Microscopic haematuria as a relative contraindication for tranexamic acid

Tranexamic acid has been advocated for patients with severe bleeding tendency due to thrombocytopenia not responding to platelet transfusions. Macroscopic haematuria is a well-known contraindication for its use in such patients. We present three clinical cases with microscopic haematuria, in whom tranexamic acid caused problems of clot formation in the urinary tract, indicating that microscopic haematuria should also be considered as a contraindication for tranexamic acid.     

Clinical features of kidney cancer in primary care: a case-control study using primary care records

Background

Kidney cancer accounts for over 4000 UK deaths annually, and is one of the cancer sites with a poor mortality record compared with Europe.

Aim

To identify and quantify all clinical features of kidney cancer in primary care.

Design

Case-control study, using General Practice Research Database records.

Method

A total of 3149 patients aged ≥40 years, diagnosed with kidney cancer between 2000 and 2009, and 14 091 age, sex and practice-matched controls, were selected. Clinical features associated with kidney cancer were identified, and analysed using conditional logistic regression. Positive predictive values for features of kidney cancer were estimated.

Results

Cases consulted more frequently than controls in the year before diagnosis: median 16 consultations (interquartile range 10–25) versus 8 (4–15): P<0.001. Fifteen features were independently associated with kidney cancer: visible haematuria, odds ratio 37 (95% confidence interval [CI] = 28 to 49), abdominal pain 2.8 (95% CI = 2.4 to 3.4), microcytosis 2.6 (95% CI = 1.9 to 3.4), raised inflammatory markers 2.4 (95% CI = 2.1 to 2.8), thrombocytosis 2.2 (95% CI = 1.7 to 2.7), low haemoglobin 1.9 (95% CI = 1.6 to 2.2), urinary tract infection 1.8 (95% CI = 1.5 to 2.1), nausea 1.8 (95% CI = 1.4 to 2.3), raised creatinine 1.7 (95% CI = 1.5 to 2.0), leukocytosis 1.5 (95% CI = 1.2 to 1.9), fatigue 1.5 (95% CI = 1.2 to 1.9), constipation 1.4 (95% CI = 1.1 to 1.7), back pain 1.4 (95% CI = 1.2 to 1.7), abnormal liver function 1.3 (95% CI = 1.2 to 1.5), and raised blood sugar 1.2 (95% CI = 1.1 to 1.4). The positive predictive value for visible haematuria in patients aged ≥60 years was 1.0% (95% CI = 0.8 to 1.3).

Conclusion

Visible haematuria is the commonest and most powerful single predictor of kidney cancer, and the risk rises when additional symptoms are present. When considered alongside the risk of bladder cancer, the overall risk of urinary tract cancer from haematuria warrants referral.     

从血尿的病因分析浅谈实习医师临床能力的培养

目的探讨实习医师临床思维、分析问题能力的培养。方法在临床教学中,通过启发式教学,从血尿病因分析出发培养实习医师正确的临床思维能力。结果实习医师临床思维、分析问题的能力明显提高。结论加强临床实践教学是提高实习医师临床能力的关键。     

Should the upper tracts be imaged for microscopic haematuria?

OBJECTIVE: To determine the relative prevalence of various definitions of microscopic haematuria (MH) in patients with renal neoplasms and controls, and to predict the likely outcome of renal imaging for those definitions. PATIENTS AND METHODS: In a retrospective case-control study 278 adult men and woman seen between 1998 and 2003 with untreated renal neoplasms were compared to controls matched for age and sex. All cases and controls had renal imaging within 6 months of a urine analysis. Patients were excluded for gross haematuria or other conditions associated with MH but not relevant to upper tract imaging. Adjusted odds ratios (OR) computed for 13 definitions of MH by conditional logistic regression were the primary outcome measures. Additional outcome measures were ORs in selected subsets. Hypothetical performance characteristics of a positive urine analysis were then derived to predict the likely results of detecting renal neoplasms for each definition of MH. RESULTS: The OR (95% confidence interval) for the entire series of cases and controls, both symptomatic and asymptomatic, was 2.0 (1.02-3.92, P = 0.04) for MH defined as > or = 4 red blood cells per high-power field (RBC/HPF) and 2.2 (1.09-4.52, P = 0.03) for > or = 5 RBC/HPF. No significant OR was calculated for < or = 3 RBC/HPF, nor for a subgroup of patients with MH in a routine urine analysis obtained during a periodic health examination. Symptomatic patients had an OR of 13.68 (1.6-117.1, P = 0.02) for MH defined as > or = 5 RBC/HPF. The sensitivity of a positive test decreased from 24.8% to 5.04% as the definition for MH became more stringent. The theoretical positive predictive value (assuming a prevalence of renal cell neoplasms of 0.25%) of the most stringent definition of MH was 0.58%. CONCLUSIONS: Patients with renal neoplasms have about twice the prevalence of MH with > or = 4 or 5 RBC/HPF in a single urine sample compared with matched controls, but this difference has little impact on the hypothetical detection rate of renal cancer. Imaging the kidney for low-grade MH in a routine urine analysis discovered at a periodic health examination in an otherwise asymptomatic patient is tantamount to screening without cause, and can be deferred for selected patients. The clinical context is as important as the degree of MH when deciding to image the kidneys.     

No effect of recall period length on prevalence of self-reported haematuria in Schistosoma haematobium-endemic areas

Assessing prevalence of haematuria by interview is commonly used as a rapid method to identify communities for mass treatment of Schistosoma haematobium infection. We analysed, using 21 published studies, to what extent the prevalence estimates of haematuria were affected by the length of the recall period for which respondents were requested to report symptoms. There was a strong positive association between prevalence of haematuria and infection, but no effect of recall period length. This suggests that the choice of recall period is of minor importance in control programmes or studies based on reported haematuria.     

Assessment of haematuria: automated urine flowmetry vs microscopy.

BACKGROUND: Microscopy of the urine sediment may be a useful method in the distinction between a glomerular and a non-glomerular source of urinary bleeding. However, microscopic techniques are time consuming and hampered by inter-observer variations. In the present study we have therefore compared bright-field microscopy with automated urine flowmetry (Sysmex UF-100), examining their ability to differentiate between glomerular and non-glomerular haematuria. METHODS: Fresh urine samples were obtained from 112 patients with a well-defined, single cause of a positive dipstick test. Their urine specimens were examined within 4 h in a blinded manner. Of them, 79 specimens had a positive dipstick for blood and thus could be evaluated for haematuria. RESULTS: The Sysmex UF-100 had a sensitivity and specificity of 0.83 and 0.94 respectively in detecting non-glomerular bleeding. The positive and negative predictive values were 0.95 and 0.78 respectively. The corresponding values of microscopy were 0.79 and 0.90 respectively, and 0.93 and 0.74 respectively. CONCLUSIONS: Automated flowmetry can be used in the distinction between glomerular and non-glomerular haematuria.