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Indian Pediatr 2010;47: 881-882 |
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Neurofibromatosis, Pathological Fracture and
Hypervitaminosis-D |
Rakesh Mondal, Madhumita Nandi and PK Chandra
From the Department of Pediatric Medicine, IPGMER and
SSKM Hospital, Kolkata, West Bengal, India.
Corrspondence to: Dr Madhumita Nandi, 6/6, Naren Sarkar
Road, Barisha, Kolkata,
West Bengal 700 008, India.
Email:
[email protected]
Received: April 15, 2009;
Initial review: May 13, 2009;
Accepted: July 7, 2009.
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Pathologic fractures in children may be due to various causes. Rarely,
it may be the presenting symptom of neurofibromatosis. A misdiagnosis of
Rickets and Vitamin D supplementation in such a case may wreak havoc in
the form of iatrogenic hypervitaminosis D. We report one such case.
Key words: Hypervitaminosis D, Neurofibromatosis, Pathologic
fractures.
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N eurofibromatosis may rarely present
with pathological fracture(1). We present such a child who was
misdiagnosed as a case of rickets and treated repeatedly with vitamin D
injection resulting in iatrogenic hypervitaminosis D.
Case Report
A four and half years old female child was referred for
management of bowing of left leg and pathological fracture. This was
associated with vomiting, abdominal pain, increased thirst and increased
volume of urine. There was no history of joint pain, convulsion and
difficulty of vision. The child was a product of a non-consanguineous
marriage. She was of average weight at birth and did not have any neonatal
problem. Her mother was having multiple cuteneous neurofibromas and was
diagnosed as a case of neurofibromatosis (NF) I.
Her developmental history revealed mild delay in motor
development. The immunization status and dietary intake was normal. She
was diagnosed as suffering from rickets by different physicians at
different places; many of whom treated her with injection arachitol
(Vitamin D3). Overall, she received about nine such injections over a
period of three months. Then she developed features of hypercalcemia with
polyuria, polydipsia, nausea, vomiting and abdominal pain.
Her anthropometry revealed height of 96 cm (<5th
percentile), weight of 10 kg (<5th percentile) and head
circumference of 47 cm. She had multiple café au lait spots over the trunk
and extremities and bowing of left leg without any features of rickets.
Her systemic and ocular examination was within normal limit.
Her hematological profile, renal function, liver
function and routine urine and stool examination were within normal
limits. Chest X-ray was also normal. X-ray spine showed
normal outline of lumbar vertebrae with normal disc space. Serum ionized
calcium was 6.9 mEq/L (normal-2.3-5.2 mEq/L), alkaline phosphatase 380 IU/L
(N 145-420 IU/L), inorganic phosphate was 2.0 mEq/L (2.3-3.5 mEq/L), and
serum parathormone level was 3.15 pg/mL(15-65 pg/mL). X-ray lower
limb showed bowing and pathological fracture of left fibula.
Discussion
Our patient met three of the seven diagnostic
criteria(2): presence of multiple café’u lait spots, an osseous lesion as
bony dysplasia in the form of bowing of legs and cortical thinning (which
had lead to pathological fracture) and mother suffering from
Neurofibromatosis (NF) I. She had been wrongly diagnosed as a case of
pathological fracture due to rickets from elsewhere and inadvertently
treated with repeated doses of vitamin D3 injections by various local
physicians causing hypervitaminosis D that manifested as hypercalcemia,
hypophosphate-mia and low serum parathormone level.
Apart from bowing of tibia and fibula, leading to
pathologic fracture, many other skeletal abnormalities like kyphoscoliosis,
dysplasia of sphenoid wing, pseudoarthosis, non-ossifying fibroma etc, may
be associated with NF(3,4). Treatment should be aimed at preventing
pathological fractures. Pseudarthrosis should be managed with corrective
operation or osteotomy as appropriate(5).
Our patient did not have any clinical or biochemical
features of rickets. Rickets or osteomalacia may also occur in
neurofibromatosis, though rarely. The exact pathogenetic mechanism for
this remains to be determined, but it may be due to phosphatonin mediated
inhibition of renal tubular reabsorption of phosphate and reduced serum
phosphorus. Characteristically, it has a later onset in adulthood. Rickets
in NF typically has multiple pseudofractures and responds to treatment
with pharmacological dose of vitamin D with or without phosphate
supplementation(6).
Contributors: All three authors were
involved in diagnosing and managing the case. RM drafted the manuscript.
MN and PKC searched the literature. All three approved the final
manuscript.
Funding: None.
Competing interests: None stated.
References
1. Arroba Basanta ML, de la Rubia Fernandez LR, del
Castillo Martin F. Neonatal pathologic fracture and neurofibromatosis. An
Esp Pediatr 1986; 25:491-492.
2. Haslam RHA. Neurocutaneous syndrome. In:
Behrman RE, Kilegman RM, Jenson HB, editors. Nelson Textbook of
Pediatrics. 18th edition. Philadelphia: WB Saunders Company; 2008. p.
2483-2484.
3. Hofmann P, Galanski M. Congenital bowing of the
tibia in neurofibromatosis von Recklinghausen (author’s transl). Fortschr
Geb Rontgenstr Nuklearmed 1976; 125: 417-421.
4. Howlett DC, Farrugia MM, Ferner RE, Rankin SC.
Multiple lower limb non-ossifying fibromas in siblings with
neurofibromatosis. Eur J Radiol 1998; 26 : 280-283.
5. Ramelli GP, Slongo T, Tschappeler H, Weis J.
Congenital pseudarthrosis of the ulna and radius in two cases of
neurofibromatosis type 1. Pediatr Surg Int 2001; 17: 239-241.
6. Konishi K, Nakamura M, Yamakawa H, Suzuki H, Saruta
T, Hanaoka H, et al. Hypophosphatemic osteomalacia in von
Recklinghausen neurofibro-matosis. Am J Med Sci 1991; 301: 322-328.
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