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Open access

Eleanor P Thong, Sarah Catford, Julie Fletcher, Phillip Wong, Peter J Fuller, Helena Teede and Frances Milat

Summary

The association between type 1 diabetes mellitus (T1DM) and bone health has garnered interest over the years. Fracture risk is known to be increased in individuals with T1DM, although bone health assessment is not often performed in the clinical setting. We describe the case of a 21-year-old male with longstanding T1DM with multilevel vertebral fractures on imaging, after presenting with acute back pain without apparent trauma. Dual-energy X-ray absorptiometry (DXA) revealed significantly reduced bone mineral density at the lumbar spine and femoral neck. Extensive investigations for other secondary or genetic causes of osteoporosis were unremarkable, apart from moderate vitamin D deficiency. High-resolution peripheral quantitative computed tomography and bone biospy revealed significant alterations of trabecular bone microarchitecture. It later transpired that the patient had sustained vertebral fractures secondary to unrecognised nocturnal hypoglycaemic seizures. Intravenous zoledronic acid was administered for secondary fracture prevention. Despite anti-resorptive therapy, the patient sustained a new vertebral fracture after experiencing another hypoglycaemic seizure in his sleep. Bone health in T1DM is complex and not well understood. There are significant challenges in the assessment and management of osteoporosis in T1DM, particularly in young adults, where fracture prediction tools have not been validated. Clinicians should be aware of hypoglycaemia as a significant risk factor for fracture in patients with T1DM.

Learning points:

  • Type 1 diabetes mellitus (T1DM) is a secondary cause of osteoporosis, characterised by reduced bone mass and disturbed bone microarchitecture.

  • Hypoglycaemic seizures generate sufficient compression forces along the thoracic column and can cause fractures in individuals with compromised bone quality.

  • Unrecognised hypoglycaemic seizures should be considered in patients with T1DM presenting with fractures without a history of trauma.

  • Patients with T1DM have increased fracture risk and risk factors should be addressed. Evaluation of bone microarchitecture may provide further insights into mechanisms of fracture in T1DM.

  • Further research is needed to guide the optimal screening and management of bone health in patients with T1DM.

Open access

Nobuhiro Miyamura, Shuhei Nishida, Mina Itasaka, Hirofumi Matsuda, Takeshi Ohtou, Yasuhiro Yamaguchi, Daisuke Inaba, Sadahiro Tamiya and Tetsuo Nakano

Summary

Hepatitis C-associated osteosclerosis (HCAO), a very rare disorder in which an extremely rapid bone turnover occurs and results in osteosclerosis, was acknowledged in 1990s as a new clinical entity with the unique bone disorder and definite link to chronic type C hepatitis, although the pathogenesis still remains unknown. Affected patients suffer from excruciating deep bone pains. We report the 19th case of HCAO with diagnosis confirmed by bone biopsy, and treated initially with a bisphosphonate, next with corticosteroids and finally with direct acting antivirals (DAA: sofosbuvir and ribavirin) for HCV infection. Risedronate, 17.5 mg/day for 38 days, did not improve the patient’s symptoms or extremely elevated levels of bone markers, which indicated hyper-bone-formation and coexisting hyper-bone-resorption in the patient. Next, intravenous methylprednisolone pulse therapy followed by high-dose oral administration of prednisolone evidently improved them. DAA therapy initiated after steroid therapy successfully achieved sustained virological response, but no additional therapeutic effect on them was observed. Our results strongly suggested that the underlying immunological alteration is the crucial key to clarify the pathogenesis of HCAO. Bone mineral density of lumbar vertebrae of the patient was increased by 14% in four-month period of observation. Clarification of the mechanisms that develop osteosclerosis in HCAO might lead to a new therapeutic perspective for osteoporosis.

Learning points:

  • HCAO is an extremely rare bone disorder, which occurs exclusively in patients affected with HCV, of which only 18 cases have been reported since 1992 and pathogenesis still remains unclear.

  • Pathophysiology of HCAO is highly accelerated rates of both bone formation and bone resorption, with higher rate of formation than that of resorption, which occur in general skeletal leading to the diffuse osteosclerosis with severe bone pains.

  • Steroid therapy including intravenous pulse administration in our patient evidently ameliorated his bone pains and reduced elevated values of bone markers. This was the first successful treatment for HCAO among cases reported so far and seemed to propose a key to solve the question for its pathogenesis.

  • The speed of increase in the bone mineral content of the patient was very high, suggesting that clarification of the mechanism(s) might lead to the development of a novel therapy for osteoporosis.