Wen-Shiung Tsai

Symptomatic Hypomagnesemia in Children

Between January 1996 and June 1998, 24 children with symptomatic hypomagnesemia were enrolled for analysis of their symptomatology, causes, and treatment outcome. Hypocalcemia and hyperphosphatemia suggesting impaired parathyroid function were the most common electrolyte disorders. Hypokalemia was also frequently noted. The related symptoms including seizure, tetany, and weakness were common. Drug-induced renal magnesium wasting was the most common cause of symptomatic hypomagnesemia, and tended to occur in older children using aminoglycoside, furosemide, and amphotericin-B. The associated gastrointestinal causes might add a minor contribution to the development of hypomagnesemia. Analyses of PTH levels in 13 children suggested that inhibition of PTH synthesis or secretion was responsible for hypomagnesemic hypocalcemia in most patients. However, peripheral PTH resistance might also account for the mechanism in a few patients. In most patients, symptomatic hypomagnesemia was transient, and improved after magnesium provision. Only one child with congenital renal magnesium wasting and two with primary hypomagnesemia needed long-term magnesium treatment.

Urinary bladder outlet obstruction in children.

Bladder outlet obstruction, either functionally or structurally, could lead to bladder trabeculation, vesicoureteric reflux, hydronephrosis and, eventually, to renal parenchymal damage. If no treatment is given, end-stage renal failure will ensue. The cases of 17 patients of bladder outlet obstruction at National Taiwan University Hospital from 1984 to 1997 were reviewed. Initial presentation, etiology and treatment were discussed. Nine patients were victims of neurogenic bladder and two patients were victims of nonneurogenic neurogenic bladder. Four patients suffered from posterior urethral valve. Ureterocele and urethral rhabdomyosarcoma were noted in one case each. The most common clinical manifestation was urinary tract infection. Ultrasonography, urodynamic study and voiding cystourethrogram were used to delineate the cause and help to decide the appropriate treatment. In conclusion, early detection and prevention of deteriorated renal function are important for children with urinary bladder outlet obstruction.

Nephrocalcinosis in childhood

Charts of 16 children with nephrocalcinosis between 1990 and 1997 were reviewed. The cause of nephrocalcinosis was believed to be iatrogenic in 7 patients (43.8%) and non-iatrogenic in 9 (56.2%). Vitamin D therapy was responsible for 5 patients of iatrogenic nephrocalcinosis, and furosemide therapy for the remaining iatrogenic patients. Non-iatrogenic cases consisted of 3 patients with renal tubular acidosis, 3 patients with idiopathic hypercalciuria, and the 3 other patients with rare underlying conditions. Abdominal X-ray detected nephrocalcinosis in only 2 (12.5%) of the total 16 patients. None showed resolution of nephrocalcinosis during these years of follow-up.