS AND METHODS

A prospective detailed urological evaluation was performed on 210 patients with glomerular or nonglomerular hematuria detected by urinary sediment, clinical radiological evaluation, endoscopy, cytology and sometimes bladder or renal biopsy. After evaluation 24 cases with an uncertain source of hematuria were excluded from study. Specialized urinalysis, volumetric analysis and clinical investigation were performed in a blind fashion. MCVU and MCVB-MCVU were registered for every patient. The Technicon H-3 system with angle laser scattering dual system allowed measurement of mean corpuscular volume in a minimal number of RBCs, and resuspension of RBC pellets in the same urinary supinate avoided effects of osmolarity and pH on RBC size and shape. Reproducibility in assessing the index was tested in 50 cases in which comparative volumetric analysis was repeated on 2 consecutive days. Unpaired t test was performed, and a threshold value of MCVB-MCVU with maximum sensitivity and specificity to detect glomerular hematuria was identified. The potential of urinary and comparative volumetric analysis to distinguish the source of hematuria was evaluated and compared by receiver operating characteristics curve analysis.

RESULTS

Hematuria was nonglomerular in 53 (28.4%) and glomerular in 133 (71.6%) patients. Mean MCVB-MCVU was significantly different for nonglomerular (0.6 fl.) and glomerular (30.5 fl.) sources (p<0.0001). There was a correlation between repeat independent measures of MCVU and MCVB-MCVU. The highest positive predictive value to detect a glomerular origin is desirable so that unnecessary investigation can be obviated without the risk of missing a nonglomerular source. With a limit of 16 fl. specificity and positive predictive value were 98 and 99%, respectively. Receiver operating characteristics curve analysis to localize the source of hematuria revealed significant differences in favor of comparative volumetric analysis versus urinary volumetric analysis alone.

CONCLUSIONS

MCVB-MCVU using the Technicon H-3 system is a useful noninvasive and accurate method to locate the source of hematuria. A value of 16 fl. or greater practically rules out a nonglomerular origin and obviates further urological investigation. We have incorporated this investigation in our diagnostic algorithm for hematuria.

Acute flank pain: a modern approach to diagnosis and management

Acute flank pain is a common and complex clinical problem. In addition to flank pain caused by ureterolithiasis, other urinary and extraurinary abnormalities can result in a similar clinical picture. Unenhanced CT can rapidly, accurately, and safely determine the presence or absence of ureteral obstruction. When obstruction is caused by ureterolithiasis, CT allows precise determination of stone size and location. These are the two most important factors used for patient management. In addition to direct stone visualization, there are many secondary CT signs of ureteral obstruction that are direct manifestations of the underlying pathophysiology. On the other hand, when obstruction is absent, CT can diagnose or exclude most other abnormalities that result in flank pain. As a result of its many advantages, unenhanced helical CT should become the dominant imaging modality for evaluation of all patients with acute flank pain in whom a clinical diagnosis is uncertain.

Urinary microscopy as seen by nephrologists

Urinary microscopy is a diagnostic tool which is largely used by nephrologists. In the opinion of the authors the best results can be achieved when all the aspects concerning this test are properly taken into account. Thus, from the methodological point of view, proper patient guidance, proper urine collection and handling, adequate microscopic equipment, and knowledge of the factors which can influence the results are all necessary. All the elements of clinical importance have to be known, namely, erythrocytes (with their morphological subtypes), leukocytes, tubular cells, uroepithelial cells (both superficial and deep), lipids, casts, crystals, and microorganisms. Then, the urinary findings have to be interpreted and, whenever possible, also combined into urinary profiles (e.g., the nephritic sediment, the nephrotic sediment). This, combined with other laboratory tests, the pathologic findings, and the clinical data, allows for the definition and management of urinary tract diseases.

[Hematuria in the child. Investigation plan in pediatric practice]

The discovery of hematuria in a child should lead the pediatrician to a methodical evaluation of the patient based on an extensive history and comprehensive physical examination. The microscopic examination of the urine is the cornerstone in the evaluation process and may suggest the origin of the hematuria. For instance, red blood cell casts indicate glomerular lesions and rule out the need for further urological examinations. According to the type of hematuria and the associated symptoms, a complete and immediate evaluation is sometimes necessary. This article presents a decisional tree to help the pediatrician to investigate an hematuria and to refer the child to a specialist, when needed.