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Biomedical subjects

V Chadha

Publications and source records attributed to V Chadha.

13 recordsLinked to original sources
PubMed2001

Measurement of urinary concentration: a critical appraisal of methodologies.

The measurement of urine concentration provides information concerning the kidney's ability to appropriately respond to variations in fluid homeostasis. It also assists in the interpretation of other tests performed on the same urine specimen. The gold standard of estimating urinary concentration is the measurement of its osmolality; however, this procedure is not readily available to the practicing physician. Therefore, urine concentration is usually determined by measurement of its specific gravity (SG), which provides a fair estimate of urine osmolality. Over the years numerous tests have been developed to measure urine SG in a simple, quick, reliable and easily available method. These tests measure SG either directly (e.g., gravimetry) or by indirect methods (e.g., refractometry and reagent strip). All these tests have certain limitations based on their underlying physical principles. Specific gravity as measured by refractometry is influenced by proteinuria, such that for each 10 g/l protein the SG increases by 0.003. SG is also influenced by glucosuria such that it increases by approximately 0.002 per 10 g/l glucose when compared with urinary osmolality. Unlike osmolality, which is only affected by the number of particles, refractometry is affected by number, mass and chemical structure of the dissolved particles; hence large molecules like radiographic contrast or mannitol will increase SG relative to osmolality. The reagent strip is minimally affected by glucose, mannitol or radiographic contrast. However, it is affected by urinary pH such that only urine in the pH range of 7.0-7.5 can be correctly interpreted. The measurement of SG by reagent strip is based on the ionic strength of the urine and thus is significantly affected by the ionic composition of the urine and by proteins which have an electric charge in solution. In our experience, SG measured by the refractometer is consistently more accurate than the reagent strip. For the clinician who is interpreting urine SG results, it is important to be aware of these limitations and understand the reasons for possible potential errors of each particular method.

Humans↗
PubMed2001

What are the clinical correlates of adequate peritoneal dialysis?

The efficacy of peritoneal dialysis in terms of the clearance of small molecules such as urea and creatinine is referred to as "adequacy." Treatment guidelines and adequacy targets have been developed and distributed by the National Kidney Foundation-Dialysis Outcomes Quality Initiative (NKF-DOQI) in an effort to reduce variations in end-stage renal disease (ESRD) treatment. Much effort has been made to determine the correlation between dialysis dose and various clinical outcome measures (eg, hospitalization, mortality) in adults in an attempt to define the optimal dialysis dose. The delineation of this issue in the pediatric ESRD population is more complex because of the small number of patients and the need to define sensitive outcome measures that are unique to children. The review addresses the possible clinical correlates of dialysis adequacy in children that exist today and the additional data on the topic that needs to be collected in the future.

Child↗
PubMed2000

Sieving coefficient inaccuracies during hemodiafiltration in patients with hyperbilirubinemia.

Hemodiafiltration has assumed an important role in the supportive therapy of critically ill patients. The viability of the filter used for hemodiafiltration can be monitored by estimating the sieving coefficient of small molecules such as creatinine and/or urea. We report on three patients with severe hyperbilirubinemia whose creatinine sieving coefficient was spuriously elevated as a result of discordance in the accuracy of creatinine measurement in plasma and ultrafiltrate respectively. This discordance was a consequence of lack of bilirubin clearance during hemodiafiltration. As a result, while the plasma creatinine determination by the kinetic Jaffe method was negatively influenced by the hyperbilirubinemia, the ultrafiltrate creatinine was not. This report is the first to document the lack of bilirubin clearance during hemodiafiltration and its impact on the calculation of sieving coefficient based on creatinine. The use of urea as the solute for determining the sieving coefficient allows for an accurate estimate and provides a valid means of monitoring this parameter in the setting of hyperbilirubinemia.

Bilirubin↗
PubMed2000

C1q nephropathy presenting as rapidly progressive crescentic glomerulonephritis.

C1q nephropathy is an immune complex glomerulonephritis defined by the presence of mesangial immunoglobulins and complement deposits, most notably C1q, and the absence of clinical and laboratory evidence of systemic lupus erythematosus. Histology in C1q nephropathy is characterized by a slight to severe increase in mesangial cellularity and matrix, with or without segmental sclerosis. C1q nephropathy usually presents with nephrotic-range proteinuria in older children and young adults, and has a poor response to steroids. Patients may have decreased creatinine clearance at presentation, but progression to end-stage renal disease (ESRD) is slow. Severe crescentic glomerulonephritis has not been reported in C1q nephropathy. We describe a 3-year-old Hispanic girl who presented with renal insufficiency. Kidney biopsy showed C1q nephropathy with severe crescentic glomerulonephritis. The clinical and serological evaluation ruled out systemic lupus erythematosus or other immunological or infectious etiologies. In spite of immunosuppressive therapy, she progressed to ESRD within 14 weeks and is currently on chronic peritoneal dialysis. The atypical features of C1q nephropathy observed in our patient, which have not been described in earlier reports, are an early age of onset, severe crescentic glomerulonephritis, and rapid progression to ESRD. C1q nephropathy should be added to the differential diagnosis of glomerulonephritis in young children and in the patient with crescentic glomerulonephritis.

Antigen-Antibody Complex↗
PubMed2000

Tenckhoff catheters prove superior to cook catheters in pediatric acute peritoneal dialysis.

Peritoneal dialysis (PD) is the most common form of renal replacement therapy in infants and young children with acute renal failure (ARF). The two most commonly used catheters for performing acute PD are the Cook catheter (CC), placed at the bedside, and the surgically placed Tenckhoff catheter (TC). In the present study, we compared the complications and survival rates of the two catheters. The records of 59 children (age, 1 day to 16.7 years) who underwent PD for ARF from March 1989 through June 1999 in our hospital were reviewed. The initial (primary) catheter was a TC in 22 patients and a CC in 37 patients. The age of the patients who received a primary TC (2.8 +/- 4.5 years) was no different than the age of those with a primary CC (1.4 +/- 2.0 years; P = not significant). The duration of use (mean +/- SD) of TCs (16.5 +/- 14.2 days) was significantly greater than the duration of CC use (4.9 +/- 4.2 days; P < 0.001). Only two patients with a TC (9%) developed complications, whereas 18 patients with a CC (49%) developed complications, 13 of whom required catheter replacement (P < 0.01). Thirty-five patients (59%) recovered renal function after undergoing dialysis for 11.5 +/- 8.0 days. Twenty-three of those patients (66%) required dialysis for more than 5 days. Only 4 patients with a primary CC had successful completion of dialysis without catheter-associated complications compared with 15 patients with a primary TC. Kaplan-Meier survival analysis showed that by day 6 of dialysis, only 46% of primary CCs were functioning without complications compared with 90% of TCs that were free of complications. We conclude that the use of a CC is associated with significantly more complications than a TC, and nearly one half of the CCs are likely to be nonfunctional beyond 5 days of dialysis, at a time when two thirds of the patients are still expected to be undergoing dialysis. Therefore, when possible, a TC should be the catheter of choice when initiating acute PD in children. In those patients for whom a CC is chosen as the initial catheter, an elective change to a TC should be considered once dialysis is expected to extend beyond 5 days.

Acute Kidney Injury↗
PubMed2000

Chest wall peritoneal dialysis catheter placement in infants with a colostomy.

The presence of a colostomy in infants with end-stage renal disease (ESRD) receiving peritoneal dialysis (PD) is associated with an inherent risk for contamination and the development of a PD catheter-associated infection. A two-piece presternal catheter designed to reduce the incidence of such infections has been used in a small number of children, but the implantation of the catheter is technically difficult, and there is a risk of disconnection of the two parts secondary to rapid patient growth in the first year of life. Alternatively, a conventional Swan neck catheter, larger than typically required, can be placed with its exit site located on the chest wall. Over the past three years, we adopted this novel approach in two patients with ESRD and a colostomy in whom PD catheters were placed at ages 4 days and 12 days, respectively. During a combined follow-up of 50 months, only one episode of peritonitis and no episodes of exit-site or tunnel infection have been observed. This experience supports the use of this unique approach to PD catheter placement in infants with ESRD and a colostomy.

Abnormalities, Multiple↗
PubMed1999

Bilateral nephrectomy reverses hypothyroidism in congenital nephrotic syndrome.

A state of biochemical hypothyroidism is commonly seen in infants with congenital nephrotic syndrome (NS) and therefore the current recommendation is to place all patients with congenital NS on supplemental thyroid preparations. We report our experience in five children with congenital NS in whom thyroid supplementation was discontinued following bilateral nephrectomy and initiation of renal replacement therapy. Immediately after nephrectomy, thyroid function tests normalized, except serum thyroid-stimulating hormone (TSH) concentration, which initially rose, but normalized later. This observation supports the hypothesis that hypothyroidism in these patients is secondary to the chronic massive proteinuria and is not the result of a defect intrinsic to the thyroid gland itself. Abatement of massive proteinuria enables discontinuation of thyroid supplementation, and a transient rise in TSH in the early post-nephrectomy stage should be potentially expected.

Child↗
PubMed1999

Capnocytophaga canimorsus peritonitis in a pediatric peritoneal dialysis patient.

Capnocytophaga canimorsus, a bacterium rarely encountered by clinicians, was responsible for the development of peritonitis in an 18-year-old white male on automated peritoneal dialysis following the puncture of his dialysis tubing by a domestic cat. Although more than 100 cases of septicemia caused by C. canimorsus have been reported, this is the first report of the organism causing peritonitis in a patient receiving peritoneal dialysis. Of interest, the patient had a prior episode of peritonitis secondary to Pasteurella multocida, also following transmission from the same cat.

Adolescent↗
PubMed1993

Rectal histopathology in endemic Shigella and Salmonella diarrhea.

Rectal histopathology was evaluated in 34 cases (2 months-12 yrs old) of endemic "invasive diarrhea" [> 20 WBCs per high-power field on stool microscopy with (RBC positive) or without (RBC negative) associated RBCs] where S. dysenteriae (n = 9), S. flexneri (n = 11), and nontyphoidal Salmonella were isolated as the sole identifiable enteropathogens. Persistent diarrhea (> 14 days duration) was more common with Salmonella infection whereas RBC-positive "invasive diarrhea" was more frequent with Shigella, particularly S. dysenteriae (all cases) infection. The histopathological profile was comparable to the earlier descriptions of infective colitis to a large extent and the nature of the infecting organism could not be determined on the basis of rectal histology alone. The other noteworthy features were as follows: (i) mild crypt distortion (26%) and branching (21%) in both Shigella and Salmonella infection; in Salmonella infection, dilation of the glands was significantly greater with persistent diarrhea; (ii) presence of chronic inflammatory cells either alone or in combination with neutrophils in 62%; a predominant neutrophilic response was significantly higher with S. dysenteriae infection and an acute presentation; (iii) pseudomembrane formation (six subjects; 18%) especially in S. dysenteriae (four cases); and (iv) a significant association of neutrophilic response, edema, and neutrophils within the vessels in the lamina propria and mucin depletion in the glands with RBC-positive "invasive diarrhea."

Ampicillin↗
PubMed1991

Hemobilia in a child with liver abscess.

Hemobilia in children is rare and has so far been described only as a complication of blunt abdominal trauma. A case of hemobilia secondary to liver abscess treated successfully by selective arterial embolization is described. Hemobilia should be considered in any case of gastrointestinal hemorrhage before any operative intervention is undertaken.

Angiography↗
PubMed1991

Periventricular hemorrhage in term newborns originating from germinal matrix.

Six term newborns, presenting with seizures, in whom cranial sonogram showed isolated periventricular hemorrhage (SEH) are described. Age of onset of seizures ranged from day one of birth to day twenty-one. Seizures appeared spontaneously in previously healthy newborns in three cases. All but one survived, and three have near normal development. Isolation of hemorrhage to the periventricular area suggests germinal matrix to be the source of hemorrhage in these cases. These cases also emphasize the need to consider diagnosis of IVH in term-newborns presenting with seizures.

Cerebral Hemorrhage↗