HYPERCALCEMIA in CHILDREN Smaranda Diaconescu, Nicoleta Gimiga, Claudia Olaru*, Marin Burlea “Grigore T
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RomanianJournalofOralRehabilitation Vol.6,No.3,JulyͲSeptember2014 HYPERCALCEMIA IN CHILDREN Smaranda Diaconescu, Nicoleta Gimiga, Claudia Olaru*, Marin Burlea “Grigore T. Popa" University of Medicine and Pharmacy - Ia܈i, Romania, Faculty of Medicine, Vth Pediatric Clinic, "Sf. Maria" Children's Hospital *Corresponding author: Claudia Olaru, MD, PhD Student “Grigore T. Popa" University of Medicine and Pharmacy - Ia܈i, Romania; e-mail: [email protected] ABSTRACT Hypercalcemia is less common in children than in adults, but is more likely to be clinically significant in younger patients as routine biochemical screening tests are rarely performed in children. The serum calcium levels are maintained through the interplay of parathyroid, renal, and skeletal factors. The most common causes of hypercalcemia are primary (hyperparathyroidism or cancer) but a variety of unusual etiologies must be considered in children. The initial approach to the medical treatment of severe or symptomatic hypercalcemia is to increase the urinary excretion of calcium. In most cases, hypercalcemia is due osteoclastic bone resorption, and the effective treatment is based on agents that inhibit or destroy osteoclasts . Parathyroid surgery is recommended for all children with primary hyperparathyroidism. Keywords: hypercalcemia, pediatrics, parathyroid Hypercalcemia is not a common pediatric regulatory hormones [2]. The three problem; the actual incidence in children is predominant sources of calcium and targets unknown, although it is less common than in for regulation are the bones, renal filtration adults. In adults, hypercalcemia is the primary and reabsorption, and intestinal absorption. malignancy-associated endocrine/electrolyte The major regulators of calcium levels are disorder; it is present in 5% of all parathyroid hormone (PTH) and vitamin D, malignancies, or in 15 per 100,000 total which target the bones, intestine, and kidney patients [1]. The normal values of blood to increase serum calcium. Calcitonin, a more calcium in children varies from 8.5 to 10.3 minor player in regulation, decreases serum mg%. Hypercalcemia is considered, calcium by its effects on bone and kidney. depending on age, at the following values: premature -> 9 mg%, term newborn -> 10, 4 Etiology mg%, child / adolescent -> 10.4 mg% . Most Hypercalcemia is caused by either primary of the body calcium (98% is in the skeleton hyperparathyroidism or cancer in over 90% of and only 2% is in circulation; half of this one cases. The rest of the etiologies are numerous. is free calcium (ionized) Ca++, (2)Primary hyperparathyroidism is a physiologically active. 1% is fastened to the pathologic and unregulated excess of PTH rest of the serum proteins. Calcium leading to elevated calcium. Malignancy is absorption and regulation involve a complex the most common cause of hypercalcemia interplay between multiple organ systems and that leads to inpatient care. Other less 91 RomanianJournalofOralRehabilitation Vol.6,No.3,JulyͲSeptember2014 frequent etiologies are bone diseases, determining the etiology may be more granulomatous conditions, and diet. In the important than the electrolyte imbalance case of malignancy or granulomatous disease, itself. Table 1. Calcium physiology Hormone Efect Bone Gut Kidney Ca reabsorbtion PTH K Ca L Po4 K Osteoclasts Indirect / Vit. D Po4 excretion K Ca K Po4 Vitamin D3 K Ca K Po4 Indirect action Indirect action absorbtion Inhibate Calcitonin L Ca L Po4 Indirect action Ca and Po4 excretion osteoclasts Hyperparathyroidism: rare instances a parathyroid carcinoma may Primary hyperparathyroidism ranges in account for the condition. severity from very mild and asymptomatic, to Less common etiologies: severe disease complicated by the Vitamin D is a fat-soluble vitamin that consequences of bone loss, including can become toxic when excessive amounts fractures and osteitis fibrosa cystica (von are taken in over time. Self-dosing or is the Recklinghausen disease). Tertiary usual cause. Overdosing with 1,alpha- hyperparathyroidism occurs in chronic renal hydroxylated vitamin D metabolites failure. (alfacalcidol or calcitriol) can easily result in Malignancy: hypercalcemia and chronic administration Hypercalcemia may be associated with must be avoided or carefully monitored. malignancies in two ways: bony involvement Exaggerated supplementation with over-the- by the tumor may lead to massive osteoclastic counter products can also readily and activity (osteolytic lesions) when the calcium frequently lead to hypercalcemia. Vitamin D flux simply overwhelms homeostatic is also elevated in granulomatous disease mechanisms; a variety of tumors release such as sarcoidosis, berylliosis, tuberculosis. PTH-related peptide acting on PTH receptors The mechanism is enhanced conversion of [3]. From 25% to 30% of patients with cancer vitamin D by macrophages. Endocrine will develop hypercalcemia at some point diseases such as hyperthyroidism can lead to over the course of their disease. Common hypercalcemia and almost always malignancies that can lead to hypercalcemia hypercalciuria as a consequence of rapid bone include: multiple myeloma, leukemia, lung turnover; another pathologic conditions are and breast cancer. When malignancies cause adrenal insufficiency, pheochromocytoma, hypercalcemia, the tumor is typically very acromegaly. Iatrogenic causes includes advanced. Malignancies which produce milk-alkali syndrome caused by excess hypercalcemia may be associated with dietary milk or alkali (e.g., because of multiple endocrine neoplasia (MEN) type 1 dyspepsia) or excess calcium supplementation and MEN type 2a or isolated familial (e.g., in postmenopausal women) [4]. Other hyperparathyroidism. There is an association drugs are lithium and vitamin A derivates, of primary hyperparathyroidism with used for acne treatment and thiazides that neurofibromatosis and von Hippel-Landau. In affect renal mechanisms and rapid bone 92 RomanianJournalofOralRehabilitation Vol.6,No.3,JulyͲSeptember2014 turnover, thus both causing hypercalcemia transient hypercalcaemia. that reverses when the drugs are stopped. Immobilization in adolescents and young Clinical presentation people (Paget disease) causes massive bone First, the clinician should take a history demineralization and hypercalcemia. Older detailing any bone pain to suggest patients can also be subject to this problem, malignancy in metastatic locations of the long but the robust state of bone mineralization in bones. A history of weight loss would young people means there is a much larger identify malignancy more likely than mobile calcium pool to create and sustain the hyperparathyroidism. History may also hypercalcemia. Excess bone metabolism of identify symptoms of high calcium such as any etiology can lead to hypercalcemia. renal stones (typical of hyperparathyroidism, Congenital causes: familial hypocalciuric lethargy), easy fatigue, confusion, depression, hypercalcemia can be confused with irritability, constipation, and hypercalcemia due to hyperparathyroidism as polyuria/polydipsia. Classic GI symptoms abnormal calcium sensing in the parathyroid may also be present (nausea, vomiting, glands and kidneys leads to mild elevation of abdominal pain, peptic ulcer, pancreatitis). PTH and reduced calcium excretion. Chronic symptoms are more consistent with Williams syndrome - is a rare hyperparathyroidism, whereas more recent neurodevelopmental disorder characterized onset of symptoms suggests malignancy. by a distinctive, "elfin" facial appearance, Symptoms from calcium elevation are along with a low nasal bridge, an unusually typically not found unless the calcium is cheerful demeanor and ease with strangers; above 12 mg/deciliter. Severe symptoms and developmental delay coupled with strong coma are likely to appear when calcium gets language skills and cardiovascular problems, above 13 mg/deciliter [5, 6]. such as supravalvular aortic stenosis and Table 2. Clinical signs of Hypercalcemia Renal symptoms Nervous system Cardiac symptoms GI system Musculoskeletal system Renal stones CNS depressyon QT shortening Gastritis Arthralgia Polyuria Decreased reflexes Sinus tahycardia Pancreatitis Bone pain Nycturia Ventricular Constipation Spontaneous fractures Hematuria extrasystoles Anorexia Laboratory data plasma total calcium should be 8.5 to 10.5 The most common causes of mg/dl and the ionized calcium should be 4.6 hypercalcemia are primary to 5.1 mg/dl. The PTH is elevated in primary hyperparathyroidism and malignancy, hyperparathyroidism, despite elevated together accounting for 90% of cases. They calcium indicating a disconnect between the can be distinguished by ordering a serum regulating hormone and the ion regulated. In PTH level and a simultaneous repeat calcium malignancy, calcium is elevated either due to test. Total serum calcium is usually a humoral abnormality with a PTH-related satisfactory but if there is an elevated or peptide or due to bone destruction in markedly depressed plasma protein metastases. In cases of malignancy, the PTH concentration, the physiologically important might even be very low or barely detectable fraction is ionized calcium. Normal serum or since the elevated calcium should inhibit PTH 93 RomanianJournalofOralRehabilitation Vol.6,No.3,JulyͲSeptember2014 secretion. Hypercalcemia Medication IͲPTH PTHrP IͲPTH PTHrP High/N Low Low High Low/N Low/N Primary Vit.D PTHrP Urinary 1,25 Endocrinolog hyperparathyroid intoxication, calcium24h dihydroxyvita ical ism Malignancy, MilkͲalkali minD Figure 1.