Elevated Bone Turnover Markers Research Articles

6564 A Case of Severe Hypercalcemia in Carney's Complex

Abstract Disclosure: J. Chippior: None. M. Rayan: None. L. Wright: None. L.S. Kirschner: Grant Recipient; Self; Medpace, Sparrow, Corcept Therapeutics, Corcept, Spruce, CinCor, Crinetics, Adrenas. S.W. Ing: Grant Recipient; Self; Alexion Pharmaceuticals, Inc., Amgen Inc, Radius Health, Inc, Takeda, Ultragenyx, Amolyt, Bridge Bio. Carney complex is a rare syndrome with fewer than 750 reported cases, characterized by lentigniosis, myxomas, and the occurrence of both endocrine and non-endocrine tumors. An inactivating mutation PRKAR1A, which encodes for the type 1A regulatory subunit of Protein kinase A, is responsible for over 70% of familial cases and 37% of sporadic cases. A 31-year-old female with a history of Carney complex, Cushing syndrome due to primary pigmented nodular adrenocortical disease (PPNAD), facial lentigines, spinal Schwannomas, and recent ischemic stroke secondary to embolization of a cardiac atrial myxoma, was transferred to our medical center for hyperemesis and severe hypercalcemia. Albumin-corrected serum calcium measured 15.4 mg/dL (8.6-10.5 mg/dL), ionized calcium 7.8 mg/dL (4.6-5.3 mg/dL) associated with suppressed PTH, normal PTH-related protein, and elevated bone turnover markers, C-telopeptide 4,273 pg/ml (150-635) and Procollagen Type 1 N-terminal Propeptide 222 mcg/L (19-83). Evaluation for etiology of hypercalcemia revealed elevated 1,25 dihydroxy vitamin D at 107.0 pg/ml (20-79) and elevated interleukin-6 at 11 pg/ml (<6.4). IL-6 is expressed by cardiac myxomas. Serum angiotensin-converting enzyme level was 50 U/L (16-85) and infectious workup was negative for potential granulomatous causes of elevated calcitriol (including testing for tuberculosis, histoplasma, blastomyces, bartonella, and coccidioides). CT angiogram of the abdomen and pelvis (completed in preparation of atrial myxoma resection) revealed ground-glass opacities in bilateral posterior lung fields and multiple pulmonary nodules, with the largest measuring 8 mm. After treatment with aggressive intravenous fluid resuscitation, intramuscular calcitonin, and intravenous zoledronic acid, corrected calcium normalized to 9.4 mg/dL at discharge. Urinary cortisol was 6.2 mcg per 24-hr (3.5-45), for which she started hydrocortisone 20 mg daily to treat suspected adrenal insufficiency as excess cortisol secretion in PPNAD may be episodic. Thus remission of hypercortisolism may have unmasked an underlying hypercalcemia, and adrenal insufficiency itself may have contributed to this finding. She had excision of left atrial myxoma and has continued to exhibit normal calcium levels on steroid replacement therapy. Repeat chest CT to further characterize these pulmonary findings is planned. This case illustrates a unique constellation of endocrine features associated with severe hypercalcemia in Carney complex. Presentation: 6/1/2024

6871 Hungry Bone Syndrome After Parathyroidectomy in End-Stage Kidney Disease: A Case Report Analysis

Abstract Disclosure: R. Rani: None. C. Mullarkey-desapio: None. Introduction: Hungry Bone Syndrome (HBS) is a rare yet severe complication following parathyroidectomy, characterized by pronounced hypocalcemia subsequent to a rapid decline in parathyroid hormone (PTH) levels. Renal hyperparathyroidism (RHPT) carries a heightened risk of HBS compared to primary hyperparathyroidism (PHPT), with prevalence varying from 15% to 25% in PHPT to as high as 75-92% in RHPT. This elevated risk in RHPT is attributed to chronically elevated PTH levels, both in terms of duration and intensity as compared to PHPT. Preoperative predictors for HBS occurrence and severity include younger age, larger gland size, lower preoperative calcium levels, elevated bone turnover markers, and the magnitude of PTH elevation. Case Report: We present a case of a 36-year-old female with End-Stage Renal Disease (ESRD) requiring dialysis, complicated by renal osteodystrophy and a radial fracture, unresponsive to medical therapy, who was admitted for parathyroidectomy. Preoperative labs revealed calcium at 8.3 mg/dL, phosphate at 4.1 mg/dL, alkaline phosphatase (ALP) at 797 IU/L, and an extremely elevated parathyroid hormone (PTH) level at 4139 pg/ml. Within 24 hours of parathyroidectomy (three and a half glands were removed, the largest weighing 0.7gm), her PTH levels declined to the 130s, accompanied by symptomatic hypocalcemia (calcium 6.5mg/dL). Initial management involved intravenous calcium gluconate and subsequent high-dose oral calcium (up to 10-16gm daily) with Calcitriol 1 mcg twice daily. Despite repletion, her calcium levels remained low on postoperative day 4 (calcium 6.8mg/dL, phosphate 1.9 mg/dL, magnesium 1.7mg/dL) with PTH at 131 pg/ml, confirming Hungry Bone Syndrome. After seven days of aggressive intravenous and oral calcium supplementation with high-dose Calcitriol, she was discharged with a calcium level of 8.9mg/dL. Discussion: Management of HBS following renal hyperparathyroidism surgery presents significant challenges due to associated comorbidities and other electrolyte abnormalities, with limited literature providing guidance on prevention and management. Our case demonstrated that early suspicion and aggressive management improved patient outcomes. Suspecting HBS in high-risk individuals and initiating interventions pre and post-surgery, including pre-treatment with calcitriol, bisphosphonates, and early aggressive intravenous calcium supplementation post-surgery, could potentially reduce morbidity and length of hospital stay. Presentation: 6/1/2024

6483 Diaphyseal Medullary Stenosis With Malignant Fibrous Histiocytoma: A Rare Skeletal Dysplasia/Sarcoma Syndrome

Abstract Disclosure: A. Grover: None. C.R. Ferreira: None. R.I. Gafni: None. S. Jumani: None. M.T. Collins: None. K.L. Roszko: None. I.R. Hartley: None. Introduction: Diaphyseal medullary stenosis with malignant fibrous histiocytoma (DMS-MFH) is a rare autosomal dominant syndrome associated with pathologic fractures, myopathy, premature hair graying, and aggressive osteosarcomas. DMS-MFH has been linked to genetic variants in the methylthioadenosine phosphorylase (MTAP) gene, which encodes an enzyme in the methionine salvage and polyamine synthesis pathway. This pathway is implicated in other skeletal fragility disorders, such as Snyder-Robinson syndrome, suggesting a still undefined role of this pathway in bone biology. We describe a kindred with DMS-MFH and identify diagnostic challenges. Case: A 53-year-old perimenopausal woman presented with four fragility fractures over one year. Relevant history included premature hair graying, esophageal strictures, and nephrolithiasis. The patient’s bone formation markers were slightly elevated; bone resorption markers were within reference range. Her only osteoporosis risk factor was perimenopausal status. Bone series showed a diffuse heterogeneous appearance of the long bones with a mixed lytic/sclerotic appearance. DEXA scan revealed osteopenia. Family history was significant for 2 sons with aggressive osteosarcomas diagnosed in their late teens; one died at age 20. The other son is currently 39-years-old with recurrent osteosarcomas in three different limbs. The family also has a multigenerational history of severe bone fragility, muscle weakness, and premature hair graying. The patient, her living son, and his father underwent genome sequencing that identified a variant in MTAP (c.885A>G; p.(R295=)) in the patient and son. This variant was previously reported in three other families with DMS-MFH and has been shown to alter splicing. Notably, commercial genetic testing did not report this as a relevant variant, and diagnosis required independent analysis of the raw sequence data. Based on these findings, the patient and her son were diagnosed with DMS-MFH. Given the bone fragility with elevated bone turnover markers we treated the patient with yearly zoledronic acid infusions with no subsequent fractures. Surveillance for osteosarcoma is also being performed with annual whole-body MRI. Conclusion: DMS-MFH has been reported in only five families to date. The sixth family described here has clinical characteristics similar to the other kindreds. Due to high risk of aggressive osteosarcoma, timely diagnosis is imperative to decrease morbidity and mortality. Commercial genome sequencing may miss this diagnosis, so targeted genetic testing should be pursued. As more cases are identified, characterization of affected families may enhance our understanding of the natural history of the disease and guide surveillance and treatment strategies. Presentation: 6/2/2024

6564 A Case Of Severe Hypercalcemia In Carney's Complex

Abstract Disclosure: J. Chippior: None. M. Rayan: None. L. Wright: None. L.S. Kirschner: Grant Recipient; Self; Medpace, Sparrow, Corcept Therapeutics, Corcept, Spruce, CinCor, Crinetics, Adrenas. S.W. Ing: Grant Recipient; Self; Alexion Pharmaceuticals, Inc., Amgen Inc, Radius Health, Inc, Takeda, Ultragenyx, Amolyt, Bridge Bio. Carney complex is a rare syndrome with fewer than 750 reported cases, characterized by lentigniosis, myxomas, and the occurrence of both endocrine and non-endocrine tumors. An inactivating mutation PRKAR1A, which encodes for the type 1A regulatory subunit of Protein kinase A, is responsible for over 70% of familial cases and 37% of sporadic cases. A 31-year-old female with a history of Carney complex, Cushing syndrome due to primary pigmented nodular adrenocortical disease (PPNAD), facial lentigines, spinal Schwannomas, and recent ischemic stroke secondary to embolization of a cardiac atrial myxoma, was transferred to our medical center for hyperemesis and severe hypercalcemia. Albumin-corrected serum calcium measured 15.4 mg/dL (8.6-10.5 mg/dL), ionized calcium 7.8 mg/dL (4.6-5.3 mg/dL) associated with suppressed PTH, normal PTH-related protein, and elevated bone turnover markers, C-telopeptide 4,273 pg/ml (150-635) and Procollagen Type 1 N-terminal Propeptide 222 mcg/L (19-83). Evaluation for etiology of hypercalcemia revealed elevated 1,25 dihydroxy vitamin D at 107.0 pg/ml (20-79) and elevated interleukin-6 at 11 pg/ml (<6.4). IL-6 is expressed by cardiac myxomas. Serum angiotensin-converting enzyme level was 50 U/L (16-85) and infectious workup was negative for potential granulomatous causes of elevated calcitriol (including testing for tuberculosis, histoplasma, blastomyces, bartonella, and coccidioides). CT angiogram of the abdomen and pelvis (completed in preparation of atrial myxoma resection) revealed ground-glass opacities in bilateral posterior lung fields and multiple pulmonary nodules, with the largest measuring 8 mm. After treatment with aggressive intravenous fluid resuscitation, intramuscular calcitonin, and intravenous zoledronic acid, corrected calcium normalized to 9.4 mg/dL at discharge. Urinary cortisol was 6.2 mcg per 24-hr (3.5-45), for which she started hydrocortisone 20 mg daily to treat suspected adrenal insufficiency as excess cortisol secretion in PPNAD may be episodic. Thus remission of hypercortisolism may have unmasked an underlying hypercalcemia, and adrenal insufficiency itself may have contributed to this finding. She had excision of left atrial myxoma and has continued to exhibit normal calcium levels on steroid replacement therapy. Repeat chest CT to further characterize these pulmonary findings is planned. This case illustrates a unique constellation of endocrine features associated with severe hypercalcemia in Carney complex. Presentation: 6/1/2024

Elevated Bone Turnover Markers After One Infusion Of Zoledronic Acid Post Denosumab Cessation

Abstract Background Denosumab is a commonly used to treat osteoporosis though should not be stopped without transitioning to bisphosphonates to reduce the risk of rebound bone loss and fracture. Recent NOGG guidelines recommend IV zoledronic acid (ZA) six months after the last denosumab injection with further infusions based on bone turnover markers (BTM). Methods We collated data (over the past 5 years) on the first follow up BTM measured after zoledronic acid treatment given to patients where denosumab was stopped. ZA was administered between 6-7 months after the last denosumab injection. The bone resorption marker (C-Telopeptide type I collagen, CTX ng/ml) was measured at different time points: 4 months, 4-6 months, and between 6-12 months. A subtherapeutic CTX was defined as > 0.300 ng/ml. Results There were 95 patients, 93% female, mean age 67.8 years and duration of denosumab therapy 4.6 years. Bone markers were significantly elevated from baseline at all timepoints. Mean CTX at 4 months was 0.450, 6 months 0.470 and 6-12 months 0.65. Overall, 45% had a subtherapeutic CTX at 4 months, 45% at 6 months and 70% between 6-12 (mean 9 months) and this was predicted by time from first ZA infusion (P=0.03). Conclusion Nearly half of patients had subtherapeutic BTM at 4-6 months and the majority at 6-12 months after receiving ZA. For patients on denosumab therapy for a similar duration (4-5 years), our results support the routine administration of a second ZA six months after their first ZA. Delays in administering a second infusion may result in a substantial rise in bone resorption markers and significant bone loss. This highlights the need for timely access to ZA for such patients transitioning off denosumab therapy.

Suspected silent pituitary somatotroph neuroendocrine tumor associated with acromegaly-like bone disorders: a case report

BackgroundGrowth hormone (GH) positive pituitary neuroendocrine tumors do not always cause acromegaly. Approximately one-third of GH-positive pituitary tumors are classified as non-functioning pituitary tumors in clinical practice. They typically have GH and serum insulin-like growth factor 1 (IGF-1) levels in the reference range and no acromegaly-like symptoms. However, normal hormone levels might not exclude the underlying hypersecretion of GH. This is a rare and paradoxical case of pituitary tumor causing acromegaly-associated symptoms despite normal GH and IGF-1 levels.Case presentationWe report a case of a 35-year-old woman with suspicious acromegaly-associated presentations, including facial changes, headache, oligomenorrhea, and new-onset diabetes mellitus and dyslipidemia. Imaging found a 19 × 12 × 8 mm pituitary tumor, but her serum IGF-1 was within the reference, and nadir GH was 0.7ng/ml after glucose load at diagnosis. A thickened skull base, increased uptake in cranial bones in bone scan, and elevated bone turnover markers indicated abnormal bone metabolism. We considered the pituitary tumor, possibly a rare subtype in subtle or clinically silent GH pituitary tumor, likely contributed to her discomforts. After the transsphenoidal surgery, the IGF-1 and nadir GH decreased immediately. A GH and prolactin-positive pituitary neuroendocrine tumor was confirmed in the histopathologic study. No tumor remnant was observed three months after the operation, and her discomforts, glucose, and bone metabolism were partially relieved.ConclusionsGH-positive pituitary neuroendocrine tumors with hormonal tests that do not meet the diagnostic criteria for acromegaly may also cause GH hypersecretion presentations. Patients with pituitary tumors and suspicious acromegaly symptoms may require more proactive treatment than non-functioning tumors of similar size and invasiveness.

Left ventricular remodeling and its association with mineral and bone disorder in kidney transplant recipients

Background The assessment of left ventricular (LV) remodeling and its association with mineral and bone disorder (MBD) in kidney transplant recipients (KTRs) have not been systematically studied. We aimed to evaluate LV remodeling changes one year after kidney transplantation (KT) and identify their influencing factors. Methods Ninety-five KTRs (68 males; ages 40.2 ± 10.8 years) were followed before and one year after KT. Traditional risk factors and bone metabolism indicators were assessed. Left ventricular mass index (LVMI), left ventricular ejection fraction (LVEF) and left ventricular diastolic dysfunction (LVDD) were measured using two-dimensional transthoracic echocardiography. The relationship between MBD and LV remodeling and the factors influencing LV remodeling were analyzed. Results One year after KT, MBD was partially improved, mainly characterized by hypercalcemia, hypophosphatemia, hyperparathyroidism, 25-(OH) vitamin D deficiency, elevated bone turnover markers, and bone loss. LVMI, the prevalence of left ventricular hypertrophy (LVH), and the prevalence of LVDD decreased, while LVEF increased. LVH was positively associated with postoperative intact parathyroid hormone (iPTH) and iPTH nonnormalization. ΔLVMI was positively associated with preoperative type-I collagen N-terminal peptide and postoperative iPTH. LVEF was negatively associated with postoperative phosphorous. ΔLVEF was negatively associated with postoperative iPTH. LVDD was positively associated with postoperative lumbar spine osteoporosis. Preoperative LVMI was negatively associated with ΔLVMI and positively associated with ΔLVEF. Advanced age, increased BMI, diabetes, longer dialysis time, lower albumin level, and higher total cholesterol and low-density lipoprotein levels were associated with LV remodeling. Conclusions LV remodeling partially improved after KT, showing a close relationship with MBD.

Elevated bone turnover markers predict bone mineral density accrual in adolescents with 21-hydroxylase deficiency.

Prognostic biomarkers for monitoring bone health in adolescents with 21-hydroxylase deficiency (21OHD) are needed. To assess associations between concentrations of baseline bone turnover markers (BTMs) including osteocalcin (OC) and type-I collagen C-terminal telopeptide (CTX) and changes in lumbar spine bone mineral density (LSBMD) in adolescents with classic 21OHD. A retrospective-prospective study of 33 adolescents with classic 21OHD who had baseline data for LSBMD, bone age (BA), and BTM concentrations. BTM concentrations were converted into z-scores according to BA. We measured LSBMD at the follow-up study visit and calculated the annual percentage change in LSBMD (%∆LSBMD). At baseline, participants (55% female, 79% Tanner 5) had mean (±SD) age of 14.6 ± 3.6 years, BA 16.7 ± 2.9 years, and average glucocorticoid (GC) dose 17.3 ± 5.6 mg/m2 /day of hydrocortisone equivalent. The mean follow-up duration was 14.4 ± 5.6 months. Median (Q1-Q3) %∆LSBMD was 3.6% (0-8.5)/year. %∆LSBMD was similar among genders or 21OHD subtypes. Prednisolone versus hydrocortisone replacement resulted in lower %∆LSBMD (p = .004). %∆LSBMD was increased across tertiles of CTX z-score (p = .014). %∆LSBMD correlated negatively with GC dose (p = .01) and positively with CTX and OC z-scores (p < .01). In regression analyses, only CTX z-score positively associated with %∆LSBMD (p = .003), adjusting for sex, BA, body mass index, testosterone, 25-hydroxyvitamin D, and GC type and dose. Higher GC dose and the use of prednisolone were associated with decreased LSBMD accrual in adolescents with 21OHD. CTX z-score independently associated with LSBMD accrual, suggesting its potential for prognostic bone biomarker.

Decreased cortical bone density and mechanical strength with associated elevated bone turnover markers at peri-pubertal peak height velocity: a cross-sectional and longitudinal cohort study of 396 girls with adolescent idiopathic scoliosis.

As part of the studies related to aetiopathogenesis of AIS, we assessed bone qualities, bone mechanical strength and bone turnover markers (BTMs) focusing at the peri-pubertal period and PHV in AIS girls. 396 AIS girls in two separate cohorts were studied. Skeletal maturity was assessed using the validated thumb ossification composite index (TOCI). Bone qualities and strength were evaluated with high-resolution peripheral quantitative computed tomography (HR-pQCT) and finite element analysis (FEA). Cohort-A included 179 girls (11.95 ± 0.95years old). Girls at TOCI-4 had numerically the highest height velocity (0.71 ± 0.24cm/month) corresponding to the PHV. Subjects at TOCI-4 had lower cortical volumetric BMD (672.36 ± 39.07mg/mm3), cortical thickness (0.68 ± 0.08mm) and apparent modulus (1601.54 ± 243.75N/mm2) than: (a) those at TOCI-1-3 (724.99 ± 32.09mg/mm3 (p < 0.001), 0.79 ± 0.11mm (p < 0.001) and 1910.88 ± 374.75N/mm2 (p < 0.001), respectively) and (b) those at TOCI-8 (732.28 ± 53.75mg/mm3 (p < 0.001), 0.84 ± 0.14mm (p < 0.001), 1889.11 ± 419.37N/mm2 (p < 0.001), respectively). Cohort-B included 217 girls (12.22 ± 0.89years old). Subjects at TOCI-4 had higher levels of C-terminal telopeptide of type 1 collagen (1524.70 ± 271.10pg/L) and procollagen type 1N-terminal propeptide (941.12 ± 161.39µg/L) than those at TOCI-8 (845.71 ± 478.55pg/L (p < 0.001) and 370.08 ± 197.04µg/L (p < 0.001), respectively). AIS girls had decreased cortical bone density and bone mechanical strength with elevated BTMs at PHV. Coupling of PHV with decreased cortical and FEA parameters could provide the link to the previously reported observation that low BMD could contribute as one of the prognostic factors for curve progression that mostly occurs during PHV in AIS.

Immobilization-induced hypercalcemia in a patient with renal failure.

SummaryImmobilization-induced hypercalcemia is an uncommon cause of elevated calcium which is usually diagnosed following extensive systemic workup and exclusion of more common etiologies. Previously reported cases have largely described this phenomenon in adolescents and young adults a few weeks to months after the initial onset of immobilization. Metabolic workup tends to demonstrate hypercalcemia, hypercalciuria, and eventual osteoporosis. While the exact mechanism remains largely unclear, a dysregulation between bone resorption and formation is central to the pathogenesis of this disease. Decreased mechanical loading from prolonged bedrest tends to increase osteoclast induced bone resorption while promoting osteocytes to secrete proteins such as sclerostin to reduce osteoblast mediated bone formation. We describe the case of an 18-year-old male who was admitted following intraabdominal trauma. He underwent extensive abdominal surgery including nephrectomy resulting in initiation of dialysis. After 6 months of hospitalization, the patient gradually began developing uptrending calcium levels. Imaging and laboratory workup were unremarkable for any PTH-mediated process, malignancy, thyroid disorder, adrenal disorder, or infection. Workup did reveal significant elevated bone turnover markers which in combination with the clinical history led the physicians to arrive at the diagnosis of immobilization induced hypercalcemia. In order to prevent decreased rates of bone loss, the patient was administered denosumab for treatment. Hypocalcemia followed treatment expectedly and was repleted with supplementation via the patient’s total parenteral nutrition.Learning pointsImmobilization-induced hypercalcemia should remain as a differential diagnosis of patients with prolonged hospitalizations with hypercalcemia.Extensive workup of common etiologies of hypercalcemia should be considered prior to arriving at this diagnosis.Denosumab, while off-label for this usage, offers an effective treatment option for immobilization-induced hypercalcemia though it carries a risk of hypocalcemia especially among patients with renal disease.

Post-Traumatic Heterotopic Ossification With Incidental Hyperparathyroidism

Background: Heterotopic ossification (HO) is a rare disease characterised by abnormal bone growth in non-osseous tissues, causing pain, immobility and impaired quality of life. Although still being elucidated, the underlying pathophysiology may relate to local macrophage-driven inflammation in response to trauma1. Case: A 35-year-old man involved in a motor vehicle accident (MVA) fractured over twenty bones (multiple vertebrae, ribs and complex open book pelvic fracture with shattered left acetabulum) with extensive soft tissue injuries requiring multiple surgeries. Past medical history included a renal calculus three years earlier. His serum corrected calcium on admission was elevated at 2.87mmol/L (2.10-2.60mmol/L). Peri-operative fluid over-resuscitation necessitated boluses of intravenous furosemide, and serum calcium transiently normalised before rapidly incrementing and peaking at 3.04 mmol/L. Serum parathyroid hormone post-operatively was inappropriately high at 9.4pmol/L (1.0–7.0pmol/L) and 25-hydroxyvitamin D low at 24nmol/L (50-150nmol/L). Oral vitamin D replacement was commenced and he received intravenous pamidronate (3x60mg infusions) which briefly restored normocalcaemia. Neck ultrasound and sestamibi scintigraphy demonstrated a left parathyroid adenoma, and he underwent parathyroidectomy. Histology revealed a single parathyroid adenoma. He has been normocalcaemic since surgery. Despite excellent overall recovery, mobility at the left hip remained restricted in all planes of movement. He could not perform simple activities such as putting on his shoe. Plain radiographs showed HO lateral to the left acetabulum, femoral head and neck, with bony bridging to the left ilium on computed tomography. Bone turnover markers (BTMs) measured eleven months post-MVA (and pamidronate) were elevated, with CTX of 750ng/L (100-600ng/L) and P1NP of 207ug/L (15-80ug/L). BTMs gradually reduced over time, plateauing two years post-MVA (CTX 480ng/L and P1NP 103ug/L). Surgery with pre-operative radiotherapy to remove the left hip HO is now planned. Discussion: This man had multiple recognised risk factors for HO, including male sex, trauma followed by immobilisation and pelvic fracture. His hyperparathyroidism may have predisposed HO development through excess calcium-phosphate product promoting soft tissue calcification. Bisphosphonates may also increase the risk2. Elevated BTMs have been demonstrated in the early phase of HO; further research may elucidate whether BTMs can guide timing of surgical intervention relative to the pathophysiological processes driving HO.

Physiological Factors of Female Runners With and Without Stress Fracture Histories: A Pilot Study.

Female runners are at increased risk of stress fractures (SFs) compared with men. Literature is lacking with regard to best practice for preventing and treating SFs in women. The purpose of the study was to compare physiological measures and running-related factors between women of various ages and running abilities with and without a history of running-related SFs. Women with and without SF histories will differ with regard to medical and menstrual history, bone health, body composition, nutrition, and running history. Prospective cohort study. Level 2. A total of 20 female runners with SF histories were matched based on age and running distance with 20 women without SF histories. Data included medical, menstrual, running, injury, and nutritional histories; blood histology related to nutritional, hormonal, and bone-related risk factors; and bone density, fat, and lean tissue using dual energy x-ray absorptiometry. Paired t tests were used to examine differences between women with and without SF histories, and Spearmen correlations were conducted to examine relationships between physiological factors. Women with SF histories had lower hip bone mineral density compared with women without SF histories (P < 0.05). SF history was moderately correlated with menstrual changes during increased training times (r = 0.580; P < 0.0001) but was not correlated with any other physiological factor. There was a moderate correlation within the SF group (r = 0.65; P = 0.004) for bone markers for resorption and formation both increasing, indicating increased bone turnover. Female runners with low hip bone mineral density, menstrual changes during peak training, and elevated bone turnover markers may be at increased risk of SF. Female runners need routine screening for risks associated with SF occurrence. As bone mineral density and bone turnover markers are not routinely assessed in this population, important risk factors may be missed.

MON-371 The Case of Dueling Femurs

Introduction: Paget’s disease of the bone is characterized by excessive osteoclastic bone resorption followed by formation of disorganized bone; which is often focal. Bone pain and deformities are common features and it often leads to complications such as pathological fractures, deafness or neurologic deficits. Elevated bone turnover markers and alkaline phosphatase reflect ongoing exaggerated bone resorption and osteoblastic activity. We present an unusual scenario of post-menopausal osteoporosis and Paget’s disease occurring in the same patient. Clinical Case: 86-year-old female with history of Type 2 Diabetes Mellitus, Hypertension,Hypothyroidism, degenerative joint disease of lumbar spine with prior interbody fusion and laminectomy was referred to our clinic by Orthopedics for evaluation of newly diagnosed Paget’s disease. 2 months ago, she noticed severe right hip pain limiting daily activities. She denied any history of falls, fractures or family history of Paget’s. Physical exam was notable for tenderness to right sacro-iliac joint and right femoral trochanteric region. Work up included MRI of Lumbar spine and Pelvis, Pelvis X-ray, DEXA scan and routine blood work.Interestingly, her DEXA scan showed T score of +2.9 in Right hip and -3.1 in Left hip. On Pelvis X-ray cortical thickening, coarse trabecula and osteoarthritic changes were noted in right femur and hip, consistent with Paget’s disease. Left femur showed strikingly thinner cortices compared to the right, due to underlying osteoporosis. MRI of lumbar spine and pelvis was consistent with polyostotic Paget’s involving L3-L5, Sacrum and Right femur. Nuclear bone scan showed areas of uptake including anterior calvarium, lumbar spine, right hip, right femur, 8th rib, left mid tibia and 1st metatarsal of left foot. Since the distribution of uptake seemed atypical for Paget’s, a skeletal survey was obtained which was negative for bone lesions suggestive of malignancy.Laboratory testing revealed serum calcium 9.8mg/dL(8.4–10.2), 25-Hydroxy Vitamin D 30ng/dL(20–30), PTH 45.6pg/mL (15–65), Alkaline Phosphatase 370U/L (35–104), Procollagen I intact N-terminal 516mcg/L (16–96) and N-Terminal Telopeptide (NTX) 126.4 nM BCE (6.2–19).Patient received one dose of IV Zoledronic acid with modest improvement in hip and lower back pain. She continues to take Calcium carbonate 600mg twice daily and vitamin D3 1000IU once daily. We plan to see her in follow up in 3 months with repeat levels bone turnover markers. Conclusion: This is a unique case of Paget’s disease and osteoporosis, two very different diseases of metabolic bone disorder spectrum found in one patient. Treatment of Paget’s disease is indicated for pain reduction, prevention of fractures and deformities and to prevent disease progression in weight bearing areas. Bisphosphonates can target pathology of both diseases by reducing osteoclastic bone resorption.

Biochemical bone turnover markers in hormonal disorders in adults: a narrative review.

Hormonal disorders are often associated with abnormal levels of bone turnover markers (BTMs). N-terminal propeptide of type I procollagen (PINP) and serum C-terminal cross-linking telopeptide of type I collagen (CTX-I) are the reference markers of bone formation and bone resorption, respectively. A comprehensive literature search within the MEDLINE and Web of Science databases was performed. Acromegaly is associated with higher BTM levels, which decrease during the remission after treatment. Adult-onset growth hormone deficiency is often associated with decreased BTM levels. Growth hormone replacement therapy stimulates bone turnover and increases BTM levels. Hypothyroidism is characterized by general slowing of bone metabolism which is reflected by lower BTM levels. The replacement thyroid hormone therapy increases the bone turnover rate and BTM levels increase. Patients with thyroid cancer receive a suppressive dose of thyroid hormones and may have slightly elevated BTM levels. Patients with overt hyperthyroidism had higher BTM levels and anti-thyroid therapy induces a rapid decrease in the BTM levels. Patients with overt primary hyperparathyroidism have higher BTM levels, whereas those with asymptomatic and normocalcemic hyperparathyroidism usually have normal BTM levels. Hypoparathyroidism is characterized by slightly decreased BTM levels. Cushing's syndrome is characterized consistently by markedly decreased osteocalcin concentration, whereas data on other BTMs are discordant. BTMs help us to better understand mechanisms of the impact of hormonal disorders and their treatment on bone metabolism. However, it is unknown whether BTMs may be used to monitor the effect of their treatments on bone in the clinical practice.

Bone Mineral Density, Body Composition, and Mineral Homeostasis Over 24 Months in Urban South African Women With HIV Exposed to Antiretroviral Therapy.

ABSTRACTHuman immunodeficiency virus‐ (HIV‐) infection and antiretroviral therapy (ART) exposure are associated with bone loss. African data are limited despite the region's HIV burden. Of 247 ART‐naïve, premenopausal, urban, black African women aged 33.9 ± 6.6 years from Soweto, South Africa, measured at baseline, 110 underwent anthropometry, DXA, and blood and urine collections at 12 and 24 months; 39 were HIV‐negative (Nref), 28 were people with HIV (PWH) not ART‐exposed for the duration of the study (ART‐N), and 43 were PWH who were ART‐exposed within the first 12 months (ART‐Y). At baseline, the ART‐Y group had lower BMI and fat mass than the Nref group. Within 12 months of ART initiation, areal bone mineral density (aBMD) had decreased at the lumbar spine and at the whole body less head, despite increased weight, and hip aBMD had not increased in line with the Nref group. There was no evidence of further bone changes between 12 and 24 months. By 24 months, the ART‐Y women had gained weight and fat mass, but remained lighter with less fat than the Nref women. ART initiation normalized the low serum albumin of the ART‐Y group at baseline, but was associated with elevated bone turnover markers at 12 and 24 months. Vitamin D status and renal phosphate handling were normal. ART‐N had similar aBMD and other characteristics to the Nref group throughout, except unlike the Nref group, weight and fat mass did not increase and serum albumin decreased. This study in African women of childbearing age demonstrated that the bone loss that had occurred in these PWH after ART initiation did not continue after 12 months and that bone loss did not occur in ART‐unexposed PWH over 2 years. At 24 months, despite gains in weight and fat mass, ART‐exposed women remained lighter, with lower aBMD, fat mass, and higher bone turnover than women without HIV. More studies are required to establish if the bone loss and fat gain reverse, stabilize, or continue with further ART exposure, particularly during and after menopause. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Can bone marrow aspirate improve mandibular fracture repair in camels (Camelus dromedarius)? A preliminary study.

BackgroundMandibular fractures are common in camels, leading to considerable economic losses. This study explored methods of improving mandibular fractures repair, adjuvant with interdental wire, or bone plate fixation. Autologous bone marrow (BM) injection enhances osteogenesis and rapid healing.ObjectivesTo investigate the effect of autologous BM aspirate as an adjuvant treatment for repairing mandibular fractures in camels with interdental wire, or bone plate fixation.MethodsThirty dromedary camels aged 5–8 years and of both sexes were randomly divided into 4 treatment groups: group 1 (n = 10) treated with stainless steel wire fixation and BM injection at the fracture line, group 2 (n = 10) treated with plate fixation and BM injection at the fracture line, group 3 (n = 5) treated with stainless steel bone wire fixation and placebo saline injection at the fracture line, and group 4 (n = 5) treated with plate fixation and placebo injection at the fracture line. The mandibular fractures were followed weekly for 12 weeks postoperatively to assess improvement and healing based on clinical evaluation, radiographic union scale, and bone turnover markers (i.e., bone alkaline phosphatase, osteocalcin, pyridinoline, and deoxypyridinoline).ResultsCompared to other groups, elevated bone turnover markers in group 1 were demonstrated (p < 0.05) on the seventh postoperative day. Likewise, compared to other groups, both clinical findings and radiographic union scale significantly improved (p < 0.05) in group 1 on the 56th postoperative day.ConclusionsBM aspirate has a promising beneficial osteogenic effect on mandibular fracture repair in camels, most notably when combined with interdental wire fixation.

Effect of cabozantinib on bone turnover markers (BTM) and bone metastases (BM) in radioiodine refractory (RAIR)-differentiated thyroid cancer (DTC).

e17580 Background: Cabozantinib is a small molecule multiple-receptor tyrosine kinase inhibitor that primarily targets MET and vascular endothelial growth factor receptor 2 (VEGFR2). We evaluated the effect of cabozantinib on BTM in RAIR DTC. We also assessed the response of BM to cabozantinib using 18F Sodium Fluoride (NaF) PET and radionuclide bone scans. Methods: This prospective analysis was performed as part of a multicenter International Thyroid Oncology Group phase II study of cabozantinibin patients with RAIR DTC who progressed on prior VEGFR-targeted therapy (NCT01811212). BTM [serum C-telopeptide (CTx), osteocalcin, N-telopeptide (NTx), procollagen type 1 (Pc1) and urinary NTx] and NaF PET or Tc-MDP scans were done at baseline and after 8 weeks of therapy. A paired t-test was used between baseline and week 8 BTM. Results: Primary study results were presented elsewhere (Shah, et al. 2015, International Thyroid Congress) showing a response rate of 36% with cabozantinib. Of 25 patients (pts) enrolled, 21 had BM, 10 of whom were on bone-modifying agents (BMA) prior to week 8. Only 2 pts had elevated BTM at baseline. In all pts who had paired BTM, there was a statistically significant decline in all BTM except NTx by week 8 (table). Pts not on BMA also had a significant decline in CTx (p 0.0003), urine NTx (p 0.0300), and Pc1 (p 0.0030) compared to baseline. 19 pts were evaluable for overall response and there was no correlation between BTM and response rate. 6/21 patients underwent paired NaF PET scans and 4/6 had minor reduction in lesion uptake at 8 weeks. Conclusions: Interestingly, most of our patients had normal baseline BTM despite BM. Cabozantinib was associated with a strikingly significant reduction in all BTM (even when BTM were within normal limits at baseline) except NTx by week 8. Minor decreases in bone lesion uptake was noted on NaF PET in 4/6 evaluable patients. Clinical trial information: NCT01811212. [Table: see text]

Elevated Bone Turnover Markers Are Associated With Distal Radius Fractures in Premenopausal Women

To examine whether premenopausal women with distal radius fractures (DRF) have lower levels of 25-hydroxyvitamin D (25[OH]D) and increased levels of serum bone turnover markers (BTM) compared with control subjects without fracture. Premenopausal women with DRF (n= 20) were prospectively enrolled and compared with age-matched individuals without a fracture (n= 20). Outcome measures included serum levels of 25(OH)D, parathyroid hormone (PTH), markers of bone formation (osteocalcin [OC], N-terminal extension propeptide of type I collagen [P1NP], and bone-specific alkaline phosphatase [BSAP]), and markers of bone resorption (C-terminal telopeptide of type I collagen [CTX]). We assessed associations between BTM and DRF with conditional logistic regression and the utility of markers for fracture prediction with a receiver operator characteristic analysis. The fracture group and control group were comparable in terms of age at menarche and BMI. Patients who had fractures had significantly greater levels of OC and P1NP, and demonstrated a nonsignificant increase in CTX. Levels of 25(OH)D, PTH, and BSAP were similar between groups. Conditional logistic regression revealed independent associations between DRF and increased levels of OC and CTX. Levels of 25(OH)D and PTH were not associated with DRF. Receiver operator characteristic analyses demonstrated moderate performance for OC, P1NP, BSAP, and CTX in predicting DRF. Levels of 25(OH)D were not associated with DRF in premenopausal women. However, patients with DRF had increased levels of BTM of formation and resorption. Bone turnover markers may be helpful in predicting future fragility fractures in premenopausal women. Prognostic II.

Elevated Bone Turnover Markers after Risk-Reducing Salpingo-Oophorectomy in Women at Increased Risk for Breast and Ovarian Cancer.

BackgroundRisk-reducing salpingo-oophorectomy (RRSO) reduces ovarian cancer risk in BRCA1/2 mutation carriers. Premenopausal RRSO is hypothesized to increase fracture risk more than natural menopause. Elevated bone turnover markers (BTMs) might predict fracture risk. We investigated BTM levels after RRSO and aimed to identify clinical characteristics associated with elevated BTMs.MethodsOsteocalcin (OC), procollagen type I N-terminal peptide (PINP) and serum C-telopeptide of type I collagen (sCTx) were measured in 210 women ≥ 2 years after RRSO before age 53. BTM Z-scores were calculated using an existing reference cohort of age-matched women. Clinical characteristics were assessed by questionnaire.ResultsBTMs after RRSO were higher than age-matched reference values: median Z-scores OC 0.11, p = 0.003; PINP 0.84, p < 0.001; sCTx 0.53, p < 0.001 (compared to Z = 0). After excluding women with recent fractures or BTM interfering medication, Z-scores increased to 0.34, 1.14 and 0.88, respectively. Z-scores for OC and PINP were inversely correlated to age at RRSO. No correlation was found with fracture incidence or history of breast cancer.ConclusionsFive years after RRSO, BTMs were higher than age-matched reference values. Since elevated BTMs might predict higher fracture risk, prospective studies are required to evaluate the clinical implications of this finding.

Impact of Dietary Intake on Bone Turnover in Patients with Phenylalanine Hydroxylase Deficiency.

Bone mineral density was normal in 44 females with PAH deficiency; however, bone turnover markers suggested uncoupling of bone resorption and formation, particularly in younger patients. Adequate nutrient intake from medical food and overall medical food compliance may positively impact bone turnover.