[Arterial Hypertension - when are which combination therapies useful?]

Arterial hypertension is a widely prevalent risk factor for cardiovascular diseases with well documented harmful effects on the heart and the vascular system. Despite a broad antihypertensive drug armamentarium control of hypertension is worldwide suboptimal. Daily practice as well as large intervention trials show that single-drug therapy often fails to adequately control blood pressure (BP). Therefore, the early introduction of a combination therapy may lead to a better and more rapid BP lowering effect, particularly in patients with more than stage I hypertension or in patients with mild hypertension and high cardiovascular risk. In addition, side effects of an antihypertensive drug can be prevented by a meaningful (low dose) combination with a second antihypertensive agent. Moreover, combination of antihypertensive drugs, especially if provided fixed, may substantially improve compliance. However, the choice of the drug combination primarily relates on the demographic features and co-morbidities of the patient. Although BP lowering is the main determinant of cardiovascular risk reduction in the treatment of hypertension, some antihypertensive drugs may exhibit protective effects beyond BP reduction that have to be considered when antihypertensive drugs are combined. In recent large intervention studies, the combination of an ACE inhibitor with a calcium channel blocker was especially advantageous in high risk hypertensive patients. The addition of a thiazide type diuretic to a blocker of the renin-angiotensin system is also sensible and popular with numerous available fixed combinations.

Impact of image quality, radiologists, lung segments, and Gunnar eyewear on detectability of lung nodules in chest CT

BackgroundDespite the increasingly higher spatial and contrast resolution of CT, nodular lesions are prone to be missed on chest CT. Tinted lenses increase visual acuity and contrast sensitivity by filtering short wavelength light of solar and artificial origin.PurposeTo test the impact of Gunnar eyewear, image quality (standard versus low dose CT) and nodule location on detectability of lung nodules in CT and to compare their individual influence.Material and MethodsA pre-existing database of CT images of patients with lung nodules >5 mm, scanned with standard does image quality (150 ref mAs/120 kVp) and lower dose/quality (40 ref mAs/120 kVp), was used. Five radiologists read 60 chest CTs twice: once with Gunnar glasses and once without glasses with a 1 month break between. At both read-outs the cases were shown at lower dose or standard dose level to quantify the influence of both variables (eyewear vs. image quality) on nodule sensitivity.ResultsThe sensitivity of CT for lung nodules increased significantly using Gunnar eyewear for two readers and insignificantly for two other readers. Over all, the mean sensitivity of all radiologist raised significantly from 50% to 53%, using the glasses (P value = 0.034). In contrast, sensitivity for lung nodules was not significantly affected by lowering the image quality from 150 to 40 ref mAs. The average sensitivity was 52% at low dose level, that was even 0.7% higher than at standard dose level (P value = 0.40). The strongest impact on sensitivity had the factors readers and nodule location (lung segments).ConclusionSensitivity for lung nodules was significantly enhanced by Gunnar eyewear (+3%), while lower image quality (40 ref mAs) had no impact on nodule sensitivity. Not using the glasses had a bigger impact on sensitivity than lowering the image quality.

Occurence of Chai Hu (Bupleuri Radix) in Prescriptions of Chinese Herbal Medicine in Switzerland

Background: Chai hu (Bupleuri radix), one of the most frequently used herbs in Chinese herbal medicine, has 3 major functions, depending on dosage and combination with other herbs. The aim of this study was to investigate how chai hu is prescribed in everyday practice in Switzerland, and whether these prescription patterns reflect its various applications. Methods: A random sample of 1,053 prescriptions was drawn from the database of Lian Chinaherb AG, Wollerau, Switzerland, and analyzed regarding the most frequently used classical formulas containing chai hu, daily dosages and combinations with other herbs. Results: 29.0% of all prescriptions contained chai hu, and 98.0% of these were in granular form. The most frequently used classical formulas were xiao yao san (‘rambling powder’), jia wei xiao yao san (‘augmented rambling powder’) and chai hu shu gan san (‘Bupleurum powder to spread the liver’). In more than half of the prescriptions, chai hu was combined with bai shao (Paeoniae Radix Alba), dang gui (Angelicae sinensis radix) or fu ling (Poria). 51.8% of the prescriptions contained a low daily dosage of chai hu, 24.9% a medium and 15.1% a high dosage. Conclusion: Chai hu was generally prescribed in classic combinations with other herbs and in a medium dosage. Due to the addition of supplementary herbs to classical formulas, its daily dose was often diminished from a high or medium dose to a low dose. This raises the question if chai hu would then still exert its desired function of, e.g., moving liver-qi in these prescriptions

Antinociceptive effects, metabolism and disposition of ketamine in ponies under target-controlled drug infusion

Ketamine is widely used as an anesthetic in a variety of drug combinations in human and veterinary medicine. Recently, it gained new interest for use in long-term pain therapy administered in sub-anesthetic doses in humans and animals. The purpose of this study was to develop a physiologically based pharmacokinetic (PBPk) model for ketamine in ponies and to investigate the effect of low-dose ketamine infusion on the amplitude and the duration of the nociceptive withdrawal reflex (NWR). A target-controlled infusion (TCI) of ketamine with a target plasma level of 1 microg/ml S-ketamine over 120 min under isoflurane anesthesia was performed in Shetland ponies. A quantitative electromyographic assessment of the NWR was done before, during and after the TCI. Plasma levels of R-/S-ketamine and R-/S-norketamine were determined by enantioselective capillary electrophoresis. These data and two additional data sets from bolus studies were used to build a PBPk model for ketamine in ponies. The peak-to-peak amplitude and the duration of the NWR decreased significantly during TCI and returned slowly toward baseline values after the end of TCI. The PBPk model provides reliable prediction of plasma and tissue levels of R- and S-ketamine and R- and S-norketamine. Furthermore, biotransformation of ketamine takes place in the liver and in the lung via first-pass metabolism. Plasma concentrations of S-norketamine were higher compared to R-norketamine during TCI at all time points. Analysis of the data suggested identical biotransformation rates from the parent compounds to the principle metabolites (R- and S-norketamine) but different downstream metabolism to further metabolites. The PBPk model can provide predictions of R- and S-ketamine and norketamine concentrations in other clinical settings (e.g. horses).

HCV-related advanced fibrosis/cirrhosis: randomized controlled trial of pegylated interferon alpha-2a and ribavirin

In patients with hepatitis C virus (HCV)-related advanced fibrosis/cirrhosis, 30% of sustained HCV clearance has been reported with pegylated interferon alpha-2a (PEG-IFN) alone, but the efficacy and tolerability of the PEG-IFN/ribavirin (RBV) combination remain poorly defined. A total of 124 treatment-naïve patients with biopsy proved HCV-related advanced fibrosis/cirrhosis (Ishak score F4-F6, Child-Pugh score < or =7) were randomized to 48 weeks of PEG-IFN (180 microg sc weekly) and standard dose of RBV (1000/1200 mg po daily, STD) or PEG-IFN (180 microg sc weekly) and low-dose of RBV (600/800 mg po daily, LOW). Sustained virologic response (SVR) rates with PEG-IFN/STD RBV (52%) were higher--albeit not significantly--than that with PEG-IFN/LOW RBV (38%, P = 0.153). In multivariate analysis, genotype 2/3 and a baseline platelet count > or =150 x 10(9)/L were independently associated with SVR. The likelihood of SVR was < 7% if viraemia had not declined by > or =2 log or to undetectable levels after 12 weeks. Nine adverse events in the STD RBV and 15 in the LOW RBV group were classified as severe (including two deaths); dose reductions for intolerance were required in 78% and 57% (P = 0.013), and treatment was terminated early in 23% and 27% of patients (P = n.s.). The benefit/risk ratio of treating compensated HCV-cirrhotics with STD PEG-IFN/RBV is favourable.

[Arginine-vasopressin in septic and vasodilatorial shock]

Current therapy of septic/vasodilatory cardiovascular failure includes volume resuscitation and infusion of inotropic and vasopressor agents. Norepinephrine is the first-line vasoconstrictor, and can stabilize hemodynamic variables in most patients. Nonetheless, irreversible cardiovascular failure which is resistant to conventional hemodynamic therapies still is the main cause of death in patients with severe sepsis and septic shock. In such advanced, catecholamine-resistant shock states, arginine-vasopressin (AVP) has repeatedly caused an increase in mean arterial blood pressure, a decrease in toxic norepinephrine-dosages, as well as further beneficial hemodynamic, endocrinologic and renal effects. Although AVP exerted negative inotropic effects in previous clinical trials and in selected animal experiments, a continuous low-dose AVP infusion during advanced septic/vasodilatory shock caused a decrease in cardiac index only in patients with a hyperdynamic circulation. Adverse effects on gastrointestinal circulation and the systemic microcirculation can not be excluded, but have not yet been confirmed in clinical prospective trials. Negative side effects of a supplementary AVP therapy are an increase in total bilirubin concentrations, and a decrease in platelet count. A transient increase in hepatic transaminases during AVP infusion is most likely related to preceding hypotensive episodes. Important points which must be considered when using AVP as a "rescue vasopressor" in septic/vasodilatory shock states are: 1) AVP infusion only in advanced shock states that can not be adequately reversed by conventional hemodynamic therapy (e.g. norepinephrine >0,5-0,6 mug/kg/min), 2) presence of normovolemia, 3) AVP infusion only in combination with norepinephrine, 4) strict avoidance of bolus injections and dosages >4 IU/h. Effects of a supplementary AVP infusion in advanced vasodilatory shock on survival are currently examined in a large, prospective multicenter trial in North America and Australia.

Behavioral and anatomical abnormalities in a sodium iodate-induced model of retinal pigment epithelium degeneration

We characterized changes in the visual behavior of mice in which a loss of the retinal pigment epithelium (RPE) was experimentally induced with intravenous (i.v.) administration of sodium iodate (NaIO3). We compared and correlated these changes with alterations in neural retinal structure and function. RPE loss was induced in 4-6 week old male C57BL/6 mice with an i.v. injection of 1% NaIO3 at three concentrations: 35, 50, or 70 mg/kg. At 1, 3, 7, 14, 21, and 28 days (d) as well as 6 months post injection (PI) a behavioral test was performed in previously trained mice to evaluate visual function. Eye morphology was then assessed for changes in both the RPE and neural retina. NaIO3-induced RPE degeneration was both dose and PI time dependent. Our low dose showed no effects, while our high dose caused the most damage, as did longer PI times at our intermediate dose. Using the intermediate dose, no changes were detectable in either visual behavior or retinal morphology at 1 d PI. However, at 3 d PI visual behavior became abnormal and patchy RPE cell loss was observed. From 7 d PI onward, changes in retinal morphology and visual behavior became more severe. At 6 months PI, no recovery was seen in any of these measures in mice administered the intermediate dose. These results show that NaIO3 dosage and/or time PI can be varied to produce different, yet permanent deficits in retinal morphology and visual function. Thus, this approach should provide a unique system in which the onset and severity of RPE damage, and its consequences can be manipulated. As such, it should be useful in the assessment of rescue or mitigating effects of retinal or stem cell transplantation on visual function.

Intravenous magnesium for acute myocardial infarction

BACKGROUND: Mortality and morbidity from acute myocardial infarction (AMI) remain high. Intravenous magnesium started early after the onset of AMI is thought to be a promising adjuvant treatment. Conflicting results from earlier trials and meta-analyses warrant a systematic review of available evidence. OBJECTIVES: To examine the effect of intravenous magnesium versus placebo on early mortality and morbidity. SEARCH STRATEGY: We searched CENTRAL (The Cochrane Library Issue 3, 2006), MEDLINE (January 1966 to June 2006) and EMBASE (January 1980 to June 2006), and the Chinese Biomedical Disk (CBM disk) (January 1978 to June 2006). Some core Chinese medical journals relevant to the cardiovascular field were hand searched from their starting date to the first-half year of 2006. SELECTION CRITERIA: All randomized controlled trials that compared intravenous magnesium with placebo in the presence or absence of fibrinolytic therapy in addition to routine treatment were eligible if they reported mortality and morbidity within 35 days of AMI onset. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed the trial quality and extracted data using a standard form. Odds ratio (OR) were used to pool the effect if appropriate. Where heterogeneity of effects was found, clinical and methodological sources of this were explored. MAIN RESULTS: For early mortality where there was evidence of heterogeneity, a fixed-effect meta-analysis showed no difference between magnesium and placebo groups (OR 0.99, 95%CI 0.94 to 1.04), while a random-effects meta-analysis showed a significant reduction comparing magnesium with placebo (OR 0.66, 95% CI 0.53 to 0.82). Stratification by timing of treatment (< 6 hrs, 6+ hrs) reduced heterogeneity, and in both fixed-effect and random-effects models no significant effect of magnesium was found. In stratified analyses, early mortality was reduced for patients not treated with thrombolysis (OR=0.73, 95% CI 0.56 to 0.94 by random-effects model) and for those treated with less than 75 mmol of magnesium (OR=0.59, 95% CI 0.49 to 0.70) in the magnesium compared with placebo groups.Meta-analysis for the secondary outcomes where there was no evidence of heterogeneity showed reductions in the odds of ventricular fibrillation (OR=0.88, 95% CI 0.81 to 0.96), but increases in the odds of profound hypotension (OR=1.13, 95% CI 1.09 to 1.19) and bradycardia (OR=1.49, 95% CI 1.26 to 1.77) comparing magnesium with placebo. No difference was observed for heart block (OR=1.05, 95% CI 0.97-1.14). For those outcomes where there was evidence of heterogeneity, meta-analysis with both fixed-effect and random-effects models showed that magnesium could decrease ventricular tachycardia (OR=0.45, 95% CI 0.31 to 0.66 by fixed-effect model; OR=0.40, 95% CI 0.19 to 0.84 by random-effects model) and severe arrhythmia needing treatment or Lown 2-5 (OR=0.72, 95% CI 0.60 to 0.85 by fixed-effect model; OR=0.51, 95% CI 0.33 to 0.79 by random-effects model) compared with placebo. There was no difference on the effect of cardiogenic shock between the two groups. AUTHORS' CONCLUSIONS: Owing to the likelihood of publication bias and marked heterogeneity of treatment effects, it is essential that the findings are interpreted cautiously. From the evidence reviewed here, we consider that: (1) it is unlikely that magnesium is beneficial in reducing mortality both in patients treated early and in patients treated late, and in patients already receiving thrombolytic therapy; (2) it is unlikely that magnesium will reduce mortality when used at high dose (>=75 mmol); (3) magnesium treatment may reduce the incidence of ventricular fibrillation, ventricular tachycardia, severe arrhythmia needing treatment or Lown 2-5, but it may increase the incidence of profound hypotension, bradycardia and flushing; and (4) the areas of uncertainty regarding the effect of magnesium on mortality remain the effect of low dose treatment (< 75 mmol) and in patients not treate...

Vasopressin in septic shock: effects on pancreatic, renal, and hepatic blood flow

INTRODUCTION: Vasopressin has been shown to increase blood pressure in catecholamine-resistant septic shock. The aim of this study was to measure the effects of low-dose vasopressin on regional (hepato-splanchnic and renal) and microcirculatory (liver, pancreas, and kidney) blood flow in septic shock. METHODS: Thirty-two pigs were anesthetized, mechanically ventilated, and randomly assigned to one of four groups (n = 8 in each). Group S (sepsis) and group SV (sepsis/vasopressin) were exposed to fecal peritonitis. Group C and group V were non-septic controls. After 240 minutes, both septic groups were resuscitated with intravenous fluids. After 300 minutes, groups V and SV received intravenous vasopressin 0.06 IU/kg per hour. Regional blood flow was measured in the hepatic and renal arteries, the portal vein, and the celiac trunk by means of ultrasonic transit time flowmetry. Microcirculatory blood flow was measured in the liver, kidney, and pancreas by means of laser Doppler flowmetry. RESULTS: In septic shock, vasopressin markedly decreased blood flow in the portal vein, by 58% after 1 hour and by 45% after 3 hours (p < 0.01), whereas flow remained virtually unchanged in the hepatic artery and increased in the celiac trunk. Microcirculatory blood flow decreased in the pancreas by 45% (p < 0.01) and in the kidney by 16% (p < 0.01) but remained unchanged in the liver. CONCLUSION: Vasopressin caused marked redistribution of splanchnic regional and microcirculatory blood flow, including a significant decrease in portal, pancreatic, and renal blood flows, whereas hepatic artery flow remained virtually unchanged. This study also showed that increased urine output does not necessarily reflect increased renal blood flow.

Effects of vasopressin on microcirculatory blood flow in the gastrointestinal tract in anesthetized pigs in septic shock

BACKGROUND: Vasopressin increases arterial pressure in septic shock even when alpha-adrenergic agonists fail. The authors studied the effects of vasopressin on microcirculatory blood flow in the entire gastrointestinal tract in anesthetized pigs during early septic shock. METHODS: Thirty-two pigs were intravenously anesthetized, mechanically ventilated, and randomly assigned to one of four groups (n=8 in each; full factorial design). Group S (sepsis) and group SV (sepsis-vasopressin) were made septic by fecal peritonitis. Group C and group V were nonseptic control groups. After 300 min, group V and group SV received intravenous infusion of 0.06 U.kg.h vasopressin. In all groups, cardiac index and superior mesenteric artery flow were measured. Microcirculatory blood flow was recorded with laser Doppler flowmetry in both mucosa and muscularis of the stomach, jejunum, and colon. RESULTS: While vasopressin significantly increased arterial pressure in group SV (P<0.05), superior mesenteric artery flow decreased by 51+/-16% (P<0.05). Systemic and mesenteric oxygen delivery and consumption decreased and oxygen extraction increased in the SV group. Effects on the microcirculation were very heterogeneous; flow decreased in the stomach mucosa (by 23+/-10%; P<0.05), in the stomach muscularis (by 48+/-16%; P<0.05), and in the jejunal mucosa (by 27+/-9%; P<0.05), whereas no significant changes were seen in the colon. CONCLUSION: Vasopressin decreased regional flow in the superior mesenteric artery and microcirculatory blood flow in the upper gastrointestinal tract. This reduction in flow and a concomitant increase in the jejunal mucosa-to-arterial carbon dioxide gap suggest compromised mucosal blood flow in the upper gastrointestinal tract in septic pigs receiving low-dose vasopressin.

The radiographic assessment of implant patients: decision-making criteria

Indications for the most frequently used imaging modalities in implant dentistry are proposed based on clinical need and biologic risk for the patient. To calculate the biologic risk, the authors carried out dose measurements. They demonstrated that the risk from a periapical radiograph is 20% of that from a panoramic radiograph. A panoramic radiograph and a series of 4 conventional tomographs of a single-tooth gap in the molar region carry 5% and 13% of the risk from computed tomography of the maxilla, respectively. Panoramic radiography is considered the standard radiographic examination for treatment planning of implant patients, because it imparts a low dose while giving the best radiographic survey. Periapical radiographs are used to elucidate details or to complete the findings obtained from the panoramic radiograph. Other radiographic methods, such as conventional film tomography or computed tomography, are applied only in special circumstances, film tomography being preferred for smaller regions of interest and computed tomography being justified for the complete maxilla or mandible when methods for dose reduction are followed. During follow-up, intraoral radiography is considered the standard radiographic examination, particularly for implants in the anterior region of the maxilla or for scientific studies. In patients requiring more than 5 periapical images, panoramic radiography is preferred.

Blockade of NMDA receptor subtype NR2B prevents seizures but not apoptosis of dentate gyrus neurons in bacterial meningitis in infant rats

BACKGROUND: Excitotoxic neuronal injury by action of the glutamate receptors of the N-methyl-d-aspartate (NMDA) subtype have been implicated in the pathogenesis of brain damage as a consequence of bacterial meningitis. The most potent and selective blocker of NMDA receptors containing the NR2B subunit is (R,S)-alpha-(4-hydroxyphenyl)-beta-methyl-4-(phenylmethyl)-1-piperid inepropanol (RO 25-6981). Here we evaluated the effect of RO 25-6981 on hippocampal neuronal apoptosis in an infant rat model of meningitis due to Streptococcus pneumoniae. Animals were randomized for treatment with RO 25-6981 at a dosage of either 0.375 mg (15 mg/kg; n = 28) or 3.75 mg (150 mg/kg; n = 15) every 3 h or an equal volume of sterile saline (250 microl; n = 40) starting at 12 h after infection. Eighteen hours after infection, animals were assessed clinically and seizures were observed for a period of 2 h. At 24 h after infection animals were sacrificed and brains were examined for apoptotic injury to the dentate granule cell layer of the hippocampus. RESULTS: Treatment with RO 25-6981 had no effect on clinical scores, but the incidence of seizures was reduced (P < 0.05 for all RO 25-6981 treated animals combined). The extent of apoptosis was not affected by low or high doses of RO 25-6981. Number of apoptotic cells (median [range]) was 12.76 [3.16-25.3] in animals treated with low dose RO 25-6981 (control animals 13.8 [2.60-31.8]; (P = NS) and 9.8 [1.7-27.3] (controls: 10.5 [2.4-21.75]) in animals treated with high dose RO 25-6981 (P = NS). CONCLUSIONS: Treatment with a highly selective blocker of NMDA receptors containing the NR2B subunit failed to protect hippocampal neurons from injury in this model of pneumococcal meningitis, while it had some beneficial effect on the incidence of seizures.

Use of ampicillin-sulbactam for treatment of experimental meningitis caused by a beta-lactamase-producing strain of Escherichia coli K-1

We evaluated the pharmacokinetics and therapeutic efficacy of ampicillin combined with sulbactam in a rabbit model of meningitis due to a beta-lactamase-producing strain of Escherichia coli K-1. Ceftriaxone was used as a comparison drug. The MIC and MBC were 32 and greater than 64 micrograms/ml (ampicillin), greater than 256 and greater than 256 micrograms/ml (sulbactam), 2.0 and 4.0 micrograms/ml (ampicillin-sulbactam [2:1 ratio, ampicillin concentration]) and 0.125 and 0.25 micrograms/ml (ceftriaxone). All antibiotics were given by intravenous bolus injection in a number of dosing regimens. Ampicillin and sulbactam achieved high concentrations in cerebrospinal fluid (CSF) with higher dose regimens, but only moderate bactericidal activity compared with that of ceftriaxone was obtained. CSF bacterial titers were reduced by 0.6 +/- 0.3 log10 CFU/ml/h with the highest ampicillin-sulbactam dose used (500 and 500 mg/kg of body weight, two doses). This was similar to the bactericidal activity achieved by low-dose ceftriaxone (10 mg/kg), while a higher ceftriaxone dose (100 mg/kg) produced a significant increase in bactericidal activity (1.1 +/- 0.4 log10 CFU/ml/h). It appears that ampicillin-sulbactam, despite favorable CSF pharmacokinetics in animals with meningitis, may be of limited value in the treatment of difficult-to-treat beta-lactamase-producing bacteria, against which the combination shows only moderate in vitro activity.

Acute respiratory distress syndrome secondary to antisynthetase syndrome is reversible with tacrolimus

Polymyositis and interstitial lung diseases, predominantly nonspecific interstitial pneumonia (NSIP), are known to be frequent in antisynthetase syndrome, where anti-aminoacyl-tRNA synthetase antibodies are often identified. An unusual case of acute respiratory distress syndrome, secondary to such proven NSIP of cellular type with predominant CD8 lymphocytes, is described herein. The patient described in the present case study initially had a poor recovery with high dose of steroids, but this was followed by a good improvement after the prescription of tacrolimus and a low dose of prednisone. A precise diagnosis in similar circumstances may be life-saving, allowing the successful application of new immunosuppressants.

Forget the blood, not the stone! Microhaematuria in acute urolithiasis and the role of early CT scanning

BACKGROUND: Although urinalysis is simple and inexpensive to perform, the finding of microhaematuria on urinalysis may be unreliable for diagnosing urolithiasis. OBJECTIVE: To evaluate microhaematuria as a diagnostic marker for urolithiasis compared with low-dose unenhanced multidetector computed tomography (MDCT) as the "gold standard". SETTING: A level 1 emergency department in a tertiary referral university teaching hospital. DESIGN: Retrospective analysis. METHODS: A study was undertaken to assess whether the finding of microhaematuria was diagnostic for urolithiasis using a low-dose unenhanced MDCT-based diagnosis as the reference standard by reviewing the records of all patients who presented to the emergency department with colicky flank pain and underwent a CT scan between January 2003 and December 2005. RESULTS: Urolithiasis was present (as defined by low-dose unenhanced MDCT) in 507/638 patients (79%); 341/638 (53%) were true positive for urolithiasis, 76 (12%) were true negative, 55 (9%) were false positive and 166 (26%) were false negative. Microhaematuria as a test for urolithiasis in patients presenting to the emergency department therefore has a sensitivity, specificity, positive predictive value and negative predictive value of 67%, 58%, 86% and 31%, respectively. 58% of the urinalysis results were negative for haematuria in the subset of patients with significant alternative diagnoses. CONCLUSIONS: The sensitivity, specificity and negative predictive value of microhaematuria on urinalysis for urolithiasis using unenhanced MDCT as the reference standard were low. This suggests that, when urolithiasis is clinically suspected, unenhanced MDCT is indicated without urinalysis being a prerequisite.