Effect of hydrochlorothiazide in pseudohypoaldosteronism with hypercalciuria and severe hyperkalemia

Severe hyperkalemia resistant to treatment with sodium chloride (NaCl) supplements plus cation exchange resins can be found in pseudohypoaldosteronism type I. In a patient with the multiple target organ variant of this condition, hyperkalemia persisted at dangerous levels (8.5 mmol/l) despite large doses of NaCl (50 mmol/kg per day) and cation exchange resins (6 g/kg per day). Hypercalciuria was also present. The total volume of fluids and supplements required was not tolerated orally. Indomethacin (2 mg/kg per day) and later hydrochlorothiazide (2 mg/kg per day) were tried to further correct imbalance. Plasma potassium (K) and Na levels, the urinary Na/K ratio, transtubular potassium gradient (TTKG), and urinary calcium/creatinine (Ca/Cr) ratio were used to evaluate the effect of hydrochlorothiazide. Under treatment, plasma Na was stable (137-144 mmol/l), K levels decreased from 8.5 to 5 mmol/l, urinary Na/K from 90 to 24, and TTKG increased from 0.3 to 1.8. Ca/Cr decreased from 3.5 to 1.5 mmol/mmol. The dosage of cation exchange resins was decreased, oral fluids were tolerated, and the patient's general condition improved. Hence: hydroclorothiazide can be useful in the treatment of severe hyperkalemia and hypercalciuria of pseudohypoaldosteronism type I.

Imaging methods in the study of urinary tract infections in children

When studying a child with urinary tract infection it is important to detect and localize any renal (scar) or urologic anomaly. Here we study the information obtained using: renal and vesical ultrasound (US), DMSA scan and radiologic or isotopic cystogram.

METHODS

We studied 148 children with more than one urinary infection and/or pyelonephritis; their mean age was 35.9 months (1-148 months); 55% were girls. The three diagnostic examinations--US, DMSA scan and cystogram were made in this order; the DMSA scan or cystogram was never made sooner than one month after the UTI.

RESULTS

In 42% of the children the three exams were normal; 4 of these children had another UTI and the urodynamic study revealed vesical disfunction. 11% had renal scars (DMSA scan) with normal US and cystogram; 30% had VUR, 50% of which had an altered US and 57% had renal scars on the DMSA scan. 12% of the children had an altered US with a cystogram showing no VUR; 66% of these had renal scars. 4% had vesical anomalies in the US and cystogram.

CONCLUSION

The three exams chosen were able to direct the diagnostic approach of UTI, being sufficient in most of the cases. We would like to emphasize the importance of the DMSA scan in diagnosing unsuspected renal scars.

Vincristine in steroid-resistant nephrotic syndrome

The therapeutic response to vincristine was examined in seven children (aged 2-15 years) with corticosteroid-resistant (CR) nephrotic syndrome (NS) with focal and segmental glomerulosclerosis (FGS). Five were also resistant to cyclophosphamide. Vincristine was given weekly (1.5 mg/m2 intravenously) for 8 weeks. Simultaneously, prednisone (60 mg/m2 per day, orally) was given for 4 weeks and then gradually tapered. Two of these patients had a complete and stable remission; in five no benefit was observed. It was not possible to identify any characteristics to predict the response to vincristine. Although there is a case for trying vincristine therapy in CR NS with FGS, the results of this study are not encouraging and a better understanding of its action and indications is necessary.

Schinzel-Giedion syndrome. A patient with hypothyroidism and diabetes insipidus

The Schinzel-Giedion is an autosomal recessive syndrome characterized by midface retraction, hypertrichosis, multiple skeletal anomalies, cardiac and renal malformations and mental retardation. We describe a female child with this syndrome and a clinical status complicated by hypernatremic dehydration, hypothyroidism and diabetes insipidus at the age of 10 months.

[Imaging methods in the study of urinary tract infections in children]

When studying a child with urinary tract infection it is important to detect and localize any renal (scar) or urologic anomaly. Here we study the information obtained using: renal and vesical ultrasound (US), DMSA scan and radiologic or isotopic cystogram.

METHODS

We studied 148 children with more than one urinary tract infection and/or pyelonephritis; their mean age was 35.9 months (1-148 months); 55% were girls. The three diagnostic examinations--US, DMSA scan and cystogram were made in the order; the DMSA scan or cystogram was never made sooner than one month after the UTI.

RESULTS

In 42% of the children the three exams were normal; 4 of these children had another UTI and the urodynamic study revealed vesical disfunction. 11% had renal scars (DMSA scan) with normal US and cystogram; 30% had VUR, 50% of which had an altered US and 57% had renal scars on the DMSA scan. 12% of the children had an altered US with a cystogram showing no VUR; 66% of these had renal scars. 4% had vesical anomalies on the US and cystogram.

CONCLUSION

The three exams chosen were able to direct the diagnostic approach of UTI, being sufficient in most of the cases. We would like to emphasize the importance of the DMSA scan in diagnosing unsuspected renal scars.

[Urinary calcium, magnesium and uric acid in normal children]

In a group of 327 normal children, aged 4 to 11, we measured Calcium (Ca) and Creatinine (Cr) in the second morning urine. In 226 of them, Magnesium (Mg) and Uric Acid (UA) were also calculated. Means and SD were respectively Ca/Cr: 0.11 +/- 0.09, Mg/Cr: 0.10 +/- 0.03, Mg/Ca: 1.56 +/- 1.48 and UA/Cr: 0.093 +/- 0.29. Distribution was not normal, so we used the 97.5 centile for the upper acceptable limit. This value was higher for Ca/Cr (0.37) and different for Mg/Cr (0.17), compared to the previous reports. Our values of Mg/Ca were related to age (p less than 0.01). These results suggest the need for local establishment of normal ranges and a better definition of hypercalciuria and hypermagnesiuria.

Comparison of prostaglandin production of skin fibroblasts grown from patients with Bartter's syndrome and from age and sex matched controls

Basal and bradykinin stimulated release of prostaglandins (6-oxo-PGF1 alpha, PGF2 alpha, PGE2) and of arachidonic acid (C20:4) from skin fibroblast cultures of two patients with Bartter's Syndrome were compared with age and sex matched controls. PG-formation from 14C-C20:4 was studied, and for PGE2 a radioimmunoassay was also employed. The data show that in basal release, Bartter's Syndrome fibroblasts produce significantly less PGE2 than controls. Stimulated release of 6-oxo-PGF1 alpha was higher, that of PGE2 lower and that of C2O:4 higher in Bartter's Syndrome than in controls, all differences being significant. Despite equal culturing conditions the estimated intracellular potassium was higher in the patients fibroblasts than in controls. In skin fibroblasts from patients with Bartter's Syndrome stimulated prostaglandin production from C2O:4 is mostly depressed, with the exeption of prostacyclin which is enhanced. The permeability of cell membranes for potassium might play a pathogenetic role.