Comparison of hemocytometer leukocyte counts and standard urinalyses for predicting urinary tract infections in febrile infants

OBJECTIVES

To compare the accuracy of standard and hemocytometer white blood cell (WBC) counts and urinalyses for predicting urinary tract infection (UTI) in febrile infants.

METHODS

Enrolled were 230 febrile infants < 12 months of age. All urine specimens were obtained by suprapubic bladder aspiration and microscopically analyzed by the standard urinalysis (UA) and by hemocytometer WBC counts simultaneously, and quantitative urine cultures were performed. Receiver-operating characteristic (ROC) curves were constructed for each method of UA. The optimal cutoff point of the UA test in predicting UTI was determined by ROC analysis.

RESULTS

There were 37 positive urine cultures of at least 1,000 CFU/ml. Of these 37 patients, 9 females and 28 males, 1 had a positive blood culture (Escherichia coli). Thirty (81%) of the positive urine cultures had a bacterial colony count > or = 100,000 colony-forming units/ml, whereas the remaining had between 1,000 and 50,000 colony-forming units/ml. The area under the ROC curve for standard UA was 0.790 +/- 0.053, compared with 0.900 +/- 0.039 for hemocytometer WBC counts (P < 0.05). For hemocytometer WBC counts, the presence of < or =10 WBC/microl appeared to be the most useful cutoff point, yielding a high sensitivity (83.8%) and specificity (89.6%). Standard UA, with a cutoff point of 5 WBC/high power field, had a lower sensitivity (64.9%) and similar specificity (88.1%). The hemocytometer WBC counts showed significantly greater sensitivity and positive predictive value (83.8 and 60.8%, respectively) than the standard urinalysis (64.9 and 51.1%, respectively) (P < 0.05). The accuracy, specificity and likelihood ratio of hemocytometer WBC counts were also greater than that of standard UA (88.7, 89.6 and 8.08% vs. 84.3, 88.1 and 5.44%).

CONCLUSION

Hemocytometer WBC counts provide more valid and precise prediction of UTI in febrile infants than standard UA. The presence of > or =10 WBC/microl in suprapubic aspiration specimens is the optimum cutoff value for identifying febrile infants for whom urine culture is warranted.

Plasma nitrate as an index of nitric oxide formation in patients with acute infectious diseases

In humans, the role of nitric oxide (NO) in host defence is controversial. We prospectively studied plasma levels of nitrate, the stable end-product of NO formation, during acute infection in 43 patients controlled with regard to dietary nitrate/nitrite. During acute gastroenteritis the mean plasma nitrate level was significantly increased compared with at recovery 4-5 weeks later (118 vs. 32.5 micromol/l; p < 0.001), in contrast with the findings in patients with acute pneumonia (PN; 34.6 vs. 42.8 micromol/l) or febrile urinary tract infection (UTI; 27.7 vs. 31.3 micromol/l). In a second group of 20 retrospectively studied patients with severe PN or UTI, of whom 70% were bacteraemic, no significantly increased nitrate levels could be demonstrated during the acute stage of infection. These findings indicate that increased NO production, as measured by plasma nitrate, is not a general finding in patients with acute infectious diseases, but may rather be associated with certain pathogens or sites of infection.

Inability of encapsulated Klebsiella pneumoniae to assemble functional type 1 fimbriae on their surface

We screened phase variants of Klebsiella pneumoniae isolates for the expression of capsule and type 1 fimbriae and found that all of the 22 blood isolates were encapsulated and did not express type 1 fimbriae while 10 of 11 urinary tract isolates expressed type 1 fimbriae but were unencapsulated. Phase variants from selected isolates were found to be either unencapsulated and fimbriated or lacked both structures. Variants expressing both structures were not detected. Fimbrial subunits FimH and FimA were localized in the periplasmic space of the parent strain and on the surface of the unencapsulated variants. The results suggest that capsule formation impedes assembly of pre-formed fimbrial subunits on the bacterial surface.

Prostatic involvement in men with febrile urinary tract infection as measured by serum prostate-specific antigen and transrectal ultrasonography

OBJECTIVE

To determine the frequency of prostatic involvement in men with community-acquired febrile urinary tract infection.

PATIENTS AND METHODS

This prospective study included 70 men (18-85 years old) who had a fever of >/=38.0 degrees C, symptoms or signs of urinary tract infection and a positive urine culture. Serum prostate-specific antigen (PSA) was measured and transrectal ultrasonography of the prostate and seminal vesicles performed during the acute phase of the disease and during a 1-year follow-up.

RESULTS

Although only six patients had a tender prostate on digital rectal examination, the initial serum PSA level was elevated in 58 (83%) patients (median 14 ng/mL, range 0.54-140). There was no correlation between PSA levels, patient age, inflammatory response to infection or presence of positive blood cultures. Despite a rapid decline in PSA level after one month, there was a protracted decrease in some patients. After 3 months the median prostate volume was reduced by 31% (range 11-54; P<0.001) in 46 of 55 patients examined, and the width of the right and left seminal vesicle was reduced by 14% and 22%, respectively. The reductions in PSA and prostate volume were significantly correlated (r=0.36, 95% confidence interval 0.09-0.58; P=0.01).

CONCLUSION

These results show that the prostate and seminal vesicles are frequently involved in men with febrile urinary tract infection and that PSA may be a useful marker of prostatic infection. The slow decline of PSA levels in some patients after appropriate antibiotic treatment indicates a protracted healing process and should be considered when PSA is used to detect prostate cancer.

Increased levels of C-reactive protein in noncontrolled type II diabetic subjects

Type II diabetes is an hemorheological disease in which hyperglycemia increases the shear stress contributing to inflammation and dysfunction of endothelium. The purpose of this study was to identify the relationship between serum C-reactive protein and glucose levels in noncontrolled type II diabetic subjects. A cross-sectional study was conducted, including 62 noncontrolled type II diabetic subjects that were assigned to two groups. One group was patients with acute diarrhea or urinary tract infection and the other group was diabetic subjects who were infectious-disease free. Sixty-two subjects without diabetes constituted the respective control groups. Heart failure, other acute febrile illnesses, asymptomatic infection, renal, hepatic, malignant or chronic inflammatory illness, and macrovascular disease were considered as exclusion criteria. Laboratory measurements were performed. Thirty (96.7%) and 29 (93.5%) diabetic patients in the groups with and without infectious disease, and 28 (90.3%) control subjects with infectious disease had elevated C-reactive protein levels (> or =10 mg/L). In contrast, healthy control subjects did not have elevated serum C-reactive protein levels. Multiple regression analysis showed a significant association between C-reactive protein levels and hyperglycemia (Odds ratio = 7.4; IC95% 2.3-11.2). This study show that hyperglycemia is a related factor to the increase of serum CRP levels in noncontrolled type II diabetic subjects.

Comparison of sparfloxacin and ciprofloxacin in the treatment of community-acquired acute uncomplicated urinary tract infection in women. Sparfloxacin Multicenter Uncomplicated Urinary Tract Infection Study Group

Urinary tract infection (UTI) is a common illness, with > or =30% of all women experiencing a UTI during their lifetime. Less than a decade ago, the standard therapy for acute uncomplicated UTIs involved treatment with > or =7 days of an antibacterial agent, but recent studies using a variety of newly introduced antibiotics, including the fluoroquinolones, have demonstrated that a 1- to 5-day treatment regimen can be equally effective. This randomized, double-masked, multicenter study was conducted to compare the efficacy and tolerability of a single dose of sparfloxacin with those of a 3-day regimen of sparfloxacin and a 7-day regimen of ciprofloxacin in the treatment of women with community-acquired acute uncomplicated urinary tract infection. A total of 1175 women were enrolled; 395 received sparfloxacin as a single 400-mg dose on day 1, 394 received sparfloxacin as a 400-mg loading dose on day 1 followed by 200 mg once daily for 2 additional days, and 386 received ciprofloxacin 250 mg twice daily for 7 days. Patients were comparable with respect to demographic characteristics and underlying conditions. A total of 954 patients were clinically assessable; 490 of these were also bacteriologically assessable. All patients treated were included in the tolerability analysis. Escherichia coli (75.4%), Klebsiella pneumoniae (4.9%), Enterococcus faecalis (4.6%), and Staphylococcus saprophyticus (4.1%) were the most commonly isolated organisms. In the all-treated population, clinical success was achieved 5 to 9 days after therapy in 91.8%, 92.2%, and 91.6% of patients in the single-dose sparfloxacin, 3-day sparfloxacin, and 7-day ciprofloxacin groups, respectively; bacteriologic success was observed in 91.7%, 92.6%, and 96.6% of those in the 3 groups. Sustained clinical success rates 4 to 6 weeks after therapy were 76.6%, 80.2%, and 79.5% in the single-dose sparfloxacin, 3-day sparfloxacin, and 7-day ciprofloxacin groups, respectively; sustained bacteriologic success rates were 80.7%, 90.1%, and 92.6%. The most common adverse events were nausea, headache, vaginal thrush, dizziness, and diarrhea; >92% of adverse events were mild or moderate in severity. The 2 drugs had comparable frequencies of adverse events, except for photosensitivity, which occurred in 3.3% of the 3-day sparfloxacin group, 1.3% of the single-dose sparfloxacin group, and 0.3% of the ciprofloxacin group (P = 0.005). The 3-day sparfloxacin regimen was effective and well tolerated. The initial response to single-dose sparfloxacin treatment was comparable to the response to the other 2 regimens, but the single-dose regimen proved less effective over time, with higher rates of clinical recurrence and bacteriologic relapse. Sparfloxacin provides an alternative to ciprofloxacin for patients with acute uncomplicated urinary tract infection who are not at risk for photosensitivity reactions or adverse events associated with a prolonged corrected QT interval.

Interleukin-6 and disease severity in patients with bacteremic and nonbacteremic febrile urinary tract infection

An interleukin-6 (IL-6) response was detected in 81 patients with febrile urinary tract infections (UTIs). Bacteremic patients (n=24) had higher serum IL-6 at inclusion and throughout the first 24 h (P<. 01) and higher urine IL-6 from 6 h after start of therapy (P<.01) than did nonbacteremic patients (n=57). The serum and urine IL-6 responses remained elevated longer in the bacteremic group. Patients with clinical signs of pyelonephritis had higher serum and urine IL-6 concentrations than did other patients in the study population (P=.058, P<.01, respectively). IL-6 high responders had higher temperatures (P<.05) and C-reactive protein levels (P<.05, P<.01) than did low responders. The results demonstrate that IL-6 responses accompany febrile UTIs regardless of bacteremia and that the response reflects disease severity. The results suggest that IL-6 produced in the urinary tract can trigger the systemic host response in the absence of bacteremia.

Procalcitonin is a marker of severity of renal lesions in pyelonephritis

OBJECTIVE

In an attempt to differentiate acute pyelonephritis from lower urinary tract infection (UTI), we measured serum procalcitonin levels, a recently described marker of infection. We compared it with other commonly used inflammatory markers and evaluated its ability to predict renal involvement as assessed by dimercaptosuccinic acid (DMSA) scintigraphy.

METHODS

Serum C-reactive protein, leukocyte counts, and procalcitonin levels were measured in 80 children, 1 month to 16 years of age, admitted for suspected pyelonephritis. Renal involvement was assessed by 99mTe-DMSA scintigraphy in the first 5 days after admission. The examination was repeated at least 3 months later if the first result was abnormal.

RESULTS

In lower UTI, the mean procalcitonin (PCT) was 0.38 micrograms/L +/- 0.19 compared with 5.37 micrograms/L +/- 1.9 in pyelonephritis. In these two groups, respectively, leukocyte counts were 10939/mm3 +/- 834 and 17429/mm3 +/- 994, and C-reactive protein (CRP) levels were 30.3 mg/L +/- 7.6 and 120.8 mg/L +/- 8.9. When inflammatory markers were correlated to the severity of the renal lesion as ranked by DMSA scintigraphy, we found a highly significant correlation with plasma levels of PCT, but borderline significance with CRP and none with leukocyte counts. Patients without vesicoureteral reflux had a mean PCT of 5.16 micrograms/L +/- 2.33, which was not significantly different from that in patients with reflux who had a mean PCT of 5.76 micrograms/L +/- 3.49. For the prediction of renal lesions at admission, CRP had a sensitivity of 100% and a specificity of 26.1%. The sensitivity and specificity of PCT were 70.3% and 82.6%, respectively.

CONCLUSION

We conclude that serum PCT levels were increased significantly in children with febrile UTI when renal parenchymal involvement (assessed by DMSA scintigraphy) was present and allowed for prediction of patients at risk of severe renal lesions.

Hyperammonaemia due to Klebsiella infection in a neuropathic bladder

A boy with a neuropathic bladder and a single hydronephrotic kidney developed hyperammonaemic encephalopathy during a urinary tract infection with Klebsiella oxytoca. Although particularly associated with Proteus infections and prune belly syndrome, hyperammonaemia can complicate infection with any urease-producing bacteria if there is urinary stasis.

Circulating interleukin (IL)-1 beta, IL-6 and tumor necrosis factor-alpha in children with febrile infection--a comparison with C-reactive protein

Circulating interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha were examined in 42 febrile children with fever lasting more than 4 days. Their diagnosis were probable viral syndrome in 22, urinary tract infection (UTI) in 10, and probable bacterial pneumonia in 10. None of our study patients had detectable serum IL-1 beta. TNF-alpha levels were significantly higher in children with pneumonia than in those with viral syndrome (p < 0.01). Children with UTI and pneumonia had significantly higher IL-6 and CRP, compared to those with probable viral syndrome (p < 0.01 for both IL-6 and CRP). When appropriate cutoff values are chosen, IL-6 had greatly improved specificity (86.4%, > 20 pg/ml) to demonstrate UTI and pneumonia, as compared to that using CRP (48%, > 40 mg/l). After three days' antibiotic treatment, IL-6 fell to control levels in children with UTI and pneumonia, while CRP remained elevated. There was no difference in TNF-alpha values before and after treatment. Thus, IL-6, rather than IL-1 beta and TNF-alpha, may be a helpful diagnostic tool for evaluation of pediatric febrile infection. Sequential studies involving more patients are needed to determine whether IL-6 is better than CRP in this clinical setting.

A comparative study of major histocompatibility complex and red blood cell antigen phenotypes as risk factors for recurrent urinary tract infections in women

Recurrent urinary tract infections (RUTI) are a significant health problem for many women, and host characteristics that increase susceptibility are not completely defined. This study evaluated data from 99 patients to examine further the question of a possible association between major histocompatibility complex (MHC) or red blood cell (RBC) antigen phenotype and predisposition to RUTIs. MHC class I and II, ABO, and Lewis RBC phenotypes were determined serologically. The MHC class II phenotypes of 55 subjects were also determined by DNA polymerase chain reaction techniques. There were no significant differences in the proportions of HLA-A or -B antigen types between patients and controls, nor in the frequencies of serologically or DNA-defined HLA-DR or -DQ phenotypes. Patient ABO and Lewis RBC phenotypes were not statistically different than those for controls. Thus, the overall risk for women to develop RUTIs does not appear to be associated with any single HLA, ABO, or Lewis phenotype.

Tolerance and pharmacokinetics of ciprofloxacin in the chick. Preliminary experience in subjects of pediatric age with urinary tract infections (UTI)

We studied the tolerance and pharmacokinetic parameters of ciprofloxacin in (2 mg/kg, i.v.) in 45 chicks. Serum concentrations of ciprofloxacin at various times of drawing (15 min, 30 min, 1 hr, 3 hr, 6 hr, 8 hr and 12 hr) peaked in the first 15 min with a trough after 6 hr, and were completely absent after 8 hr. We found no neurotoxic effects or behavioral changes. Encouraged by a good tolerance for this quinolone, we conducted a preliminary study concerning the therapeutic efficacy of ciprofloxacin in 8 subjects of pediatric age (8-14 years) with urinary tract infections (UTI) that are resistant to classic antibiotics. The results and normality of hematologic parameters, checked before and after therapy, allow us to recommend the monitored use of ciprofloxacin in children with UTI resulting from bacteria resistant to other antibiotics.

Evaluation of plasma (1-->3)-beta-D-glucan measurement by the kinetic turbidimetric Limulus test, for the clinical diagnosis of mycotic infections

The present multicentre clinical study was conducted to assess the clinical utility of a new diagnostic method for deep mycosis in which (1-->3)-beta-D-glucan, a fungal cell wall component existing in plasma, was quantitatively measured by the kinetic turbidimetric Limulus test (WB003). Plasma (1-->3)-beta-D-glucan concentrations were 0.57 +/- 0.10 microgram/l in 92 healthy subjects and 0.62 +/- 0.32 microgram/l in 26 patients with non-mycotic diseases (disease control group). In comparison with these healthy subjects and patients with non-mycotic diseases, patients with mycosis had significantly higher plasma (1-->3)-beta-D-glucan concentrations: 19.63 +/- 73.28 micrograms/l in 12 patients with candidaemia, 11.28 +/- 21.42 micrograms/l in 7 patients with urinary Candida infection, 4.84 +/- 12.71 micrograms/l in 5 patients with pulmonary candidiasis, and 12.21 +/- 31.31 micrograms/l in 4 patients with invasive pulmonary aspergillosis. On the statistical analysis of these data, a cut-off value was set at 1.0 microgram/l. Using this cut-off value, 3 patients with pulmonary cryptococcosis and 4 patients (4/6) with pulmonary aspergilloma were all negative with low plasma (1-->3-beta-D-glucan levels. The test WB003 provided equivalent or higher efficiency of diagnosis of candidiasis and aspergillosis, in comparison with commercially available antigen detection kits, demonstrating its utility as a diagnostic reagent. It may also be useful in assessing therapeutic effectiveness when used periodically after treatment.

Long-lasting NO overproduction in cirrhotic patients with spontaneous bacterial peritonitis

Nitric oxide production was studied in cirrhotic patients with spontaneous bacterial peritonitis (SBP) or with other infections. We followed up on the time course of serum nitrate levels in 51 hospitalized patients aged between 34 and 81 years. Four groups were defined: patients with SBP (group 1, n = 14), patients with bacteremia (group 2, n = 11), patients with urinary tract infection (group 3, n = 11) and patients in a stable clinical condition (group 4, n = 20). The four groups did not differ in terms of Pugh score (11 +/- 1, 10 +/- 1, 11 +/- 1, and 10 +/- 1, respectively). Serum nitrate levels averaged 31 +/- 2 micromol/L in group 4 (84 samples). On the day results of cytobacteriological examination were positive, mean serum nitrate levels were 75 +/- 17, 63 +/- 9, and 36 +/- 9 micromol/L, respectively, in groups 1 (17 cases), 2 (11 cases), and 3 (11 cases) (P < .001). The maximum nitrate values recorded during follow-up were higher in groups 1 (149 +/- 15 micromol/L) and 2 (112 +/- 11 micromol/L) than in group 3 (66 +/- 7 micromol/L; P < .001 and < .01, respectively). These maximum values were recorded in all groups approximately 2 weeks after the infection was diagnosed. The mean duration of NO overproduction, as defined by nitrate level (3)90 micromol/L, was 15 +/- 3 days in group 1 and 5 +/- 1 day in group 2. When the nitrate concentration was studied in serum and ascitic fluid sampled on the same day, it was found to be higher in ascitic fluid than in serum in eight cases of SBP in the period preceding the peak serum nitrate concentration (100 +/- 17 vs. 63 +/- 14 micromol/L; P < .001). Our data indicate that SBP in cirrhotic patients led to a long-lasting increased local production of NO. This overproduction may contribute to maintaining splanchnic vasodilation and thus worsen the hyperkinetic state in these patients.

Early detection of infected ureteral obstruction after SWL employing C-reactive protein

Infection of the obstructed upper urinary tract is a severe complication of stone disease. Early detection and therapy is crucial to prevent septicemia. The authors investigated prospectively whether C-reactive protein (CRP) might act as a marker for the early detection of infected upper urinary tract obstruction. The serum concentration of CRP was compared with the classic markers of inflammation--white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), and temperature--in the follow-up of 85 patients undergoing 173 extracorporeal shockwave lithotripsy (SWL) treatments. Post-SWL, 69% of the patients showed dilation of the upper tract on ultrasonography and 16.5% became symptomatic and required intervention. In this group, the mean CRP value was increased 18-fold, whereas the WBC count, ESR, and temperature were not markedly raised. In contrast, patients with no need for additional treatment showed no more than a 2-fold increase in CRP. C-Reactive protein seems to be a useful indicator for the early detection of infected upper urinary tract obstruction.

[The thrombophilic status of patients with inflammatory diseases]

BASIC PROBLEM AND OBJECTIVE OF STUDY

Inflammatory reactions are taken to be nonspecific defensive measures of the organism and are associated with complex changes at cellular and humoral level. Activation of blood coagulation plays an important part in this, especially as it is accompanied by an increased risk of thromboembolism. It was the aim of this investigation to assess this risk by measuring sensitive markers of coagulation activation.

PATIENTS AND METHODS

Biochemical markers of coagulation activation (prothrombin-fragment F1 + 2 and thrombin-antithrombin III complex [TAT]) and fibrin formation (D-dimer) were measured in 130 patients (61 men, 69 women; mean age 56.9 [20-89] years). 44 had pneumonia, 44 bronchitis and 42 urinary tract infections. A healthy control group for comparison consisted of 11 men and 15 women (mean age 48.7 [23-79] years).

RESULTS

F1 + 2, TAT and D-dimer were significantly increased, compared with the controls, in all three patient groups (P < 0.01). The greatest rises occurred in the patients with pneumonia: F1 + 2: median 1.2 vs 0.6 nmol/I, TAT: 6.2 vs 2.1 micrograms/l and D-dimer 2476 vs 223 ng/ml.

CONCLUSION

These findings underline the importance of consistent thrombosis prophylaxis in patients with inflammatory disease, especially those at an increased risk.

Abnormalities of erythrocyte sodium transport in reflux nephropathy

Hypertension is a complication of reflux nephropathy commonly occurring during adolescence and young adult life. We studied cellular sodium transport in an adolescent cohort with this condition as abnormal sodium transport is a feature of human hypertension. Thirty males and 52 females with reflux nephropathy, (median age 20.3 years) had erythrocyte ouabain sensitive sodium-potassium ATPase (Na/K ATPase) pump site number (Bmax) and red cell sodium concentration (RBC Na+) measured in 1988. Six years later, 55 of those had red cell sodium-lithium counter transport (LCT) measured. On both occasions, their renal function and blood pressure (BP) were determined. Bmax in the study group (median 10.3 nmol/l) was significantly less than that of controls (median 11.45 nmol/l). Nine patients who were diagnosed as having hypertension during the 6 year study period appeared to have a lower Bmax compared with that of normotensives in the group. RBC Na+ and LCT of the study group were not significantly different from that of controls. The Na/K ATPase activity is diminished, and sodium-lithium counter transport is unchanged in reflux nephropathy. Further study is needed to ascertain the link between these observations and the onset of high BP.

Random amplified polymorphic DNA (RAPD) analysis of Escherichia coli strains: comparison of urinary and concomitant blood isolates of urosepsis patients

The discriminatory power of random amplified polymorphic DNA (RAPD) analysis was assessed for detection of intraspecies variation in Escherichia coli strains of clinical origin. Three primers (OPF 5, OPF 7 and OPF 8) were preselected from commercial 10-mer primers by the number of distinct bands obtained. These primers were used in testing 26 urinary and 13 blood isolates from 26 patients and E. coli ATCC 25922, OPF 5, OPF 7 or OPF 8 alone separated the strains into 15 to 21 RAPD types. A combination of the results of the three primers gave 25 RAPD types. When blood and urine isolates of each patient were analysed in parallel, all blood-urine pairs were found identical, and with one exception they were also unique. RAPD analysis had a high discriminatory power. It separated the strains equally well or better than ribotyping, and obviously better than serotyping which grouped the urine strains into 8 serogroups leaving 18 strains untypable or incompletely typed. Thus, to verify the identity or non-identity of isolated E. coli strains, RAPD analysis was shown to be a sensitive and reproducible technique which is technically less demanding, more rapid and more economical than either serotyping or ribotyping. However, in its present application, this technique cannot fully replace determination of the serotype or virulence factors which may show correlations with different manifestations of infection.

Early 99mTc dimercaptosuccinic acid (DMSA) scintigraphy in symptomatic first-time urinary tract infection

During a 2 year period, 175 children below 6 years of age (median 0.4 year) with non-obstructive symptomatic urinary tract infection were studied by 99mTc dimercaptosuccinic acid (DMSA) scintigraphy. DMSA scintigraphy was performed at a median of 10 days after the start of treatment and was abnormal in 73 children (42%), equivocal in 29 (16%) and normal in 73 (42%). Reflux was seen in 27% of all children and in 38% of the renal units that were abnormal at DMSA scintigraphy. A decreasing frequency of abnormalities at DMSA scintigraphy was seen within the first 14 days after the start of treatment. C-reactive protein and grade of reflux correlated significantly with abnormal DMSA studies. To demonstrate renal involvement in acute urinary tract infection, DMSA scintigraphy should be performed within days after the start of treatment. It is noteworthy that reflux was seen in less than half of renal units with abnormal DMSA scintigraphy.

15-year follow-up of renin and blood pressure in reflux nephropathy

BACKGROUND

Beginning in 1978 a cohort of patients with reflux nephropathy first seen at a London Childrens hospital have had 5-yearly follow-ups. This is the fourth (15-year) report from that series.

METHODS

Of the original 100 normotensive children with reflux nephropathy 78 were traced for the 15-year study in 1994. Five patients were excluded because of nephrectomy, ten for other reasons, and eight refused to take part, leaving 55. 26 were on oral contraceptives. Supine blood pressure and plasma renin activity (PRA) were measured, and daily sodium excretion was assessed on a sample of overnight urine.

FINDINGS

Of the 55 patients (15 male, 40 female, median age 27 years, range 20-31), five had systolic and two had diastolic hypertension. Compared with the 10-year (1988) follow-up there was no change in blood pressure standard deviation scores (SDS) in this cohort. PRA showed an increasing dissociation from controls after 15 years of age and was significantly above that of controls by age 25. Exclusion of the patients on oral contraceptives did not significantly alter the results. The PRA values in 1988 were not individually predictive of the development of hypertension over the ensuing 5 years.

INTERPRETATION

Previously, in the long-term study of reflux nephropathy, blood pressure SDS had progressively increased with age. By 15 years blood pressure had levelled out and the PRA, though raised, did not predict the development of hypertension. Oral contraceptive use did not significantly modify the results.

Febrile urinary infection in the institutionalized elderly

PURPOSE

Bacteriuria is common among institutionalized elderly populations, but the contribution of urinary infection to febrile morbidity is unknown because of difficulties in clinical ascertainment. This study was undertaken to febrile morbidity using both clinical and serologic criteria.

METHODS

Episodes of fever in residents of two long-term care institutions were identified prospectively for 2 years. Serum and urine specimens were obtained initially and at 4 weeks. The proportion of episodes attributable to urinary infection was determined by both standard clinical criteria proposed for use in these populations and serum antibody response to uropathogens.

RESULTS

For 372 fewer episodes, 211 met clinical criteria for infection: 147 (40%) of the respiratory tract; 26 (7%) of the genitourinary tract; 25 (6%) of the gastrointestinal tract; and 13 (3%) of skin and soft tissue. Of the remaining 161 fever episodes, 2 (1%) were noninfectious and 159 (43%) were of unknown origin. The prevalence of bacteriuria for residents with nongenitourinary sources of fever varied from 32% to 75%. An antibody response meeting serologic criteria for urinary infection occurred in 26 (8.3%) of 314 episodes with paired sera obtained; 10 (43%) of 23 identified clinically as genitourinary infection, 14 (11%) of 132 unknown, 1 (4%) of 25 gastrointestinal, and 1 (0.8%) of 122 respiratory. The positive predictive value of bacteriuria for febrile urinary infection identified by clinical criteria was was 11% (95% confidence interval [CI] 4%, 18%) and identified by serologic criteria was 12% (95% CI 7%, 17%).

CONCLUSIONS

Urinary infection contributes to less than 10% of episodes of clinically significant fever in this high-prevalence bacteriuric population. A restrictive clinical definition for genitourinary infection has poor sensitivity and specificity compared with serologic criteria for identification of fever of urinary source, and bacteriuria has a low predictive value for identifying febrile urinary infection.

P1 blood group phenotype, secretor status in patients with urinary tract infections

We have examined the distribution of P antigen, Lewis blood group phenotypes and secretor status of 65 patients with E. coli UTI (20 asymptomatic bacteriuria, 20 cystitis and normal radiology, 25 reflux nephropathy) and 45 controls who have never experienced a UTI episode. The distribution of Lewis blood group antigens was similar in all UTI groups and in the controls. The incidence of non-secretors in the reflux nephropathy group was similar to that in controls (24% versus 31%). The P1 phenotype was present in 100% of patients with asymptomatic bacteriuria, 80% with cystitis and controls and only 44% with reflux nephropathy. The combined P1/non-secretor phenotype was observed in 45% of patients with asymptomatic bacteriuria, 30% with cystitis, 12% with reflux nephropathy and in 22% of control healthy individuals. P2/secretor phenotype was demonstrated in 44% of patients with reflux nephropathy and in only 11% of controls. Our data suggest that having P2 blood group protects against asymptomatic colonization of the urinary tract, but is associated with the type of infection responsible for scarring in reflux nephropathy. It also appears that being a non-secretor does not predispose to renal scarring and that combined P2/secretor phenotype may be linked with susceptibility to reflux nephropathy.