E031 A rare case of diffuse osteosclerosis

Abstract

Abstract Background/Aims Diffuse skeletal fluorosis is a common condition in countries with high content of fluoride in the ground water like India and China. Skeletal fluorosis in the UK is rare and presents with non-specific findings such as back pain, elevated ALP or bone sclerosis. We describe a case referred from haematology for investigation of osteosclerosis. Methods 74-year-old female presented to the emergency department on several occasions with recurrent abdominal pain, severe low back pain and swelling of her lower limbs. Her mobility had been reduced due to previous femoral nerve injury. Blood tests on admission showed mild macrocytic anaemia. Alkaline phosphatase, renal, liver function tests and electrolytes were within normal range. Furthermore, calcium, phosphate, vitamin D and parathyroid hormone levels were within normal limits. CT CAP was done and no obvious or sinister cause for abdominal pain was found. However, it showed diffuse bony sclerosis. Bone densitometry DXA scan results as follows: T-score of + 1.6 in the hip and +1.7 in the neck of femur, they were unable to scan the lumbar spine as the patient was unable to tolerate positioning for the scan. This confirmed relatively raised bone density for patient’s age despite having risk factors for osteoporosis like previous wrist fracture, strong family history of osteoporosis, early menopause following total hysterectomy at age 41, coeliac disease and multiple falls due to poor mobility. Results A bone marrow aspirate and trephine biopsy and immunophenotyping were carried out and did not demonstrate any evidence of myeloid or lymphoid neoplasm. The next line of investigations included an isotope bone scan and blood tests including serum tryptase, uric acid and fluoride levels. Fluoride level came back as 411 which is 8-times more than the normal value. Patient mentioned that she uses fluoride toothpaste and brushed her teeth at least 10-14 times/day. X-ray of the hands showed no evidence of periosteal reactions or sclerosis. We recommended that she use fluoride free toothpaste and referred her for a dental opinion. While there is no effective therapeutic agent to reduce fluoride levels, patient was encouraged to use fluoride free toothpaste and also consult with her dentist for further evaluation. Conclusion This case emphasises the need for a comprehensive history and maintaining a high index of suspicion of skeletal fluorosis when encountered with a patient with a high bone mineral density (BMD) score on the DXA scan or diffuse skeletal sclerosis. The increase in bone mineral density is thought to be related to fluoride’s enhanced osteoblastic activity. Disclosure S. Mohamed: None. A. Phillips: None. J. Thomas: None. D. Makkuni: None.