Caracterización clínica de pacientes chilenos con displasia fibrosa/síndrome de McCune-Albright / Clinical features of Chilean patients with Fibrous Dysplasia/McCune-Albright Syndrome

BACKGROUND: Fibrous Dysplasia/McCune-Albright Syndrome (FD/MAS) is characterized by a spectrum of manifestations that may include fibrous dysplasia of bone and multiple endocrinopathies. AIM: To describe the clinical spectrum, the study and follow-up of patients with FD/MAS cared at our institution. MATERIAL AND METHODS: Review of medical records of 12 pediatric and adult patients (11 women) who met the clinical and genetic diagnostic criteria for FD/ MAS. RESULTS: The patients' mean age at diagnosis was 4.9 ± 5.5 years. The most common initial clinical manifestation was peripheral precocious puberty (PPP) in 67% of patients and 75% had café-au-lait spots. Fibrous dysplasia was present in 75% of patients and the mean age at diagnosis was 7.9 ± 4.7 years. Ten patients had a bone scintigraphy, with an age at the first examination that varied between 2 and 38 years of age. The most frequent location of dysplasia was craniofacial and appendicular. No patient had a recorded history of cholestasis, hepatitis, or pancreatitis. In four patients, a genetic study was performed that was positive for the pathogenic variant of guanine nucleotide binding protein, alpha stimulating (GNAS). CONCLUSIONS: These patients demonstrate the variable nature of the clinical presentation and study of FD/MAS. It is essential to increase the index of diagnostic suspicion and adherence to international recommendations.

Osteoporosis postmenopáusica: relevancia de la búsqueda estructurada de causas secundarias / A search for secondary causes of osteoporosis or low mineral density in postmenopausal women

BACKGROUND: A secondary cause can be found in up to one third of women with osteoporosis, potentially modifying their therapeutic approach. AIM: To determine the prevalence of secondary causes and risk factors for decreased bone mineral density (BMD) and osteoporosis. Material and Methods: We included postmenopausal women with a diagnosis of osteoporosis or low BMD who consulted for the first time in an endocrinology clinic between October 2018 and March 2020. A complete medical history, physical examination and a standardized laboratory assessment to identify secondary causes were performed. RESULTS: During the study period, 114 women were evaluated, 30 of them with low BMD and 84 with osteoporosis. After obtaining a medical history and a structured laboratory screening, at least one secondary cause was found in 50% of patients with osteoporosis and in 67% of those with low BMD. Most patients with no identified secondary cause had at least one risk factor for fragility fractures. Conclusions: A structured evaluation that includes medical history and standardized laboratory study in postmenopausal women with osteoporosis or low BMD, is a valuable tool to identify secondary causes of osteoporosis.

Puesta al día: carcinoma paratiroideo / An update on parathyroid carcinoma

Parathyroid carcinoma is a rare malignant disease that presents as a sporadic or familial primary hyperparathyroidism (PHP). The latter is associated with some genetic syndromes. It occurs with equal frequency in both sexes, unlike PHP caused by parathyroid adenoma that is more common in women. It should be suspected in cases of severe hypercalcemia, with high parathyroid hormone levels and a palpable cervical mass. Given the difficulty in distinguishing between parathyroid carcinoma and adenoma prior to the surgery, the diagnosis is often made after parathyroidectomy. The only curative treatment is complete surgical resection with oncologic block resection of the primary tumor to ensure free margins. Adjuvant therapies with chemotherapy or radiation therapy do not modify overall or disease-free survival. Recurrences are common and re-operation of resectable recurrent disease is recommended. The palliative treatment of symptomatic hypercalcemia is crucial in persistent or recurrent disease after surgery since morbidity and mortality are more associated with hypercalcemia than with tumor burden.

Hipofosfatemia inducida por drogas: fierro carboximaltosa e imatinib. Casos clínicos / Hypophosphatemia induced by carboxymaltose iron and imatinib. Report of two cases

Hypophosphatemia is a relatively frequent and a potentially serious adverse drug effect. Clinically it is characterized by bone pain and muscle weakness. There are several mechanisms by which a drug can induce hypophosphatemia and they can be classified according to whether or not they are mediated by an excess of Fibroblast Growth Factor 23 (FGF23). We report two patients with the condition: (i) A 49-year-old woman with Chronic Myeloid Leukemia (CML) and gastric sleeve surgery at 46 years of age. After receiving intravenous carboxymaltose iron in one occasion due to refractory anemia, she developed symptomatic hypophosphatemia. Urinary phosphate losses associated with high FGF23 levels were confirmed. Plasma phosphate returned to normal values 90 days after the iron administration. (ii) A 40-year-old man with a history of CML in whom imatinib was started. He developed symptomatic hypophosphatemia due to non FGF23-mediated hyperphosphaturia. As treatment with imatinib could not be interrupted, hypophosphatemia and its symptoms resolved with oral phosphate intake. These cases illustrate the importance of recognizing and treating drug-induced hypophosphatemia in a timely manner, and thus avoid the morbidity associated with this entity.

Recomendaciones para el uso correcto de densitometría ósea en la práctica clínica. Consenso de la Sociedad Chilena de Endocrinología y Diabetes / Guidelines of the Chilean Endocrinology Society for the correct clinical use of bone densitometry

Osteoporosis is a silent and frequent disease, which increases fracture risk. Approximately half of women and one of five men over 50 years old will suffer an osteoporotic fracture throughout their lives. Dual-energy x-ray absorptiometry (DXA) allows a real bone mineral density (BMD) measurement in different parts of the skeleton and is considered the "gold standard" for quantifying osteoporosis with high accuracy and precision. The Board of the Chilean Society of Endocrinology and Diabetes (SOCHED) required from the Bone Disease Study Group to develop a consensus about the "Correct use of bone densitometry in clinical practice in Chilean population". Therefore, we elaborated 25 questions which addressed key aspects about the indications for a DXA scan, and the details of how to perform and report this test. Since some of the evidence obtained was of low quality or inconclusive, we decided to create a multidisciplinary group of national experts in osteoporosis to develop a consensus in this subject. The group consisted of 22 physicians including endocrinologists, gynecologists, geriatricians, radiologists, rheumatologists and nuclear medicine specialists. Using the Delphi methodology to analyze previously agreed questions, we elaborated statements that were evaluated by the experts who expressed their degree of agreement. The final report of this consensus was approved by the SOCHED board.

Pseudohipoparatiroidismo de presentación tardía: reporte de dos casos / Pseudohypoparathyroidism: report of two cases of late presentation

Pseudohypoparathyroidism (PHP) is a group of rare genetic disorders that share organ targeted resistance to the action of parathyroid hormone (PTH) as a common feature. Biochemically, they may present with hypocalcemia, hyperphosphatemia and elevated PTH. Some forms present with a specific phenotype: short stature, round facies, short neck, obesity, brachydactyly and subcutaneous calcifications, called Albrigth's Hereditary Osteodystrophy (AHO). This spectrum of disorders are caused by several alterations in the gene coding for the alpha subunit of the G protein (GNAS): an ubiquitous signaling protein that mediates the action of numerous hormones such as PTH, TSH, gonadotropins, and ACTH, among others. According to their inheritance with maternal or paternal imprinting, they may manifest in a diversity of clinical forms. Although most commonly diagnosed during childhood, PHP may manifest clinically during adolescence or early adulthood. We report two late presenting cases of pseudohypoparathyroidism. A 21-year-old female with biochemical abnormalities characteristic of pseudohypoparathyroidism who was misdiagnosed as epilepsy and a 13-year-old boy with the classic AHO phenotype but without alterations in phospho-calcium metabolism, compatible with pseudopseudohypoparathyrodism.

Salud ósea en pacientes sometidos a trasplante de precursores hematopoyéticos: un nuevo problema a considerar / Vitamin D and parathyroid hormone levels and bone mineral density in patients undergoing hematopoietic cell transplantation

Background: Patients undergoing hematopoietic cell transplantation (HCT) are at increased risk of developing osteoporosis. Aim: To determine the frequency and severity of Vitamin D deficiency, secondary hyperparathyroidism and low bone mass in patients undergoing HCT. Patients and Methods: Analysis of the database of patients undergoing HCT in our institution in the 2010-2015 period. We searched for patients with measurements of 25-OH vitamin D (25OHD), parathyroid hormone (PTH) and bone densitometry by double beam X ray absorptiometry (DXA) prior and up to one year after HCT. Results: Ninety patients were included, 53 were evaluated prior to HCT and 37 after HCT. They represent 73% of all patients undergoing HCT in the period. Median 25OHD was 12 ng/ml (range 4-41.4). Ninety seven percent of patients had levels considered insufficient and 85% compatible with deficiency. Median PTH was 60.5 pg/ml (range 21-186). Forty five percent of patients had secondary hyperparathyroidism. DXA was performed in 65 patients (prior to HCT in 54 and after HCT in 11). Of these, 11% had had a low bone mineral density. Conclusions: Patients undergoing HCT have a high risk of vitamin D deficiency, secondary hyperparathyroidism and low bone mineral density.

Compromiso óseo en mastocitosis sistémica: una asociación frecuente, pero muchas veces inadvertida / Bone involvement in systemic mastocytosis: report of two cases

Systemic mastocytosis (SM) is characterized by pathologic expansion and activation of mast cells. The main clinical manifestations of SM include skin involvement, gastrointestinal symptoms and anaphylaxis due to the release of its mediators. Thirty percent of pat ients with SM have a low bone mass and 20% fractures. At the same time, SM affects 10% of male patients with idiopathic osteoporosis. Measuring serum tryptase is essential for the screening of MS. We report two cases of SM with bone involvement. A 25-year- old woman with prior diagnosis of SM, based on skin involvement, flushing, high serum tryptase and compatible bone marrow (BM) biopsy and genetic study. Low bone mass was diagnosed and treatment was started with calcium and vitamin D plus oral bisphosphona tes with adequate response. A 47 years old man who presented with multiple osteoporotic vertebral fractures and low bone mass. Treatment with vitamin D and alendronate was started, but the patient developed new vertebral fractures. The study was extended w ith measurement of serum tryptase that was elevated. Diagnosis of SM was confirmed with BM biopsy and the patient was referred to hematology for specific care. These cases emphasize the importance of bone assessment in SM, as well as the need to rule out S M in patients with osteoporosis and no evident cause.

Pericarditis constrictiva como presentación grave e infrecuente de lupus eritematoso sistémico: reporte de un caso y revisión de la literatura / Constrictive pericarditis as a serious and rare presentation of systemic lupus erythematosus: Report of one case

Constrictive Pericarditis (CP) is an unusual disease. Its most common causes are idiopathic or secondary to cardiac surgery. Less frequently it is caused by connective tissue diseases. We report a 30 years old woman hospitalized due to progressive dyspnea, chest pain and signs of right sided heart failure. During her stay, a Systemic Lupus Erythematosus (SLE) was diagnosed. The echocardiogram suggested a CP and the diagnosis was confirmed by cardiac catheterization. Pericardiectomy was successfully performed. The biopsy confirmed a nonspecific chronic pericarditis, with extensive fibrosis and absence of caseating granulomas. The patient had a satisfactory recovery.

Un curso de docencia clínica para residentes mejora la autopercepción de preparación para enseñar / A clinical teaching course for residents improves self-perception about preparation to teach

Background: Medical doctors need to be competent to teach patients, their families, students, and the health care team. In a previous study we determined that although the residents attach great importance to have teaching skills, they do not feel prepared to meet this role. Aim: To assess self-perception of learning in a formal course of training how to teach for residents. Material and Methods: In 2004 we implemented the course "Residents as Clinical Teachers", based on the Stanford Faculty Development Center for Medical Teachers Model (SFDC), for residents of a Medical School. Residents of all the post graduate programs were invited to take the course as an elective during the period 2004-2011. At the end of the course each resident completed the pre/post Seminar Series Housestaff/student Questionnaire; assessing perceptions of learning, expressed in a Likert scale from 1-5. Results: The implementation of the course in 111 residents significantly improved self-perception of general preparation for teaching and improved self-perception of preparedness in each educational category. The personal goals most commonly established by participants were on feedback (52,2%), control of session (44%) and communication of goals (40%). Barriers for teaching most frequently identified were lack of time to do clinical teaching (51,3%) and environmental limitations (16,2%). The main impact of the course reported by residents were acquisition of teaching skills or tools for teaching (39,6%), enhancing of motivation (14%), and a richer understanding of teaching principles (14%). Conclusions: A clinical teaching course for residents improves their self-perception of preparation to teach and enhances motivation for clinical teaching.