Leucocitúria / Urine leukocytes

A leixocitúria pode ser detectada, no exame de urina rotina, pela pesquisa de esterase leucocitária e pelo exame do sedimento urinário. Admitem-se 5 leucócitos/campo como ponto de corte do valor de referência. O jato médio urinário constitui a amostra mais utilizada para a avaliação de leucocitúria. A causa mais comum de leucocitúria é a infecção bacteriana do trato urinário. Outras causas incluem doenças inflamatórias renais ou do trato urinário, calculose, exercício físico extenuante e febre. O uso de nitrofurantoina e o emprego de formalina como conservante são causas de falso positivo no teste da esterase leucocitária e proteinúria (> 500 mg/dl), glicosúria (> 3g/dl), densidade elevada e a eliminação de alguns antimicrobianos e de ácido ascórbico são causas de falso negativo. A densidade baixa é a principal causa de falso negativo observada na sedimentoscopia.

Leukocyturia is usually detected by a positive leukocyte esterase test and/or by the microscopic examination of urine sediment. Although there is not an agreement on the number of urine leukocytes that means leukocyturia, the cut off used by most authors is 5 leukocytes/high power field. First-morning clean-catch midstream specimens are preferred but other samples such as timed, catheterized, or suprapubic ones may occasionally be colected. Any blood leukocyte may be found in the urine but the most common are polymorphonuclear neutrophils, that are frequently associated with bacterial urinary rract infections. Other causes of leukocyturia are renal diseases (tumors, glomerulonephritis, interstitial nephritis), nephrolithiasis, fever, and strenuous exercise. Cellular lysis, common in low specific graviry urine, is the most common cause of false negative results in the microscopic analysis. False positive results are commonly due to specimen contamination. Leukocyte esterase false results are due to pigmented foodstuffs or drugs (positive) or increased proteinuria, glucosuria, and specific graviry or the presence of gentamycin or cephalosporin (negative).

Low bacterial counts in infants with urinary tract infection.

We analyzed the number of colony-forming units in urine cultures obtained by suprapubic aspiration in a group of 366 unselected infants with symptomatic urinary tract infection to relate these findings to factors such as pyuria and vesicoureteric reflux. Seventy-three (20%) of 366 infants had fewer than 100,000 colony-forming units per milliliter. Such low counts were significantly related to low numbers of leukocytes in the urine. Vesicoureteric reflux was equally distributed among children, irrespective of the number of bacteria in quantitative culture. The findings emphasize the importance of sampling technique; in infants, the method of choice is suprapubic aspiration, or catheterization, which eliminates the risk that urinary tract infection is overlooked because of low bacterial counts.

Nephropathy in low income diabetics: the Mexico City diabetes study

Among the most serious complications associated with diabetes mellitus (DM) is nephropathy (DN). In Mexico, there is little information on the frequency and clinical characteristics of DN in the Mexican population. We present results of a population-based survey designed to estimate the prevalence of DN. The low income population consisted of 15,532 inhabitants. All 35- to 64-year-old males and non-pregnant women residing in the survey area were identified as eligible for the study (3505; 22.6 percent). A home interview was obtained in 2810 (80.2 percent). A physical exam with oral glucose tolerance test wasobtained in 2282 (81.2 percent of those interviewed). DM was diagnosed in 304 (crude rate 13.3 percent). Mean age for men and women with DM was 51.6 ñ 8.4 and 52.2 ñ 7.5, respectively. Duration of DM in men was 9.2 ñ 8.1 and in women, 7.3 ñ 6.7 years. Hypertension was diagnosed in 19.8 percent of men and 18.1 percent of women. Diabetic retinopathy of any level was found in 55.4 percent of men and 45.7 percent of women. Mean glycohemoglobin in men was 9.6 ñ 2.1 and in women 9.5 ñ 2.2 percent (normal 4 - 8 percent). At baseline, proteinuria (1+ or more, by dipstick) was found in 24.7 percent of men and 9.6 percent of women, microalbuminuria (MA) in 84.4 percent of men and 63.8 percent of women. Quantitative albuminuria was abnormally high in 54.7 percent of men and 40.3 percent or women. In the 203 diabetic studied with 24 h urine collection from creatinine clearance, normal renal function was found in 69.1 percent of men and 47.5 percent of women, reduced renal function was found in 26 percent of men and 50 percent of women, ranl insufficiency was diagnosed in 4.9 percent of men and 1.6 percent of women. One patient was on dialysis and in a subsequent follow up, we found that 2.3 percent of the patients had died of renal failure, six men (46 -63 years) and a woman of 62 years. We concluded that DN is a very serious threat to this population. The high case fatality rate associatd with this condition maintains a low prevalence. It is important to develop a program to diminish the frequency of this condition

Prevalence of urinary tract infection in febrile infants.

Urinary tract infection (UTI), a relatively common cause of fever in infancy, usually consists of pyelonephritis and may cause permanent renal damage. This study assessed (1) the prevalence of UTI in febrile infants (temperature > or = 38.3 degrees C) with differing demographic and clinical characteristics and (2) the usefulness of urinalysis in diagnosing UTI. We diagnosed UTI in 50 (5.3%) of 945 febrile infants if we found > or = 10,000 colony-forming units of a single pathogen per milliliter in a urine specimen obtained by catheterization. Prevalences were similar in (1) infants aged < or = 2 months undergoing examination for sepsis (4.6%), (2) infants aged > 2 months in whom UTI was suspected, usually because no source of fever was apparent (5.9%), and (3) infants with no suspected UTI, most of whom had other illnesses (5.1%). Female and white infants had significantly more UTIs, respectively, than male and black infants. In all, 17% of white female infants with temperature > or = 39 degrees C had UTI, significantly more (p < 0.05) than any other grouping of infants by sex, race, and temperature. Febrile infants with no apparent source of fever were twice as likely to have UTI (7.5%) as those with a possible source of fever such as otitis media (3.5%) (p = 0.02). Only 1 (1.6%) of 62 subjects with an unequivocal source of fever, such as meningitis, had UTI. As indicators of UTI, pyuria and bacteriuria had sensitivities of 54% and 86% and specificities of 96% and 63%, respectively. In infants with fever, clinicians should consider UTI a potential source and consider a urine culture as part of the diagnostic evaluation.