Biochemical vitamin K deficiency in early infancy: diagnostic limitation of conventional coagulation tests

Thrombotest, factor II and factor X determinations were performed in two groups of children, one receiving a low vitamin K diet (breast-feeding) and one receiving a high vitamin K regimen (formula-feeding). No infant received vitamin K at birth. Thrombotest values were found to be lower at day 30, 60 and 90 after birth, and factor II levels unexpectedly higher at day 30 and 60 in breast-feeding group compared to the formula-feeding group. No difference in factor X levels could be detected. Compared to the direct measurement of PIVKA II by a highly sensitive immunological method, these coagulation tests are inadequate to detect biochemical vitamin K deficiency.

Influence of the type of feeding on the presence of PIVKA-II in infants

PIVKA-II levels were studied by a highly sensitive immunological method in two groups of infants, breast-fed and bottle-fed, at the age of 4 days, 1 month, 2 months, and 3 months. PIVKA-II could be demonstrated in 9 infants after the age of 1 month when they were breast-fed. In none of the bottle-fed infants PIVKA-II was present during the same period. This significant difference can probably be explained by the lower vitamin K1 content of human milk compared to commercial formulas. The frequently occurring biochemical deficiency of vitamin K indicates the need of prophylactic administration of vitamin K to all newborns.

[Echography of the normal kidney in infants]

In 33 infants from 0 to 11 months old, apparently without urinary tract disease, the kidneys were examined sonographically. Renal length was correlated with age and bodyweight. The renal echopattern was studied: Normal kidneys in newborn and young infants have several distinct sonographic features: the renal cortex is more echogenic, the medullary pyramids are prominent and relatively anechoic, the central sinus echo is reduced. This pattern occurs until the age of 3 months and changes to the adult pattern at the age of 5 months.

[The enlarged kidney in infancy--echographic findings]

Experience in the use of ultrasound to evaluate renal masses during infancy is reported. Ultrasonography revealed hydronefrosis (20 cases), multicystic kidney (5 cases), polycystic kidney disease (3 cases) and neoplasm (4 cases). The differential diagnosis between hydronefrosis and multicystic kidney can be difficult. Hydronefrosis is diagnosed by the demonstration of communication between adjacent fluid-filled spaces.

A neurophysiological study of children with the cerebro-hepato-renal syndrome of Zellweger

The aim of this study was to describe the EEGs, brainstem auditory evoked potentials and somatosensory evoked potentials obtained in eleven children with the Zellweger syndrome. In six out of the eleven patients BAEPs and in five of them SSEPs were performed. Severe abnormalities could be demonstrated, reflecting diffuse cerebral dysfunction as well as long myelinated fiber tracts dysfunction. In four of six patients no response was obtained by BAEPs and in two the central conduction time was delayed. The specific (until 60 ms) and aspecific (after 60 ms) complex of the SSEPs was delayed or the potential could not be elicited. During sleep as well as wakefulness characteristic abnormalities of the EEGs were found in nine patients. These abnormalities consisted of continuous negative sharp waves and spikes at the vertex.

Platelet aggregating factor in the epidemic form of hemolytic-uremic syndrome in childhood

Plasma from six out of eleven children with the epidemic forms of hemolytic-uremic syndrome caused the aggregation of homologous platelets as has been described in thrombotic thrombocytopenic purpura. IgG purified from normal adults inhibited the platelet aggregation induced by plasma collected from three children during the acute phase of the disease. This inhibition by IgG may contribute to the reported successful management by infusions of plasma or plasma exchanges.

[Peroxisomes--in search of their function in man]

Peroxisomes are ubiquitous subcellular organelles present in eukaryotic cells. The limiting membrane is a single membrane consisting of a triple layered structure. An increasing number of enzymes are localized in the peroxisomes. The knowledge about fatty acid beta oxidation and glycerolipid biosynthesis has increased considerably. Aberration of the peroxisomal function have been demonstrated in acatalasemia, the cerebro-hepato-renal syndrome of Zellweger, hyperpipecolic acidemia, trihydroxycoprostanic acidemia and adrenoleukodystrophy. Other peroxisomal disorders will be detected in the near future.

Disturbed very long chain (C24-C26) fatty acid pattern in fibroblasts of patients with Zellweger's syndrome

The very long chain fatty acids in cultured fibroblasts from six patients with the cerebro-hepato-renal syndrome of Zellweger, from six of their parents, from three controls, and also in three amniotic fluid control cell lines were analysed by gas chromatography. Increased concentrations of hexacosanoic acid (C26:O) were consistently found in the Zellweger syndrome. Also the ratios C26:O/C22:O, C25:O/C22:O, and C24:O/C22:O were elevated. The very long chain fatty acid levels and ratios in fibroblasts from the patients' parents were within the normal range. Findings in amniotic fluid cell lines indicate the possibility of antenatal diagnosis for Zellweger's syndrome. The similarities between neonatal adrenoleukodystrophy and Zellweger's syndrome suggest the applicability of this technique also in neonatal adrenoleukodystrophy.

Pipecolic acid levels in serum and urine from neonates and normal infants: comparison with values reported in Zellweger syndrome

Pipecolic acid (PA) excretion from normal newborn, preterm and/or small-for-dates infants has been determined and correlated with gestational age, sex and age after birth. An effect of fetal sex was not detectable. Only small-for-dates infants with a gestational age of greater than 34-37 weeks had a lower urinary excretion of PA than the appropriate-for-dates infants with the same gestational age. Preterm infants had a higher excretion of PA than term neonates. PA excretion of infants decreases with age after birth. This higher excretion in "younger" infants can be explained by a higher serum concentration and less efficient tubular reabsorption. PA level in serum and urine remains a valuable tool for the confirmation of the clinical diagnosis of Zellweger syndrome when gestational age and age after birth are taken into consideration. No PA was detected in serum or urine of four children suffering from hyperthyroidism.

Disturbed adrenocortical function in cerebro-hepato-renal syndrome of Zellweger

An ACTH stimulation test was performed in six patients suffering from the cerebro-hepato-renal syndrome of Zellweger. In contrast to controls, no rise in cortisol was observed. None of these patients showed clinical symptoms of adrenal insufficiency. The sudden death, which occurs in this syndrome, can probably be explained by an impaired stress reaction. In stress situations, such as respiratory infection, corticosteroids should be administered to these patients. A striking resemblance exists between the Zwellweger syndrome and the neonatal form of adrenoleukodystrophy.

The renin-angiotensin-aldosterone system in infancy and childhood in basal conditions and after stimulation

Plasma renin activity (PRA), aldosterone (PA), sodium and potassium concentration were measured in 107 healthy infants and children under basal conditions of normal diet and recumbency. Urinary aldosterone (UAldo), sodium and potassium were also measured (n = 51). A significant (P less than 0.001) age-related decrease in PRA (r = -0.67), PA (r = -0.67), UAldo (r = -0.56) was observed, with a striking scatter of values especially in infancy. The reninangiotensin-aldosterone system (RAAS) was also studied after stimulation by standardised sodium restriction during 4 days, followed by acute postural change (n = 40). After salt restriction a rise of PRA and UAldo was noted, but a rise in PA could not be demonstrated in children aged 0-6 months. The influence of postural change on the RAAS seems more important in older children. The reported values not only in basal but also in stimulated conditions allow study of the RAAS in diseases such as salt loss and hypertension.

The basal levels of active and inactive plasma renin concentration in infancy and childhood

Basal plasma renin activity, active and inactive plasma renin concentration were measured in 89 healthy recumbent children aged between 1 week and 16 years. A significant (P less than 0.001) age-related decrease for active (r = -0.60), inactive (r = -0.59) and total renin concentration (r = -0.66) was observed. After correction for the influence of age, active renin concentration correlated with plasma renin activity (r = 0.81), but not with inactive renin concentration (r = 0.18). The proportions of active and inactive renin were not related to age, and the overall percentage of inactive renin was 79%.

[Pseudohypoaldosteronism: a special form of sodium loss in infancy]

An infant with urinary sodium wasting is described. The plasma renin activity and plasma aldosterone concentration were distinctly raised. Administering DOCA was without effect. The condition pseudohypoaldosteronism is due to renal tubular unresponsiveness to endogenous aldosterone and can be adequately treated by salt replacement.

[Role of intravascular coagulation in the pathophysiology of the hemolytic-uremic syndrome]

Endothelial cell injury of capillaries and arterioles is considered to be the primary event in the hemolytic uremic syndrome. Intravascular coagulation increases the damaging processes. This intravascular coagulation can still be active after admission to the clinic. Several new data are available: prostacyclin deficiency can be present possibly due to the absence of a stimulating factor in plasma; the platelets are exhausted; an inhibitor of glomerular fibrinolysis has been demonstrated. A generally accepted therapy for HUS is still lacking.

Response to indomethacin and hydrochlorothiazide in nephrogenic diabetes insipidus

Four boys with classical nephrogenic diabetes insipidus have been treated by indomethacin, by hydrochlorothiazide, and by the combination of indomethacin and hydrochlorothiazide. Hydrochlorothiazide treatment was slightly more effective than indomethacin treatment in reducing the urine volume and increasing the urine osmolality. The combination of indomethacin and hydrochlorothiazide appeared to be additive and especially helpful in infants and young children before the autonomy of drinking.

Renin disappearance rate in puppies

The disappearance rate of endogenous renin from the circulating blood after bilateral nephrectomy was studied in 4 puppies aged 16-21 days. Mean half-times of the fast and slow component of the disappearance curves of renin were 9.15 min +/- 0.87 (SD) and 84.0 min +/- 16.8 (SD), respectively. These values are not different from the values reported for adult dogs in the literature. The metabolic degradation of renin is not different between young and adult dogs and does not contribute to the elevated plasma renin activity in the puppy.

Renal disorders in the branchio-oto-renal syndrome

Intravenous urography and measurements of renal function were performed in 16 patients suffering from branchio-oto-renal syndrome. Malformations were visible by intravenous urography in all patients. Four out of 16 patients had a diminished glomerular filtration rate. Renal histology available in two patients revealed oligomeganephronic renal hypoplasia and multicystic dysplasia, respectively. Without renal agenesis or severe renal hypoplasia or dysplasia present in early infancy, renal abnormality does not seem to be a progressive disorder.

Levels of renin, angiotensin I and II, angiotensin-converting enzyme and aldosterone in infancy and childhood

Basal plasma renin activity (PRA), angiotensin I and II (AI, AII), angiotensin-converting enzyme (ACE) activity and plasma aldosterone (PA) and sodium and potassium concentration were simultaneously measured in 55 healthy recumbent children aged between 1 week and 13 years. A significant (P less than 0.001) age-related decrease for PRA (r = -0.73), AI (r = -0.72), AII (r = -0.51) and PA (r = -0.71) was observed but not for ACE (r = 0.26, P = 0.06). After correction for age the correlation between PRA or PA and AI or AII was still significant (P less than 0.005). The strong correlation between AI and AII in the group as a whole (r = 0.82, P less than 0.001) and also in separate age groups, and an AI to AII ratio which was not different between the various age groups suggest that ACE activity in this age range is not rate-limiting for AII generation.

Influence of the stress of venepuncture on basal levels of plasma renin activity in infants and children

The influence of venepuncture on plasma renin activity (PRA), cortisol, and serum noradrenaline and adrenaline concentration in infants and children was evaluated by comparing values obtained immediately on insertion of an indwelling intravenous line (venepuncture value) and 5 and 60 minutes later. PRA values 5 min after venepuncture in the total group of infants and children were significantly higher (P less than 0.001) than venepuncture values. There was no significant difference between PRA values at 60 min compared to venepuncture or 5 min values. A well performed venepuncture does not systematically affect the PRA values obtained. A significant difference between values for noradrenaline, adrenaline and cortisol at the various points of time could not be demonstrated. The number of lower values for noradrenaline and adrenaline at 60 min, however, prevailed. The stress of a well performed venepuncture is not an explanation for the greater scatter of basal PRA levels in infants and young children.

[A child with Zellweger's cerebrohepatorenal syndrome]

A child suffering from the cerebro-hepato-renal syndrome of Zellweger is presented. The clinical features are hypotonia, slow or absent feeding, profound psychomotor retardation, severe impairment of hearing, disturbed visual acuity and a characteristic facial appearance including high forehead and large fontanels. The biochemical abnormalities are disturbed liver function tests, increased concentration of pipecolic acid in serum, cerebrospinal fluid and urine, di- and trihydroxycoprostanic acid detectable in bile, serum and urine and an increased excretion of para-hydroxy-phenyllactate in urine.

Hyporeninemic hypoaldosteronism in infancy

Hyporeninemic hypoaldosteronism was observed in an infant at the age of 3 months. Persistent hyperkalemia, hyperchloremic acidosis and salt wasting were present. All abnormal electrolyte values were corrected by the administration of fludrocortisone. Both active and inactive renin were lowered. This infant had also an unexplained spastic quadriplegia and psychomotor retardation. Hyporeninemic hypoaldosteronism should be considered to be one of the causes of salt-losing in infancy.

Cerebro-hepato-renal syndrome of Zellweger: clinical symptoms and relevant laboratory findings in 16 patients

The clinical features of 16 patients suffering from cerebro-hepato-renal syndrome are presented. Five of these children lived beyond 2 years. Four of them are still alive. The increase of pipecolic acid in serum and cerebrospinal fluid (CSF), the abnormality of the bile acids and the increased excretion of p-OH-phenyl lactate were a consistent finding. The concentration of pipecolic acid in urine was not always distinctly elevated. A loading test with DL-pipecolic acid was always abnormal.