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Biomedical subjects

M Majd

Publications and source records attributed to M Majd.

At least 37 records · Page 2Linked to original sources
PubMed1995

Outcome analysis of pediatric pyeloplasty as a function of patient age, presentation and differential renal function.

PURPOSE: We retrospectively reviewed a consecutive series of patients who underwent pyeloplasty. In all cases preoperative and postoperative isotope renal scans were performed to assess the surgical outcome with particular emphasis on the change in renal function postoperatively. MATERIALS AND METHODS: The clinical records of 108 consecutive children with ureteropelvic junction obstruction were reviewed. Individual renal function was evaluated and obstruction was confirmed by diuretic assisted 99mtechnetium diethylenetriaminepentaacetic acid or mercaptoacetyltriglycine renography. A total of 100 pyeloplasties in 98 children between 5 days and 16 years old was included. Results were analyzed by groups according to patient age and symptoms at presentation. RESULTS: Drainage half-times improved in 98% of patients and only 1 required reoperation. Improved renal function greater than 5% was noted in about a third of each age group. Function remained stable in 68% of the kidneys and decreased in only 1. Of the improved kidneys 77% had impaired function preoperatively (40% or less of the total contribution). Those presenting with a renal mass had the greatest improvement in function. There was no statistically significant difference in improvement in renal function by age group or patient presentation. Regression analysis revealed that preoperative differential renal function was the only statistically significant predictor of improvement in renal function after pyeloplasty. CONCLUSIONS: Pyeloplasty in children is safe and renal functional improvement can be expected in the majority of kidneys with impaired function at presentation. However, there was no indication that early pyeloplasty in infants is more likely to result in improved function than in older children.

Adolescent↗
PubMed1994

Blunt renal trauma in children: healing of renal injuries and recommendations for imaging follow-up.

Initial CT grading of renal injury was correlated with the frequency of complications and the time course of healing in 35 children. All renal contusions (grade 1, 8) and small parenchymal lacerations (grade 2, 8) healed without complications. All lacerations extending to the collecting system (grade 3, 9) resulted in mild to severe loss of renal function with progressive healing over 4 months. One of four segmental infarcts (grade 4A), and five of six vascular pedicle injuries (grade 4B) resulted in severe loss of renal function. Complications, including urinoma (2), sepsis (1), hydronephrosis (1), and persistent hypertension (2), were limited to grade 3 and 4 injuries. Our results suggest that mild renal injuries do not require follow-up imaging. Major renal lacerations and vascular pedicle injuries, however, often result in loss of renal function and should be followed up closely due to the risk of delayed complications. Follow-up examinations should continue for 3-4 months until healing is documented.

Adolescent↗
PubMed1994

Association of Lewis blood group phenotypes with urinary tract infection in children.

Many blood group antigens, genetically controlled carbohydrate molecules, are found on the surface of uroepithelial cells and may affect bacterial adherence and increase the frequency of urinary tract infection (UTI) in adults. Sixty-two children aged 2 weeks to 17 years (mean, 2.3 years) who were hospitalized with fever in association with UTIs caused by Escherichia coli had complete (n = 50) or partial (n = 12) erythrocyte antigen typing to determine the role of erythrocyte antigens and phenotypes in UTI in children; 62 healthy children undergoing nonurologic elective surgery, matched 1 to 1 for age, sex, and race to the patient group, formed the control group. In univariate tests, patients and control subjects did not differ in ABO, Rh, P, Kell, Duffy, MNSs, and Kidd systems by the McNemar test of symmetry (p > 0.05). The frequency of the Lewis (Le) (a-b-) phenotype was higher (16/50 vs 5/50; p = 0.0076) and the frequency of the Le(a + b +) phenotype was lower (8/50 vs 16/50; p = 0.0455) in the patient population than in the control subjects. A stepwise logistic regression model to predict UTI with the explanatory variables A, B, O, M, N, S, s, Pl, Lea, and Leb showed that only the Lea and Leb antigens entered the model with p < 0.1. The Le(a-b-) phenotype was associated with UTI in this pediatric population. The relative risk of UTI in children with the Le(a-b-) phenotype was 3.2 (95% confidence interval, 1.3 to 7.9). Specific blood group phenotypes in pediatric populations may provide a means to identify children at risk of having UTI.

Adolescent↗
PubMed1994

Pediatric pyeloplasty: is routine retrograde pyelography necessary?

To evaluate the necessity for retrograde pyelography in the preoperative evaluation of children undergoing pyeloplasty, we reviewed the records of 108 consecutive patients (age range 5 days to 18 years, median 1 year) who underwent pyeloplasty at our institution during a 6-year period. The routine preoperative evaluation consisted of a renal/bladder sonogram, furosemide renal scan (99mtechnetium-diethylenetriaminepentaacetic acid or 99mtechnetium-mercaptoacetyltriglycine) and voiding cystogram. No other imaging studies were obtained in 95 patients (88%). Other upper tract studies usually performed before referral included excretory urography in 9 cases and computerized tomography in 5. Preoperative retrograde pyelography was only performed in 1 symptomatic patient before referral to our institution. Surgical findings confirmed obstruction at the ureteropelvic junction in all patients. Undetected ureteral dilatation, which might suggest undiagnosed distal obstruction, was not encountered. After pyeloplasty 2 patients were lost to followup, renal drainage improved in 104 (98%) and drainage failed to improve in 2 of whom 1 (0.9%) required reoperation. All patients who presented with symptomatic uretero-pelvic junction obstruction experienced postoperative resolution of the presenting complaints. Our series demonstrates that routine retrograde pyelography to define the level of obstruction is not necessary for successful primary pyeloplasty. In experienced hands and with careful attention to detail, the combination of renal/bladder sonography and diuretic renography can reliably exclude the possibility of distal obstruction in children with hydronephrosis before pyeloplasty.

Adolescent↗
PubMed1994

Urinary N-acetyl-beta-glucosaminidase and beta-2-microglobulin in the diagnosis of urinary tract infection in febrile infants.

Urinary N-acetyl-beta-glucosaminidase (NAG) and beta-2-microglobulin (B2M) concentrations were measured in 24 pediatric patients with febrile urinary tract infection (UTI) and compared with the technetium-99m-labeled dimercaptosuccinic acid (DMSA) renal scan results, in order to evaluate a noninvasive means to localize the site of UTI. Increased urinary B2M and NAG were not associated with renal inflammation (pyelonephritis), as defined by positive dimercaptosuccinic acid scan. Median NAG concentrations were 114.2 mumol/hour/mg creatinine (CR) (range, 5.7 to 305.4) in 17 febrile UTI patients vs. 13.8 (range, 3.4 to 104.3) in 17 age and sex-matched febrile controls with negative urine cultures, P = 0.0001. The sensitivity and specificity of NAG > or = 40 mumol/hour/mg of CR in predicting UTI in febrile patients, regardless of the site of infection, were 88 and 88%, respectively. Increased urinary NAG is associated with UTI in febrile patients regardless of the level of infection (scan status), and may be an informative indicator of UTI.

Acetylglucosaminidase↗
PubMed1994

The value of urinalysis in differentiating acute pyelonephritis from lower urinary tract infection in febrile infants.

There is an ongoing debate on the best way to screen febrile infants for urinary tract infection. We examined the urinanalysis (UA) findings on admission among infants less than 16 weeks old, with and without acute pyelonephritis (APN), as defined by the dimercaptosuccinic acid (DMSA) renal scan findings, performed during a 57-month period. Forty-nine cases with a positive DMSA scan were compared with 79 negative study cases. A negative UA for leukocytes (< 5 white blood cells/high power field) was found in 4 of 49 (8.1%) cases with APN by DMSA, and in 34 of 79 (43%) cases with a negative DMSA (odds ratio 10.88 (95% confidence interval, 2.31 to 70.3; P < 0.001)). Three of the 4 infants not suspected to have APN by their UA findings would have been admitted for a full sepsis workup based on their clinical presentation and/or their laboratory findings on admission. We conclude that a fresh UA may be a sufficient screening method for the exclusion of APN in infants assessed for fever of no obvious origin.

Acute Disease↗
PubMed1994

Real-time, automated echocardiographic measures of ventricular area and area change: comparison with radionuclide technique.

Echocardiography now permits tracking of the blood-endocardial border and automatic measurement of ventricular area throughout the cardiac cycle. To determine the accuracy of this technique, we compared echocardiographic measurements of area with similar measurements made by radionuclide technique in 19 children, ages 4-24 years (mean 13 years). The blood-endocardial border was tracked from the apical two-chamber view and radionuclide measurements were made from the left anterior oblique view. We measured echocardiographic end-diastolic area, end-systolic area, and fractional area change from the average of five cardiac cycles. The radionuclide area measurements were made from a gated blood pool study incorporating 700-1200 cardiac cycles. Results were compared by bias analysis. The mean differences (+/- 1 S.D.) between left ventricular area measurements were: end-diastole 1.13 +/- 2.3 cm2, end-systole -0.90 +/- 1.33 cm2, and fractional area change 7.4 +/- 9.3 (%). Differences between the measurements were within the limit of agreement (mean +/- 2 S.D.) in 55 of 57 measurements. The area measurements were not free from bias; the mean differences of area measurements were significantly different from zero for end-diastolic area (P < or = 0.05), end-systolic area (P < or = 0.01), and fractional area change (P < or = 0.002). Echocardiography tended to underestimate end-diastolic area and fractional area change and it tended to overestimate end-systolic area. Real-time tracking of the blood-endocardial border is possible and allows accurate measurement of ventricular area.

Adolescent↗
PubMed1993

Mineral balance and bone turnover in adolescents with anorexia nervosa.

We evaluated seven female adolescents with anorexia nervosa to determine whether calcium metabolism was affected by their disorder. We measured calcium absorption, urinary calcium excretion, and calcium kinetics, using a dual-tracer, stable-isotope technique during the first weeks of an inpatient nutritional rehabilitation program. Results were compared with those from a control group of seven healthy adolescent girls of similar ages. The percentage of absorption of calcium was lower in subjects with anorexia nervosa than in control subjects (16.2% +/- 6.3% vs 24.6% +/- 7.2%; p < 0.05). Urinary calcium excretion was greater in subjects with anorexia nervosa than in control subjects (6.4 +/- 2.5 vs 1.6 +/- 0.7 mg.kg-1 x day-1; p < 0.01) and was associated with bone resorption rather than calcium hyper-absorption. Calcium kinetic studies demonstrated a decreased rate of bone formation and an increased rate of bone resorption. These results suggest marked abnormalities in mineral metabolism in patients with anorexia nervosa. From these results, we hypothesize that improvement in bone mineralization during recovery from anorexia nervosa will require resolution of hormonal abnormalities, including hypercortisolism, in addition to increased calcium intake.

Absorption↗
PubMed1993

Diuretic renography in the evaluation of neonatal hydronephrosis: is it reliable?

Arguments against the use of diuretic renography in the assessment of newborn hydronephrosis include immature function of neonatal kidneys, previously reported poor diuretic response and nonreproducible drainage patterns. To address these concerns we reviewed the initial and followup renal scans of 17 neonates with hydronephrosis without ureterectasis diagnosed by perinatal ultrasonography. All patients were evaluated with an initial diuretic renal scan up to the age of 28 days, and all had normal cystograms. A total of 19 dilated kidneys was studied of which 13 ultimately required pyeloplasty and 6 were managed nonsurgically. Patient study parameters included age and weight at the time of each renal scan, side of hydronephrosis, differential function of each kidney, pre-diuretic and post-diuretic urine output, and drainage half-time of each kidney. The diuretic renal scans followed a standardized protocol. There was no statistically significant difference between neonatal and followup differential function (p > 0.05), and the correlation coefficient was highly significant (r = 0.968). Comparison of response to diuretic stimulation (ml./kg. per minute) revealed no statistically significant difference as the patients aged with brisk urine output 3 to 5 times greater than previously reported. The distribution and mean drainage half-times for normal nonhydronephrotic kidneys were similar when comparing those performed as neonates and at followup. Hydronephrotic kidneys managed nonsurgically maintained almost identical patterns. Those repaired surgically demonstrated appropriate improvement in drainage but function remained unchanged. These results refute each of the criticisms against the use of diuretic renography to evaluate neonatal hydronephrosis and demonstrate its reliability in neonates.

Furosemide↗
PubMed1992

Renal cortical scintigraphy in the diagnosis of acute pyelonephritis.

Comparative clinical studies have shown renal cortical scintigraphy, using technetium-99m (99mTc)-labeled glucoheptonate or dimercaptosuccinic acid (DMSA), to be significantly more sensitive than either intravenous pyelography or renal sonography in the diagnosis of acute pyelonephritis. However, due to uncertainties about the diagnostic accuracy of the clinical and laboratory parameters used in these studies, true sensitivity of renal cortical scintigraphy was unknown. Therefore, we evaluated the accuracy of [99mTc]DMSA scintigraphy in the diagnosis of experimentally induced acute pyelonephritis in piglets using strict histopathologic criteria as the standard of reference. The sensitivity and specificity of the DMSA scan for the diagnosis of acute pyelonephritis were 91% and 99%, respectively, with an overall 97% agreement between the scintigraphic and histopathologic findings. Based on the results of this experimental study, we used the [99mTc]DMSA scan as the standard of reference for the diagnosis of acute pyelonephritis, and conducted a prospective clinical study of 94 children hospitalized with the diagnosis of acute febrile urinary tract infection (UTI). The aims of this study were (1) to determine the relationship among vesicoureteral reflux, P-fimbriated Escherichia coli, acute pyelonephritis, and renal scarring, and (2) to evaluate the diagnostic reliability of the clinical and laboratory parameters commonly used in the diagnosis of acute pyelonephritis. We documented acute pyelonephritis in 62 (66%) of 94 patients. Vesicoureteral reflux was demonstrated in 29 (31%) of the total group and in only 23 (37%) of 62 patients with acute pyelonephritis. The prevalence of P-fimbriae in the E coli isolates was 64% in the patients with acute pyelonephritis and 78% in those with a normal DMSA scan. Even in patients without reflux, P-fimbriae were found in 71% of isolates from the patients with acute pyelonephritis and in 75% of those with a normal renal scan. Follow-up DMSA scans were obtained in 33 patients with acute pyelonephritis in 38 kidneys. We found complete resolution of the acute inflammatory changes in 58% of the involved kidneys and renal scarring in the remaining 42%, including 40% of the kidneys associated with reflux and 43% of those without reflux.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗
PubMed1992

Pyelonephritis in male infants: how important is the foreskin?

We investigated the association of the uncircumcised foreskin and pyelonephritis in male infants less than 6 months old. During a 21-month prospective study 94 children (age range 2 weeks to 18.9 years) were hospitalized for febrile urinary tract infection. The male-to-female ratio for 35 patients less than 6 months old was 2.2:1. Of 59 patients older than 6 months the male-to-female ratio was reversed at 0.25:1 (p less than 0.001). In 13 of 24 infants (54%) less than 6 months old and in 8 of 12 boys (67%) older than 6 months a dimercaptosuccinic acid renal scan documented acute parenchymal damage (p = 0.72). Vesicoureteral reflux or other genitourinary abnormalities were found in only 3 of 24 patients (12.5%) less than 6 months old compared with 6 of 12 boys (50%) older than 6 months (p = 0.036). Of 24 infants less than 6 months old 22 (92%) were uncircumcised compared with 6 of 12 boys (50%) older than 6 months (p = 0.009). We then retrospectively compared the circumcision status of the infants who had febrile urinary tract infection with a control group of 63 infants matched for age, race and socioeconomic status hospitalized with febrile upper respiratory infection during a similar period. The frequency of uncircumcised infants in the control group with febrile upper respiratory infection was only 44% (28 of 63) compared with 91% of infants with febrile urinary tract infection (p less than 0.001). Overall the findings of the male predominance among patients less than 6 months old with febrile urinary tract infection, the disproportionately high frequency of infants with febrile urinary tract infection who were not circumcised, and the disproportionately low occurrence of vesicoureteral reflux and other genitourinary abnormalities in infants with febrile urinary tract infection strongly support an association between circumcision status and the risk for febrile urinary tract infection and pyelonephritis in male infants.

Acute Disease↗
PubMed1992

Dimercaptosuccinic acid renal scintigraphy for the evaluation of pyelonephritis and scarring: a review of experimental and clinical studies.

Renal cortical scintigraphy has been reported to be useful in children for confirmation of the diagnosis of acute pyelonephritis. Subsequent experimental studies have demonstrated that dimercaptosuccinic acid (DMSA) scintigraphy, when compared directly with histopathology, is highly reliable for the detection and localization of parenchymal inflammatory changes associated with acute pyelonephritis. Recent clinical studies of acute pyelonephritis using DMSA scintigraphy reveal that the majority (50 to 91%) of children with febrile urinary tract infections have abnormal DMSA renal scan findings and that the majority of these children do not have demonstrable vesicoureteral reflux. However, when vesicoureteral reflux is present, renal cortical abnormalities are demonstrated by DMSA scintigraphy in 79 to 86% of the kidneys. In children with febrile urinary tract infections routine clinical and laboratory parameters are not reliable in the differentiation of acute pyelonephritis, documented by DMSA renal scan findings, from urinary tract infections without parenchymal involvement. Furthermore, the presence of P-fimbriated Escherichia coli associated with febrile urinary tract infections does not reliably predict those kidneys that have acute parenchymal inflammation demonstrated by DMSA renal scans. DMSA is also the isotope agent of choice for the detection of renal scarring. Clinical studies report greater sensitivity of DMSA renal scintigraphy for the detection of renal scarring when compared with the excretory urogram, particularly in infants and young children. In a recent prospective study of post-pyelonephritic renal scarring in children we found that acquired renal scarring only occurs in sites corresponding exactly to previous areas of acute pyelonephritis demonstrated by DMSA scintigraphy at the time of infection. Furthermore, once acute pyelonephritis occurs, ultimate renal scarring is independent of the presence or absence of vesicoureteral reflux. These findings provide convincing evidence that renal parenchymal infection, rather than vesicoureteral reflux, is the prerequisite for acquired (postnatal) renal scarring. Vesicoureteral reflux as a risk factor for acquired renal scarring is directly related to its role as a risk factor for acute pyelonephritis. We conclude that DMSA scintigraphy is a valid tool for confirming the diagnosis of acute pyelonephritis in children and for identifying kidneys at risk for subsequent renal scarring.

Acute Disease↗
PubMed1992

Renal scarring following reflux and nonreflux pyelonephritis in children: evaluation with 99mtechnetium-dimercaptosuccinic acid scintigraphy.

99mTechnetium dimercaptosuccinic acid (DMSA) scintigraphy is the imaging modality of choice for the detection of acute pyelonephritis and chronic renal scarring in children. Using the DMSA scan we prospectively evaluated renal scarring after reflux and nonreflux pyelonephritis in children. The study population consisted of 33 patients with acute pyelonephritis documented by a DMSA renal scan at infection. The children were evaluated for renal scarring with a followup DMSA scan 4 to 42 months (mean 10.7 months) after the acute infection. All new scarring on followup DMSA scans occurred at sites corresponding exactly to areas of acute inflammation on the initial DMSA scan. Therefore, only those kidneys with acute changes on the initial scan were subsequently analyzed. Of 38 kidneys new or progressive scarring developed in 16 (42%), including 6 of 15 (40%) with associated vesicoureteral reflux and 10 of 23 (43%) without demonstrable reflux. New renal scarring developed in 6 of the 7 kidneys (86%) associated with a neuropathic bladder or posterior urethral valves. In contrast, new scarring developed in only 10 of 31 kidneys (32%) associated with a normal bladder (p = 0.028). Excluding the kidneys associated with a neuropathic bladder or posterior urethral valves, new renal scarring developed in 3 of 12 (25%) with primary reflux, compared with 7 of 19 (37%) without vesicoureteral reflux. Except for the white blood count and the species of infecting bacteria, no other statistically significant differences could be found between those cases in which scars did or did not develop. We conclude that acquired renal scarring only occurs at sites corresponding to previous areas of acute pyelonephritis, the acute parenchymal inflammatory changes of acute pyelonephritis are reversible and do not lead to new renal scarring in the majority of cases, and once acute pyelonephritis has occurred ultimate renal scarring is independent of the presence or absence of vesicoureteral reflux.

Adolescent↗
PubMed1992

Escherichia coli virulence factors and 99mTc-dimercaptosuccinic acid renal scan in children with febrile urinary tract infection.

Correlation of virulence factors of Escherichia coli with renal inflammation documented by 99mTc-dimercaptosuccinic acid renal scan was undertaken in 59 children with febrile urinary tract infections to identify more accurately the role of bacterial virulence factors in the development of pyelonephritis. P fimbriae were present in 63% of isolates from the positive scan group and 83% of those from the negative scan group (P = 0.126). Multivariate regression analysis showed no significant role for established E. coli virulence factors in the development of pyelonephritis. The pap genome was independently associated with negative scan (P less than 0.007) and with the absence of reflux (P = 0.031). E. coli pyelonephritogenic clone O16:K1:H6 was isolated from negative scan patients and did not produce hemolysin. We conclude that P fimbriae are important in the development of febrile urinary tract infection regardless of the level of infection. Virulent E. coli clones described in prior Scandinavian urinary tract infection studies were not common causes of pyelonephritis in our patient population.

Adolescent↗
PubMed1992

Diagnostic imaging in the evaluation of the first urinary tract infection in infants and young children.

The evaluation of infants and children after the first urinary tract infection has undergone change in recent years. Standard diagnostic imaging studies are being utilized on a more frequent basis, because these procedures can provide information which often has a direct impact on patient care. Selection of the proper tests requires an understanding of how they are performed and the basis for their choice. The rationale for the use of different imaging studies and their application to patient care are discussed.

Child↗
PubMed1991

Relationship among vesicoureteral reflux, P-fimbriated Escherichia coli, and acute pyelonephritis in children with febrile urinary tract infection.

Ninety-four children with febrile urinary tract infection were studied prospectively to determine the relationship between vesicoureteral reflux, P-fimbriated Escherichia coli, and acute pyelonephritis, and to evaluate the diagnostic reliability of commonly used clinical and laboratory observations. By using renal scan with dimercaptosuccinic acid labeled with technetium 99m as the standard of reference, we documented acute pyelonephritis in 62 (66%) of 94 patients. Vesicoureteral reflux was demonstrated in 29 (31%) of the total group and in only 23 (37%) of 62 patients with pyelonephritis. Of the 70 E. coli urinary isolates, 48 (69%) were P-fimbriated, including 30 (64%) of 47 isolates from patients with pyelonephritis and 18 (78%) of 23 isolates from patients with normal renal scans. The prevalence of P-fimbriated E. coli in patients with pyelonephritis and vesicoureteral reflux was 46%, compared with 71% in those with pyelonephritis who had no concurrent vesicoureteral reflux (p = 0.222). Multiple clinical and laboratory variables commonly used in the diagnosis of acute pyelonephritis did not adequately predict the presence or absence of parenchymal involvement. These data show the following: (1) Acute pyelonephritis in the absence of demonstrable vesicoureteral reflux is common. (2) Febrile urinary tract infections in children are commonly associated with P-fimbriated E. coli, both in the presence and absence of vesicoureteral reflux. (3) The presence of P fimbriae alone does not fully explain the pathophysiology of renal parenchymal invasion by bacteria in the absence of vesicoureteral reflux. (4) The diagnosis of acute pyelonephritis in children with febrile urinary tract infections on the basis of clinical and laboratory observations is unreliable.

Acute Disease↗
PubMed1991

Diagnosis of acute pyelonephritis in children: comparison of sonography and 99mTc-DMSA scintigraphy.

Ninety-one children 1 week to 10 years old with culture-documented febrile urinary tract infection were evaluated with renal sonography and renal cortical scintigraphy by using 99mTc-labeled dimercaptosuccinic acid (DMSA). On the basis of previous experimental studies, DMSA scintigraphy was used as the standard of reference for the diagnosis of acute pyelonephritis. The DMSA scans showed changes consistent with acute pyelonephritis in 63% (57/91) of the patients. Sonograms showed changes consistent with acute pyelonephritis in 24% (22/91) of the whole group and in only 39% (22/57) of the patients with scintigraphically documented acute pyelonephritis. Pertinent sonographic findings were areas of increased cortical echogenicity in 14 patients and decreased echogenicity in eight, including three patients with renal abscesses. Dilatation of the renal collecting system was noted in nine patients and renal enlargement was noted in three. We conclude that renal sonography is a relatively insensitive test for the detection of acute inflammatory changes of renal cortex. Therefore, it should not be used as the primary imaging technique for the diagnosis of acute pyelonephritis. However, sonography is a useful technique in evaluating the nature of the defects seen on the DMSA scan and in detecting obstructive uropathies that may be associated with urinary tract infections.

Acute Disease↗