Body mass index in pediatric kidney transplant selection criteria.

BACKGROUND: Obesity is associated with increased complications, rejection, and graft loss after kidney transplantation in adult and pediatric recipients. Elevated body mass index (BMI) is a common contraindication to transplant at adult kidney transplant programs; however, there is no data on such limitations for pediatric patients. METHODS: Between October and December 2022, we conducted a survey of Pediatric Nephrology Research Consortium centers assessing the use of BMI in pediatric kidney transplant evaluation. Centers reporting utilization of BMI cutoffs were invited to submit patient-level data on children declined for active transplant listing due to BMI. RESULTS: Thirty-nine centers responded to the survey (42% response rate); 51% include BMI in their written listing criteria, with a median BMI "cutoff" of 39 kg/m2 (range 30-50 kg/m2). Between January 1, 2016, and December 31, 2021, 30 children at 15 transplant centers were declined for listing status due to BMI. Patient-level data was provided for 19 children (63%) who were denied active listing status; median BMI was 42 kg/m2 (range 35.8-49.4 kg/m2) and 84% were on dialysis. One year after evaluation, seven patients (37%) had proceeded to active wait list status. Eight (42%) remained in inactive status and four (21%) were unlisted; ten of these 12 patients (83%) were on dialysis. CONCLUSIONS: The use of BMI in pediatric kidney transplant evaluation and listing varies among centers, but BMI limits access to transplant for some children. More information is needed on the outcomes of obese pediatric kidney candidates who are and are not transplanted, to guide development of national and international consensus.

Safety and infectious outcomes in pediatric kidney transplant recipients after COVID-19 vaccination: A pediatric nephrology research consortium study.

BACKGROUND: Adult kidney transplant recipients (KTRs) fully vaccinated against COVID-19 have substantial morbidity and mortality related to SARS-CoV-2 infection compared with the general population. However, little is known regarding the safety and efficacy of the COVID-19 vaccination series in pediatric KTRs. METHODS: A multicenter, retrospective observational study was performed across nine pediatric transplantation centers. Eligible KTRs fully vaccinated against COVID-19 were enrolled and data were collected pertaining to SARS-CoV-2 infection incidence and severity, graft outcomes and post-vaccination safety profile, as well as overall patient survival. RESULTS: A total of 247 patients were included in this investigation with a median age at transplantation of 11 years (IQR 5-15). SARS-CoV-2 infection was observed in 30/110 (27.27%) of fully vaccinated patients, tested post-transplant, within the defined follow-up period. Of these patients, 6/30 (18.18%) required hospitalization and 3/30 (12.12%) required reduction in immunosuppression, with no reported deaths. De novo donor-specific antibodies (DSAs) were found in 8/86 (9.30%) of DSA-tested patients with two experiencing rejection and subsequent graft loss. The overall incidence of rejection and graft loss among the total cohort was 11/247 (4.45%) and 6/247 (3.64%), respectively. A 100% patient survival was observed. CONCLUSIONS: Observationally, infectious outcomes of SARS-CoV-2 in fully vaccinated pediatric KTRs are excellent, with a low incidence of infection requiring hospitalization and no associated deaths. Though de novo DSAs were observed, there was minimal graft rejection and graft loss reported in the total cohort.

Antibody-mediated rejection in pediatric kidney transplant recipients: A report from the Pediatric Nephrology Research Consortium.

BACKGROUND: Antibody-mediated rejection (AMR) is a major cause of kidney allograft loss. There is a paucity of large-scale pediatric-specific data regarding AMR treatment outcomes. METHODS: Data were obtained from 14 centers within the Pediatric Nephrology Research Consortium. Kidney transplant recipients aged 1-18 years at transplant with biopsy-proven AMR between 2009 and 2019 and at least 12 months of follow-up were included. The primary outcome was graft failure or an eGFR <20 mL/min/1.73 m2 at 12 months following AMR treatment. AMR treatment choice, histopathology, and DSA class were also examined. RESULTS: We reviewed 123 AMR episodes. Median age at diagnosis was 15 years at a median 22 months post-transplant. The primary outcome developed in 27.6%. eGFR <30 m/min/1.73 m2 at AMR diagnosis was associated with a 5.6-fold higher risk of reaching the composite outcome. There were no significant differences in outcome by treatment modality. Histopathology scores and DSA class at time of AMR diagnosis were not significantly associated with the primary outcome. CONCLUSIONS: In this large cohort of pediatric kidney transplant recipients with AMR, nearly one-third of patients experienced graft failure or significant graft dysfunction within 12 months of diagnosis. Poor graft function at time of diagnosis was associated with higher odds of graft failure.

Prevalence of mycophenolate mofetil discontinuation and subsequent outcomes in pediatric kidney transplant recipients: A PNRC study.

BACKGROUND: Mycophenolate Mofetil (MMF) is an effective immunosuppressant used in kidney transplant recipients to prevent acute rejection. Complications such as diarrhea, leukopenia, and infections may necessitate the reduction or discontinuation of MMF. The objective of the study was to investigate the prevalence, timing, and reasons for MMF discontinuation and its association with outcomes in pediatric kidney transplant recipients. METHODS: Seven Pediatric Nephrology Research Consortium (PNRC) centers participated in a retrospective analysis of kidney transplant recipients <21 years of age. Characteristics and outcomes of patients in whom MMF was discontinued were compared to those who continued taking MMF throughout the first 2 years post-transplant. RESULTS: The study population included 288 participants (mean age 11.2 years) from 7 North American transplant centers. MMF was discontinued in 93/288 (32%) of participants. Common reasons for discontinuation included infections (35%), diarrhea (32%), leukopenia (15%), and others (18%). Increased cumulative alloimmunity (55% vs. 42%, p = .02), increased number of hospitalizations (82% vs. 67%, p = .01), and viral replications (79% vs. 47%, p < .0001) were observed in the MMF discontinuation group compared to the continuation group. Greater eGFR decline also occurred in the MMF discontinuation group over 2 years of follow-up (-7 vs. -1 mL/min/1.73 m2 , p = .05). CONCLUSIONS: Almost a third of pediatric kidney transplant recipients who begin MMF for maintenance immunosuppression have it discontinued within the first 2 years post-transplant, and this subset of patients is more likely to experience adverse outcomes. New strategies are needed to manage MMF therapy and improve post-transplant outcomes.

Unique presentation of late-onset Pneumocystis pneumonia in a pediatric kidney transplant recipient.

BACKGROUND: Restrictive lung disease leading to abnormal lung function in kidney transplant recipients is commonly associated with noninfectious complications or medications used for post-transplant immunosuppression. Herein, we report an interesting case of pediatric kidney transplant recipient with weight loss and abnormal spirometry who was diagnosed to have late-onset Pneumocystis pneumonia. CASE REPORT: A 17-year-old male patient with a history of allergic rhinitis, mild persistent asthma, and deceased donor kidney transplant, performed 18 months prior, presented for routine evaluation of his asthma to the pulmonology clinic. He was clinically asymptomatic except for a weight loss of 8 kg over 6-month period prior to presentation. Patient's spirometry was suggestive of a restrictive pattern and further investigation using a high-resolution computed tomography (HRCT) of the chest showed bilateral diffuse ground-glass reticulonodular opacities with subpleural sparing suggestive of interstitial pneumonitis. A bronchoscopy with bronchoalveolar lavage revealed organisms consistent with Pneumocystis jirovecii on gomori-methenamine-silver (GMS) staining. Beta-d-glucan testing in serum revealed a level of >500 pg/mL (normal 0-59 pg/mL) further supportive of Pneumocystis jirovecii infection. Patient was treated with a 6-week course of trimethoprim-sulfamethoxazole. His weight loss and beta-d-glucan levels improved over a course of 6 months, and he continues to be on trimethoprim-sulfamethoxazole prophylaxis. CONCLUSION: Late-onset Pneumocystis jirovecii infection in kidney transplant recipients can have an atypical presentation. Treating physicians should consider PJP in the differential diagnosis of unexplained weight loss in pediatric kidney transplant recipients, especially those receiving a large cumulative burden of immunosuppression.

Nephrogenic diabetes insipidus with new onset diabetic ketoacidosis in a child - challenges in fluid and electrolyte management.

BACKGROUND: Intensive care management of diabetic ketoacidosis (DKA) is targeted to reverse ketoacidosis, replace the fluid deficit, and correct electrolyte imbalances. Adequate restoration of circulation and treatment of shock is key. Pediatric treatment guidelines of DKA have become standard but complexities arise in children with co-morbidities. Congenital nephrogenic diabetes insipidus (NDI) is a rare hereditary disorder characterized by impaired kidney concentrating ability and treatment is challenging. NDI and DKA together have only been previously reported in one patient. CASE DIAGNOSIS/TREATMENT: We present the case of a 12-year-old male with NDI and new onset DKA with hyperosmolality. He presented in hypovolemic shock with altered mental status. Rehydration was challenging and isotonic fluid resuscitation resulted in increased urine output and worsening hyperosmolar state. Use of hypotonic fluid and insulin infusion led to lowering of serum osmolality faster than desired and increased the risk for cerebral edema. Despite the rapid decline in serum osmolality his mental status improved so we allowed him to drink free water mixed with potassium phosphorous every hour to match his urinary output (1:1 replacement) and continued 0.45% sodium chloride based on his fluid deficit and replacement rate with improvement in his clinical status. CONCLUSIONS: This case illustrates the challenges in managing hypovolemic shock, hyperosmolality, and extreme electrolyte derangements driven by NDI and DKA, as both disease processes drive excessive urine output, electrolyte and acid-base imbalances, and rapid fluctuation in osmolality.

Treatment of BK virus with a stepwise immunosuppression reduction and intravenous immunoglobulin in pediatric kidney transplant.

BACKGROUND: BKV and BKVN are common in pediatric kidney transplant, but there is limited data on treatment approaches. Our objective was to study the prevalence of BKV and BKVN utilizing only plasma qPCR and report treatment outcomes with stepwise IR and IVIG. METHODS: A retrospective study of all pediatric kidney transplants from 2013 to 2020. Excluded patients >21 years at transplant and immediate graft failure. Surveillance was conducted using only plasma BK qPCR at 1, 3, 6, 9, 12, 18, and 24 months and annually. BKV defined as ≥250 copies/ml and resolution as <250 copies/ml. Presumed BKVN as >10 000 copies/ml despite IR; and BKVN if confirmed on histology. RESULTS: Fifty-six patients were included in the study; 20 (35.7%) had BKV. BKV was associated with longer duration of stent, 40 vs. 33.5 days (p = .004). Two patients (3.5%) had confirmed, and 2(3.5%) had presumed BKVN. The first-line treatment was IR in 100% of patients. BKVN confirmed and presumed received IVIG every month for six doses. Viral resolution was achieved in 70%, and no difference was noted in estimated glomerular filtration rate between BKV and non-BKV group (p = .438). There were no rejection episodes, and graft survival was 100% over median follow-up of 3 years. CONCLUSIONS: Plasma qPCR alone is adequate for screening and monitoring treatment of BKV and BKVN. A stepwise IR and IVIG resulted in BKV resolution in the majority of patients. Larger studies are required to study the role of IVIG in the treatment of BKVN.

Emergency Department Utilization and Serious Bacterial Infection Rates in Children With Renal Transplants.

OBJECTIVES: Emergency department (ED) visits by children with solid organ transplants have increased significantly. Our objectives were to describe the common complaints, diagnosis, types, and rates of serious bacterial infection (SBI) in children with renal transplant (RT) who present to the hospital. METHODS: We conducted a retrospective study from 2012 to 2016 of RT children up to 18 years who presented to the ED or were directly admitted. We excluded patients who presented for a procedure. We collected demographics, transplant type, immunosuppressive data, chief complaints, diagnostic testing with results, interventions performed, and final diagnosis. RESULTS: We analyzed 131 visits in 29 patients during the study period. Most common chief complaints were infectious (34.4%) and gastrointestinal (26%). Infection was proven in 42.0% of visits with only 3.1% being organ rejection. Serious bacterial infection was diagnosed in 34 visits (26.0%) with urinary tract infection (UTI) being the most common (20.6%). Of the 33 visits for fever, SBI occurred in 16 (48.5%) patients with the most common SBI being UTI 10 (30.3%). Bacteremia occurred in 1 patient and hypotension in 4 patients. Antibiotic administration was the most common intervention performed (78; 59.5%). Significant interventions were uncommon (2 patients). Logistic regression revealed no factors to be associated with SBI. CONCLUSIONS: Our cohort of children with RT presented most commonly with infections to the hospital with UTI being the most common SBI. Bacteremia and significant interventions were rare. Future studies are needed to identify subgroups of low-risk pediatric RT patients who can possibly be safely discharged home from the ED.

Clinical profile of children incidentally found to have advanced kidney failure.

INTRODUCTION: No data exist on the epidemiology of children incidentally diagnosed with advanced kidney failure (KF) during evaluation for non-specific symptoms. This is likely related to unrecognized symptoms and signs of CKD. The objective of our study was to evaluate incidentally diagnosed patients with advanced KF requiring long-term kidney replacement therapy (KRT). METHODS: An IRB-approved retrospective chart review of children who started KRT with dialysis (hemo- or peritoneal) was conducted. Included were children with no prior knowledge or diagnosis of underlying kidney disease with chronic kidney disease (CKD) disease stage 4 (GFR 15-29 mL/min/1.73 m2) or 5 (GFR < 15 mL/min/1.73 m2) at initial presentation and started on chronic KRT within 2 months of presentation. RESULTS: Of 177 patients initiating KRT during the study period, 26 (15%) were categorized as incidental advanced KF. This cohort with mean age 12.25 years consisted of 42% males, 54% African Americans included 46% with glomerular, and 54% with non-glomerular etiology for kidney failure. Vomiting (42%) and fatigue (39%) were most common, while growth failure (19%) and hyperkalemia (7%) were less frequent on initial presentation. Anemia (100%), hypertension (96%), hyperparathyroidism (96%), and hyperphosphatemia (92%) were the most frequently seen CKD comorbidities. Chronic KRT was started within 24 h in 62% and within 2 weeks in 88% of the cohort. CONCLUSION: Under-diagnosis of patients with advanced KF is most likely related to milder non-specific clinical symptoms and normal growth in the majority of patients. A higher resolution version of the Graphical abstract is available as Supplementary information.

Acute Kidney Injury in Pediatric Acute SARS-CoV-2 Infection and Multisystem Inflammatory Syndrome in Children (MIS-C): Is There a Difference?

Objective: To evaluate the prevalence and factors associated with the risk of acute kidney injury (AKI) in pediatric patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and multisystem inflammatory syndrome in children (MIS-C). Study Design: We performed a retrospective chart review of 113 patients with SARS-CoV-2 infection with or without MIS-C admitted at Children's Hospital of Michigan (CHM) from March to August 2020. Patient demographic details, laboratory data, imaging studies, echocardiography reports, and treatment data were collected. Results: Of the 92 patients included in the final analysis, 22 (24%) developed AKI with 8/22 (36%) developing stage 3 AKI. The prevalence of AKI was much higher in patients with MIS-C 15/28 (54%) vs. those with acute SARS-CoV-2 infection 7/64 (11%), (p < 0.001). Overall, when compared to patients without AKI, patients with AKI were older in age (11 vs. 6.5 years, p = 0.007), African American (86 vs. 58%, p = 0.028), had MIS-C diagnosis (68 vs. 19%, p < 0.001), required ICU admission (91 vs. 20%, p < 0.001), had cardiac dysfunction (63 vs. 16%, p < 0.001), required inotropic support (59 vs. 6%, p < 0.001) and had a greater elevation in inflammatory markers. In a multivariate analysis, requirement of inotropes [Odds Ratio (OR)-22.8, p < 0.001], African American race (OR-8.8, p = 0.023) and MIS-C diagnosis (OR-5.3, p = 0.013) were the most significant predictors for AKI. All patients had recovery of kidney function, and none required kidney replacement therapy. Conclusion: Children with acute SARS-CoV-2 infection and MIS-C are at risk for AKI, with the risk being significantly greater with MIS-C. The pathogenesis of AKI in acute SARS-CoV-2 infection appears to be a combination of both renal hypo-perfusion and direct renal parenchymal damage whereas in MIS-C, the renal injury appears to be predominantly pre-renal from cardiac dysfunction and capillary leak from a hyperinflammatory state. These factors should be considered by clinicians caring for these children with a special focus on renal protective strategies to aid in recovery and prevent additional injury to this high-risk subgroup.

Low-Dose Antithymocyte Globulin Has No Disadvantages to Standard Higher Dose in Pediatric Kidney Transplant Recipients: Report From the Pediatric Nephrology Research Consortium.

INTRODUCTION: Rabbit antithymocyte globulin (rATG) dosing strategies for induction in pediatric kidney transplantation vary between centers. It is not known whether a lower rATG induction dose provides safe and effective immunosuppression compared with a "standard" higher dose. METHODS: We performed a retrospective multicenter study of all isolated first-time kidney transplant recipients <21 years old who received rATG induction between 1 January 2010 and 31 December 2014 at 9 pediatric centers. An a priori cutoff of a 4.5-mg/kg cumulative rATG dose was used to identify low (≤ 4.5 mg/kg) and standard (> 4.5 mg/kg) exposure groups. Outcomes examined included 12 months posttransplant graft function (estimated glomerular filtration rate [eGFR]); the occurrence of acute rejection, donor-specific antibody (DSA), neutropenia, and viral infection (cytomegalovirus [CMV], Epstein-Barr virus [EBV], and BK virus); and 24-month outcomes of posttransplant lymphoproliferative disorder (PTLD) occurrence and patient and graft survival. RESULTS: Two hundred thirty-five patients were included. Baseline features of the low and standard rATG dose groups were similar. By 12 months, the rATG dose group had no significant impact on the occurrence of neutropenia, positive DSA, or viral polymerase chain reaction (PCR). Graft function was similar. Acute rejection rates were similar at 17% (low dose) versus 19% (standard dose) (P = 0.13). By 24 months, graft survival (96.4% vs. 94.6%) and patient survival (100% vs. 99.3%) were similar between the low- and standard-dose groups (P = 0.54 and 0.46), whereas the occurrence of PTLD trended higher in the standard-dose group (0% vs. 2.6%, P = 0.07). CONCLUSION: A low rATG induction dose ≤ 4.5 mg/kg provided safe and effective outcomes in this multicenter low immunologic risk pediatric cohort. Prospective studies are warranted to define the optimal rATG induction dose in pediatric kidney transplantation.

Practice patterns and influence of allograft nephrectomy in pediatric kidney re-transplantation: A pediatric nephrology research consortium study.

INTRODUCTION: There are no guidelines regarding management of failed pediatric renal transplants. MATERIALS & METHODS: We performed a first of its kind multicenter study assessing prevalence of transplant nephrectomy, patient characteristics, and outcomes in pediatric renal transplant recipients with graft failure from January 1, 2006, to December 31, 2016. RESULTS: Fourteen centers contributed data on 186 pediatric recipients with failed transplants. The 76 recipients that underwent transplant nephrectomy were not significantly different from the 110 without nephrectomy in donor or recipient demographics. Fifty-three percent of graft nephrectomies were within a year of transplant. Graft tenderness prompted transplant nephrectomy in 91% (P < .001). Patients that underwent nephrectomy were more likely to have a prior diagnosis of rejection within 3 months (43% vs 29%; P = .04). Nephrectomy of allografts did not affect time to re-listing, donor source at re-transplant but significantly decreased time to (P = .009) and incidence (P = .0002) of complete cessation of immunosuppression post-graft failure. Following transplant nephrectomy, recipients were significantly more likely to have rejection after re-transplant (18% vs 7%; P = .03) and multiple rejections in first year after re-transplant (7% vs 1%; P = .03). CONCLUSIONS: Practices pertaining to failed renal allografts are inconsistent-40% of failed pediatric renal allografts underwent nephrectomy. Graft tenderness frequently prompted transplant nephrectomy. There is no apparent benefit to graft nephrectomy related to sensitization; but timing / frequency of immunosuppression withdrawal is significantly different with slightly increased risk for rejection following re-transplant.

Pheochromocytoma and paraganglioma-an update on diagnosis, evaluation, and management.

Pheochromocytomas and paragangliomas (PPGLs) generally grouped together are rare catecholamine-secreting endocrine tumors. Symptoms of catecholamine excess are non-specific and therefore a high index of suspicion in children with sustained hypertension, family history of endocrine tumors, or features of syndromes associated with PPGLs leads to a timely diagnosis and treatment. Free metanephrines in the plasma or 24-h urine are the preferred tests to establish catecholamine excess. Considerations for false-positive conditions improve diagnostic yield and accuracy. Functional imaging, targeting either specific cell membrane transporters or vesicular catecholamine transport systems, is indicated for incidental lesions suspicious for PPGLs with inconclusive biochemical testing, assessment of regional extension or multifocality, and exclusion of metastases. Surgery is the mainstay of treatment for PPGLs. Preoperatively, sequential use of alpha adrenergic receptor blockade and volume expansion followed by beta blockade is mandatory to reduce intraoperative intravascular instability and blood pressure fluctuation due to tumor manipulation. Since genetic mutations have been reported in tumor susceptibility genes in nearly 50% of patients with PPGLs, genetic counselling and testing should be considered in all patients with a confirmed tumor.

Barriers to live donor kidney transplants in the pediatric population: A single-center experience.

A decrease in live donor pediatric kidney transplants has occurred in the United States. This study investigates barriers that may influence access to live donor kidney transplants in children. Retrospective chart review was conducted for 91 children (69% male, mean age 11.9 years) who underwent pretransplant workup from 2005 to 2015 at an urban pediatric hospital. Fifty-four percent were African American, 32% Caucasian, 8% Arabic, 3% Hispanic, and 3% Others. Government-sponsored insurance (Medicaid/Medicare) was utilized by 73%, and 54% had dual caregivers. Only nine of 68 kidney transplants were live donor transplants. Live donor transplants (11%) were significantly (P=.008) lower than deceased donor transplants (59%) in African Americans. Private insurance was reported by 56% of live donor recipients and 25% of deceased donor recipients. Among live donor recipients, 78% were from dual caregiver families. Caregiver, health-related, financial, and religious/cultural barriers to live donor transplants were reported, several of which may be amenable to positive intervention.

Atypical hemolytic uremic syndrome: a clinical conundrum.

BACKGROUND: Patients negative for Shiga toxin-producing E. coli (STEC) are categorized as having atypical hemolytic uremic syndrome (HUS) and are associated with an increased risk for complement mutations and poorer prognosis compared with typical HUS. However, STEC identification is limited by the natural history of HUS. METHODS: The current study is aimed at identifying HUS patients with poor outcomes based on the presence or absence of diarrhea (D) or Shiga toxin (S). A single-center retrospective review (2003-2012) of 42 HUS patients (follow-up 31.3 ± 38.7 months) was carried out. HUS was managed clinically with supportive treatments such as dialysis, plasma therapy, and eculizumab. RESULTS: There was no significant difference in the D+S+ (31 %), D+S- (50 %) and D-S- (19 %) groups in the outcome variables of chronic kidney disease stages I-II (100 % vs 81 % vs 67 %) and proteinuria at follow-up (20 % vs 12.5 % vs 33.3 %), hospitalization duration (16.0 ± 8.7 vs 18.1 ± 9.5 vs 23.7 ± 12.9 days); dialysis requirement (50 % vs 81 % vs 66.7 %), and dialysis duration (10.2 ± 1.9 vs 33.3 ± 72.8 vs 10.3 ± 8.1 days). There was no significant difference in study outcomes in STEC+ (59 %) versus STEC- (41 %) groups. Genetic testing was performed in 12 % of HUS patients based on age, recurrent HUS, familial HUS, persistently low C3, or prolonged dialysis, and 80 % of the patients tested were positive for genetic mutations. CONCLUSIONS: Our study does not show poorer outcomes in STEC- HUS. Indications and the cost-effectiveness of genetic testing, eculizumab, and plasmapheresis in STEC- HUS need to be evaluated further.

Pharmacologic Treatment of Pediatric Hypertension.

Prevalence of hypertension is increasing in children and adolescents. Uncontrolled hypertension in children not only causes end organ damage but also increases the risk of adult hypertension and cardiovascular disease. Clinical trials have proven efficacy of antihypertensive medications in children. These medications are well tolerated by children with acceptable safety profile. The choice of agent is usually driven by underlying etiology of hypertension, profile of its side effects, and clinician's preference. This article will review currently available pediatric data on mechanism of action, common adverse effects, pediatric indication, recent clinical trial, and newer drugs in the common classes of antihypertensive medications.

Sweat chloride concentrations in children with Idiopathic Nephrotic Syndrome.

BACKGROUND: Idiopathic Nephrotic Syndrome (INS) has been believed to cause a false positive elevation of sweat chloride concentrations, as measured by the sweat test. METHODS: Sweat tests were done for 11 children with acute onset INS at admission and again while they were in remission, with results being compared to normal historical controls. RESULTS: The initial sweat chloride concentration for 10 patients was normal (mean16.7 ± 11.02 mmol/L) and 1 patient had inadequate collection. This latter patient and two others were excluded during follow-up because of diagnoses other than INS. Sweat test results for the eight INS patients during follow up remained unchanged when they were in remission (16.94 ± 7.88 mmol/L; P = 0.98; Wilcoxon Matched-Pairs Signed Rank Test). In comparing sweat chloride concentrations from INS patients to those from 20 historical control subjects, we found no significant differences (Mann-Whitney Test; initial vs. control P = 0.643; follow up vs. control P = 0.806). CONCLUSIONS: INS does not cause a false positive sweat test. Further studies should be done to objectively assess the conditions that have been reported to affect sweat chloride concentrations.

Treatment of Hypertension in Children With Catecholamine-Secreting Tumors: A Systematic Approach.

Management of blood pressure in children with pheochromocytoma and other catecholamine-secreting tumors (CSTs) is unique and challenging. The authors report a single-center experience using sequential α-adrenergic blockade (phenoxybenzamine), increased fluid intake, and ß-blockade for presurgical management of 10 CSTs in children. In this retrospective review, mean duration for blood pressure control in preparation for surgery was 4.5±2.6 weeks. Intraoperative hypertension was noted transiently (<2 hours) in eight patients (80%) and was treated with continuous infusion of short-acting antihypertensive agents. Two (20%) patients required vasopressor medication infusion to manage intraoperative hypotension. Only two (20%) patients developed postoperative hypotension and required vasopressor medication infusion for <24 hours. All antihypertensive medications were discontinued in the immediate (≤4 days) postoperative period in 80% of patients. In conclusion, a systematic and multidisciplinary approach utilizing adrenergic blockade is effective in treating children with CSTs.

Body fluid composition.

UNLABELLED: Body fluid composition is maintained in a normal physiologic range by regulatory mechanisms that control sodium and water metabolism. A detailed knowledge of the homeostatic mechanisms will help in understanding the pathogenesis and management of disorders of sodium and water balance. OBJECTIVES: After completing this article, readers should be able to: 1. Understand the distribution of fluid and solute in different body compartments. 2. Demonstrate the homeostatic mechanisms involved in maintaining sodium and water metabolism. 3. Calculate osmolality and recognize the clinical importance of maintaining osmotic equilibrium. 4. Recognize common disorders of hypernatremia or hyperosmolality and evaluate and understand the role of calculating free water deficit in the treatment of these disorders. 5. Recognize common disorders of hyponatremia or hypo-osmolality, appreciate the role of urine sodium and urine osmolality in evaluation,and understand the importance of slow correction of these disorders.