The Pheochromocytoma/Paraganglioma syndrome: an overview on mechanisms, diagnosis and management

ABSTRACT Pheochromocytomas/paragangliomas (PPGL) are rare, metastatic, and potentially fatal neuroendocrine tumors, often neglected because they present symptoms similar to other prevailing clinical conditions such panic syndrome, thyrotoxicosis, anxiety, hypoglycemia, etc., delaying diagnosis and treatment. The rate of diagnosis of PPGL has been increasing with the improvement in the measurement of catecholamine metabolites and the expanding availability of imaging procedures. Its essential genetic nature has been extensively investigated, comprising more than 20 genes currently related to PPGL and more new genes will probably be revealed. This overview will shed some light on the clinical, laboratory, topographical, genetic diagnosis, and management of PPGL.

The Pheochromocytoma/Paraganglioma syndrome: an overview on mechanisms, diagnosis and management.

Pheochromocytomas/paragangliomas (PPGL) are rare, metastatic, and potentially fatal neuroendocrine tumors, often neglected because they present symptoms similar to other prevailing clinical conditions such panic syndrome, thyrotoxicosis, anxiety, hypoglycemia, etc., delaying diagnosis and treatment. The rate of diagnosis of PPGL has been increasing with the improvement in the measurement of catecholamine metabolites and the expanding availability of imaging procedures. Its essential genetic nature has been extensively investigated, comprising more than 20 genes currently related to PPGL and more new genes will probably be revealed. This overview will shed some light on the clinical, laboratory, topographical, genetic diagnosis, and management of PPGL.

Diagnosis of Overtraining Syndrome: Results of the Endocrine and Metabolic Responses on Overtraining Syndrome Study: EROS-DIAGNOSIS.

OBJECTIVES: Overtraining syndrome (OTS), a common dysfunction among elite athletes, causes decreased performance and fatigue and has no standardized diagnostic criteria. The Endocrine and Metabolic Responses on Overtraining Syndrome (EROS) study identified more than 45 potential biomarkers of OTS. In the present study, we hypothesized that combinations of these biomarkers could be an accurate diagnostic tool for OTS. METHODS: We selected parameters with largest difference and fewest overlapping results compared to healthy athletes and highest feasibility and reproducibility. Among the multiple combinations attempted, we chose those that did not show overlapping results, according to the objective. RESULTS: We included 11 clinical parameters, 4 basal hormones, and 5 hormonal responses in Insulin Tolerance Test (ITT). The three selected diagnostic tools were the (i) EROS-CLINICAL, with only clinical parameters, which was suitable as an initial assessment for athletes suspected of OTS; (ii) EROS-SIMPLIFIED, with clinical parameters and basal hormones, when the EROS-CLINICAL was inconclusive; and (iii) EROS-COMPLETE, with basal and hormonal responses to stimulation tests, which was valuable for population-based screening, research purposes, and unusual presentations of OTS. CONCLUSION: We identified innovative tools with 100% accuracy for the diagnosis of OTS, without the need to exclude confounding disorders.

The value of signal intensity on T1-weighted chemical shift magnetic resonance imaging combined with proton magnetic resonance spectroscopy for the diagnosis of adrenal adenomas.

OBJECTIVE: To investigate the advantages of using modified signal intensity measurements on chemical shift imaging alone or in conjunction with proton magnetic resonance spectroscopy in the differential diagnosis of adrenal adenomas. MATERIALS AND METHODS: This was a prospective study involving 97 patients with adrenal nodules or masses. The signal intensity index (SII) was calculated as [(signal intensity on the in-phase image - signal intensity on the out-of-phase image) ∕ (signal intensity on the in-phase image)] × 100%. We determined the averages of the minimum, mean, and maximum signal intensity values measured on three consecutive images. When that was not possible (for smaller lesions), we used one or two images. We employed a region of interest that covered one half to two thirds of the mass. All indices were compared with metabolite ratios derived from spectroscopy: lactate/creatine; glutamine-glutamate/creatine; choline/creatine; choline/lipid; 4.0-4.3 ppm/Cr; and lipid/creatine. RESULTS: Of the 97 patients evaluated, 69 were diagnosed with adenomas and 28 were diagnosed with nonadenomas. All SII measurements and spectroscopy-derived metabolite ratios were significant to the differentiation between adenomas and nonadenomas, except for the lipid/creatine and choline/lipid ratios. In 37.8% of the cases, it was not possible to perform spectroscopy. When it was possible, the lactate/creatine ratio was found to have higher accuracy than did the SII. CONCLUSION: Determining the SII and metabolite ratios increased the accuracy of the differential diagnosis of adrenal adenomas.

OBJETIVO: Investigar as vantagens do uso de medições do índice de intensidade de sinal modificadas em imagens de deslocamento químico (chemical shift), isoladamente ou em conjunto com a espectroscopia por ressonância magnética de prótons, no diagnóstico diferencial de adenomas adrenais. MATERIAIS E MÉTODOS: Estudo prospectivo envolvendo 97 pacientes com nódulos ou massas adrenais. O índice de intensidade do sinal (SII) foi calculado como [(intensidade do sinal na imagem em fase ­ intensidade do sinal na imagem fora de fase) ∕ (intensidade do sinal na imagem em fase)] × 100%. Determinamos as médias dos valores mínimo, médio e máximo da intensidade do sinal medida em três imagens consecutivas. Quando isso não foi possível (para lesões menores), usamos uma ou duas imagens. Nós empregamos uma região de interesse que cobria de metade a dois terços da massa. Todos os índices foram comparados com razões metabólicas derivadas da espectroscopia: lactato/creatina, glutamato-glutamina/creatina, colina/creatina, colina/lipídio, 4,0­4,3 ppm/creatina e lipídio/creatina. RESULTADOS: Dos 97 pacientes avaliados, 69 foram diagnosticados como adenomas e 28 foram diagnosticados como não adenomas. Todas as medições SII e razões de metabólitos derivados da espectroscopia foram significativas para a diferenciação entre adenomas e não adenomas, exceto as razões lipídio/creatina e colina/lipídio. Em 37,8% dos casos não foi possível realizar espectroscopia. Quando possível, a razão lactato/creatina apresentou maior precisão do que o SII. CONCLUSÃO: A determinação das razões SII e metabólitos aumentaram a acurácia do diagnóstico diferencial de adenomas adrenais.

The value of signal intensity on T1-weighted chemical shift magnetic resonance imaging combined with proton magnetic resonance spectroscopy for the diagnosis of adrenal adenomas / O valor da intensidade do sinal na sequência de deslocamento químico ponderada em T1 associada a espectroscopia de ressonância magnética no diagnóstico de adenomas adrenais

Abstract Objective: To investigate the advantages of using modified signal intensity measurements on chemical shift imaging alone or in conjunction with proton magnetic resonance spectroscopy in the differential diagnosis of adrenal adenomas. Materials and Methods: This was a prospective study involving 97 patients with adrenal nodules or masses. The signal intensity index (SII) was calculated as [(signal intensity on the in-phase image − signal intensity on the out-of-phase image) ∕ (signal intensity on the in-phase image)] × 100%. We determined the averages of the minimum, mean, and maximum signal intensity values measured on three consecutive images. When that was not possible (for smaller lesions), we used one or two images. We employed a region of interest that covered one half to two thirds of the mass. All indices were compared with metabolite ratios derived from spectroscopy: lactate/creatine; glutamine-glutamate/creatine; choline/creatine; choline/lipid; 4.0-4.3 ppm/Cr; and lipid/creatine. Results: Of the 97 patients evaluated, 69 were diagnosed with adenomas and 28 were diagnosed with nonadenomas. All SII measurements and spectroscopy-derived metabolite ratios were significant to the differentiation between adenomas and nonadenomas, except for the lipid/creatine and choline/lipid ratios. In 37.8% of the cases, it was not possible to perform spectroscopy. When it was possible, the lactate/creatine ratio was found to have higher accuracy than did the SII. Conclusion: Determining the SII and metabolite ratios increased the accuracy of the differential diagnosis of adrenal adenomas.

Resumo Objetivo: Investigar as vantagens do uso de medições do índice de intensidade de sinal modificadas em imagens de deslocamento químico (chemical shift), isoladamente ou em conjunto com a espectroscopia por ressonância magnética de prótons, no diagnóstico diferencial de adenomas adrenais. Materiais e Métodos: Estudo prospectivo envolvendo 97 pacientes com nódulos ou massas adrenais. O índice de intensidade do sinal (SII) foi calculado como [(intensidade do sinal na imagem em fase - intensidade do sinal na imagem fora de fase) ∕ (intensidade do sinal na imagem em fase)] × 100%. Determinamos as médias dos valores mínimo, médio e máximo da intensidade do sinal medida em três imagens consecutivas. Quando isso não foi possível (para lesões menores), usamos uma ou duas imagens. Nós empregamos uma região de interesse que cobria de metade a dois terços da massa. Todos os índices foram comparados com razões metabólicas derivadas da espectroscopia: lactato/creatina, glutamato-glutamina/creatina, colina/creatina, colina/lipídio, 4,0-4,3 ppm/creatina e lipídio/creatina. Resultados: Dos 97 pacientes avaliados, 69 foram diagnosticados como adenomas e 28 foram diagnosticados como não adenomas. Todas as medições SII e razões de metabólitos derivados da espectroscopia foram significativas para a diferenciação entre adenomas e não adenomas, exceto as razões lipídio/creatina e colina/lipídio. Em 37,8% dos casos não foi possível realizar espectroscopia. Quando possível, a razão lactato/creatina apresentou maior precisão do que o SII. Conclusão: A determinação das razões SII e metabólitos aumentaram a acurácia do diagnóstico diferencial de adenomas adrenais.

Allelic Variants of ARMC5 in Patients With Adrenal Incidentalomas and in Patients With Cushing's Syndrome Associated With Bilateral Adrenal Nodules.

Objective: Germline ARMC5 mutations are considered to be the main genetic cause of primary macronodular adrenal hyperplasia (PMAH). PMAH is associated with high variability of cortisol secretion caused from subclinical hypercortisolism to overt Cushing's syndrome (CS), in general due to bilateral adrenal nodules and rarely could also be due to non-synchronic unilateral adrenal nodules. The frequency of adrenal incidentalomas (AI) associated with PMAH is unknown. This study evaluated germline allelic variants of ARMC5 in patients with bilateral and unilateral AI and in patients with overt CS associated with bilateral adrenal nodules. Methods: We performed a retrospective multicenter study involving 123 patients with AI (64 bilateral; 59 unilateral). We also analyzed 20 patients with ACTH pituitary independent overt CS associated with bilateral adrenal nodules. All patients underwent germline genotyping analysis of ARMC5; abdominal CT and were classified as normal, possible or autonomous cortisol secretion, according to the low doses of dexamethasone suppression test. Results: We identified only one pathogenic allelic variant among the patients with bilateral AI. We did not identify any pathogenic allelic variants of ARMC5 in patients with unilateral AI. Thirteen out of 20 patients (65%) with overt CS and bilateral adrenal nodules were carriers of pathogenic germline ARMC5 allelic variants, all previously described. The germline ARMC5 mutation was observed in only one patient with bilateral AI; it was associated with autonomous cortisol secretion and showed to be a familial form. Conclusion: The rarity of germline ARMC5 mutations in AI points to other molecular mechanisms involved in this common adrenal disorder and should be investigated. In contrast, patients with overt Cushing's syndrome and bilateral adrenal nodules had the presence of ARMC5 mutations that were with high prevalence and similar to the literature. Therefore, we recommend the genetic analysis of ARMC5 for patients with established Cushing's syndrome and bilateral adrenal nodules rather than patients with unilateral AI.

Novel insights of overtraining syndrome discovered from the EROS study.

BACKGROUND: Excessive training and inadequate recovery could cause 'overtraining syndrome' (OTS), which is characterised by underperformance and fatigue. The pathophysiology of OTS is unclear. We aimed to describe novel mechanisms and risk factors associated with OTS, and thereby facilitate its early identification and prevention, from a comprehensive joint qualitative analysis of the findings from all the four arms of the Endocrine and Metabolic Responses on Overtraining Syndrome (EROS) study. METHODS: We compared the types and proportions of behavioural patterns of 67 evaluated parameters of OTS from 51 participants-athletes with OTS (OTS, n=14), healthy athletes (n=25) and healthy non-physically active controls (n=12). We performed overall and pairwise comparisons for statistically significant differences between the three groups (p<0.05). RESULTS: A total of 44 (65.7%) markers exhibited significant differences between the three groups: 32 (72.7%) showed a loss of the conditioning effect of exercise ('deconditioning'), 7 (15.9%) showed changes exclusive to OTS, 3 (6.8%) maintained the exercise-induced conditioning effects and 2 (4.5%) revealed an exacerbation of the adaptive changes to exercises. CONCLUSION: Our findings suggest that OTS is likely triggered by multiple factors, not restricted to excessive training, resulted from a chronic energy deprivation, leading to multiple losses in the conditioning processes typically observed in healthy athletes, as a combination of 'paradoxical deconditioning' processes, which explains the gradual and marked loss of physical conditioning found in OTS. We, therefore, suggest that the term 'paradoxical deconditioning syndrome' better represents the features of this syndrome.

Development of a strategy of physician-patient relationship for improving care for patients with disorders of sex development: a qualitative study / Desenvolvimento de uma estratégia de relacionamento médico-paciente para a melhoria do atendimento aos pacientes com desordens do desenvolvimento do sexo: um estudo qualitativo

ABSTRACT: CONTEXT AND OBJECTIVE: Care for patients with disorders of sex development (DSD) should be provided in integrated-care centers by a multidisciplinary team. Implementation of this project within the teaching clinic routine presents several challenges: 1) difficulties in relationships between the medical team and patients and their families; 2) age, ethnic and cultural differences; 3) DSD-related prejudice; and 4) physicians' anxiety. We report on a psychologist's work strategy that focused on creating arrangements that could contribute towards development of the relationship between the medical team and patients and their families, as a way of preparing the clinical staff to manage treatment of adult DSD patients. DESIGN AND SETTING: Prospective qualitative study. METHODS: Between February 2010 and April 2015, we conducted a qualitative study in the Adrenal Outpatient Clinic of Escola Paulista de Medicina (São Paulo, Brazil), based on interviews, team discussions and group dynamics with resident physicians, postgraduate students and attending physicians. RESULTS: Implementation of the project allowed residents to build a story of differentiated care for their patients, thus facilitating dialog between them and making it possible to address taboo topics. Sequential care provided by the same resident led patients to feel that their doctor cared for them, with individuality, continuity and a sense of interest in their story. CONCLUSION: Presence of a psychologist in the outpatient routine enabled inclusion of subjective factors in the routine of medical consultations, thus broadening the notion of healthcare for patients with DSD, facilitating bonds and providing support for difficulties faced.

RESUMO: CONTEXTO E OBJETIVO: Pacientes com desordens do desenvolvimento do sexo (DDS) e seus familiares devem ser atendidos em centros de atenção integral, por equipe multidisciplinar. A efetivação desse projeto no cotidiano da clínica-escola apresenta vários desafios: 1) dificuldades nas relações entre equipe médica, paciente e família, 2) diferenças etárias, étnicas e culturais, 3) preconceitos relacionados às DDS, e 4) angústia dos médicos. Relatamos o desenvolvimento de uma estratégia de trabalho do psicólogo, que teve como foco a criação de dispositivos que contribuíssem para o aprimoramento da relação entre equipe médica, paciente e família, preparando o staff clínico para administrar o tratamento de pacientes adultos com DDS. DESENHO E LOCAL: Estudo qualitativo prospectivo. MÉTODOS: De fevereiro de 2010 até abril de 2015, realizamos uma pesquisa qualitativa no Ambulatório de Adrenal da Escola Paulista de Medicina (São Paulo, Brasil), baseada em entrevistas, discussões de equipe e dinâmica de grupo com médicos residentes, pós-graduandos e assistentes. RESULTADOS: A implementação do projeto possibilitou aos residentes construir uma história de atendimento diferenciado com seus pacientes, facilitando o diálogo entre eles e permitindo que temas-tabus fossem abordados. O fato de ter sido atendido seguidamente pelo mesmo residente possibilitou ao paciente a sensação de cuidado, individualidade, continuidade e a sensação de que havia interesse, por parte do médico, sobre a sua história. CONCLUSÃO: A presença do psicólogo no cotidiano do ambulatório permitiu que aspectos subjetivos fossem incluídos na rotina das consultas médicas, ampliando a noção de saúde e cuidado aos pacientes com DDS, facilitando o vínculo e dando suporte para as dificuldades encontradas.

Development of a strategy of physician-patient relationship for improving care for patients with disorders of sex development: a qualitative study.

CONTEXT AND OBJECTIVE: Care for patients with disorders of sex development (DSD) should be provided in integrated-care centers by a multidisciplinary team. Implementation of this project within the teaching clinic routine presents several challenges: 1) difficulties in relationships between the medical team and patients and their families; 2) age, ethnic and cultural differences; 3) DSD-related prejudice; and 4) physicians' anxiety. We report on a psychologist's work strategy that focused on creating arrangements that could contribute towards development of the relationship between the medical team and patients and their families, as a way of preparing the clinical staff to manage treatment of adult DSD patients. DESIGN AND SETTING: Prospective qualitative study. METHODS: Between February 2010 and April 2015, we conducted a qualitative study in the Adrenal Outpatient Clinic of Escola Paulista de Medicina (São Paulo, Brazil), based on interviews, team discussions and group dynamics with resident physicians, postgraduate students and attending physicians. RESULTS: Implementation of the project allowed residents to build a story of differentiated care for their patients, thus facilitating dialog between them and making it possible to address taboo topics. Sequential care provided by the same resident led patients to feel that their doctor cared for them, with individuality, continuity and a sense of interest in their story. CONCLUSION: Presence of a psychologist in the outpatient routine enabled inclusion of subjective factors in the routine of medical consultations, thus broadening the notion of healthcare for patients with DSD, facilitating bonds and providing support for difficulties faced.

Radiofrequency Ablation of Functioning Adrenal Adenomas: Preliminary Clinical and Laboratory Findings.

PURPOSE: To evaluate clinical and laboratory findings in patients undergoing radiofrequency (RF) ablation for functioning adrenal adenomas. MATERIALS AND METHODS: Eleven adult patients, nine with Conn syndrome and two with Cushing syndrome, underwent percutaneous computed tomography-guided RF ablation for benign adrenal neoplasms. Systolic, diastolic, and mean blood pressure and the number of classes of antihypertensive drugs used by each patient were analyzed before and 1, 4, and 12 weeks after the procedure. Serum hormone levels were analyzed within 30 days before and 12 weeks after the procedure. RESULTS: Of the nine patients with Conn syndrome, eight showed normal serum aldosterone levels after the procedure and one patient had a nodule located very close to the inferior vena cava, resulting in incomplete ablation. The two patients with Cushing syndrome had normal serum and salivary cortisol levels after the procedure. Mean aldosterone concentration at baseline was 63.3 ng/dL ± 28.0 and decreased to 13.3 ng/dL ± 13.5 at 12 weeks postoperatively (P = .008). Systolic, diastolic, and mean blood pressures decreased significantly in the first week after the procedure (P < .001) and remained stable during further follow-up. CONCLUSIONS: In patients with Conn syndrome or Cushing syndrome, percutaneous RF ablation of functioning adrenal adenomas may result in normalization of hormone secretion, improvement in blood pressure, and reduced need for antihypertensive drugs.

Percutaneous ablation of functioning adrenal adenoma: a report on 11 cases and a review of the literature.

PURPOSE: Percutaneous ablation of functioning adrenal adenomas has been an alternative to videolaparoscopic treatment. This study aimed to evaluate the feasibility, safety and efficacy of radiofrequency ablation (RFA) in the treatment of functioning adrenal tumors using a computed tomography (CT)-guided percutaneous technique as demonstrated by our experience and the literature. METHODS: Eleven adult patients (mean age 46 years) with a diagnosis of functioning adrenal adenoma underwent CT-guided RFA between October 2011 and August 2012. All RFA procedures were performed using a needle electrode with a single lateral filament and the RITA(®) 1500X radiofrequency generator. The RFA protocol consisted of two cycles of 5 min each with 1-min interval, with no additional ablation cycles. Contrast-enhanced CT scans were obtained and analyzed for immediate treatment success and possible complications. RESULTS: Maximum tumor dimension ranged from 1.2 to 3.4 cm. The mean procedure time was 74 min, and length of hospital stay ranged from 0.9 to 3.2 days (mean 1.8 days). One patient had residual pneumothorax and one patient had neuritis involving the T10 dermatome. Of 11 patients, 10 recovered from their condition. Only one patient remained with hyperaldosteronism, but with reduced anti-hypertensive medication. CONCLUSIONS: CT-guided percutaneous RFA was a safe and effective treatment for functioning adrenal adenomas, with short hospital length of stay and low complication rate.

Final height in congenital adrenal hyperplasia: the dilemma of hypercortisolism versus hyperandrogenism.

OBJECTIVE: The purpose of this study was to identify factors that might interfere with reaching the final height in patients with 21-hydroxylase deficiency (21-OHD). SUBJECTS AND METHODS: Thirty-one patients with classical 21-OHD who reached their FH in our Institution were evaluated in order to compare the Z score for final height (FHZ) with: (1) the target height, (2) the standard height for the population, and (3) the hydrocortisone treatment schedule. RESULTS: The FHZ of -2.13 ± 1.11 had a significant negative correlation with the hydrocortisone doses used throughout the period of study. Patients who reached FH within the normal population range were those who received lower doses of hydrocortisone, as compared to those whose FH remained below -2 SDS. CONCLUSION: We conclude that careful treatment adjustments have a major influence on growth of children with CAH, and that the dose range for hydrocortisone replacement that does not lead to side effects is relatively narrow. The better height outcome was achieved in 21-OHD patients who received lower doses of hydrocortisone.

Final height in congenital adrenal hyperplasia: the dilemma of hypercortisolism versus hyperandrogenism / Altura final na hiperplasia suprarrenal congênita: o dilema do hipercortisolismo versus hiperandrogenismo

OBJECTIVE: The purpose of this study was to identify factors that might interfere with reaching the final height in patients with 21-hydroxylase deficiency (21-OHD). SUBJECTS AND METHODS: Thirty-one patients with classical 21-OHD who reached their FH in our Institution were eva­luated in order to compare the Z score for final height (FHZ) with: (1) the target height, (2) the standard height for the population, and (3) the hydrocortisone treatment schedule. RESULTS: The FHZ of -2.13 ± 1.11 had a significant negative correlation with the hydrocortisone doses used throughout the period of study. Patients who reached FH within the normal population range were those who received lower doses of hydrocortisone, as compared to those whose FH remained below -2 SDS. CONCLUSION: We conclude that careful treatment adjustments have a major influence on growth of children with CAH, and that the dose range for hydrocortisone replacement that does not lead to side effects is relatively narrow. The better height outcome was achieved in 21-OHD patients who received lower doses of hydrocortisone.

OBJETIVO: O objetivo do estudo foi a identificação de fatores que podem interferir na aquisição de altura final de pacientes com a deficiência de 21-hidroxilase (21OHD). SUJEITOS E MÉTODOS: A altura final (escore Z: FHZ) de 31 pacientes com a forma clássica da 21OHD, acompanhados em nossa instituição, foi comparada com: (1) a altura alvo, (2) o padrão de referência para a população, e (3) a dose de hidrocortisona durante o acompanhamento. RESULTADOS: Observou-se correlação negativa significativa entre o FHZ de -2,13 ± 1,11 e as doses de hidrocortisona utilizadas durante o período de estudo. Os pacientes que atingiram altura final dentro do padrão de referência para a população usaram doses mais baixas de hidrocortisona quando comparados àqueles que permaneceram abaixo de -2 DP. CONCLUSÃO: O cuidado nos ajustes das doses durante o tratamento da 21OHD tem grande influência sobre o crescimento das crianças. A faixa de variação da dose de reposição da hidrocortisona que não causa efeitos colaterais é relativamente estreita. O melhor resultado estatural foi observado nos pacientes com 21OHD tratados com doses mais baixas de hidrocortisona.

Desenvolvimento de um radioimunoensaio de dexametasona no soro como subsídio para o diagnóstico da síndrome de Cushing / Development of serum dexamethasone radioimmunoassay to corroborate Cushing's syndrome diagnosis

INTRODUÇÃO: O teste de supressão com 1 mg de dexametasona (TSDx) é amplamente empregado no rastreamento da síndrome de Cushing (SC) dada sua elevada acurácia diagnóstica. A SC é um distúrbio endocrinometabólico resultante do hipercortisolismo crônico com característica de ausência de supressão do cortisol no TSDx. OBJETIVO: Desenvolver um radioimunoensaio (RIE) para a dosagem de dexametasona (Dx) no soro para complementar o TSDx. MÉTODOS: Foram imunizados três coelhos com o conjugado dexametasona-21-hemissuccinato-BSA para escolha do melhor anticorpo e o RIE foi desenvolvido de acordo com as recomendações da RE 899/2003 da Agência Nacional de Vigilância Sanitária (ANVISA). Analisamos 96 voluntários, sendo 67 submetidos ao TSDx e 29 não, e 12 pacientes com SC, estudados na Universidade Federal de São Paulo (UNIFESP) e na Santa Casa de Misericórdia de São Paulo. RESULTADOS: O anticorpo contra Dx selecionado mostrou boa especificidade, coeficiente de variação (CV por cento) intra e interensaio < 20 por cento, exatidão de 93,8 por cento e dose mínima detectada de 19,5 ng/dl. A concentração de Dx no soro foi semelhante nos voluntários e pacientes com SC (ausência/supressão do cortisol): 205 a 703 ng/dl e 174 a 661 ng/dl (intervalo de confiança [IC] 95 por cento), respectivamente; os valores foram indetectáveis naqueles que não se submeteram ao teste. DISCUSSÃO: O anticorpo empregado apresenta boa afinidade e especificidade para quantificar a Dx no soro. O RIE mostrou reprodutibilidade e eficiência na determinação dos níveis séricos de Dx durante o TSDx. CONCLUSÃO: O presente RIE para a dosagem de Dx no soro é acurado e confiável, permitindo estabelecer uma faixa de referência de valores para subsidiar a interpretação do TSDx.

INTRODUCTION: The 1 mg dexamethasone suppression test (DxST) is widely used to screen Cushing's syndrome (CS) due to its high diagnostic accuracy. CS is an endocrine-metabolic disorder caused by hypercorticism, which is characterized by the absence of cortisol suppression in DxST. OBJECTIVE: To develop a radioimmunoassay (RIA) for the measurement of serum dexamethasone (Dx) to complement DxST. METHODS: Three rabbits were inoculated with dexamethasone-21-hemisuccinate-BSA in order to choose the best antibody. Serum Dx RIA was performed according to RE 899/2003 (Agência Nacional de Vigilância Sanitária [ANVISA]) regulations. Serum samples from 96 volunteers from Universidade Federal de São Paulo (UNIFESP) and Santa Casa de Misericórdia de São Paulo were analyzed, 67 of which were submitted to DxST and 29 were not. There were 12 patients with CS. RESULTS: The Dx antibody chosen showed good specificity. Intra- and interassay CV were < 20 percent with 93.8 percent accuracy and the lowest detection limit was 19.5 ng/dl. Serum Dx concentration was similar among both volunteers and CS patients (absence of cortisol suppression): 205 to 703 ng/dl and 174 to 661 ng/dl (95 percent CI), respectively. Values were undetectable among those that were not submitted to the test. Discussion: The anti-Dx antibody shows high specificity and reliability to quantify serum Dx in DxST. The Dx RIA presented reproducibility and reliability in the determination of serum Dx levels during DxST. CONCLUSION: The current RIA for serum Dx is accurate and reliable, which permits to establish a reference value range to substantiate DxST interpretation.

A very low dose intravenous dexamethasone suppression test as an index of glucocorticoid sensitivity.

BACKGROUND/AIMS: The wide variability of responses to corticotherapy suggests a role for individual recognition of steroid sensitivity in order to customize treatment. Oral dexamethasone (DEX) administration may be hindered by the rate of its intestinal absorption and the liver first-passage effect. In this study we suggest that an intravenous very low dose DEX suppression test (VLD IV-DST) can be used as an index for glucocorticoid (GC) sensitivity. METHODS: We evaluated 87 normal subjects: 44 prepubertal children, 23 adolescents and 20 adults with a VLD IV-DST using 20 mug/m(2) of DEX (dose able to recognize GC sensitivity). Cortisol was initially measured at several time-points after DEX prompting us to establish its nadir and subsequent simplification of the test by measuring cortisol at baseline and after 120 min. RESULTS: Baseline cortisol was similar in adolescents and in adults, but lower in children. There was a spectrum of individual responses in all age groups. The percent reduction of cortisol after 120 min was different in these three age groups, with median values of 44.4% in children, 25.9% in adolescents and 61.6% in adults. CONCLUSION: This simplified VLD IV-DST using 20 mug/m(2) of DEX is useful to evaluate individual sensitivity to GC in different age groups.

Aplicação da cromatografia líquida de alta eficiência para quantificação direta da 17`alfa'-hidroxiprogesterona sérica / Application of reversed-phase liquid-cromatography (RP-HPLC) to direct quantification of 17-`alpha'-hydroxyprogesterone in serum

A determinação dos níveis séricos de 17`alfa'-hidroxiprogesterona (17OHP) é essencial no diagnóstico laboratorial da hiperplasia adrenal congênita (CAH) por deficiência de 21-hidroxilase. Essa condição é responsável por pseudo-hermaffroditismo em meninas e precocidade sexual em ambos os sexos. A 17OHP foi quantificada diretamente empregando-se cromatografia líquida de alta eficiência no modo fase reversa (RP-HPLC) em amostras de soro previamente extraídas com éter. Utilizou-se coluna ODS-Hypersil® e fase móvel composta de água-metanol (4:6 v/v) com vazão de 1,0 mL/min. A determinação deu-se em 246 nm. A 17OHP apresentou tempo de retenção de 5,6 min. O método mostrou-se eficaz e eficiente com sensibilidade e linearidade (r²=0,9993) na faixa de concentração estudada de 500 a 100.000 ng/dL...