SAT-085 Severe Dyslipidemia Secondary to Autoimmune Hypothyroidism: A Case Report

Background: Up to 28% of patients have an underlying potential secondary cause for dyslipidemia. Frequently, the treatment of the underlying cause can lead to normalization of lipid profile. Case report: A 34-year-old male presented with a 12-months history of asthenia, facial swelling, cold intolerance, sleepiness, poor concentration, but stable weight. Physical examination highlighted bilateral palpebral edema. His past medical history was significant for mixed dyslipidemia at least for 2 years (total cholesterol [TC] 326 mg/dL, high-density lipoprotein cholesterol [HDL-C] 84 mg/dL, low-density lipoprotein cholesterol [LDL-C] 199 mg/dL and triglycerides [TG] 211 mg/dL), but no secondary causes of dyslipidemia were excluded, namely hypothyroidism, neither treatment was instituted. He also had overweight (body mass index [BMI]&nbsp;of 29 kg/m(2)) and hepatic steatosis. There was no familial history of dyslipidemia. Laboratory assessment revealed TC 426 mg/dL, HDL-C 89 mg/dL, LDL-C 293.6 mg/dL, TG 217 mg/dL, thyroid-stimulating hormone (TSH) > 100 μUI/mL (reference: 0.550-4.780), free thyroxine (FT4) < 0.3 ng/dL (reference: 0.70-1.58), free triiodothyronine (FT3) < 0.195 pg/mL (reference: 1.71-3.71), positive thyroglobulin antibody and negative peroxidase antibody. Thyroid ultrasonography showed a normal size gland, with heterogeneous texture and pseudonodular areas, without nodular lesions, suggesting thyroiditis. Given the diagnosis of primary autoimmune overt hypothyroidism and mixed dyslipidemia, the patient was given oral levothyroxine up to 137 μg/day and atorvastatin 10 mg/day. After normalization of thyroid function by treatment with levothyroxine, there was an important improvement in overall well-being and in the lipid profile (TC 184 mg/dL, HDL-C 46 mg/dL, LDL-C 115 mg/dL, TG 113 mg/dL), leading to statin withdrawal. Conclusion: This case highlighted a severe dyslipidemia secondary to overt autoimmune hypothyroidism in a young male. The delayed diagnosis of hypothyroidism could have been avoided if a secondary cause for dyslipidemia was initially suspected. Secondary causes of dyslipidemia, namely hypothyroidism, should be considered and excluded in any young patient with no or few risk factors.