Value of laboratory studies in assessment of dehydration in children.

BACKGROUND: Due to the lack of a reliable way of clinically measuring dehydration, laboratory tests are usually used to improve the accuracy of clinical assessment of dehydration in children. The purpose of this study was to compare the relationship between clinical and laboratory parameters in the assessment of dehydration and to evaluate the improvement of those parameters over time. METHODS: We conducted a retrospective study to assess the relationship between clinical assessment of dehydration and laboratory findings. RESULTS: Three hundred children were eligible for the study. Twenty-six per cent of those with mild dehydration had serum urea concentrations greater than 14.3 mmol/L, compared with 38% and 5% of those with moderate or no dehydration, respectively. Urea concentration showed a good specificity, 95%. Creatinine concentrations and mean pH were similar whether or not dehydration was present. Bicarbonate and base excess concentrations decreased with the increasing severity of dehydration and were significantly greater in subjects with moderate dehydration than in those without. The sensitivity (71%) and specificity (74%) of both tests were rather poor. All groups had an abnormal anion gap, which was significantly greater in those with mild or moderate dehydration. CONCLUSION: This study confirms that there is a discrepancy between clinical assessment and laboratory parameters of dehydration. Urea showed good specificity, and anion gap was the most sensitive laboratory parameter for assessment of dehydration. These findings need further validation.

Demographic characteristics of patients with community-acquired bacteriuria and susceptibility of urinary pathogens to antimicrobials in northern Israel.

BACKGROUND: Urinary tract infection is one of the most common bacterial infections. Since antibiotics are given empirically, it is necessary to assess the distribution and susceptibility of the microorganisms in each case. OBJECTIVES: To evaluate the demographic characteristics of ambulatory patients with UTI, the distribution and susceptibility of uropathogens, and the risk factors associated with trimethoprim-sulfamethoxazole resistant bacteria in women. METHODS: During 12 days in August 1997 all the urine cultures sent to the Tel-Hanan Laboratory (Haifa) were evaluated. Demographic characteristics of the patients, their underlying diseases and the previous use of antibiotics were obtained. RESULTS: During the 12 day survey 6,495 cultures were sent for evaluation. Of the 1,075 (17%) that were positive 950 were included in the study; 83.7% were from females, of whom 57% were > or = 50 years old. Escherichia coli was the most common pathogen, with 74.7% in the female and 55% in the male population; 86.2% of the E. coli were resistant to amoxicillin, 38.8% to cephalexin and 46.8% to TMP-SMX. Cefuroxime (4.2%), ofloxacin (4.8%), ciprofloxacin (4.8%) and nitrofurantoin (0.4%) showed the lowest rates of resistance. By a multivariant analysis, post-menopause and recurrent UTI were found to be independent factors related to TMP-SMX resistance in women. CONCLUSION: In northern Israel, ampicillin, cephalexin and TMP-SMX cannot be used empirically in the treatment of community-acquired UTI. Post-menopause and recurrent UTI are independent factors associated with TMP-SMX resistant pathogens in women.