P-76 Down Syndrome and Thyroid hormone levels - how low can you go?

Abstract

Abstract Introduction Down syndrome (DS) is the most common chromosomal condition among live-born infants. It is associated with intellectual disability as well as medical issues ranging from congenital heart disease, obstructive sleep apnea, celiac disease, to endocrinopathies, namely thyroid disorders. The spectrum of thyroid dysfunction in patients with DS include congenital hypothyroidism, subclinical hypothyroidism, acquired hypothyroidism, and hyperthyroidism. Identifying medical comorbidities in these patients can be crucial to optimize their quality of life. Clinical Case This is the case of a male patient, 30 years old, caucasian, institutionalized, with DS and known medical history of esophageal dilation, macroglossia, valvular heart disease with mild aortic insufficiency and left ventricular moderated hypertrophy, macrocytic anemia, and pulmonary embolism 10 months earlier. Due to pallor, somnolence, fatigue, thin and fragile hair, and bradycardia, blood tests were requested and revealed an elevated TSH (385.20 mUI/L, N 0.27-4.20) with undetectable free T4 levels (<0.5 pmol/L, N 12.0-22.0), macrocytic anemia (Hb 11.4 g/dL; MCV 102 fL), renal dysfunction (creatinine 1.73 mg/dL) and hypercholesterolemia (total cholesterol 310 mg/dL; LDL 236 mg/dL). The chest X-ray revealed an heart silhouette enlargement and the echocardiogram showed left ventricular hypertrophy with preserved ejection fraction, diastolic dysfunction, and mild pericardial effusion. The thyroid ultrasound revealed a globally reduced gland, with diffuse hyperechogenicity and heterogeneity, suggesting thyroiditis. The patient was referred to the emergency department and the additional study revealed the presence of anti-TPO and anti-TG antibodies and a severe CK elevation (9280 UI/L, N 46-171). The patient, although lethargic, presented with normal blood pressure, heart rate, and body temperature during the hospital admission. Searching our national health system database, it was found the patient already had TSH elevation with undetectable free T4 levels at least 12 years before, in another hospital, but had lost follow-up there after the blood tests, and therefore remaining undiagnosed and untreated. Oral levothyroxine reposition was started, first with 50 micrograms and then 100 micrograms and the patient was discharged after 5 days with follow-up at the Endocrinology department. Two months later, there were already clinical and laboratory changes, with improved level of consciousness and normalized free T4 levels. Conclusion Although hypothyroidism is a common and widely recognized condition, this case emphasizes how challenging the diagnosis can be in a person with DS. Knowing that this syndrome is associated with several organic dysfunctions, namely endocrine disorders with non-specific clinical manifestations, there must be a high level of suspicion in order to screen, diagnose, and treat the comorbidities that may appear.