Serum PTH reference values in an adult Brazilian population: implications for the diagnosis of hyperparathyroidism

ABSTRACT Objective: To define serum parathyroid hormone (PTH) reference values in carefully selected subjects following the recommended pre-analytical guidelines. Subjects and methods: First, 676 adults who would be submitted to thyroidectomy were evaluated. Patients using interfering medications or with malabsorption syndrome, hypomagnesemia, hyper- or hypophosphatemia, hypo- or hypercalcemia, 25-hydroxyvitamin D < 30 ng/dL, estimated glomerular filtration rate < 60 mL/min/1.73 m2, urinary calcium/creatinine ratio ≥ 0.25, thyroid dysfunction, parathyroid adenoma detected during surgery were excluded. The sample consisted of 312 subjects. Results: The median, minimum, maximum, and 2.5th and 97.5th percentiles of the PTH values obtained were 30, 7.2, 78, 10.1, and 52 pg/mL, respectively. Thus, the reference range was 10 to 52 pg/mL. PTH > 65 pg/mL, the upper limit of normal according to the manufacturer of the kit, was observed in only one subject (0.3%). Considering the upper limit proposed by the kit's manufacturer, 1/6 hypercalcemic patients and 4/8 normocalcemic patients with PHPT had normal PTH. Using the upper limit established in this study, only one normocalcemic patient had normal PTH. Thus, the sensitivity of PTH in detecting asymptomatic primary hyperparathyroidism (PHPT) using the values recommended by the kit and established in this study was 64% and 93%, respectively (50% versus 87.5% for normocalcemic PHPT). Conclusion: The upper reference limit of PTH obtained for a rigorously selected sample was 20% lower than that provided by the assay, which increased its sensitivity in detecting PHPT.

Bloqueio atrioventricular avançado no hiperparatireoidismo: uma complicação rara e irreversível / Advanced atrioventricular block in hyperparathyroidism: a rare and irreversible complication

Hiperparatireoidismo associado a hipercalcemia causando bradicardia significativa é uma combinação rara. Relatamos o caso de uma paciente de 62 anos de idade em pré-operatório de paratireoidectomia total decorrente de hiperparatireoidismo primário sintomático, que evoluiu com bloqueio atrioventricular avançado percebido durante a internação. A paciente necessitou de implante de marcapasso definitivo, pois permaneceu com bloqueio cardíaco avançado mesmo após correção da hipercalcemia

The combination of hyperparathyroidism and hypercalcemia leading to significant bradycardia is rare. Here we report the case of a 62-year -old female patient in the preoperatory of a total parathyroidectomy due to symptomatic primary hyperparathyroidism, which evolved with an advanced atrioventricular block during hospitalization. The patient required a definitive pacemaker implantation, since the advanced heart block persisted after the correction of hypercalcemia

Vitamin D (25(OH)D) in patients with chronic kidney disease stages 2-5 / Niveles de vitamina D (25(OH)D) en pacientes con enfermedad renal crónica estadios 2 a 5

Abstract Objective: To establish the impact the chronic kidney disease stage has in the native vitamin D levels in patients not undergoing dialysis treatment. Methods: A study performed in Manizales, Colombia, a city located 2,200 meters above sea level, without important stational variations. Patients with 18 years of age or more, with chronic kidney disease stages 2 to 5 and not undergoing dialysis treatment were recruited for this study. Demographic and anthropometric variations were evaluated as well as solar exposure, CKD etiology and laboratory variables related to bone and mineral diseases. For each CKD clinical stage, correlations were evaluated for vitamin D levels, laboratory results for bone and mineral diseases, solar exposure and ethnicity. Results: Three hundred thirty-three patients were evaluated with a median age of 71 years, most of them mestizo (71%), 173 were women. The main CKD etiology was hypertensive nephropathy (32.2%). 21.1% of patients had normal vitamin D levels, 70.1% were within insufficient range and 8.8% were in deficit. A negative correlation was found between the levels of vitamin 25 (OH) D and the values for: creatinine, phosphorous, calcium x phosphorous product, PTH, 24 hours urine protein and BMI. A positive relationship was found for calcium and albumin. Positive significant statistical correlation was found for vitamin 25(OH) D levels and solar exposure for stages 3b and 4 of CKD. Conclusions: It is common to find low levels of vitamin 25(OH) D in patients with CKD; these can contribute to the appearance of secondary hyperparathyroidism.

Resumen Objetivo: Establecer el impacto del estadio clínico en los niveles de vitamina D nativa en pacientes con enfermedad renal crónica (ERC) sin diálisis. Métodos: Estudio realizado en Manizales, Colombia, una ciudad tropical ubicada a 2,200 metros de altura sobre el nivel del mar, sin variaciones estacionales importantes a lo largo del año. Se incluyeron pacientes mayores de 18 años, con enfermedad renal crónica estadio 2 a 5 sin tratamiento dialítico. En ellos se evaluaron variables demográficas, antropométricas, grado de exposición solar, etiología de la enfermedad, y variables de laboratorio relacionadas con desórdenes óseos y minerales. Para cada estadío clínico se evaluó la correlación entre los niveles de vitamina D y los resultados de las pruebas de laboratorio relacionadas con desordenes óseos y minerales, exposición solar y etnia. Resultados: Se evaluaron 331 pacientes, con una edad media de 71 años, la mayoría mestizos (71%), 173 mujeres. La principal etiología de ERC fue nefropatía hipertensiva (33.2%). El 21.1% de los pacientes tenían niveles normales de vitamina D, fueron insuficientes en 70.1% y 8.8% en déficit. Se detectó correlación negativa, entre los niveles de vitamina 25(OH)D y los valores de creatinina, fósforo, producto calcio x fósforo, PTH, proteínas en orina de 24 horas e IMC. Correlación positiva para el calcio y la albumina. Se encontró significancia estadística positiva entre los niveles de vitamina 25(OH)D y la exposición solar para los estadios 3b y 4. Conclusiones: En pacientes con ERC es comun detectar bajos niveles de 25(OH)D, los cuales pueden contribuir a la generación de hiperparatiroidismo secundario.

Requests of laboratory tests for the diagnosis and management of calcium-phosphate disorders in Spain / Solicitud de pruebas de laboratorio para el diagnóstico y manejo de los desórdenes del metabolismo fosfocálcico en España

Background: Knowledge about the variability in the request of calcium-phosphate metabolism laboratory tests in primary care is important to design strategies to improve health system efficiency. Aim: To compare the inter-practice variability in calcium-phosphate metabolism laboratory tests requested by general practitioners from diverse regions across Spain. Material and Methods: One hundred and forty one clinical laboratories were invited to participate in an observational cross-sectional study. They informed the number of serum calcium, phosphate, parathyroid hormone and 25-hydroxyvitamin D requested by general practitioners. Appropriateness indicators were calculated as number of test requests per 1,000 inhabitants and ratio of related tests requests. The differences according to hospital setting, region and type of management were analyzed. Results: We recruited 76 laboratories (17,679,195 inhabitants). General practitioners requested 3,260,894 calcium-phosphate metabolism tests. The rate of request ranged from 2.97 per 1,000 inhabitants for 25-hydroxyvitamin D to 98.89 per 1,000 inhabitants for calcium. The rates of request for calcium, phosphate, parathyroid hormone in some areas were 30, 100 and 340 times higher than in other areas. Parathyroid hormone and 25-hydroxyvitamin D were highly requested in private management areas. There were also differences in phosphate, parathyroid hormone and 25-hydroxyvitamin D requesting between regions across Spain. Conclusions: The high variability observed is difficult to explain by differences in patient case mix between regions. Depending on the area, calcium could be under requested to detect primary hyperparathyroidism.

Objetivo: Conocer la variabilidad en la solicitud de pruebas de laboratorio en atención primaria es importante para diseñar estrategias que mejoren la eficiencia del sistema de salud. La propuesta de este estudio fue comparar la variabilidad en la solicitud de pruebas para la evaluación del metabolismo fosfocálcico por médicos de atención primaria de diversas regiones de España. Material y Método: Se invitó a participar a 141 laboratorios clínicos de diversas regiones españolas. Completaron una encuesta con el número de determinaciones de calcio, fósforo, hormona paratiroidea y 25-hidroxivitamina D solicitadas por médicos de atención primaria de sus áreas. Se calcularon las tasas en relación a la población y se construyeron indicadores de adecuación. Los resultados se compararon por características del hospital, región y tipo de gestión. Resultados: Obtuvimos los datos de 76 laboratorios (17.679.195 habitantes). Los médicos de atención primaria solicitaron 3.260.894 pruebas de metabolismo fosfocálcico. La tasa de solicitud varió de 2,97 por 1.000 habitantes de 25-hidroxivitamin D a 98,89 por 1.000 habitantes de calcio. Las tasas de calcio, fósforo, hormona paratiroidea en algunas áreas fue 30, 100 y 340 veces más alta respecto a otras. Hormona paratiroidea y 25-hidroxivitamina D fueron más solicitadas significativamente en hospitales con gestión privada. También hubo diferencias en fósforo, hormona paratiroidea y 25-hidroxivitamina D solicitas entre distintas regiones de España. Discusión: La alta variabilidad observada es difícil de explicar por las diferencias de las características de los pacientes. Dependiendo de la región podría haber una infra solicitud para la detección del hiperparatiroidismo primario.

Diagnosis and management of primary hyperparathyroidism: a scientific statement from the Department of Bone Metabolism, the Brazilian Society for Endocrinology and Metabolism / Diagnóstico e manejo do hiperparatireoidismo primário: uma posição científica do Departamento de Metabolismo Ósseo, a Sociedade Brasileira de Endocrinologia e Metabolismo

OBJECTIVE: To conduct a literature review on the diagnosis and management of primary hyperparathyroidism including the classical hipercalcemic form as well as the normocalcemic variant. MATERIALS AND METHODS: This scientific statement was generated by a request from the Brazilian Medical Association (AMB) to the Brazilian Society for Endocrinology as part of its Clinical Practice Guidelines program. Articles were identified by searching in PubMed and Cochrane databases as well as abstracts presented at the Endocrine Society, Brazilian Society for Endocrinology Annual Meetings and the American Society for Bone and Mineral Research Annual Meeting during the last 5 years. Grading quality of evidence and strength of recommendation were adapted from the first report of the Oxford Centre for Evidence-based Medicine. All grades of recommendation, including "D", are based on scientific evidence. The differences between A, B, C and D, are due exclusively to the methods employed in generating evidence. CONCLUSION: We present a scientific statement on primary hyperparathyroidism providing the level of evidence and the degree of recommendation regarding causes, clinical presentation as well as surgical and medical treatment.

OBJETIVO: Conduzir uma atualização das últimas evidências científicas a respeito da apresentação, do diagnóstico e do manejo clínico e cirúrgico do hiperparatireoidismo primário clássico e normocalcêmico. MATERIAIS E MÉTODOS: Este documento foi concebido pelo Departamento de Metabolismo Ósseo da Sociedade Brasileira de Endocrinologia e Metabologia (SBEM) a partir daquele oriundo do Programa de Diretrizes da Associação Médica Brasileira (AMB) da SBEM. Realizamos uma revisão dos artigos mais relevantes obtidos nos bancos de dados PubMed e Cochrane, além de abstracts apresentados nos encontros anuais da Endocrine Society, da Sociedade Brasileira de Endocrinologia e da American Society for Bone and Mineral Research dos últimos cinco anos, e classificamos as evidências em níveis de recomendações de acordo com a força científica por tipo de estudo, adaptando o primeiro relato do "Oxford Centre for Evidence-based Medicine". Todos os graus de recomendação, incluindo-se o "D", foram basea-dos em evidência científica, sendo as diferenças entre o A, B, C e D devidas exclusivamente ao desenho empregado na geração da evidência. CONCLUSÃO: Apresentamos uma atualização científica a respeito do hiperparatireoidismo primário, classificando e graduando em níveis de recomendações as principais evidências científicas sobre as suas causas, as variadas formas de apresentação, seu diagnóstico e tratamento.

Hiperparatiroidismo terciario: a propósito de tres pacientes con complicaciones diferentes / Tertiary hyperparathyroidism: representation of the complications in three different cases

El hiperparatiroidismo terciario ha sido reconocido como una hiperfunción autónoma de las glándulas paratiroides. Cuando esta enfermedad se instaura, la única opción terapéutica efectiva es la paratiroidectomía. Estos pacientes frecuentemente tienen hiperplasia paratiroidea por lo que la exploración cervical debe ser bilateral. Presentación de casos: Presentamos 3 pacientes, cada uno con una complicación diferente a propósito del hiperparatiroidismo terciario. La primera paciente con arteriolopatía cálcico-urémica, la segunda con calcinosis tumoral de la cadera, y la tercera paciente con tumor pardo bimaxilar. A todos los pacientes los tratamos con paratiroidectomía total con auto trasplante de la glándula más sana en el músculo recto anterior del abdomen. El estudio anatomopatológico reveló hiperplasia de las glándulas paratiroideas resecadas en todos los pacientes. La complicación principal de este procedimiento fue la hipocalcemia sintomática, requiriendo infusión de calcio endovenoso. Dos pacientes presentaron síndrome de hueso hambriento, que se resolvió progresivamente y en el seguimiento se observó normocalcemia. Hubo desenlace fatal en 2 pacientes como consecuencia de complicaciones sistémicas. El hiperparatiroidismo terciario es una enfermedad rara que el clínico debe reconocer para tratarla oportunamente. La paratiroidectomía total es terapéuticamente efectiva en esta condición, pero la hipocalcemia profunda posoperatoria es frecuente y necesita de un manejo cuidadoso.

Tertiary hyperparathyroidism has been recognized as an autonomous hyperfunction of the parathyroid glands. When this disease is established, the only effective therapeutic option is parathyroidectomy. These patients often have parathyroid hyperplasia so that the the neck exploration must be bilateral. Cases presentation: We report 3 patients, each with a different complication as a consequence of tertiary hyperparathyroidism. The first patient with calcic uremic arteriolopathy, the second with tumoral calcinosis of the hip, and the third patient with bimaxillary brown tumor. We treated all this patients with total parathyroidectomy, followed by healthy gland autotransplantation in the anterior rectus abdominal muscle. The anatomopathological study revealed hyperplasia of the resected parathyroid glands, in all the specimens. The main complication of this procedure were the symptomatic hypocalcemia, requiring intravenous calcium infusion. Two patients had the hungry bone syndrome, which was solved progressively. Two parients died due to systemic complications. Tertiary hyperparathyroidism is a rare disease that the clinician should recognize in order to treat it promptly. Total parathyroidectomy is therapeutically effective in this condition, but the postoperative profound hypocalcemia is frequent and needs a careful management.

Relationship between Vitamin D, Parathyroid Hormone, and Bone Mineral Density in Elderly Koreans

There is controversy regarding definition of vitamin D inadequacy. We analyzed threshold 25-hydroxyvitamin D (25[OH]D) below which intact parathyroid hormone (iPTH) increases, and examined age- and sex-specific changes of 25(OH)D and iPTH, and association of 25(OH)D and iPTH with bone mineral density (BMD) in elderly Koreans. Anthropometric parameters, serum 25(OH)D and iPTH, lumbar spine and femur BMD by dual-energy radiography absorptiometry (DXA) were measured in 441 men and 598 postmenopausal women. iPTH increased below serum 25(OH) of 36.7 ng/mL in men, but failed to reach plateau in women. Femur neck BMD above and below threshold differed when threshold 25(OH)D concentrations were set at 15-27.5 ng/mL in men, and 12.5-20 ng/mL in postmenopausal women. Vitamin D-inadequate individuals older than 75 yr had higher iPTH than those aged < or = 65 yr. In winter, age-associated iPTH increase in women was steeper than in summer. In conclusion, vitamin D inadequacy threshold cannot be estimated based on iPTH alone, and but other factors concerning bone health should also be considered. Older people seemingly need higher 25(OH)D levels to offset age-associated hyperparathyroidism. Elderly vitamin D-inadequate women in the winter are most vulnerable to age-associated hyperparathyroidism.

Tumor pardo bimaxiliar superior e hiperparatiroidismo terciario: reporte de un caso y revisión de la literatura / Brown tumor bimaxiliar upper and tertiary hyperparathyroidism: a case report and literature review

El tumor pardo u osteoclastoma constituye una manifestación de la osteítis fibrosa quística, siendo esta última el estadio terminal del proceso de remodelación ósea que ocurre en el hiperparatiroidismo. Su localización más frecuente es en los huesos largos, siendo la afectación de los maxilares poco común. Se presenta el caso de una paciente de 37 años de edad, con enfermedad renal crónica e hiperparatiroidismo terciario con tumor pardo bimaxilar. Se discuten los aspectos clínicos radiológicos y terapéuticos de estos procesos.

Brown tumor or osteoclastoma, is a manifestation of osteitis fibrosa cystica, which represents the terminal stage of the bone remodeling process in hyperparathyroidism. Brown tumors are preferentially situated in the long bones, being maxillary presentation very rare. We present a 37 year old female patient with chronic renal disease and tertiary hyperparathyroidism with bimaxillary brown tumor. Clinical, radiological and therapeutic aspects of these processes are discussed.

Hiperparatiroidismo / Hyperparathyroidism

El calcio es esencial para varias funciones del cuerpo, incluyendo la contracción muscular, la conducción nerviosa y el funcionamiento apropiado de muchas enzimas. La mayor parte del calcio del cuerpo se almacena en los huesos, pero también se encuentra en las células y en la sangre. El organismo controla con "toda precisión" la cantidad de calcio tanto en la célula como en la sangre. Para mantener este equilibrio entra en competencia la hormona para tiroidea, secretada por las glándulas paratiroidea. La actividad de las glándulas paratiroideas está controlada por el nivel de calcio libre (ionizado) de la sangre. El descenso de los niveles de este calcio estimula la síntesis y secreción de hormonas paratiroideas, si la cantidad de calcio libre en sangre aumenta, estamos frente a una alteración metabólica "La Hipercalcemia" la cual consiste en una concentración elevada de calcio en sangre superior a 10.5 miligramos por decilitro de sangre, la que puede ser causada por aumento en la ingestión de calcio, pero la causa más común de la hipercalcemia es el "Hiperparatiroidismo", el cual se debe a la hipersecreción de hormonas paratiroideas. Esta alteración puede deberse a un adenoma paratiroide (80%). Hiperplasia primaria (15%). Carcinoma paratiroide (5%). Fenómeno secundario típico de los pacientes con insuficiencia renal crónica. El hiperparatiroidismo puede manifestarse en la cavidad bucal en forma de hiperplasia gingival y lesiones osteolíticas de los maxilares (Tumores pardos) que son asintomáticas. El objetivo de este trabajo es realizar una revisión bibliográfica actualizada sobre esta patología y resaltar la importancia que representan las manifestaciones orales de esta patología sistémica para el odontólogo en general, especialmente para el cirujano oral y maxilofacial.

Neoplasia endocrina múltiple tipo 1 / Multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (NEM1) is an uncommon autosomal dominant disease caused by an alteration of menin, a tumor suppression protein and is characterized by the presence of primary tumors in at least two different endocrine tissues. It is described as the “three P disease”since it involves mainly the pituitary, parathyroid and pancreas. However more than 20 different tumor locations have been described. Most tumors are benign and primary hyperparathyroidism is the first manifestation of the disease in 90 percent of cases enteropancreatic tumors appear in approximately 60 percent of patients and pituitary adenomas, usually prolactinomas, in 30 percent. Skin lesions, non functional adrenal adenomas and neuroendocrine tumors such as carcinoid are also part of the disease. We describe the pathogenesis, clinical presentation, diagnosis and treatment of NEM1.

Carcinoma de paratireóide / Parathyroid carcinoma

O carcinoma de paratireóide uma neoplasia incomum. Corresponde a menos de 1 por cento dos casos de hiperparatireoidismo primário. Manifesta-se por hipercalcemia severa e mais de 50 por cento dos pacientes terão doença renal ou óssea concomitante...

Parathiroid carcinoma is a incommon malignancy. It accounts for less than one per cent of cases of primary hyperparathiroidism. It is manifested by severe hypercalcemia and up to 50 per cent of patients will have concomitant kidney or bone disease...

Aspectos radiológicos e epidemiológicos do granuloma central de células gigantes / Radiological and epidemiological aspects of central giant cell granuloma

OBJETIVO: Este estudo teve como objetivo avaliar os principais aspectos radiográficos e epidemiológicos das lesões de células gigantes (granulomas centrais de células gigantes e tumores marrons do hiperparatireoidismo). MATERIAIS E MÉTODOS: A amostra consistiu de 26 lesões de células gigantes diagnosticadas em 22 pacientes divididos em dois grupos, um deles composto por 17 pacientes que não tinham hiperparatireoidismo (grupo A) e o outro formado por cinco pacientes portadores de tal distúrbio (grupo B). RESULTADOS: O sexo feminino (72,7 por cento) foi o mais acometido. As lesões ocorreram mais freqüentemente na segunda década de vida, com média de idade de 27 anos. A mandíbula (61,5 por cento) foi o arco mais envolvido. Radiograficamente, 57,7 por cento das lesões eram multiloculares e 42,3 por cento eram uniloculares com limites definidos. Todas as 26 lesões provocaram expansão óssea, 15,4 por cento produziram reabsorção radicular, 50 por cento causaram deslocamento dentário e 11,5 por cento produziram dor. Na mandíbula, 18,7 por cento das lesões cruzavam a linha média. O grupo A apresentou 66,7 por cento das lesões na mandíbula e o grupo B mostrou igualdade na distribuição das lesões entre os arcos. O grupo A apresentou 66,7 por cento das lesões multiloculares e 33,3 por cento, uniloculares. O grupo B apresentou 62,5 por cento das lesões uniloculares e 37,5 por cento, multiloculares. CONCLUSÃO: As lesões de células gigantes podem manifestar-se, radiograficamente, com um amplo espectro, desde pequenas lesões uniloculares de crescimento lento até extensas lesões multiloculares. Elas apresentam características de benignidade, embora algumas lesões possam demonstrar um comportamento localmente agressivo.

OBJECTIVE: The present study was aimed at evaluating main radiological and epidemiological aspects of giant cell lesions (central giant cell granuloma and brown tumors of hyperparathyroidism). MATERIALS AND METHODS: The sample consisted of 26 giant cell lesions diagnosed in 22 patients divided into two groups, one of them including 17 patients who were not affected by hyperparathyroidism (group A) and another including five patients with such a disorder (group B). RESULTS: Prevalence was higher in female patients (72.7 percent). Most frequently, lesions occurred more in the second decade of life (mean age, 27 years). The mandible arc was most frequently involved (61.5 percent). Radiographically, 57.7 percent of lesions were multilocular and 42.3 percent were unilocular with defined limits. All of the 26 lesions caused expansion of bone, 15.4 percent radicular resorption, 50 percent dental displacement, and 11.5 percent produced pain. In the mandible 18.7 percent of the lesions crossed the midline. Group A showed 66.7 percent of lesions in the mandible and group B showed an even distribution of lesions between arches. In group A 66.7 percent of lesions were multilocular, and 33.3 percent unilocular; in group B 62.5 percent were unilocular, and 37.5 percent multilocular. CONCLUSION: Giant cells lesions may present themselves with a wide spectrum, from small, slow-growing unilocular lesions to extensive multilocular lesions. They present features of benignity, though some lesions may demonstrate a locally aggressive behavior.

Analysis of the diagnostic presentation profile, parathyroidectomy indication and bone mineral density follow-up of Brazilian patients with primary hyperparathyroidism

Primary hyperparathyroidism is an endocrine disorder with variable clinical expression, frequently presenting as asymptomatic hypercalcemia in Western countries but still predominantly as a symptomatic disease in developing countries. The objective of this retrospective study was to describe the diagnostic presentation profile, parathyroidectomy indication and post-surgical bone mineral density follow-up of patients with primary hyperparathyroidism seen at a university hospital. We found 115 patients (92 women, median age 56 years) with primary hyperparathyroidism diagnosed during the last 20 years. We defined symptomatic patients based on the presence of any classical symptom affecting bone, kidney or the neuromuscular system. Surgical criteria followed the guidelines of the National Institutes of Health regarding asymptomatic primary hyperparathyroidism. Symptomatic patients and patients meeting surgical criteria for parathyroidectomy were 66 and 93 percent of the sample, respectively. Median calcium and parathyroid hormone values were 11.9 mg/dL and 189 pg/mL, respectively. After surgical treatment, 97 percent of patients were cured, with increases in bone mineral density of 19.4 percent in the lumbar spine and 15.7 percent in the femoral neck 3 years after surgery. Greater bone mass increases were detected in pre-menopausal women, men, and in symptomatic and younger patients, both in the lumbar spine and femoral neck. Our results support the previous findings of a predominantly symptomatic disease with a presentation profile that could be mainly related to a delayed diagnosis. Nevertheless, genetic and racial backgrounds, and nutritional factors such as calcium and vitamin D deficiency may play a role in the clinical presentation of primary hyperparathyroidism of Brazilian patients.

Evolution of PTH assays / Evolução dos ensaios para paratormônio

PTH metabolism is complex and the circulating forms include the intact 1-84 molecule as well as several carboxyl-terminal fragments. The first generation of PTH assays included several types of competitive assays, with specificities that spanned carboxyl, mid-region and amino-terminal portions of the molecule. The limitations of these assays and the methodological evolution led to the description of 2nd generation non-competitive immunometric assays for PTH in the late 80's, based on the recognition of the PTH molecule by two different antibodies, one directed against de amino-terminal and other against the carboxyl-terminal segments. The observation that in some circumstances "long" carboxyl-terminal segments were also measured by 2nd generation assays led to the development of 3rd generation assays based on amino-terminal specific antibodies that are specific for the first amino acids, measuring only the molecular forms that activate PTH1R. The practical and cost-benefit advantages of these assays are still debatable. The recent observation that carboxyl-terminal fragments of PTH have biological activity via a distinct receptor than PTH1R, points to the future need of more than one assay in order to evaluate parathyroid hormone function.

O metabolismo do PTH e complexo e as formas circulantes incluem o PTH 1-84, assim como fragmentos C-terminal. A primeira geração de ensaios para o PTH incluía vários ensaios competitivos com especificidades para as regiões carboxi, meio da molécula e amino-terminal. A limitação destes ensaios e a evolução metodológica, levaram ao desenvolvimento dos ensaios não competitivos de 2ª. geração no final dos anos 80, baseados no reconhecimento por dois anticorpos diferentes, contra a porção amino e carboxi-terminal respectivamente. A observação que em algumas circunstâncias segmentos carboxiterminais longos também eram detectados, levou ao desenvolvimento dos ensaios de 3ª. geração, baseados em anticorpos específicos para a porção aminoterminal com maior especificidade para os primeiros aminoácidos, e assim mensurando apenas a forma molecular que ativa o PTH1R. As vantagens práticas e o custo-benefício deste ensaio ainda e motivo de debate. A observação recente de que fragmentos carboxiterminais têm atividade biológica via receptor distinto, aponta para a necessidade futura de mais de um ensaio para avaliar a função do paratormônio.

Neoplasia endócrina múltipla tipo 2 / Multiple endocrine neoplasia type 2

O termo neoplasia endócrina múltipla tipo 2 (NEM 2) foi sugerido em 1968, por Steiner e cols., para diferenciar a síndrome clínica caracterizada pela presença de carcinoma medular de tireóide (CMT), feocromocitoma e hiperparatireoidismo, então denominada síndrome de Sipple, da síndrome de Wermer ou NEM tipo 1, que acomete as glândulas paratireóides, pâncreas e hipófise. Sizemore e cols. (1974) complementaram a diferenciação através da classificação da NEM 2 em 2 subgupos: pacientes com CMT, feocromocitoma, hiperparatireoidismo e aparência normal (NEM 2A) e pacientes sem acometimento das paratireóides e fenótipo caracterizado por ganglioneuromatose intestinal e hábitos marfanóides (NEM 2B). CMT é usualmente o primeiro tumor a ser diagnosticado. O diagnóstico do CMT determina que seja avaliada a extensão da doença e rastreamento do feocromocitoma e hiperparatireoidismo. O diagnóstico de CMT esporádico ou hereditário é realizado através da análise molecular do proto-oncogene RET. Neste artigo são discutidos os aspectos fisiopatológicos, as anormalidades genéticas e os aspectos clínicos da NEM 2. A abordagem diagnóstica e terapêutica nos indivíduos afetados, carreadores assintomáticos e familiares em risco também são discutidos. Os avanços relacionados ao rastreamento genético e intervenção precoce permitiram uma melhoria no prognóstico a longo prazo. No entanto, ainda não dispomos de tratamento eficaz para doença metastática.

Tumor marrom do hiperparatireoidismo dos maxilares / Hyperparathyroidism brown tumor of the jaws

O tumor marrom do hiperparatiroidismo é uma doença óssea metabólica podendo acometer todo o esqueleto, inclusive os ossos maxilares. O objetivo deste trabalho é de ressaltar a importância desta doença no diagnóstico diferencial das lesões do complexo máxilo-mandibular e realizar uma revisão da literatura quanto à sua etiologia, características clínicas e radiográficas e tratamento.