ABSTRACT
BACKGROUND: Aberrant thyroid function is highly prevalent in Down syndrome (DS). We aimed to find whether subclinical hypothyroidism (SCH) or low-normal free T4 (FT4) are associated with a detrimental clinical outcome in untreated DS patients. METHODS: 157 patients assessed at Hadassah Down Syndrome Center between 2004 and 2010 by comprehensive clinical evaluation and tests for hemoglobin, FT4 and thyroid-stimulating hormone (TSH) were subdivided into subgroups including: clinical hypothyroidism, SCH, euthyroid submedian or supramedian FT4, and alternatively for euthyroidism and TSH levels (submedian or supramedian TSH). RESULTS: Hypothyroidism was found in 21.7% and SCH in another 14.9% of the patients. Moderate/severe hypotonia were more frequent among SCH patients compared to euthyroid patients (52.6 vs. 16.4%, p = 0.002). Patient's hemoglobin levels were lower in the euthyroid submedian FT4 group compared to the euthyroid supramedian FT4 group (10.9 vs. 0% below the normal range, p = 0.001). Interestingly, FT4 levels correlated negatively with increasing age among euthyroid DS patients (Pearson's correlation coefficient = -0.324, p = 0.009). CONCLUSION: SCH and euthyroid submedian FT4 may have significant clinical sequelae, such as hypotonia and anemia. Interventional studies with L-thyroxine replacement may be indicated in these subpopulations. Our finding that FT4 levels decrease with age in DS (contrasting the general population trend) may indicate redefining the normal FT4 levels range in DS.
Subject(s)
Down Syndrome , Hormone Replacement Therapy/adverse effects , Hypothyroidism , Muscle Hypotonia , Thyroxine , Adolescent , Child , Child, Preschool , Down Syndrome/blood , Down Syndrome/complications , Down Syndrome/drug therapy , Female , Humans , Hypothyroidism/blood , Hypothyroidism/complications , Hypothyroidism/drug therapy , Infant , Male , Muscle Hypotonia/blood , Muscle Hypotonia/chemically induced , Retrospective Studies , Thyrotropin/blood , Thyroxine/adverse effects , Thyroxine/blood , Thyroxine/therapeutic useABSTRACT
BACKGROUND: Down syndrome is one of the most common chromosomal abnormalities. Children and adults with DS have significant medical problems and require life-long medical follow-up. OBJECTIVES: To determine the adequacy of medical surveillance of individuals with DS as recommended by the American Academy of Pediatrics. METHODS: The study was conducted at a multidisciplinary center specializing in the care of DS during the period 2004-2006. At their first visit to the Center, caregivers of individuals with DS were questioned about the medical status of their child including previous evaluations. Medical records brought in by the parents were reviewed. RESULTS: The caregivers of 150 individuals with DS (age ranging from newborn to 48-years-old, median age 5 years) were interviewed and the medical records were reviewed. The prevalence of specific medical problems differed between our population and the reported prevalence from other surveys. For example, 39.3% of our population had documented auditory deficits while the reported prevalence is 75%. For gastrointestinal and thyroid disease, the prevalence was higher in the studied population than that reported in the literature. In terms of compliance with the AAP recommendations, most children (94%) underwent echocardiography, but only 42.7% and 63.3% had been tested for auditory or visual acuity respectively. Only 36.3% over the age of 3 years had cervical spine films. DISCUSSION: Many individuals with DS are not receiving appropriate medical follow-up and the consequences of inadequate surveillance can be serious.