Endocrine Abstracts

Case report: An 11-year-old boy presented with an increasingly waddling gait and backache. He had been born small for gestational age (BW 1.8kg; -4.7 SDS) and had a history of dyspraxia and autism. He reported reasonable dairy intake and had no history of previous fractures or clinical signs of osteogenesis imperfecta (OI). Spinal imaging revealed multiple vertebral fractures. Malignancy and systemic inflammatory causes were excluded. An OI gene panel revealed a single pathogenic PLOD2 variant, but as a second variant was not identified the osteoporosis could not be attributed to Bruck syndrome. Bone biopsy showed high turnover osteopenia which was not typical of Juvenile Idiopathic Osteoporosis (JIO) but could represent early-stage disease. Given his clinical picture of multiple vertebral fractures and low bone density (lumbar spine BMAD -2.0 SDS, Total body less head -2.0 SDS), he was treated as JIO. Treatment with three monthly pamidronate was commenced; in combination with physiotherapy and hydrotherapy this led to a significant clinical improvement. One year later he was changed to six monthly Zoledronic acid infusions. However, at this time he developed increasing bone and muscle pains, swollen joints and reduced mobility requiring the use of a wheelchair. This was followed by pain in the gums; osteonecrosis of the jaw (from bisphosphonates) was excluded by the specialist dental team. The bone biochemistry was normal apart from a low ALP of 100 (128-420) and coeliac screen negative. He developed a mild anaemia. Clinical photographs showed enlarged gums, a swollen knee and some bruising. Further enquiry revealed an increasingly selective diet. In combination with the bone and muscle pains, low ALP, anaemia and gum hypertrophy a diagnosis of scurvy was suspected. This was confirmed with a low Vitamin C of <3.0umol/l (26.1-84.6). There was a remarkable improvement within two weeks of commencing an over-the-counter preparation of Vitamin C.

Conclusions: JIO and hypovitaminosis C are two rare and unrelated conditions. JIO is a diagnosis of exclusion and managed with bisphosphonates. Nutrient deficiencies such a Vitamin C should be considered as an alternative or contributory factor if clinically indicated or if there are ongoing generalised systemic symptoms.