Low Free Thyroxine (FT4) in critically ill juvenile systemic lupus erythematosus: a diagnostic approach

• Published in: Intisari Sains Medis (ISM) (Manado) Vol. 15; no. 1; pp. 245 - 249
• Main Authors: Yuwono, Elien, Wati, Ketut Dewi Kumara, Arimbawa, I Made
• Format: Journal Article
• Language: English
• Published: 15.03.2024
• ISSN: 2089-9084; 2503-3638
• DOI: 10.15562/ism.v15i1.1926

Introduction: Thyroid dysfunction was frequent in systemic lupus erythematosus (SLE) patients, which may present as euthyroid, hypothyroid, or hyperthyroid states. Critical conditions have a higher chance of euthyroid sick syndrome due to alterations in the hypothalamic-pituitary-thyroid (HPA) axis. Renal impairment was associated with an increased risk of low FT4 due to proteinuria followed by thyroid loss. Case Description: We reported one patient, a 15-year-old girl, who complained of shortness of breath and revealed acute respiratory distress syndrome, valve regurgitation, and pericardial effusion. She also felt joint pain over the leg and odor urination. Further evaluation showed non-scaring alopecia, pyuria, proteinuria >0.5 gram/24 hours, urinary cast, and acute kidney injury stage failure.  ANA (IF) pattern: scattered with titer 1:100, ANA profile indicated Smith (Sm) antigen (+) and C3 108.3 mg/d, which fulfilled Systemic Lupus International Collaborating Clinics (SLICC) 2015 and European League Against Rheumatism (EULAR) 2019 criteria for SLE. On the fourth day of treatment, the patient had acute confusion, hypothermia, and sinus bradycardia, while the investigation of  FT4 hormone was 0.45 ng/dL, TSH 2.39 uIu/ml, which revealed euthyroid sick syndrome. After treatment with a high dose of methylprednisolone, cyclophosphamide, rituximab, levothyroxine, a phosphodiesterase inhibitor, and a diuretic, she deteriorated and passed away. Conclusion: The higher prevalence of thyroid dysfunction in juvenile SLE patients necessitates further attention. Lupus nephritis, increased creatinine level, detection of Smith (Sm) antigen, and critical condition were also at higher risk of low FT4 in juvenile SLE patients. This condition may have a worsened prognosis with prompt diagnosis and treatment.