Renal failure due to 2,8-dihydroxyadenine urolithiasis

A four-year-old girl presented in renal failure due to dihydroxyadenine urolithiasis. Prior to this she had been fed a high purine macrobiotic diet, rich in pulses and grain. She was comatose, anuric, requiring peritoneal dialysis, and bilateral radiolucent renal calculi were revealed by ultrasonography and retrograde pyelography. 2,8-dihydroxyadenine stones were found at pyelolithotomy, renal biopsy revealed interstitial birefringent crystals, and a complete lack of adenine phosphoribosyl transferase (APRT) was found subsequently in erythrocyte lysates. APRT levels were initially falsely raised due to a blood transfusion on admission. The mother was shown to have heterozygote levels. The child was treated successfully with allopurinol, and a reduction in dietary purine but with only partial return of renal function.

Acute renal failure complicating cardiopulmonary bypass surgery

Acute renal failure developed in 24 (5.3%) of 456 children undergoing cardiopulmonary bypass surgery during a 2-year period. It was more common in younger children, in those with complex cardiac lesions, and in those with long overall bypass times. Fourteen (58%) recovered renal function; renal failure was responsible for death in only two. Early vigorous peritoneal dialysis is advocated after cardiopulmonary bypass surgery if there is oliguria (less than or equal to 1.0 ml urine/kg per hour) resistant to volume repletion, dopamine infusion and diuretics, intractable fluid overload, or hyperkalaemia.

Analysis of steroids in urine for differentiation of pseudohypoaldosteronism and aldosterone biosynthetic defect

The salt-losing syndromes in the neonatal period and early infancy due to adrenal disease can be differentiated by the pattern of excretion of steroids in urine. The presence or absence of metabolites of cortisol, aldosterone, and corticosterone as well as certain precursors can be established in a single analysis of steroids in urine by using gas chromatography with open tubular capillary columns. The profiles of steroid excretion in the urine of 8 infants with renal tubular insensitivity to aldosterone were compared with those in 5 infants with isolated aldosterone biosynthetic defects. The excretion in urine of 18 hydroxytetrahydro-compound A was elevated in all 13 children, but relative to the excretion of tetrahydroaldosterone, a high ratio was found for the biosynthetic defect and clearly distinguished the 2 conditions. Age-related changes in steroid metabolism are described. The diagnosis in each case was supported by clinical investigation together with determinations of PRA and aldosterone concentrations.

Uric acid crystal-induced nephropathy: evidence for a specific renal lesion in a gouty family

Gout is principally a disease of middle-aged men. There has been a lot of discussion over the cause of the renal lesion, whether it is age, hypertension or crystal induced, as single factors or in combination. We have recently been able to study renal biopsies from three related young women with an hereditary gout, and another girl with 2,8-dihydroxyadenine crystal nephropathy. All were normotensive. These findings were compared with the findings of a crystal-induced nephropathy in pigs. In the renal biopsies many stages of acute and chronic nephritis were found which were similar to the crystal nephropathy in pigs. We concluded that the cause of the original lesion in the women was crystal deposition in the tubules, that crystals were not necessary to keep a non-specific nephritis active and that age and hypertension need not be contributory factors.

Renin-angiotensin-aldosterone system

There is increased activity of the renin, angiotensin, aldosterone (RAA) system in infancy and childhood. An inverse relationship between plasma renin, aldosterone and age has been demonstrated. In childhood hypertension due to renovascular disease or pyelonephritic scarring peripheral plasma renin is increased. Renal vein renin measurements in children with renal hypertension have proved valuable in predicting surgical curability of the underlying lesion. The upper limit of normal for the renal venous renin ratio in normotensive children without renal disease is 1.5. Pharmacological blockade of the RAA system has a place in diagnosis and treatment of hypertensive children. The plasma renin aldosterone profile is diagnostically useful in the investigation of salt-wasting disease and can easily distinguish between aldosterone biosynthetic defects and pseudohypoaldosteronism.

Pseudohypoaldosteronism

10 infants are described with pseudohypoaldosteronism, 5 in detail and a further 5 briefly. They all presented with hyperkalaemia, urinary salt-wasting disease, and ostensibly normal renal and adrenocortical function. Diagnosis was established by demonstrating the greatly increased values of plasma renin activity and plasma aldosterone concentration, plus the increased excretion of aldosterone and its metabolites on gas chromatographic and mass spectrometric analyses of urine. The children were treated with sodium chloride supplements, up to 60 mmol/day, but by the time most of the infants were about a year old these could be stopped. Exogenous mineralocorticoids were without effect in those to whom they were administered. The precise aetiology of the condition remains conjectural; lack of renal tubular response to aldosterone seems probable. Pseudohypoaldosteronism may be more common than has been thought and new techniques for investigating salt-wasting disorders may show its true incidence.

Hypertension in a four-year-old child: gas chromatographic and mass spectrometric evidence for deficient hepatic metabolism of steroids

A 4-yr-old boy with hypertension and hypokalaemic alkalosis had low plasma aldosterone levels and renin activity. The hypertension and hypokalemia responded to spironolactone and triamterene therapy. A partial response to dexamethasone was observed. Analysis of urinary steroid metabolites by gas chromatography-mass spectrometry showed that the excretion of metabolites of deoxycorticosterone and aldosterone was subnormal, and there was no evidence for sizeable excretion of unusual steroids with potential mineralocorticoid activity. The cortisol excretion rate, however, was subnormal, and the relative excretions of individual metabolites of this hormone were not typical. In particular, the excretion of tetrahydrocortisone was markedly reduced, and the excretions of allotetrahydrocortisol and free cortisol and metabolites were elevated. These findings suggest that modified or deficient metabolism of adrenal steroids could give rise to elevated blood pressure. It is not known whether the inappropriate production of unusual cortisol metabolites were responsbile for the high blood pressure or whether the altered metabolism is indicative of similar abnormality in the metabolism of other adrenal steroids, resulting in hyperproduction or extended half-life of minor but highly active mineralocorticoids of unknown structures.

Renal vein renin measurements in normotensive children

Renal venous PRA was measured in 49 normotensive children without renal disease undergoing routine cardiac catheterization. PRA levels did not differ significantly between both renal veins and were significantly higher in the renal veins than in the IVC. There was a constant mean ratio of 1.21 between the renal veins and the IVC at low, intermediate, and high absolute PRA levels. Three patients had a renal venous PRA ratio greater than 1.4 and the highest ratio observed was 1.55. This fidning supports 1.5 as an acceptable upper limit of normality for the interpretation of renal vein PRA ratios in the investigation of patients with suspected renal hypertension. In four patients, PRA in the renal veins was significantly lower than in the IVC. The possibility of renin removal by these kidneys is discussed.

Blindness and paraplegia in severe childhood hypertension

3 children with severe renal hypertension and bilateral infarction of the optic nerves are described. 1 patient also had a transverse myelopathy. Such complications may perhaps be prevented by earlier detection of hypertension and gradual reduction of blood-pressure.

Bartter's syndrome: 10 cases in childhood. Results of long-term indomethacin therapy

Ten children with Bartter's syndrome are described. Their ages at diagnosis ranged from three months to 15 years and there was an equal sex distribution. A wide spectrum of severity of clinical and biochemical features was found. Hypercalcaemia, hypophosphataemia, hypercalcuria, nephrocalcinosis, rickets and urine acidification defects were seen in some patients. Two affected children were siblings. Six children were treated over periods of six to 24 months with indomethacin with remarkable clinical and biochemical improvement. Catch-up growth was demonstrated in all treated cases. Tolerance to indomethacin appeared to develop in some children. Only one serious complication was seen with this therapy, a duodenal ulcer in a child on high dosage. Of those children not treated with indomethacin, one died, one is now on indomethacin elsewhere and two are well without therapy.

Clinical evaluation and comparison of the Infrasonde, Arteriosonde, and mercury sphygmomanometer in measurement of blood pressure in children

Both systolic and diastolic pressures can be measured in children with the mercury sphygmomanometer, the Arteriosonde and the Infrasonde. Estimates made blindly with these instruments were compared with directly measured intra-arterial blood pressures in 50 children aged between 4 days and 14 years. Systolic and diastolic estimates with the three techniques showed highly significant correlations with simultaneous intra-arterial measurements (P less than 0.001). The Infrasonde diastolic estimates were least satisfactory and the slope of the regression line against the intra-arterial pressure differed significantly from unity (y=0.54x+29.53). In 11 small children a satisfactory diastolic estimate could not be obtained with the mercury sphygmomanometer. While the mercury sphygmomanometer should remain the standard hospital equipment, an Arteriosonde would be valuable if it is difficult to hear Korotkoff's sounds on auscultation and if a diastolic pressure is required. For research investigations into childhood blood pressure an Arteriosonde or mercury sphygmomanometer, coupled with a device to exclude observer bias, is probably most suitable. Although the Infrasonde is not sufficiently accurate for research purposes, it is acceptable for routine ward use.

Malnutrition in infants receiving cult diets: a form of child abuse

Severe nutritional disorders, including kwashiorkor, marasmus, and rickets, were seen in four children and were due to parental food faddism, which should perhaps be regarded as a form of child abuse. All disorders were corrected with more normal diets and vitamin supplements. In view of the potentially serious consequences of restricted diets being fed to children, families at risk should be identified and acceptable nutritional advice given. When children are found to be suffering from undernutrition due to parental food faddism a court order will normally be a necessary step in providing adequate treatment and supervision.

'Epidemic neuromyasthenia' at the Hospital for Sick Children, Great Ormond Street, London

An outbreak of an illness with features in common with 'epidemic neuromyasthenia' affected the staff of the Hospital for Sick Children in London between August 1970 and January 1971. At least 145 cases were observed and the majority of these were nurses. Symptomatology was protean, clinical findings minimal and relapses frequent. Care was taken to minimize anxiety and fear in a vulnerable population, and laboratory investigations were purposefully limited in number for this reason. In general, laboratory findings, including virological investigations were negative. A high incidence of anti-complementary activity and the presence of ill defined aggregates in some acute sera on electron microscopy were interesting and possibly significant findings suggesting the presence of immune complexes. These findings, plus the ability of lymphocytes from some patients to proliferate in vitro, were thought to represent possible evidence of an infective process. Although no children were affected during the 1970 outbreak, it is interesting that seven children have recently been referred to the hospital with features compatible with 'epidemic neuromyasthenia'.

Renin and blood-pressure in children with renal scarring and vesicoureteric reflux

Plasma-renin-activity (P.R.A.) was raised in 9 of 15 hypertensive children with pyelonephritic scarring secondary to urinary-tract infection and vesicoureteric reflux and also in 8 of 100 normotensive children with such scars. P.R.A. was much less likely to fall with age in normotensive children with renal scarring than in normal children. The identification of hyperreninaemic normotensive children with renal scarring is important, since P.R.A. may prove to be of value in early identification of children at risk of developing hypertension. A longitudinal follow-up is proposed to establish this hypothesis.

Renal vein renin measurements in children with hypertension

Renal venous renin activity was measured in 50 children with hypertension. Main renal vein and segmental renal vein sampling was feasible in children as young as 15 months. In all cases in which there was a clear difference in renin secretion between the kidneys--that is, a main vein renin ratio above 1.5--surgery, when undertaken, successfully restored normal blood pressure. Most of the children with main renal vein renin ratios below 1.5 had bilateral disease or apparently normal kidneys. Segmental renal vein sampling contributed useful information additional to that provided by main renal vein measurements and permitted identification of local sources of renin production. In children with renal transplants who developed hypertension renal vein renin measurements helped in determining the cause and facilitating the management of the raised blood pressure.

Renin and aldosterone response in human newborns to acute change in blood volume

Increased activity of the renin/aldosterone system in the neonatal period is now well established in both animals and man but the control mechanisms are poorly understood. We have monitored the plasma renin activity (PRA) and plasma aldosterone concentration (PAldo) in 14 infants undergoing 21 exchange transfusions. PRA and PAldo were measured before and at 5, 10, 15, 30, 45, and 60 minutes after the injection, and 5, 10, 15, and 30 minutes after the withdrawal of 7 ml blood/kg birthweight immediately before exchange transfusions. PRA increased to a maximum of 53% and decreased to a maximum of 39% of the resting values after withdrawal or injection of blood respectively. PAldo values did not change significantly during the same period. Thus the renin-angiotensin system in the newborn infant is responsive to changes in blood volume.

Congenital adrenal hyperplasia: renin and steroid values during treatment

Plasma renin activity (PRA), aldosterone (Aldo), 17alpha-hydroxyprogesterone (17-OHP) and testosterone (T), together with urine sodium, pregnanetriol, 17-oxosteroids and the 11-oxygenation index (11-OH) were estimated in 23 patients (age 5.7--18 yrs.) with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency during glucocorticoid treatment. Elevated PRA levels (1400--17200 ng Al/l/hr) were found in 13 out of 15 patients with a history of salt loss. Three non-salt losers showed high PRA levels and in the remaining 5 the levels were in the upper normal range (540--900 ng Al/l/hr). Plasma Aldo levels were normal (25--620 pmol/l) in 18 patients and slightly elevated (690--2360 pmol/l) in 5. While these results indicate persistent impairment of sodium homeostasis in CAH patients, no significant correlations between log. PRA, log. Aldo and urinary sodium excretion were found. Mid-day 17-OHP levels ranged from 9 to 117 nmol/l and T from 0.3 to 18.0 nmol/l. Neither the 17-OHP nor the T results correlated well with the clinical assessment of therapeutic control. The results of the urinary steroid determinations showed better agreement with the clinical assessment of treatment and the 17-oxosteroid, pregnanetriol and 11-OH index results appeared to be better discriminants between good and poor control. Twelve of the patients with a history of early salt loss were reinvestigated after one month's treatment with oral 9 alpha-flurohydrocortisone (0.05 mg/day). PRA was reduced in 7 patients and 17-OHP fell in 10 patients. No consistent changes were found in Aldo, T, or urinary sodium and steroid excretion during this low-dose mineralocorticoid treatment.

Salt-losing syndrome in 2 infants with defective 18-dehydrogenation in aldosterone biosynthesis

Two infants presented with a salt-losing syndrome, the presenting features of which were subtle. One case appeared to be transient. Deficient production of aldosterone was shown by plasma renin activity and plasma aldosterone profile. Gas chromatography-mass spectrometry of urine indicated a defect in 18-dehydrogenation of 18-hydroxycorticosterone. Treatment with salt supplements and 9alpha-fludrocortisone reversed the salt-losing state and in one case treatment was later stopped. Although the disease may appear transient, the biochemical defect is persistent and for adequate growth a positive salt-balance is necessary.

Plasma renin activity and aldosterone concentration in the human newborn

Twenty-one healthy newborn infants whose mothers had normal pregnancies and deliveries were studied. Plasma renin activity (PRA) and plasma aldosterone concentration (PAldo) were measured by semimicro methods in cord blood and on the 6th day of life. PRA and PAldo were increased in cord blood compared with values previously found in healthy infants between 1 month and 1 year of age. There was a twofold reduction in both values by the 6th day. PRA and PAldo were positively correlated when cord blood and 6th-day values were considered as a whole, but no significant correlations were found between either cord blood PRA or cord blood PAldo and their respective values on the 6th day. The PRA and PAldo findings were not related to birthweight, the infant's sex, weight change, 6th-day urinary sodium, or blood pressure measurements. The type of milk feed did not influence PRA but PAldo was slightly greater in bottle-fed babies on the 6 day. These observations confirmed that the inverse relationship between PRA, PAldo, and age extends into the neonatal period but they suggest that the balance of factors controlling these variables at birth is different to that operating at the age of 6 days.

Plasma renin activity and aldosterone concentration in children

Using semi-micro methods, plasma renin activity (PRA) and plasma aldosterone concentration (PA) were measured concurrently in 79 healthy children aged 1 month to 15 years to establish a reference range. PRA and PA varied inversely with age. Eleven children with renal hypertension had higher PRA and PA than age-matched controls. In contrast, PRA was much greater in 38 saline-depleted children. PA was not uniformly increased in this group and was within the normal range in children with adrenal diseases compared with the high values seen in other salt-wasting states. The findings emphasise the need to relate data from patients to age-matched control values before attempting interpretation and suggest that sodium depletion is a more potent stimulator of renin-aldosterone release than renovascular disease or renal scarring in children. Plasma renin-aldosterone profiles were also valuable in discriminating between renal and adrenal causes of salt loss in childhood.