Avaliação da massa óssea, hormônios e outros fatores relacionados à perda óssea em pacientes com lesão medular
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Data
2014-10-31
Autores
Gaspar, Alexandra Passos [UNIFESP]
Orientadores
Castro, Marise Lazaretti Castro [UNIFESP]
Tipo
Dissertação de mestrado
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Introduction: Spinal cord injury (SCI) as physical disability is an important public health problem, once the majority of these subjects are young men between 27 and 32.4 years of age and at their professional and personal productivity. The SCI patient?s life expectancy is growing every year and the mean survival rate, for those between 25 and 34 years of age, is 38 years after spinal cord injury. This increasing survival rate determines several complications in this population, as osteoporosis /low bone mass loss and secondary fractures. Diagnosing osteoporosis/low bone mass in this population is still a challenge and there is not any specific protocol for densitometry measures. The main segments for bone mass loss in SCI patients are distal femur and proximal tibia, differing from the population that don´t have SCI. Besides, the pathophysiology of bone mass loss is complex and involves many different factors that are not yet well determined. Objective: Evaluate bone mass loss by DXA comparing SCI complete traumatic paraplegic patients compared to control group paired by sex and age ,using a non-standard bone site , distal femur (DF),describing the technical and practical aspects of the procedure. Another aim of the study was to evaluate potential modifiable factors that could interfere in the bone mass loss in SCI patients compared to control group. Evaluate sexual hormones, vitamin D and bone biomarkers trying to find potential correlations with bone mass. Subjects and Methods: Twenty nine patients were included in the study and seventeen able-bodied male adults were compared as a control group and were paired by age and sex. The subjects (SCI and controls) did BMD by DXA exams; the following bone sites were scanned: femoral neck (FN), total femur (TF), LS and distal femur (DF) and also body composition. Blood samples were collected from all subjects with 8 hours morning fasting including: Creatinine (Crea), urea (U), aspartate transaminase (AST), alanine transaminase (ALT), total calcium (Ca), parathyroid hormone (PTH) level, 25(OH)D level, alkaline phosphatase (AP), collagen type I C-terminal telopeptide (CTX), Total testosterone (TTesto), lutein hormone (LH), follicle stimulating hormone (FSH), Prolactin (PRL), sexual hormone binding globulin (SHBG). Free testosterone (FTesto) was calculated. All patients did lumbar spine and inferior limbs X-Ray. Results: The median time of spinal cord injury was 36 months. The level of injuries varied from T2-T12. SCI patients had lower BMD at all inferior limbs sites when compared to controls, but this was not observed at lumbar spine. We didn´t find any of the subjects in control group with Z-Score < - 2.0 (low bone mass).Although for the patients we found 7 (28%) subjects with low bone mass in total femur (TF), 5 (20%) in femoral neck (FN) and 2 (8%) in lumbar spine (LS). We found correlation between femoral neck and distal femur (DF) for controls (r= 0.73, p < 0.001) and patients (r= 0.50, p < 0.007). There was an inverse relationship between DF and time of injury (r= -0.380, p =0.05). We also find correlation between % of lean bone mass and all femoral sites for control group, although in patients it was observed only for DF (r=0.41, p=0.02). CTX showed an inverse relationship with the time since injury (r= -0.60, p <0.001). Patients had lower free testosterone levels (LM 12.00±2.91 vs. controls 19.51±5.72 ng/dL; p?0.001) and the majority of cases, had inappropriate normal gonadotropins. Only 3 patients had FSH levels under normal limits. The control group had correlation between free testosterone and LS BMD (r=0.63, p =0.07) and unexpectedly, for the SCI subjects, we observed an inverse relationship between total testosterone and the BMDs of the TF (r =-0.49, p =0.007) and LS (r = - 0.35, p = 0.043). The mean levels of 25(OH)D were not significantly different between the groups, although the mean value for the SCI subjects was lower than that for the controls (p=0.075). There was a high positive correlation between FTesto and 25(OH)D in the control group (r=0.68, p=0.03), but this relationship was lost in the SCI subjects (r= 0.12, p= 0.51). Conclusions: The analysis of BMD by DXA was capable to demonstrate bone mass loss at all femoral sites, but not in lumbar spine. We did not observe fractures in SCI patients. The non-standard region of interest, the distal femur (DF), was created and seemed to be more sensitive to bone mass loss in this population than proximal femur. The technical and practical description of densitometry could facilitate the reproducibility in future studies. The potential modifiable factors, such as standing and the levels of 25(OH)D did not show any correlation with bone mineral density ( BMD),although patients showed more 25(OH)D deficiency when compared to control group thus, this deficiency must be corrected. Patients had lower levels of total and free testosterone with inappropriate gonadotropins levels, suggesting hypogonadotropic hypogonadism. . The loss rate was inversely related to the time since injury (as shown by the biomarker CTX); thus, earlier antiresorptive interventions should be considered, The 25(OH)D rate levels was correlated with free testosterone in control group, although this was not observed in patients.
A DMO por DXA foi capaz de demonstrar a perda óssea nos diversos sítios do fêmur, mas não na coluna lombar. Não observamos fraturas em pacientes. A região de interesse não padronizada, o fêmur distal (FD), foi criada e mostrou ser mais sensível à perda óssea nesta população do que fêmur proximal. A descrição de aspectos técnicos e práticos da densitometria facilitará reprodutibilidade da técnica em estudos futuros. Os potenciais fatores modificáveis como ortostatismo e 25(OH)D não mostraram correlação com a DMO, entretanto pacientes apresentaram maior frequência de deficiência de 25(OH)D em relação ao grupo controle, que devem ser corrigidos. Os pacientes apresentaram valores menores de testosterona total e livre, acompanhados de gonadotrofinas inapropriadamente normais, sugerindo hipogonadismo hipogonadotrófico. Os níveis de CTX apresentaram correlação inversa com o tempo de LM. A 25(OH)D apresentou significante correlação com testosterona no grupo controle não observado nos pacientes com LM
A DMO por DXA foi capaz de demonstrar a perda óssea nos diversos sítios do fêmur, mas não na coluna lombar. Não observamos fraturas em pacientes. A região de interesse não padronizada, o fêmur distal (FD), foi criada e mostrou ser mais sensível à perda óssea nesta população do que fêmur proximal. A descrição de aspectos técnicos e práticos da densitometria facilitará reprodutibilidade da técnica em estudos futuros. Os potenciais fatores modificáveis como ortostatismo e 25(OH)D não mostraram correlação com a DMO, entretanto pacientes apresentaram maior frequência de deficiência de 25(OH)D em relação ao grupo controle, que devem ser corrigidos. Os pacientes apresentaram valores menores de testosterona total e livre, acompanhados de gonadotrofinas inapropriadamente normais, sugerindo hipogonadismo hipogonadotrófico. Os níveis de CTX apresentaram correlação inversa com o tempo de LM. A 25(OH)D apresentou significante correlação com testosterona no grupo controle não observado nos pacientes com LM
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GASPAR, Alexandra Passos. Avaliação da massa óssea, hormônios e outros fatores relacionados à perda óssea em pacientes com lesão medular. 2014. 145 f. Dissertação (Mestrado) - Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, 2014.