Diagnóstico y seguimiento de los pacientes con hipotiroidismo congénito diagnosticados por cribado neonatal

The screening program of congenital hypothyroidism (CH) is probably one of the best achievements in paediatrics. Thyroid hormones are essential for brain development and brain maturation that continue through the neonatal period. Hypothyroidism that begins in the first months of life causes irreversible damage to the central nervous system, and is one of the most frequent and preventable causes of mental retardation. As children with congenital hypothyroidism are born with a normal appearance, analytical studies are required to immediately start the appropriate therapy.This article analyses the aims, diagnostic procedures, tests required, aetiology, and differential diagnosis in this disorder. Especially relevant is to perform frequent monitoring to ensure dose adjustments of L-Thyroxine therapy, avoiding infra- or supra-dosing that negatively affects neurosensory functions. Re-evaluation of the aetiology permanent vs transient hypothyroidism is always recommended after 3 years of chronological age.The relevance of this screening program should be widely discussed in paediatrics. The main objective is to avoid cerebral damage in these patients, and has been highly successful and economically beneficial.Other aspects are required to optimise patient outcomes, to perform all the controls according to the recommendations and to include, in the near future, the diagnosis of central hypothyroidism. Implementation of this program is necessary to progress in accordance with current scientific knowledge.     

Monoclonal gammopathy of renal significance: Early diagnosis is key

Monoclonal gammopathy of renal significance is a clinical–pathological entity grouping renal disorders secondary to the secretion of a monoclonal immunoglobulin synthesized by a B-cell-derived clone and/or plasma cells in a patient with no diagnostic criteria for multiple myeloma. This term applies to a concept recently introduced owing to the need to differentiate this entity from monoclonal gammopathy of undetermined significance, given the negative prognostic impact of its high morbidity and mortality resulting from both renal and systemic involvement, occasionally even progressing to advanced chronic kidney disease. The renal damage occurs via both direct pathogenic mechanisms, with the deposition of the monoclonal protein in different renal structures, as well as indirect mechanisms, acting as an autoantibody provoking dysregulation of the alternative complement pathway. The detection of this monoclonal protein and an early hematologic study are essential, as is the need for a kidney biopsy to establish the associated nephropathological diagnosis. Consequently, this then leads to the start of specific hematologic treatment to detain the production of the monoclonal protein and minimize renal and systemic injury.     

Thyroid hormone levels and thyroid dysfunction of French adults participating in the SU.VI.MAX study

Abnormal thyroid function has important public health consequences. However, the various degrees of thyroid dysfunction remain unsettled. The SU.VI.MAX cohort provided a unique opportunity to conduct a cross-sectional study of abnormal thyroid function in a large representative population of 11256 men and women representing the geographic distribution of the French continental adult population. Thyroid status was measured, in fasting blood samples, at baseline in 1994-1995. Serum thyrotropin (TSH) levels (abnormal < 0.4 mU/l or > or =4.0 mU/l) and free thyroxine (fT4) were both performed in duplicate on the same sample. Subjects with previous or present thyroid diseases or who were taking thyroid hormones or antithyroid drugs (n=920) were excluded (8.1%). Thus, the final study group consisted of 10346 subjects, 4121 men aged 45-60 years (mean +/-SD) (51.8+/-4.7 yrs), 2641 women aged 35-44 years (40.6+/-2.8 yrs), and 3584 women aged 45-60 years (51.4+/-4.4 yrs). Median (2.5th and 97.5th percentiles) for TSH (mU/l) were 1.52 (0.20-4.54) for men, 1.78 (0.22-5.54) for women aged 35-44 years, and 1.96 (0.22-6.80) for women aged 45-60 years. The TSH distribution of women was shifted to the right compared with men. Arithmetic mean fT4 (+/-SD) was 10.7+/-1.7 ng/l (13.8 +/-2.2 pmol/l) for men and 10.9+/-1.8 ng/l (14.0+/-2.3 pmol/l) for women. The prevalence of abnormal TSH values in men, and in women (35-44 yrs and 45-60 yrs) were TSH<0.4 mU/l 7.0%, 5.3% and 4.4%; TSH 4.0-9.9 mU/l 4.0%, 7.2% and 11.1% and TSH > or =10.0 mU/l 0.2%, 0.4% and 0.7%, respectively. Geometric mean serum TSH and arithmetic mean serum fT4 concentrations showed significant overall inter-regional differences for men and women (p<0.0001). There was also an inter-regional difference in the prevalence of thyroid dysfunction for men (p=0.003), and for the older group of women (i.e. > or =45 yrs) (p=0.04) exclusively. Over the age of 45 years, the women: men ratio for unrecognized elevated TSH levels (> or =4.0 mU/l) was 2.82, whereas it was 0.64 for low TSH levels (<0.4 mU/l). In summary, abnormal TSH values and thyroid dysfunction were more prevalent in women than men, increased with age and were significantly associated with environmental factors. A high prevalence of identified thyroid diseases in the French population was confirmed by the high number of subjects in this study with laboratory evidence of abnormal biochemical thyroid function. Further studies are needed to determine the geographical determinants of thyroid dysfunctions, especially regional differences in iodine intakes, and to assess the long-term adverse effects of biochemical thyroid dysfunction on all-cause morbidity.