Michael B. Kodroff

Renal tubular acidosis type 4 in neonatalunilateral kidney diseases

Three neonates, two with unilateral renal vein thrombosis and one with unilateral dysplastic kidney, developed type 4 renal tubular acidosis, manifested by nonazotemic hyperkalemic metabolic acidosis with alkaline urine pH and reduced potassium excretion. Normal plasma concentrations of sodium, aldosterone, and renin activity, together with normal renal fractional excretion of sodium, supported the diagnosis of renal tubular acidosis type 4, subtype 5. Arginine HCl loading studies showed that despite their ability to bring the urine pH to

Short rib-polydactyly syndrome type II (Majewski syndrome): a case report.

The Majewski type of Short Rib-Polydactyly syndrome is a rare lethal dwarfism syndrome that has recently been recognized as a distinct entity. The full range of associated anomalies remains to be described. This case report details the clinical and autopsy findings in this condition and reviews the differential diagnosis of polydactylous dwarfing syndromes.

RENAL TUBULAR ACIDOSIS TYPE 4 IN NEONATAL UNILATERAL KIDNEY DISEASES

Three neonates, two with unilateral renal vein thrombosis and one with unilateral dysplastic kidney, developed type 4 renal tubular acidosis, manifested by non-azotemic hyperkalemic metabolic acidosis with alkaline urine pH and reduced potassium excretion. Normal plasma sodium, aldosterone and renin activity together with normal fractional excretion of sodium, support the diagnosis of renal tubular acidosis type 4, subtype 5. To further define the acidification defect, all underwent arginine-hydrochloride loading studies. Despite urine pH <5.8, net acid excretion was inadequate relative to the corresponding plasma bicarbonate concentration.Treatment with oral bicarbonate, 3-6 mEq/kg/day, resulted in sustained normalization of blood acid-base status and accelerated linear growth in the first two infants, in whom spontaneous recovery occurred by ages eight and 15 months, without further need for alkali therapy. Radiologic evaluation revealed shrinkage of the affected kidney with contralateral compensatory hypertrophy in both patients. In the third infant, persistent acidosis and growth failure obtained from medical non-compliance; removal of the dysplastic kidney at seven months of age was followed by normalized hydrogen and potassium excretion as well as blood acid-base status. We conclude that neonatal unilateral kidney diseases can give rise to renal tubular acidosis type 4, subtype 5. Early diagnosis and treatment provide an excellent prognosis.

Congenital renal dysplasia Osathanondh-Potter type II polycystic kidneys

Congenital renal dysplasia represents a group of nonhereditary kidney malformations frequently encountered in infants and children. The dysplasia may involve one or both kidneys totally or segmentally. The clinical presentation and prognosis depend on the extent of renal involvement and further development of the dysplastic renal tissue as well as the severity of coexisting malformations in other organs. The unifying factor in each instance is the characteristic histologic appearance of the dysplastic renal tissue. Congenital multicystic kidney and multilocular renal cyst are the best known members of the group. Radiologic features in conjunction with the clinical picture can suggest the correct diagnosis in most cases.