Helena Poggi M

Anticuerpos anti-tiroglobulina en el seguimiento de pacientes con cáncer diferenciado de tiroides: ¿Marcadores de enfermedad residual o recidivante?

Background: Anti thyroglobulin antibodies are present in 25% of patients treated for a differentiated thyroid cancer, invalidating thyroglobulin determination. Those patients subjected to total thyroidectomy and free of disease, should reduce the production of these antibodies, due to the lack of antigenic stimulus. Therefore, anti thyroglobulin antibodies could be useful to detect early relapses. Aim: To assess the relationship between anti thyroglobulin antibodies and the evolution of the disease in patients treated for thyroid cancer. Material and methods: Retrospective analysis of 26 patients treated for thyroid cancer with positive anti thyroglobulin antibodies, followed for three years. These were divided in those with or without lymphocytic thyroiditis (19 and 7 respectively). Results: At the first year of follow up, anti thyroglobulin antibody concentration was 401±94.9 UI/ml (x±sem) in patients with thyroiditis and 38.9±8.9 UI/ml in those without thyroiditis (p < 0.005). During the three years of follow up, no differences in anti thyroglobulin antibodies were observed between patients with or without tumor relapse. Conclusions: Concentration of anti thyroglobulin antibodies was higher in patients with thyroiditis and did not differentiate patients with tumor relapse (Rev Med Chile 2002; 130: 167-72)

Perfil epidemiológico de la candidiasis invasora en unidades de pacientes críticos en un hospital universitario

La epidemiologia de candidiasis invasora (CI) ha cambiado, lo cual no ha sido suficientemente estudiado en Chile. Objetivo: Describir el perfil epidemiologico y microbiologico de CI en pacientes criticos. Metodos: Estudio observacional prospectivo entre octubre 2001 y agosto 2003, en pacientes criticos adultos con sospecha o confimnacion de CI. Resultados: 53 pacientes cumplieron criterios de CI. De ellos, 18 (33,9%) tuvieron candidemia, 22(41,5%) CI diseminada y 13(24,5%) CI local. Entre las candidemias, hubo 8 C. albicans (44,4%) y 10 Candida no albicans (55,6%), predominando C. tropicalis (27,7%). Un 88,8% de las candidemias fueron susceptibles a fluconazol. La mortalidad hospitalaria global fue 24,5%, significativamente menor en pacientes con candidemias vs CI diseminada (16,6 vs 31,8%, p = 0,02). Conclusiones: Se observo una mayor proporcion de Candida no albicans en candidemias de pacientes criticos. Sin embargo, la mayoria de estas cepas fue susceptible a fluconazol. La mortalidad global fue menor en candidemias.

Identificación de mutaciones en el gen CFTR en pacientes chilenos con fibrosis quística

Background: Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the CFTR gene, that codes for a chloride channel located in the apical surface of epithelial cells. The main role of this protein is the regulation of chloride transport, and secondarily, of sodium and water to the extracellular space. More than 900 gene mutations have been described, and their relative frequency in different populations depends on their ethnic origin. Aim: To report the findings of Chilean patients with cystic fibrosis, in whom the presence of 20 common mutations was analyzed. Patients and methods: Fifty seven patients with established diagnosis or suspicion of CF were studied. The simultaneous identification of 20 mutations and the normal DF508 allele was done using polymerase chain reactions with a commercial assay. Results: Eight mutations were found. Fifty patients fulfilled diagnostic criteria proposed by the Consensus Panel of the CF Foundation and 66% of alleles were identified in this group. ∆F508 mutation was found in 45%. We did not identify mutations in any of the remaining 7 patients. Conclusions: Our results suggest that the majority of undetected mutations are associated with atypical phenotypes or that some patients in this series could have other diseases. We recommend to include mutation analysis in the evaluation of Chilean patients with CF. It is useful to establish prognosis and genetic counselling (Rev Med Chile 2001; 129: 841-7).

Alta prevalencia de enfermedad tiroidea subclínica en sujetos que concurren a control de salud

Background: There is no information about the prevalence of thyroidal diseases in the general Chilean population. Aim: To assess the prevalence of thyroidal diseases in individuals attended in occupational health examinations. Subjects and methods: Four hundred seventy two individuals were examined between 1998 and 1999. In all, serum levels of thyroid hormones, TSH and anti thyroidal antibodies (anti microsomal, anti thyroid peroxidase and anti thyroglobulin) were measured. Results: Forty four subjects were excluded from the study due to an incomplete medical record and 18 due to a personal history of thyroidal disease. Abnormal serum levels of thyroid hormones or TSH were detected in 28 subjects (6.8%). Four (1%) had hypothyroidism, 23 a subclinical hypothyroidism (5.6%) and one (0.2%) had hyperthyroidism. In 87 subjects (21.2%) at least one of the antibodies was positive. Positive anti thyroid antibodies were found in 14 of 28 subjects (50%) with abnormal thyroid hormone levels, compared with 73 of 382 subjects (19.1%) with normal thyroid hormone levels. Thyroid dysfunction was twice as frequent in women than in men. Conclusions: In this sample, a 6.8% prevalence of abnormal thyroid function tests was detected. (Rev Med Chile 2001; 129: 155-60).

Presencia de metalo-ß-lactamasas en Pseudomonas aeruginosa resistente a imipenem

Background: Metallo-s-lactamases (MBL) confer high resistance to carbapenems in Pseudomonas aeruginosa (Psae). They are encoded in mobile elements of different genes (VIM, IMP, SMP, GIM), along with other resistance genes. Aim: To detect the presence of MBL in imipenem resistant Psae strains. Material and methods: Fifty-nine imipenem resistant Psae strains isolated from January 2004 to August 2005 in a University Clinical Hospital, were included. The presence of MBL was studied by Etest (phenotypic) and genotypic polymerase chain reaction (PCR) methods. To rule out a nosocomial outbreak, MBL positive strains, were studied by pulse field gel electrophoresis. Results: The presente of MBL was detected in eleven strains. AH were type VIM and were not clonally related. There was no concordance between phenotypic and genotypic MBL detecting methods. AH the strains were also multiresistant. Conclusions: The presence of MBL was detected in 19% of imipenem resistant Psae strains

Correlación genotipo-fenotipo de un grupo de pacientes con fibrosis quística

Background: Cystic fibrosis (CF) is the most common lethal autosomic disease in Caucasians, with a global incidence of 1:3000 newborns. More than 900 mutations have been described, involving the Cystic Fibrosis Transmembrane Regulator (CFTR). The ∆F508 mutation is present in 60% of alleles studied worldwide. Aim: To report 25 patients with cystic fibrosis in whom a genetic study was done. Material and methods: Twenty five patients (14 men, aged between 18 months and 25 years) with a diagnosis of cystic fibrosis based on clinical features plus two abnormal sweat tests are reported. The genetic study considered the 20 most common mutations in cystic fibrosis and was done in genomic DNA of peripheral lymphocytes, by polymerase chain reaction. Results: A mutation was found in 75% of analyzed alleles. DF508 was present in 50% of cases (DF508/DF508 in 8 and DF508/other in 11). When DF508 was present, pancreatic insufficiency was always a feature and nutritional status was worse. Respiratory involvement was variable, both for homozygous and heterozygous cases. Other severe mutations such as W1282X and G542X were related to clinical manifestations similar to those found in DF508 mutation. Diagnosis was made before six months of age in 12 patients. The clinical presentation was meconium ileus and there was a family history of the disease in most cases. The majority of cases of early diagnosis presented severe mutations, but milder respiratory symptoms and lesser nutritional compromise at the time of assessment. Conclusions: Most patients studied had a severe cystic fibrosis mutation, which was associated with more severe respiratory, pancreatic and nutritional involvement. The early diagnosis of the disease, which would allow to improve the prognosis and the quality of life, must be emphasized (Rev Med Chile 2002; 130: 475-81)

Angiomatosis bacilar por Bartonella quintana en un paciente con infección por virus de inmunodeficiencia humana

Reportamos el primer caso de angiomatosis bacilar por Bartonella quintana en un paciente con infeccion por VIH en nuestro pais. Este corresponde a un hombre de 27 anos, heterosexual, indigente, seropositivo para VIH conocido desde septiembre de 2003, en control irregular. En abril de 2005, el paciente desarrollo un aumento progresivo de volumen en la region frontal y aparicion de papulas eritematosas en las extremidades, que luego se extendieron a la cara, torax y mucosas, tornandose nodulares y violaceas. El diagnostico de angiomatosis bacilar se planteo inicialmente por el cuadro clinico del paciente, siendo confirmado por serologia y tincion de Warthin Starry positiva en la biopsia de piel. El agente causal se identifico como Bartonella quintana por RPC universal para el gen del 16S ARNr de un nodulo cutaneo. Se inicio terapia antimicrobiana con azitromicina y ciprofloxacina, ademas de terapia antiretroviral, con desaparicion de las lesiones en forma progresiva

Medición de 17-OH progesterona sanguínea en recién nacidos chilenos: antecedentes para implementar un programa de detección neonatal de hiperplasia suprarrenal congénita

BACKGROUND: The early diagnosis and therapy of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency can prevent adrenal crises and erroneous gender assignment in affected newborns. To achieve this goal neonatal mass-screening programs have been developed, measuring blood 17 alpha-hydroxyprogesterone (17OHP). In Chile there is no experience with this type of screening. AIM: To develop a method for measuring 17OHP in filter paper blood specimens. To obtain reference ranges and determine neonatal 17OHP threshold levels according to gestational age and birth weight. To analyze factors affecting the cost-efficiency ratio and suggest recommendations for the organization of a neonatal screening program for CAH in Chile. MATERIAL AND METHODS: Nine hundred twenty two newborns were studied. 17OHP was measured using double antibody radioimmunoassay in filter paper blood samples obtained 48 h after birth. Reference ranges were determined according to gestational age and birth weight and a cutoff point of 25 ng/ml was established. RESULTS: Seventeen newborns had 17OHP over the cutoff value. They were assessed by a pediatric endocrinologist and in none of them, CAH was confirmed. Therefore the false positive rate of the determination was 1.8%. Among these newborns with elevated 17OHP, 66% had a birth weight below 1.5 kg and 5.8%, a birth weight between 1.5 and 2.5 kg. The cost per reported result was US

Diagnóstico de la infección por Treponema pallidum en pacientes con sífilis temprana y neurosífilis mediante reacción de la polimerasa en cadena

1. Timing of the recall was between the 3 and 10 days of life. No newborn missed the follow-up. DISCUSSION: To increase the cost-efficiency ratio of an eventual neonatal screening program, newborns with birth weights below 1.5 kg should be excluded and cutoff points should be defined according to birth weight (Rev Med Chile 2000; 128: 1113-18).

Aviso de valores de alerta por parte del laboratorio clínico en una red de salud universitaria

Syphilis is a sexually transmitted disease caused by Treponema pallidum. The diagnosis is based mainly in clinical presentation and non-specific assays. PCR-based diagnosis has been suggested as an attractive alternative method. The aim of this study was the validation of a PCR-based test for the diagnosis of early syphilis (ES) and neurosyphilis (NS). Clinical samples of mucocutaneous lesions and cerebrospinal fluid (CSF) specimens from patients previously diagnosed for ES and NS respectively using an enlarged gold standard, were tested by PCR. The reaction was done using primers targeting the tpN47 gene. Twenty out of 21 mucocutaneous samples from patients diagnosed with ES were positive by PCR, with a clinical sensitivity of 95%. Four out of 8 CSF samples from patients previously diagnosed with NS were positive by PCR, with a clinical sensitivity of 50%. The clinical specificity for both ES and NS was 100%. The PCR sensitivity and specificity for mucocutaneous samples allowed us to implement this assay in our laboratory for routine diagnosis. Although the sensitivity of the PCR in CSF was low, it may be useful to support clinical diagnosis.