Background Type 1 diabetes mellitus (T1D) is an emerging but under-recognised risk factor for osteoporosis. Patients with T1D have a 7-fold risk of fracture compared to controls1; importantly, this increased risk is present throughout the lifespan2. Multiple mechanisms, such as hypoinsulinaemia, osteoblast dysfunction and inflammation have been linked to impaired bone formation and defects in trabecular bone architecture3,4,5.
Case Report We present a 21-year-old male with a 12-year history of T1D, who sustained extensive vertebral fractures in the setting of nocturnal hypoglycaemic seizures. Severe osteoporosis was diagnosed on Dual-energy X-ray Absorptiometry (DXA). Moderate vitamin D deficiency was identified in the absence of other comorbidities potentially contributing to bone fragility. Disturbance of trabecular architecture, including reduced numbers, thinning and reduced connectivity, consistent with diabetes-related bone pathology, was appreciated on imaging with high-resolution peripheral quantitative computed tomography (HRpQCT), as well as on tetracycline-labelled bone biopsy.
Discussion This case illustrates multi-level vertebral fractures in an otherwise healthy and young patient with chronic T1D, and is the first case report to demonstrate T1D-related trabecular bone defects on both HR-pQCT and bone histomorphometry. Hypoglycaemia is a common adverse effect of insulin therapy; severe hypoglycaemia may lead to seizures, where muscle contractions during convulsions are forceful enough to cause vertebral fractures6. The majority of vertebral fractures in this population may be asymptomatic7, and a high index of clinical suspicion is required for diagnosis. Although there is increasing awareness of the association between impaired bone quality in T1D, guidelines for assessment of bone in T1D patients are lacking and additional research is necessary to identify and manage patients at high fracture risk.