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Indian Pediatr 2013;50: 429-430 |
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Vitamin D Intoxication: Too Much of a Good
Thing!
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Meenakshi Bothra and Vandana Jain
Division of Pediatric Endocrinology, Department of
Pediatrics, All India Institute of Medical Sciences,
Ansari Nagar, New Delhi, India,
Email: [email protected]
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Vitamin D deficiency is common among Indian children [1].
The recommended therapy for vitamin D deficiency rickets is
1,00,000–6,00,000 IU [2]. The increasing awareness about
beneficial effects of vitamin D has led to an increase in
its prescription [3]. However, one needs to be cautious
while prescribing vitamin D, as overdose can lead to severe
hypercalcemia.
We present the case of an 18-month-old
girl, referred with lethargy and vomiting for 10 days, and
polyuria for 5 days. She was noticed to have bowing of legs
3 months ago, and diagnosed to have rickets. Her 25-hydroxy
D 3 level was
37.5 nmol/L (normal: 75-250 nmol/L). She was started on oral
calcium and cholecalciferol 60,000 IU per day, for 6 weeks.
In follow-up, the prescription was repeated for another 6
weeks. Meanwhile, the parents consulted another practitioner
for the ‘persistent’ bowing, who administered 6 lakh IU
vitamin D3 intramuscularly. The cumulative dose of vitamin D
received by her was nearly ten times the therapeutic dose.
At presentation, the child was irritable
and dehydrated, with BP of 136/94. Serum ionized calcium was
2.83 mmol/L, total calcium 20 mg/dL (normal: 9-11 mg/dL),
phosphate 2.63 mg/dL (normal 2.5-4.5 mg/dL), alkaline
phosphatase 513 IU/ L (normal 240-840 IU/L), 25-hydroxy D 3
> 3500 nmol/L and parathormone level 23.48 pg/mL. Renal and
liver function tests were normal. Urinary calcium/creatinine
ratio was 2 (normal <0.2). Ultrasonography of kidneys and
CECT brain was normal. Wrist skiagram showed healed rickets.
She was started on intravenous fluids (1.5 times
maintenance), furosemide and hydrocortisone. Injection
Calcitonin was added on 2nd day, in view of persistent
hypercalcemia. Ionized calcium fell to1.56 mmol/L initially,
followed by rebound increase 48 hours later. For control of
hypertension, child required amlodipine and enalapril. Child
was discharged after 12 days with serum calcium 13 mg/dl and
BP 106/70, on tapering doses of oral prednisolone,
furosemide and anti-hypertensives.
Furosemide and enalapril were stopped
after 3 weeks, whereas amlodipine was continued for 6 months
in view of persistent hypertension. The serial serum Calcium
was 10.5, 10.8 and 10.6 mg/dL, phosphate was 2.4, 5.1 and
5.6 mg/ dL, 25-hydroxy D3 was 3446, 3484 and 1785 nmol/L,
and Parathormone was 16, 14.9 and 25 pg/mL at 2, 4 and 12
weeks after discharge. Ultrasonography at 3 and 6 months did
not reveal nephrocalcinosis.
The manifestations of vitamin D
intoxication are related to hypercalcemia, and require
prompt treatment. Since vitamin D is stored in fatty
tissues, the toxicity may last for up to 6-8 months. Calcium
induced hypercatecholaminemia, and direct effect on vascular
smooth muscle are responsible for hypertension [4].
Treatment modalities include diet with low calcium and
phosphorus, hydration, loop diuretics, glucocorticoids,
calcitonin and bisphosphonates [5]. Hemodialysis is useful
in life Threatening hypercalcemia.
Before starting vitamin D for children
with rickets, parents should be asked about previous vitamin
D administration. In case of doubt regarding either the
diagnosis of vitamin D deficiency, or previous intake of
vitamin D, it is prudent to check 25-hydroxy vitamin D
levels. Parents should also be counseled that bowing of legs
would take time to resolve and does not require repeated
courses of vitamin D. Vitamin D needs to be used with
caution, and only when indicated, to avoid adverse effects.
References
1. Jain V, Gupta N, Kalaivani M, Jain A,
Sinha A, Agarwal R. Vitamin D deficiency in healthy
breastfed term infants at 3 months and their mothers in
India: Seasonal variation and determinants. Indian J Med
Res. 2011;133:267-73.
2. Misra M, Pacaud D, Petryk A, Collett-Solberg
PF, Kappy M. Vitamin D deficiency in children and its
management: Review of current pediatrics knowledge and
recommendations. Pediatrics. 2008;122;398-417.
3. Autier P, Gandini S. Vitamin D
supplementation and total mortality: a meta-analysis of
randomized controlled trials. Arch Intern Med.
2007;167:1730-7.
4. Eiam-Ong S, Eiam-Ong S, Punsin P,
Sitprija V, Chaiyabutr N. Acute hypercalcemia-induced
hypertension: the roles of calcium channel and alpha-1
adrenergic receptor. J Med Assoc Thai. 2004;87:410-8.
5. Barrueto F, Wang-Flores HH, Howland MA, Hoffman RS,
Nelson LS. Acute vitamin D intoxication in a child.
Pediatrics. 2005;116:e453–e6.
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