Abstract:
Children affected with osteogenesis imperfecta (OI)
have increased morbidity and mortality and no definite
treatment has been found yet. Recurrent fractures and bone
deformities are the main complications of this disease.
Recent studies have shown the ability of intravenous
pamidronate to prevent fractures, when given in a cyclical
manner [1]. This treatment is being used currently to
prevent recurrence of fractures in children with OI but the
clinical experience with such therapy is greatly limited. In
this brief communication, we report our experience in
treating OI children with the intravenous pamidronate
during the last 4 years.
Total of 28 children with age range of 21 days to 9
years were treated from August 2001 to December 2004.
These patients were either direct admissions to paediatric
units in Karapitiya Hospital or referred by paediatricians
in other hospitals. All patients had suffered at least one
fracture in either long bones or ribs before admission.
The diagnosis of OI was made clinically by paediatricians
in the team, and other metabolic bone diseases such as
rickets and renal tubular acidosis were excluded by relevant
biochemical tests. Parents were interviewed and benefits
and complications of therapy were explained.
Children were treated with pamidronate sodium
(Aradia by Novartis) 1.5–2.0 mg per kg bodyweight as an
infusion in 1/5 isotonic saline over 6-hour period for three
consecutive days. This was repeated every 3 months in
cyclical manner until either the total bone mineral content
(TBMC) became normal (defined as within 2 standard
deviations from the mean TBMC of age and sex matched
population) or for a maximum of 6 cycles. Children were
kept under supervision during therapy for possible sideeffects
and open access was given to parents to report
any unexpected side-effects. Serum calcium level was done
at the end of each treatment session.
TBMC was assessed in 18 children by dual energy
xray absorptiometry (DXA) using Norland Eclipse XR
scanner (Norland Corp, USA). A rapid increase in TBMC
was seen in all children, except one, during the period of
treatment (Figure 1). All children had either one or more
fractures prior to treatment and only two patients suffered
fractures after commencing treatment. No major side
effects were reported during the therapy. One child had
spontaneous rupture of sclera and enucleation due to an
accidental trauma while on therapy and he was referred to
an ophthalmologist. One child died of pneumonia
2 months after the first cycle. Anaphylactic reaction was
noticed in one child and no further pamidronate was given
to him. Asymptomatic and mild hypocalcaemia was seen
in some children.