PROXIMAL RENAL TUBULAR ACIDOSIS IN TETRALOGY OF FALLOT

ABSTRACT: Rodriguez-Soriano, J., Vallo, A., Chouza, M. and Castillo, G. (Department of Paediatrics, Hospital Infantil de la Seguridad Social, Bilbao, Spain). Proximal renal tubular acidosis in tetralogy of Fallot. Acta Paediatr Scand, 64:671, 1975.–A 9-year-old girl presented with tetralogy of Fallot and moderate metabolic acidosis. Despite a Blalock's fistula there was evidence of chronic hypoxia with cyanosis, clubbing of fingers and toes and very elevated blood hematocrit values. Renal acidification and bicarbonate titration demonstrated the existence of proximal renal tubular acidosis: renal bicarbonate threshold was low (18 mmoles/1) and normal urinary acidification was present at subthreshold serum bicarbonate levels. Following corrective heart surgery, blood acid-base values and renal reabsorption of bicarbonate became normal. A causal relationship between extracellular fluid volume expansion dependent on the high hematocrit and proximal renal tubular acidosis is suggested.     

RENAL TUBULAR ACIDOSIS ASSOCIATED WITH TYPE III GLYCOGENOSIS

ABSTRACT. Cohen, J. and Friedman, M. (Department of Paediatrics, Whittington Hospital, London, England). Renal tubular acidosis associated with type III glycogenosis. Acta Paediatr Scand, 68: 779, 1979.—Two children who presented with severe failure to thrive were found to have Type III glycogen storage disease. They both also had defects of tubular acidification, an association not previously described. The nature of the tubular lesion is characterized and the explanation and therapeutic implications are discussed.     

CONGENITAL,PERSISTENT PROXIMAL TYPE RENAL TUBULAR ACIDOSIS IN TWO BROTHERS1

Abstract. Two brothers showed severe and persistent hyperchloraemic metabolic acidosis (capillary blood pH 7.07–7.15) due to a low renal bicarbonate threshold at 11 mmol/l. The maximal tubular capacity for bicarbonate reabsorption was reduced to about half the normal. A high dose of acetazolamide (25 mg/kg) lowered the tubular bicarbonate reabsorption substantially, indicating the presence of carbonic anhydrase. Both the glomerular filtration rate, the renal blood flow and the renal concentrating capacity were slightly reduced. The clinical characteristics were: growth retardation, mental retardation, nystagmus, corneal opacities, cataract, glaucoma and enamel defects of the permanent teeth. Serum thyroxine was pathologically low without clinical signs of hypothyreosis. The erythrocytes showed an increased osmotic resistance. Autopsy of the younger brother, who died 4 1/2 years old, revealed thyroid and thymus weights of 25% of the normal. The kidney tubular cells were swollen with vacuoles. The glomeruli had a normal appearance.     

NEONATAL ACIDOSIS ASSOCIATED WITH TRANSIENT METHYLMALONICACIDURIA AND VITAMIN B12 DEFICIENCY

Abstract Investigation of a neonate presenting with a metabolic acidosis, vomiting and an apnoeic attack revealed abnormal urinary excretion of methylmalonic acid (MMA) associated with a low serum vitamin B12. Restriction of dietary protein was followed by normalisation of acid-base balance. Reintroduction of normal daily protein intake did not precipitate further acidosis or increased excretion of MMA. The transient methylmalonicaciduria was probably due to deficiency of vitamin B12.     

THE EFFECT OF CALCIUM INFUSIONS ON RENAL HANDLING OF AMINO ACIDS IN HYPOPHOSPHATEMIC VITAMIN D RESISTANT RICKETS

ABSTRACT: Colombo, J. P. and Donath, A. (Department of Clinical Chemistry and Department of Paediatrics, Inselspital, University of Berne and the Division of Nuclear Medicine, Department of Internal Medicine, University of Geneva, Switzerland). The effect of calcium infusions on renal handling of amino acids in hypophosphatemic vitamin D resistant rickets. Acta Paediatr Scand, 64:703, 1975.–Amino acid clearances were studied in four patients with hypophosphatemic vitamin D resistant rickets. The clearances of the single amino acids in the patients did not differ from that of control individuals for all amino acids tested. The reabsorption of amino acids and phosphate was further investigated with the use of calcium infusions. Under these conditions there was a significant decrease in the filtered fraction of phosphate and amino acid excreted in the vitamin D resistant group suggesting a depression of parathyroid hormone secretion. It seems likely, as demonstrated in the vitamin D resistant group, that in this disorder the renal tubule is particularly sensitive to changes in parathyroid hormone secretion in respect to amino acid reabsorption.     

FAMILIAL HYPOPHOSPHATEMIC VITAMIN D RESISTANT RICKETS

Survey of all available data of infants with familial hypophosphatemia vitamin D resistant rickets observed partially or throughout the first year of life indicates that hypophosphatemia begins in the neonatal period regardless of whether or not the mother had been treated with vitamin D in high doses. Growth failure in vitamin D resistant rickets cannot be prevented even when treatment with high doses of vitamin D is begun early.     

THE SYNDROME OF RENAL TUBULAR ACIDOSIS WITH NERVE DEAFNESS

Abstract. Two brothers with renal tubular acidosis and nerve deafness are described. Studies of the physiopathological characteristics of the renal acidification defect show that the defect is limited to the distal tubule. Renal tubular acidosis with nerve deafness is a distinct nosologie entity that is determined by an autosomal recessive trait.     

ALKALINE PHOSPHATASE ACTIVITY OF DUODENAL JUICE IN RICKETS DUE TO VITAMIN D DEFICIENCY

Duodenal juice alkaline phosphatase activity of 17 children with rickets was assayed and not found to be different from the control values. Malnutrition did not seem to affect this activity.     

THE ACIDIFICATION DEFECT IN THE SYNDROME OF RENAL TUBULAR ACIDOSIS WITH NERVE DEAFNESS

Abstract. An 8-year-old boy with renal tubular acidosis and nerve deafness, has been followed for seven years. Repeated studies of his renal acidification defect showed that until the age of six years the tubular defect was mixed, proximal and distal (type 1,2 hybrid). After that age the defect of proximal acidification disappeared and the patient only presented a distal renal tubular acidosis type 1. When this is associated with nerve deafness, it is considered a distinct nosological entity.     

RENAL TUBULAR ACIDOSIS AND HYPERGAMMAGLOBULINAEMIC PURPURA IN A 10 YEAR OLD GIRL WITH ROENTGENOGRAPHIC SIGNS SUGGESTING MEDULLARY SPONGE KIDNEY

A 10-year-old girl presenting roentgenographic signs suggesting medullary sponge kidney, renal tubular acidosis and hypergammaglobu-linaemic purpura is reported. The possible relationships between this conditions are discussed.     

DEFECTIVE NEUTROPHIL MOTILITY IN HYPOVITAMINOSIS D RICKETS

ABSTRACT. The chemotactic activity and random motility of neutrophils, was studied in 38 patients with hypovitaminosis D rickets, and compared with 29 healthy controls of matched age. The chemotactic activity derived from the activated rickets serum as well as the amounts of the complement components C4, C3 and C5 was normal, but the cell motility was clearly defective (p<0.001). A possible relationship between defective neutrophil movement and the recurrent infections seen in these patients is suggested. The possible mechanisms responsible for the defect could be the alteration in Ca/P metabolism or a defective action of the vitamin D on the neutrophils.     

DEFECTIVE NEUTROPHIL MOTILITY IN HYPOVITAMINOSIS D RICKETS

Abstract. The chemotactic activity and random motility of neutrophils, was studied in 38 patients with hypovitaminosis D rickets, and compared with 29 healthy controls of matched age. The chemotactic activity derived from the activated rickets serum as well as the amounts of the complement components C4, C3 and CS was normal, but the cell motility was clearly defective ( p <0.001). A possible relationship between defective neutrophil movement and the recurrent infections seen in these patients is suggested. The possible mechanisms responsible for the defect could be the alteration in Ca/P metabolism or a defective action of the vitamin D on the neutrophils.     

PLASMA CONCENTRATIONS OF VITAMIN D METABOLITES IN A CASE OF RICKETS OF PREMATURITY

ABSTRACT. Rickets was diagnosed in an extremely low-birthweight infant 16 weeks after birth. She had a normal plasma concentration of 25-hydroxyvitamin D, a relatively low level of 24,25-dthy-droxyvitamin D, and a markedly elevated 1,25-dihydroxyvitamin D level compared with adult standards. The plasma concentrations of the vitamin D metabolites were, however, indistin-guishable from those of healthy preterm infants who received a similar diet of human milk and vitamins. The results indicate that rickets was not caused by vitamin D deficiency or by abnormal vitamin D metabolism, but by calcium and/or phosphate deficiency, and that the calcium and phosphorous content of human milk may be inappropriately low for very low-birthweight infants.     

Congenital rickets due to maternal vitamin D deficiency in a sunny island of Greece

A full-term male infant presented with clinical and biochemical findings consistent with the diagnosis of congenital rickets: weak muscle tone, craniotabes, episodes of tremor, hypocalcaemia, elevated serum alkaline phosphatase, secondary hyperparathyroidism, decreased 25-hydroxyvitamin D and normal 1,25-dihydroxyvitamin D serum levels. The mother's history and biochemical findings suggested nutritional vitamin D deficiency. Treatment with calcium and vitamin D resulted in the disappearance of clinical findings of rickets, normalization of the baby's biochemical profile and normal growth. It is surprising that this case occurred in an affluent setting, in the Mediterranean island of Crete, with an abundance of sunlight throughout the year. Conclusion: We report this case in order to emphasize the continuing occurrence of congenital rickets even in populations not considered at risk for hypovitaminosis D. A high index of suspicion is required for prompt diagnosis and treatment, thus preventing complications.     

A CASE OF HYPOPHOSPHATAEMIC VITAMIN D-RESISTANT RICKETS TREATED WITH INITIAL MASSIVE DOSES OF 1α-HYDROXY-VITAMIN D3 ALONE

ABSTRACT. A 1 5/12-year-old girl with hypophosphataemic vitamin D-resistant rickets was treated with initial massive doses of 1α-hydroxy-vitamin D₃ (1α- OH-D ₃) alone. A dramatic improvement of bone lesions and growth rate and normalization of the characteristic biochemical defects were noted within four months after the start of massive 1α-OH-D₃ therapy. The results of this study suggest that early therapy with massive doses of 1α-OH-D₃ alone improves the radiological findings and restores to normal the biochemical defects and the growth rate as early as possible. This regimen may improve motor strength and endurance and obviate the need for corrective orthopaedic procedures.     

NEONATAL CONGENITAL LACTIC ACIDOSIS WITH PYRUVATE CARBOXYLASE DEFICIENCY IN TWO SIBLINGS

Abstract. The authors report 2 familial cases of neonatal congenital lactic acidosis with pyruvate carboxylase deficiency in the liver. In both cases, disorders started immediately after birth and were characterized by major neurological symptoms, acute metabolic acidosis with hyperketonemia and hyperammonemia. Course was rapidly fatal despite intensive care, bicarbonate therapy and several therapeutic attempts with biotin and thiamine. Hyperlactacidemia was associated with dramatic increase in lactate/pyruvate ratio, without anoxia, in contrast with decreased β hydroxybutyrate/acetoacetate ratio. This unusual metabolic pattern may be assumed to result from decreased oxaloacetate synthesis as a result of pyruvate carboxylase deficiency, and impairment of oxaloacetate dependent mitochondrial redox shuttles. Post mortem enzymatic study of the liver and kidney showed biotin unresponsive total deficiency of pyruvate carboxylase. Other gluconeogenic enzyme activities were normal.     

CONGENITAL HYPERPARATHYROIDISM AND VITAMIN D DEFICIENCY SECONDARY TO MATERNAL HYPOPARATHYROIDISM

Abstract. A new case of congenital hyperparathyroidism secondary to maternal hypoparathyroidism is described. Neonatal roentgenograms of the skeleton showed severe bone demineralisation and the distal metaphyses of the long bones were spread, frayed and cupped. Elevated levels of serum immunoreactive parathormone (iPTH) were found at the age of 41 days=270 μlEq/ml (Normal: <50 μlEq/ml). A very low plasma 25-OH-D concentration (<4 ng/ml) was found at the same time in spite of previous administration of 600 units of vitamin D every day for 18 days and in spite of healing of the bone lesions. At the age of 3 months, 15 mg of vitamin D was given orally: iPTH levels which remainded high 3 weeks before (210 μlEq/ml) were found to be normal one week after this vitamin D load (37 μlEq/ml). It is suggested that in congenital hyperparathyroidism secondary to maternal hypoparathyroidism, hyperparathyroidism increases the infants needs for vitamin D. This could result in a state of vitamin D deficiency which in turn would maintain the parathyroid hyperactivity.