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Biomedical subjects

Michael L Moritz

Publications and source records attributed to Michael L Moritz.

At least 19 recordsLinked to original sources
PubMed2006

Acute post-streptococcal glomerulonephritis in a 14-month-old boy: why is this uncommon?

Acute post-streptococcal glomerulonephritis (APSGN) is rare in children under 2 years of age. This is related in part to the disease patterns of group A streptococcus (GAS) and in part to impaired immunogenicity in infants. We report the case of a 14-month-old child with APSGN following GAS pharyngitis. This case illustrates that APSGN needs to be considered in the evaluation of both gross and microscopic hematuria in this age group. We review the literature of both GAS and APSGN and discuss the pathogenesis and epidemiologic reasons for this association.

Acute Disease↗
PubMed2006

Acute renal failure from xanthine nephropathy during management of acute leukemia.

Tumor lysis syndrome is a potentially life-threatening complication of induction chemotherapy for treatment of lymphoproliferative malignancies. Serious complications of tumor lysis syndrome are rare with the preemptive use of allopurinol, rasburicase, and urine alkalinization. We report a case of oliguric acute renal failure due to bilateral xanthine nephropathy in an 11-year-old girl as a complication of tumor lysis syndrome during the treatment of T-cell acute lymphoblastic leukemia. Xanthine nephrolithiasis results from the inhibition of uric acid synthesis via allopurinol which increases plasma and urinary xanthine and hypoxanthine levels. Reports of xanthine nephrolithiasis as a cause of tumor lysis syndrome are rare in the absence of defects in the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) enzyme. Xanthine nephropathy should be considered in patients who develop acute renal failure following aggressive chemotherapy with appropriate tumor lysis syndrome prophylaxis. Urine measurements for xanthine could aid in the diagnosis of patients with nephrolithiasis complicating tumor lysis syndrome. Allopurinal dosage should be reduced or discontinued if xanthine nephropathy is suspected.

Acute Kidney Injury↗
PubMed2006

Antilymphoid antibody preconditioning and tacrolimus monotherapy for pediatric kidney transplantation.

OBJECTIVE: Heavy post-transplant immunosuppression may contribute to long-term immunosuppression dependence by subverting tolerogenic mechanisms; thus, we sought to determine if this undesirable consequence could be mitigated by pretransplant lymphoid depletion and minimalistic post-transplant monotherapy. STUDY DESIGN: Lymphoid depletion in 17 unselected pediatric recipients of live (n = 14) or deceased donor kidneys (n = 3) was accomplished with antithymocyte globulin (ATG) (n = 8) or alemtuzumab (n = 9). Tacrolimus was begun post-transplantation with subsequent lengthening of intervals between doses (spaced weaning). Maintenance immunosuppression, morbidity, graft function, and patient/graft survival were collated. RESULTS: Steroids were added temporarily to treat rejection in two patients (both ATG subgroup) or to treat hemolytic anemia in two others. After 16 to 31 months (mean 22), patient and graft survival was 100% and 94%, respectively. The only graft loss was in a nonweaned noncompliant recipient. In the other 16, serum creatinine was 0.85 +/- 0.35 mg/dL and creatinine clearance was 90.8 +/- 22.1 mL/1.73 m2. All 16 patients are on monotherapy (15 tacrolimus, one sirolimus), and 14 receive every other day or 3 times per week doses. There were no wound or other infections. Two patients developed insulin-dependent diabetes. CONCLUSION: The strategy of lymphoid depletion and minimum post-transplant immunosuppression appears safe and effective for pediatric kidney recipients.

Adolescent↗
PubMed2006

Dysnatremias: why are patients still dying?

Dysnatremias are a common clinical entity that are often associated with poor outcomes. This review takes a case study approach to understand how dysnatremias can result in devastating neurologic consequences. Concrete guidelines are provided for prevention, early recognition and treatment along with a discussion of how urinary electrolytes and osmolality can be used to guide therapy. Case studies in hyponatremic encephalopathy include the post-operative state, thiazide diuretics, extreme exercise and DDAVP use. Reasons to avoid using hypotonic parenteral fluids, risk factors for hyponatremic encephalopathy such as age, gender, and hypoxia, and the appropriate use of 3% sodium chloride are discussed. Case studies in hypernatremia include hypernatremia in the ICU setting and the emerging condition of breastfeeding-associated hypernatremia in infants.

Ambulatory Care↗
PubMed2006

Sirolimus rescue for tacrolimus-associated post-transplant autoimmune hemolytic anemia.

Autoimmune hemolytic anemia (AIHA) has been reported to occur after renal transplantation, and typically does so in the first few weeks post-transplant. We report on a 3-yr-old child who developed cold AIHA nearly 1 yr after an ABO identical, living donor renal transplant from his mother. Numerous transfusions, pulse steroids, repeat plasma exchange treatments, and IVIG were unsuccessful. Nearly 3 wk into his illness, tacrolimus was changed to cyclosporine, and then to sirolimus, and resulted in a prompt response. He currently has a normal renal function and a normal hemoglobin level on sirolimus monotherapy.

Anemia, Hemolytic, Autoimmune↗
PubMed2005

Preventing neurological complications from dysnatremias in children.

Dysnatremias are among the most common electrolyte abnormalities encountered in hospitalized patients. In most cases, a dysnatremia results from improper fluid management. Dysnatremias can occasionally result in death or permanent neurological damage, a tragic complication that is usually preventable. In this manuscript, we discuss the epidemiology, pathogenesis and prevention and treatment of dysnatremias in children. We report on over 50 patients who have suffered death or neurological injury from hospital-acquired hyponatremia. The main factor contributing to hyponatremic encephalopathy in children is the routine use of hypotonic fluids in patients who have an impaired ability to excrete free-water, due to such causes as the postoperative state, volume depletion and pulmonary and central nervous system diseases. The appropriate use of 0.9% sodium chloride in parenteral fluids would likely prevent most cases of hospital-acquired hyponatremic encephalopathy. We report on 15 prospective studies in over 500 surgical patients that demonstrate that normal saline effectively prevents postoperative hyponatremia, and hypotonic fluids consistently result in a fall in serum sodium. Hyponatremic encephalopathy is a medical emergency that should be treated with hypertonic saline, and should never be managed with fluid restriction alone. Hospital-acquired hypernatremia occurs in patients who have restricted access to fluids in combination with ongoing free-water losses. Hypernatremia could largely be prevented by providing adequate free-water to patients who have ongoing free-water losses or when mild hypernatremia (Na>145 mE/l) develops. A group at high-risk for neurological damage from hypernatremia in the outpatient setting is that of the breastfed infant. Breastfed infants must be monitored closely for insufficient lactation and receive lactation support. Judicious use of infant formula supplementation may be called for until problems with lactation can be corrected.

Brain Diseases↗
PubMed2005

Infantile systemic lupus erythematosus presenting with pulmonary hemorrhage.

Systemic lupus erythematosus in infants born to healthy mothers is a rare entity. We describe a male infant who presented at 1 month of age with pulmonary hemorrhage and glomerulonephritis due to systemic lupus erythematosus, confirmed serologically and histologically. He was managed with a combination of prednisone and intermittent cyclophosphamide, but also received mycophenolate mofetil, with a complete serological and clinical remission at 30-month follow-up. This case underscores the importance of a broad approach to the evaluation of pulmonary hemorrhage and glomerulonephritis in the very young and the need for aggressive immunosuppressive therapy to achieve sustained serological and clinical remission.

Cyclophosphamide↗
PubMed2005

Breastfeeding-associated hypernatremia: are we missing the diagnosis?

OBJECTIVES: To assess the incidence and complications of breastfeeding-associated hypernatremic dehydration among hospitalized neonates. STUDY DESIGN: A retrospective study was conducted at Children's Hospital of Pittsburgh over a 5-year period, to identify otherwise healthy term and near-term (> or =35 weeks of gestation) breastfed neonates (<29 days of age) who were admitted with serum sodium concentrations of > or =150 mEq/L and no explanation for hypernatremia other than inadequate milk intake. RESULTS: The incidence of breastfeeding-associated hypernatremic dehydration among 3718 consecutive term and near-term hospitalized neonates was 1.9%, occurring for 70 infants. These infants were born primarily to primiparous women (87%) who were discharged within 48 hours after birth (90%). The most common presenting symptom was jaundice (81%). Sixty-three percent of infants underwent sepsis evaluations with lumbar puncture. No infants had bacteremia or meningitis. Infants had hypernatremia of moderate severity (median: 153 mEq/L; range: 150-177 mEq/L), with a mean weight loss of 13.7%. Nonmetabolic complications occurred for 17% of infants, with the most common being apnea and/or bradycardia. There were no deaths. CONCLUSION: Hypernatremic dehydration requiring hospitalization is common among breastfed neonates. Increased efforts are required to establish successful breastfeeding.

Apnea↗
PubMed2004

Antihypertensive and renoprotective efficacy and safety of losartan. A long-term study in children with renal disorders.

BACKGROUND: Hypertension is a major risk factor for progressive renal failure. We assessed the long term efficacy and safety of losartan in lowering blood pressure (BP) and in preserving renal function in hypertensive children with chronic renal disorders. METHODS: Losartan was used in 45 consecutive hypertensive children with chronic renal parenchymal disorders and mean glomerular filtration rate (GFR) 99.4 mL/min/1.73 m(2). Of the children, 21 had hypertension alone (H) and 24 had both hypertension and proteinuria (H+P). Assessment was done at baseline and at preselected time points: visit I, <0.25 years; visit II, >/=0.25 and <0.5 year;visit III, 0.5 to 1.0 year; and visit IV >1 year. Both BP control and GFR were the principal outcome measures, and proteinuria was a secondary outcome measure. RESULTS: The mean age was 12.85 years and follow-up was 2.42 years (visit IV). Compared with baseline the systolic, diastolic, and mean arterial BP (MABP) fell by 9 to 12 mm Hg (all P < .01) in visit I. Diastolic BP and MABP remained significantly lower in all visits (P < .05 to .001), whereas systolic BP was not statistically lower in visit II. In visit IV the proportion of normotensive children increased significantly compared with baseline (P < .03 for systolic BP, P < .0004 for diastolic BP). In the H+P subgroup, optimal reduction in proteinuria ranging from 66% to 71% occurred in visits II to IV (all P < .01). Mean GFR declined at a rate of 9.3 mL/min/1.73 m(2) /year before starting losartan, and 1.4 mL/min/1.73 m(2) /year subsequently (P = NS). On long term follow-up, GFR fell by 15.9 mL/min/1.73 m(2) in the H subgroup and by 5.5 mL/min/1.73 m(2) in the H+P subgroup (P = NS). There was no correlation between BP measures and GFR or between the magnitude of BP lowering and proteinuria. Adverse effects (one serious) led to discontinuation of losartan in five children (11%). CONCLUSIONS: Losartan therapy was associated with prolonged and sustained antihypertensive and renoprotective benefits in children with a variety of chronic renal parenchymal disorders. Such benefit may be more pronounced in children with combined hypertension and proteinuria. The agent was well tolerated in the majority of the children.

Adolescent↗