Chronic vitamin A intoxication. A multisystem disease that could reach epidemic proportions

Nutrition in children with exocrine pancreatic insufficiency

Exocrine pancreatic insufficiency (EPI) is a condition defined as pancreatic loss of exocrine function, including decreased digestive enzymes and bicarbonate secretion, which leads to maldigestion and malabsorption of nutrients. It is a common complication in many pancreatic disorders. If left undiagnosed, EPI can cause poor digestion of food, chronic diarrhea, severe malnutrition and related complications. Nutritional status and fat-soluble vitamins should be carefully assessed and monitored in patients with EPI. Early diagnosis of EPI is clinically important for appropriate nutritional support and initiating pancreatic enzyme replacement therapy (PERT) which could significantly improve patient outcomes. The evaluation of nutritional status and related unique management in children with EPI will be discussed in this review.

Role of Vitamin A in the Immune System

Vitamin A (VitA) is a micronutrient that is crucial for maintaining vision, promoting growth and development, and protecting epithelium and mucus integrity in the body. VitA is known as an anti-inflammation vitamin because of its critical role in enhancing immune function. VitA is involved in the development of the immune system and plays regulatory roles in cellular immune responses and humoral immune processes. VitA has demonstrated a therapeutic effect in the treatment of various infectious diseases. To better understand the relationship between nutrition and the immune system, the authors review recent literature about VitA in immunity research and briefly introduce the clinical application of VitA in the treatment of several infectious diseases.

Hypercalcaemia secondary to hypervitaminosis a in a patient with chronic renal failure

Vitamin A toxicity is a well-described medical condition with a multitude of potential presenting signs and symptoms. It can be divided into acute and chronic toxicity. Serum vitamin A concentrations are raised in chronic renal failure even with ingestion of less than the usual toxic doses. Hypercalcaemia can occasionally be associated with high levels of vitamin A but it is rare. In this report, we describe a 67- year old female patient with chronic kidney disease who was taking vitamin A supplements for approximately 10 years. The patient had worsening of her chronic kidney disease over the last years and developed chronic hypercalcaemia. Her vitamin A level was elevated with a daily intake of 7000 IU. The vitamin A supplement was stopped. A few months later, vitamin A level diminished substantially and serum calcium levels returned to normal.

The use of vitamin A-deficient diets and jugular vein ligation to increase intracranial pressure in chickens (Gallus gallus)

A technique was developed to record intracranial cerebrospinal fluid pressure (iCSFp) in chicks and mature chickens. Using that procedure, 2 methods were found to effect a significant elevation in intracranial pressure: 1) feeding a purified diet to roosters for 40 d containing 25% of the bird's requirement for vitamin A, and 2) ligating both jugular veins in birds. The purified diet significantly reduced plasma retinol levels from 1.080 to 0.046 microg/mL, and iCSFp was significantly elevated from 63.0 to 106.0 mmH2O (P < or = 0.05). Two limitations for using hypovitaminosis A diets were capillary fragility and a cisterna magna that did not develop to the size of that structure in birds of the same age fed control diets with adequate vitamin A content. The second procedure, a reversible surgical technique, showed that within 2.5 h from jugular vein ligation, intracranial pressure rose to 109.7 mmH2O, comparable with levels attained following feeding a vitamin A deficient diet to roosters. Bilateral clamping of the jugular veins overnight resulted in an elevation of iCSFp to 127 +/- 8.86 mmH2O. Results suggest that the chicken may be a useful animal model to investigate intracranial hypertension and its accompanying headaches known to occur in humans.

Hypercalcemia caused by iatrogenic hypervitaminosis A

Vitamin A toxicity produces protean clinical manifestations involving a wide variety of tissues and systems. Hypercalcemia can occasionally be associated with high vitamin A levels, but is rare. In this report we describe a patient who was receiving a commercially prepared enteral feeding formula for 2 years. He developed asymptomatic hypercalcemia and had serum vitamin A levels several fold above normal. Subsequently, a custom-made enteral feed was used which contained negligible amounts of vitamin A. Several months later, vitamin A levels diminished substantially and serum calcium levels returned to normal.

High serum retinyl esters are not associated with reduced bone mineral density in the Third National Health And Nutrition Examination Survey, 1988-1994

Hypervitaminosis A is sometimes associated with abnormalities of calcium metabolism and bone mineral status. A recent study found a negative association between reported dietary vitamin A intake and bone mineral density (BMD). Some segments of the U.S. population have high fasting serum retinyl ester concentrations, a physiological marker that may reflect high and possibly excessive vitamin A intake. We examined the association between fasting serum retinyl esters and BMD in the Third National Health and Nutrition Examination Survey, 1988-1994 (NHANES III), a large, nationally representative sample of the U.S. population. BMD was measured for the femoral neck, trochanter, intertrochanter, and total hip on all nonpregnant participants aged > or = 20 years; 5,790 participants also had complete data on fasting serum retinyl esters and covariates including age, body mass index (BMI), smoking, alcohol consumption, dietary supplement use, diabetes, physical activity, and, among women, parity, menopausal status, and the use of oral contraceptives or estrogen-replacement therapy. The sample included non-Hispanic white, non-Hispanic black, and Mexican American men and women. We examined the association between fasting serum retinyl esters and BMD at each site, controlling for covariates with multiple linear regression. We examined the association with osteopenia and osteoporosis with multiple logistic regression. Although the prevalences of high fasting serum retinyl esters concentration and low BMD were both substantial in this sample, there were no significant associations between fasting serum retinyl esters and any measure of bone mineral status.

[Vitamin A poisoning revealed by hypercalcemia in a child with kidney failure]

BACKGROUND

Patients with chronic renal failure are at risk of vitamin A intoxication, a risk that must be evoked when unexplained hypercalcemia occurs.

CASE REPORT

An 8 year-old boy with Alagille syndrome and chronic renal failure was admitted because of general deterioration, and bone pain. Severe hypercalcemia (3.9 mmol/L) was present. Serum phosphate, parathyroid hormone and 25 OH D3 levels were normal; 1-25 (OH)2 D3 levels were undetectable. Hypercalcemia was attributed to vitamin A intoxication, due to the administration of a mean daily dose of 12000 IU of vitamin A for at least 2 years. The diagnosis was confirmed by high plasma levels of retinol (1475 micrograms/L). Hypercalcemia only partially responded to treatment with bisphosphonates, calcitonin and dialysis with low calcium dialysate. Serum vitamin A levels remained elevated one month after vitamin A withdrawal. The boy died two months after admission from atrioventricular block.

CONCLUSION

Vitamin A administration induces a high risk of intoxication in patients with chronic renal failure. Serum vitamin A concentrations are elevated in these patients, because of decreased renal metabolism of retinol, and vitamin A supplements must be avoided.

Retinoic acid induces osteoclast-like cell formation by directly acting on hemopoietic blast cells and stimulates osteopontin mRNA expression in isolated osteoclasts

Although retinoic acid (RA) has been considered to be a bone-resorbing agent both in vivo and in vitro, its mechanism remains still unclear. The present study was performed to examine the effect of RA on osteoclast-like cell formation in the presence or absence of osteoblasts and to study whether RA would affect osteopontin mRNA expression in isolated rabbit osteoclasts. RA (10(-8) and 10(-6) M) significantly stimulated the formation of osteoclast-like cell in osteoblast-containing mouse bone cell cultures. Also, RA caused a stimulation of osteoclast-like cell formation from hemopoietic blast cells supported by granulocyte macrophage-colony stimulating factor (GM-CSF) in mouse spleen cell cultures. However, RA did not affect blast cell number in these cultures and significantly inhibited GM-CSF-stimulated proliferation of hemopoietic blast cells. On the other hand, RA stimulated the bone-resorbing activity of mature osteoclasts in mouse bone cell cultures. Moreover, RA caused a stimulation of osteopontin mRNA expression in isolated rabbit osteoclasts. The present study demonstrated for the first time that RA stimulated osteoclast-like cell formation, presumably through directly acting on the hemopoietic blast cells, and that RA stimulated osteopontin mRNA expression in isolated rabbit osteoclasts.

Liver damage caused by therapeutic vitamin A administration: estimate of dose-related toxicity in 41 cases

Clinical presentation, changes in liver function test results, and liver morphology were examined in 41 consecutive patients with vitamin A hepatoxicity. The cause of liver disease was suspected at initial interview in only 13 instances, whereas histological evidence of fat-storing cell hyperplasia with fluorescent vacuoles led to the diagnosis in the remaining cases. Cirrhosis was found in 17, mild chronic hepatitis in 10, noncirrhotic portal hypertension in 5, and "increased storage" alone in 9 cases. During a mean follow-up period of 4.6 years, 6 patients died of causes related to the liver disease. A precise appraisal of drug consumption was obtained in 29 cases. Among them the total cumulative intake was the highest in patients with cirrhosis (423 +/- 103 x 10(6) IU) and significantly lower in those with noncirrhotic liver disease (88.5 +/- 41; P less than 0.02). The smallest continuous daily consumption leading to cirrhosis was 25,000 IU during 6 years, whereas higher daily doses (greater than or equal to 100,000 IU) taken during 21/2 years resulted in similar histological lesions. It was concluded that at least in some western countries chronic vitamin A consumption might represent an appreciable cause of chronic liver disease, the recognition of which mainly relies on expert liver biopsy interpretation. The data also indicate that prolonged and continuous consumption of doses in the low "therapeutic" range can result in life-threatening liver damage.

Gout and vitamin A intoxication: is there a connection?

Several lines of indirect evidence implicate vitamin A intoxication, associated mainly with impaired renal function, in the etiopathogenesis of gouty arthritis. The enzyme xanthine oxidase is involved not only in the conversion of xanthine to uric acid but also in that of retinol to its more toxic metabolite, retinoic acid. Retinoic acid should therefore be present in high concentration in hyperuricemic states.

Comparative assessment of the toxicology of vitamin A and retinoids in man

As the title implies, any assessment of the toxic effects of vitamin A derivatives must distinguish between vitamin A in the truest sense, i.e. retinol, and retinoic acid and its synthetic derivatives. Just as no single description is universally applicable to the mode of action of vitamin A derivatives, so too do their toxic effects defy generalization. The recommendation made in 1982 by IUPAC [Eur. J. Biochem., 129 (1989) 1] to designate all derivatives with the typical structure of the vitamin as being retinoids may be chemically logical and correct but, when it comes to describing the effects and side-effects of vitamin A derivatives, it leads to misunderstandings. Retinol, which is frequently used as synonym for vitamin A, can eliminate all symptoms of vitamin A deficiency if it is taken in sufficient quantity with the diet. The term retinol will therefore be used here as a synonym for vitamin A whereas retinoic acid and its derivatives--including the synthetic ones--will be referred to as retinoids because they do not cover the whole spectrum of effects exerted by retinol and because they also vary markedly in their side-effects. In contrast to the nomenclature proposed by IUPAC, this system provides a clear and logical distinction for describing biological processes. Other authors have favoured it in recent times [Chytil, F., J. Am. Acad. Dermatol., 15 (1986) 741; Olson, J.A., Semin. Oncol., x (3) (1983) 290; Olson, J.A., Am. J. Clin. Nutr., 45 (1987) 704; Zbinden, G., Acta Dermatovener., 74 (1975) 36]. By vitamin A, therefore, is meant all derivatives that can possibly originate from retinol in the organism. This also covers the small quantities of retinoic acid formed from retinol. On the other hand, by retinoids is meant the natural retinoic acid derivatives and their synthetic forms in their special modes of action. Since retinoic acid cannot be reduced to retinol in the organism, this nomenclature provides a clear demarcation within the biological system. Vitamin A is essential to the growth and development of higher life forms and functions in many different ways within the organism. Although vitamin A was one of the first vitamins to be described, even today there is still some uncertainty as to its mode of action, with the exception of that of retinal (vitamin A aldehyde) in vision.(ABSTRACT TRUNCATED AT 400 WORDS)

Systemic lupus erythematosus, renal disease, hemodialysis and vitamin A

Recent studies indicate that clinically-active systemic lupus erythematosus (SLE) is uncommon in patients with end-stage renal disease undergoing long-term hemodialysis. Several lines of indirect evidence suggest that the dialysis procedure itself may be responsible for inducing remission; that SLE could reflect a toxicity reaction to excessive tissue levels of vitamin A; and that remission associated with dialysis may be due to a gradual reduction in vitamin A levels at the sites of SLE activity.

Freeze-replica study of lipid droplets in the Ito cells of rat liver

The structure of lipid droplets in the Ito cells was studied by the freeze-replica method in vitamin A-treated rats. Most lipid droplets were fractured in planes through their lipid contents. Some of them were surrounded by a membrane structure that had intramembranous particles (IMP), which were more numerous on the protoplasmic face than the exoplasmic face. Those with the membrane containing IMP correspond to the membrane-bounded lipid droplets (lipid droplets surrounded by lysosomes) seen in the electron microscopic observation of conventional thin section preparations. There were no lipid droplets showing concave or convex multilayered structures in the Ito cells from properly fixed livers. Since these multilayered structures were observed only in the materials fixed by immersion with glutaraldehyde or fixed 40 minutes after the death of animals, it is likely that they represent an artifact, showing an autolytic change, caused by poor fixation or postmortem change.

Limb pain in childhood

As the presenting complaint in 7 per cent of pediatrician visits, pain in the limbs is a common problem in childhood. It is important that the diagnosis be made expeditiously. The authors review the possible organic cause of limb pain, as well as limb pain from conversion reactions and from growing pains, giving special attention to the differential diagnosis so that appropriate treatment for the pain can be initiated.

Food faddism in pediatrics

An understanding of the nutritional requirements of healthy, growing infants and children is required to guide parents in appropriate feeding practices which are consistent with their chosen life styles. Among the several prevalent types of food faddism are some that are not harmful or can beneficial, such as breast-feeding, others than can be of long-term benefit but that have limitations in infants and children, and others that can affect infants and children adversely. Those wishing to feed their children unconventional diets should have such diets carefully evaluated to avoid deficiencies of essential nutrients.

Value of computerized dietary analysis in pediatric nutrition: an analysis of 147 patients

A computerized dietary analysis program was used in an ambulatory setting to assess adequacy of intake and alterations in a variety of dietary constituents. A TRS-80 microcomputer was programmed using 1980 National Academy of Sciences Recommended Dietary Allowances. Seventy-two hour dietary intakes of 147 patients were analyzed for average intake of 13 nutrients, nutrients per kilogram body weight, comparison with 1980 RDA, and percent of total calories as carbohydrate, fat, and protein. Six groups were studied, including patients with failure to thrive without diarrhea, with diarrhea without malabsorption, with diarrhea with malabsorption, with cystic fibrosis, and with constipation, and controls. A wide range of values for different dietary constituents was found in all groups and in individual patients. This program is an easy, practical, and rapid method for analyzing dietary intake, and can be used to screen for a variety of nutritional disorders.

Vitamin A: evidence for its preventive role in human cancer

Both the provitamin beta-carotene and natural vitamin A and its derivatives (the retinoids) are being proposed as potential chemopreventive agents. The biochemistry and pharmacology of vitamin A suggest a number of mechanisms whereby carcinogenesis can be affected. Epidemiologic studies have consistently demonstrated an increased relative risk of cancer for people with low vitamin A intake or low-to-normal serum retinol values. Chemoprevention trials in humans are only now beginning. In the interim, daily consumption of vitamin-A-containing foods may be a "prescription" worth following.