Hyperammonemia in distal renal tubular acidosis: is it more common than we think?

The hyperammonemia in distal renal tubular acidosis, previously only described in two cases, is considered an unusual occurrence. After the report published in 2005, we observed plasma ammonia levels above normal range during metabolic decompensation in two other consecutive pediatric patients suffering from distal renal tubular acidosis. The ammonia plasma levels returned to normal range after treatment with sodium bicarbonate and potassium salt. In distal renal tubular acidosis, hyperammonemia is probably the result of an imbalance between the increased ammonia synthesis, in response to metabolic acidosis, and the impaired ammonia excretion, typical of distal renal tubular acidosis. According to this physiopathological mechanism, our observation shows that hyperammonemia is not an uncommon finding in distal renal tubular acidosis, and should be included among differential diagnosis of hyperammonemia in infants and children.

Hemolytic uremic syndrome in an infant following Bordetella pertussis infection.

Reported here is the case of a 6-week-old female infant with a severe Bordetella pertussis infection requiring supportive pressure-positive ventilation in the intensive care unit. After being discharged from the intensive care unit, she developed hemolytic anemia, thrombocytopenia and acute renal failure, which suggested a diagnosis of hemolytic uremic syndrome. The clinical outcome was favorable with no renal consequences. This case suggests there may be a direct cause-effect relationship between B. pertussis infection and hemolytic uremic syndrome.

Hyperammonaemia in a child with distal renal tubular acidosis.

A 5-month-old girl with distal renal tubular acidosis (RTA) and hyperammonaemia that had lasted for 12 days, despite metabolic acidosis correction, is presented in this report. The patient showed failure to thrive, poor feeding, hypotonia and vomiting crisis in absence of inborn errors of metabolism. Probably, hyperammonaemia was the result of an imbalance between the increased ammonia synthesis, in response to metabolic acidosis, and the impaired ammonia excretion, typical of distal RTA. Our case confirms that hyperammonaemia may be observed in distal RTA, mimicking an inborn error of metabolism, and it underlines that hyperammonaemia may persist several days after metabolic acidosis correction.

Efficacy of hemodiafiltration in a child with severe lactic acidosis due to thiamine deficiency.

We report the case of a child in whom severe lactic acidosis (LA) and hyperammonemia developed after twenty days of total parenteral nutrition (TPN) for diffuse esophageal damage due to caustic ingestion. The revision of TPN preparation revealed that thiamine was never included and the hypothesis of thiamine deficiency was later confirmed measuring the serum thiamine level. Because severe metabolic acidosis the dialytic treatment with hemodiafiltration (HDF) and bicarbonate infusion were performed: the patient very quickly recovered with dramatic reestablishment of the acid-basic balance. Thiamine administration restored lactate metabolism. We emphasize that HDF is a useful and prompt treatment for LA to get over the critical phase of neurological and cardiological damage.

[Acute gouty arthritis in adolescents with renal transplants]. / Artrite acuta gottosa in adolescenti con trapianto renale.

Hyperuricemia is a common metabolic abnormality in subjects with renal transplantation: in fact in transplanted adults receiving immunosuppressive and diuretic drugs the frequency of hyperuricemia varied from 30 to 84% according to treatment. Conversely, the gout is an uncommon eventuality, representing less than 10%; predisposing factors are impaired renal function and older age. In the younger patients with renal transplantation hyperuricemia is also frequent, but the gout doesn't considered a possible complication in paediatric age. We reported our observation of 5 patients (3 males and 2 females), 13-18 years old who developed gout 2-84 months after renal transplantation. All the patients were receiving cyclosporine, 4 even with prednisone and azathioprine. Two patients were treated with furosemide because hypertension. The average of uric acid serum levels in the post transplantation follow-up was 7 +/- 2 mg/dl; at the moment of gout attack the uric acid serum levels raised to 12 +/- 1 mg/dl. The arthritis diagnosis were made by clinical, laboratory and instrumental data (Rx and US). In the most severe cases, uricasi therapy resolved clinical picture. The analysis of immunosuppressive and diuretic treatment, renal function and dietary uses induces us to think that the gout episode may be the result of many concomitant factors, in adolescents with renal transplant.

Magnetic resonance imaging of renal osteodystrophy in children.

BACKGROUND: Improved life expectancy of children with chronic renal failure (CRF) has increased the number of patients with renal osteodystrophy and has brought to light novel and severe forms of the disease. These factors have contributed to the need to evaluate new, noninvasive imaging modalities for the detection of bone involvement. OBJECTIVES: To evaluate the potential of MRI in the detection of the bone changes of renal osteodystrophy as compared to conventional X-rays. MATERIALS AND METHODS: Fourteen children with CRF were examined with a 0.5-T MR unit using TI-weighted and STIR sequences and conventional radiographs. The following features were reviewed in a nonblinded study: skeletal deformities, thickening of cortical bone, trabecular pattern, intraosseous soft-tissue masses, osteonecrosis, extraskeletal calcifications and bone marrow signal changes. RESULTS: MRI adequately demonstrated skeletal deformities, cortical thickening and irregular trabecular pattern. It showed osteonecrosis and intraosseous soft-tissue masses more conspicuously than X-ray. In addition, it revealed diffuse nonspecific signal changes in the bone marrow. CONCLUSION: MRI is a potentially useful tool for evaluating the bone changes of renal osteodystrophy.

[Non-comparative open study of the efficacy and tolerance of cefaclor in the prevention of urinary tract infections in children]. / Studio aperto non comparativo sull'efficacia e tollerabilità del cefaclor nella profilassi delle infezioni delle vie urinarie del bambino.

Cefaclor has been investigated as an additional prophylactic agent in the UTI. It is active against virtually all common urinary pathogens, is well absorbed in the upper gastrointestinal tract, is well tolerated and safe. The Authors have carried out a clinical trial of the prophylactic use of cefaclor in the prevention of recurrent urinary tract infection in children. We studied 52 children (25 females and 27 males, median age 7 +/- 19 months) with UTI, investigated by imaging (sonography, micturating cystourethrography, renal scintigraphy) and by urodynamic studies. We found vesicoureteral reflux in 37 cases, primitive megaureter in 6 cases, in 1 patient duplication of the collecting system in 1 patient and substenosis of ureteropelvic junction in 1 case. In the others 5 cases the UTI were associated with bladder disfunction and finally in 1 case the UTI occurred in absence of urinary malformations. All patients received cefaclor, as prophylaxis, at the dosage of 10-20 mg/kg/die, administrated as a single bedtime dose. The mean time of treatment with cefaclor was 8 +/- 3,48 months. We observed an optimal compliance in all patients, also in the first year of life. In only two out of 52 patients, during the prophylaxis, we found documented bacteriuria. We stopped treatment in two cases because of an adverse effect (in both children has been demonstrated a cutaneous rash). In conclusion our study shows that cefaclor is an effective, well tolerated and safe agent in the UTI prophylaxis, also in the first year of life, when it seems to offer an optime alternative to other agents.

[Vitamin D-dependent type-1 rickets: diagnosis and treatment of a further case]. / Rachitismo vitamina D dipendente tipo 1. Diagnosi e trattamento di un nuovo caso.

We describe a child with vitamin D dependent rickets type 1, who developed clinical signs of the disease at three months of age. The principal manifestations were hypocalcemia and seizure with EEG abnormalities. The circulating level of 1 alpha, 25 (OH)2D3 was low despite a normal level of 25 (OH)D3 and an adequate vitamin D supplementation. The patient responded to calcium gluconate infusions and pharmacologic doses of 1 alpha, 25 (OH)2D3 and a normalization of calcemia was obtained. After six months the therapy was progressively reduced to physiological dosage with optimal metabolic control. The patient is now 2.5 years old and receive a maintenance dose of calcitriol of 0.125 mcg/day. His clinical, biochemical and radiologic features are normal.

Progression of bone lesions in a child with primary hyperoxaluria type 1: evaluation by roentgenology and MRI.

We report the radiological and MRI findings of bone oxalosis and their rapid and extensive progression in a child with primary hyperoxaluria (PH) type 1. We emphasize the spectrum of skeletal changes and their differences from renal osteodystrophy and the role played by imaging in the diagnosis and follow-up of oxalosis.

[An echocardiographic study of the left ventricular functional indices in pediatric patients on hemodialysis and in treatment with recombinant human erythropoietin (r-HuEPO)]. / Studio ecocardiografico degli indici di funzione ventricolare sinistra in pazienti pediatrici emodializzati e in trattamento con eritropoietina umana ricombinante (r-HuEPO).

Recombinant human erythropoietin (r-HuEPO) is efficient in the treatment of anaemia in chronic renal failure on hemodialysis. We investigated the changes in cardiac function under r-HuEPO therapy using echocardiography. Seven patients with severe renal anaemia (Ht 19%) were treated with 50 U/kg r-HuEPO EV three times/week. Echocardiographic studies were performed in the anemic state and when hematocrit values were stable at levels (Ht 30%). Left ventricular function as showed by fractional shortening (D%) improved, the thickness of the interventricular septum and left ventricular hypertrophy were reduced. Our data indicate that the correction of renal anaemia by r-HuEPO can improve myocardial function in patients on maintenance hemodialysis.

[An open non-comparative study of the efficacy and tolerability of sultamicillin in the therapy of respiratory infections in childhood]. / Studio aperto non comparativo dell'efficacia e tollerabilità della sultamicillina nella terapia delle infezioni respiratorie in età pediatrica.

Forty-eight children (25 males + 23 females), mean age 3.5 years +/- 2.6 (range 1-11), were treated for the following respiratory infections: pharyngotonsillitis (9), bronchitis (18), bronchopneumonia (14), asthmatic bronchitis (4) and pneumonia (3). The average duration of treatment was 5.3 +/- 2.0 days (range 3-13). Sultamicillin was administered at the dose of 50 mg/kg/day. Patients with fever experienced a defervescence on the second day of therapy. Forty-six children (96%) showed a good clinical response. The tolerability of the drug was excellent or good in 93.8% of the cases.

[A case of 9p partial monosomy caused by paternal translocation. Clinical and cytogenetic aspects]. / Un caso di monosomia parziale 9p- da traslocazione paterna. Aspetti clinici e citogenetici.

The authors describe a case of partial monosomy 9p in a newborn infant, with breakpoint in the region p221, due to a father's balanced translocation with karyotype 46 XY t(9;16)(p221;q224). The phenotypical features of our patient reproduce those reported in other 35 cases described up to now in the literature: trigonocephaly, upward slanting palpebral fistures, little and horizontal mouth, disproportionally long fingers and toes. Some peculiar clinical and cytogenetical features of the case are discussed, particularly the early closure of the sternal body ossification centers (already detected during the prenatal life), the partial agenesia of the splenium corporis callosi and the partial anomalous pulmonary venous return. The Authors point out the importance of an early diagnosis, based on the awareness to the clinical abnormalities and dysmorphisms, in order to provide for an adequate and opportune genetic counseling.

[A new case of fronto-nasal dysplasia associated with craniosynostosis]. / Una nuova osservazione di displasia fronto-nasale associata a craniosinostosi.

The Authors report a case of frontonasal dysplasia, a rare congenital syndrome, accompanied by multiple cranial synostosis. According to Cohen, frontonasal dysplasia associated with craniosynostosis may be considered as a separate syndrome and Cohen himself has described its occurrence in members of two families as "Craniofrontonasal Dysplasia". The Authors describe a sporadical case presenting various minor abnormality reported by Cohen, in addition to the hypoplasia of the corpus callosum, demonstrated by the Cranial Ultrasonography and by the NMR study of the brain.