151/158. X-linked hypophosphatemia: normal renal function despite medullary nephrocalcinosis 25 years after transient vitamin D2-induced renal azotemia. nephrocalcinosis (NC) detected by ultrasound is a recognized abnormality for some patients with X-linked hypophosphatemia (XLH) who received vitamin D2 and inorganic phosphate therapy, but is commonly observed in XLH patients treated with 1,25-dihydroxyvitamin D3 and inorganic phosphate supplementation. Nevertheless, long-term follow-up of kidney function in XLH patients with NC detected ultrasonographically has not been reported. We investigated two women with XLH, ages 31 (patient 1) and 39 (patient 2) years, each of whom had suffered at least one documented episode of vitamin D2-induced hypercalcemia and renal azotemia during childhood. Patient 2 had also been treated with inorganic phosphate. No medications for XLH had been taken during adulthood. Renal ultrasonography at our institution demonstrated marked bilateral medullary NC in both women. No other explanation was found for their NC that apparently occurred several decades earlier from medical therapy for XLH. Detailed studies (including creatinine clearance, beta2-microglobulin excretion, and fasting urinary osmolality and acidification) revealed no impairment of kidney function in either patient. Our findings indicate that subradiographic medullary NC acquired during medical therapy for XLH may persist for decades, but with no adverse renal sequelae. Definitive (long-term) assessment of kidney function in the XLH population with NC, however, will be necessary to fully understand the risk of current medical treatment for this most common heritable form of rickets. ( info) |
| We report three new Kuwaiti patients with carbonic anhydrase ii deficiency (CA II) from two unrelated families. Each patient had osteopetrosis, distal renal tubular acidosis, and cerebral calcification. patients from family 1 (a brother and a sister) had some facial anomalies and delayed development. At the age of 14 months, ultrasound studies in the girl showed medullary nephrocalcinosis which has not been previously described in association with CA II, while cerebral CT scan revealed dilated ventricles. The patient from family 2, who had two previously reported affected siblings, developed bilateral recurrent renal stones and hypercalciuria but no nephrocalcinosis. None of his affected siblings had nephrocalcinosis or urolithiasis. dna analysis of patients from both families showed that each of them was homozygous for the "Arabic" mutation in the CA II gene. We report new features in three Arab patients with CAII deficiency. Also review all previously reported CA II cases from kuwait in order to highlight the inter-/intra-familial variability of the disease in this part of the world despite the overwhelming prevalence of the same "Arabic" mutation among the patient population. ( info) |
153/158. Medullary nephrocalcinosis associated with vesicoureteral reflux. A case of medullary nephrocalcinosis developing in the course of vesicoureteral reflux is described. It is suggested that the probable mechanism of nephrocalcinosis was the stagnation of urine in collecting tubules favouring precipitation of calcium salts. ( info) |
154/158. Hyperammonaemia with distal renal tubular acidosis. The case is reported of an infant with hyperammonaemia secondary to severe distal renal tubular acidosis. A clinical association between increased concentrations of ammonia in serum and renal tubular acidosis has not previously been described. In response to acidosis the infant's kidneys presumably increased ammonia synthesis but did not excrete ammonia, resulting in hyperammonaemia. The patient showed poor feeding, frequent vomiting, and failure to thrive, but did not have an inborn error of metabolism. This case report should alert doctors to consider renal tubular acidosis in the differential diagnosis of severely ill infants with metabolic acidosis and hyperammonaemia. ( info) |
| Idiopathic hypercalciuria (IH) associated with nephrocalcinosis was found in three of six siblings. After the three affected children were maintained on a low-calcium diet, they demonstrated increasing hypercalciuria, parathyroid hormone, and vitamin D3 levels. An oral calcium loading test was not necessary to diagnose renal IH. During treatment with hydrochlorothiazide, the calcium excretion was normalized. These patients are remarkable because nephrocalcinosis is generally regarded as a rare complication of renal IH. Moreover, the fact that three of six siblings are affected raises the question of whether the renal form of IH is genetically distinct from other forms of IH. ( info) |
| We describe an unusual case of selective iga deficiency complicated by recurrent vasculitis of the central nervous system (CNS). The patient suffered from two episodes of CNS vasculitis, one of which was located in the cerebrum and the other in the cerebellum. The vasculitic process resulted in brain tumor-like lesions shown by computed tomography. There was no evidence of associated connective tissue diseases. vasculitis in other organs or tissues was not noted. This is the first detailed description in the English literature of pathologically proven CNS vasculitis in a patient with selective iga deficiency. Our report demonstrates that isolated CNS angiitis can be a rare clinical feature of selective iga deficiency. ( info) |
157/158. Dental changes in hypervitaminosis D. vitamin d is required for the normal development of teeth and bones. When there is excess vitamin d, systemic and dental changes may occur. This is a case report of a girl who experienced hypercalcemia secondary to excess vitamin d derived from the consumption of milk that was incorrectly fortified. The changes in the permanent dentition to date are enamel hypoplasia and focal pulp calcification. These changes correspond to the timing of the toxemia caused by hypervitaminosis D. ( info) |
158/158. Asymmetric medullary nephrocalcinosis in two children. Medullary nephrocalcinosis (MNC) is usually a bilateral process with symmetric involvement of both kidneys. Asymmetric medullary nephrocalcinosis has been previously reported in the literature, but has not been well illustrated or explained. We report the sonographic findings in two pediatric patients with hypercalcemia. In both patients an unrelated unilateral renal abnormality, (renal vein thrombosis in one and obstructive hydronephrosis in the other) prevented the development of MNC in the affected kidney, probably by decreasing the glomerular filtration rate and/or altering the renal tubular function. ( info) |