Rodriguez Vilmarie, Gonzales Kristen M, Iqbal Anoop Mohamed, Arbelo-Ramos Natasha, Wyatt Kirk D, Lteif Aida N, Castro M Regina
AACE Clin Case Rep. 2020 Jun 23;6(6):e282-e285. doi: 10.4158/ACCR-2020-0055. eCollection 2020 Nov-Dec.
To describe a case of Graves disease (GD) and coexistent pancytopenia associated with autoimmune vitamin B deficiency. While thyrotoxicosis and antithyroid drugs can cause pancytopenia, other autoimmune conditions such as vitamin B deficiency can occur, leading to severe anemia and pancytopenia.
A 19-year-old female with GD treated with methimazole presented with thyrotoxicosis and evidence of pancytopenia. Diagnostic studies included a complete blood cell count, peripheral blood smears, thyroid function tests, and a bone marrow biopsy.
White blood cells were 2.4 × 10 cells/L (reference range [RR] is 3.4 to 9.6 × 10 cells/L), hemoglobin was 7.9 g/dL (RR is 11.6 to 15.0 g/dL), neutrophil count was 1.2 × 10 cells/L, and platelets were 84 × 10 cells/L (RR is 157 to 371 × 10 cells/L). Thyroid-stimulating hormone was <0.01 mIU/L (RR is 0.50 to 4.30 mIU/L), free thyroxine was 3.7 ng/dL (RR is 1.0 to 1.6 ng/dL), and total triiodothyronine was 221 ng/dL (RR is 91 to 218 ng/dL). Due to suspicion for drug-induced pancytopenia, methimazole was discontinued. Three days later, she was hospitalized for a syncopal episode with a further decline in hemoglobin to 6.7 g/dL, neutrophils to 0.68 × 10 cells/L, and platelets to 69 × 10 cells/L. Bone marrow biopsy findings showing marrow hypercellularity and hypersegmented neutrophils suggested vitamin B deficiency. Vitamin B was <70 ng/L (RR is 180 to 914 ng/L). Intramuscular vitamin B injections were initiated, and pancytopenia resolved within 1 month.
Although rarely described in the literature, autoimmune vitamin B deficiency can be missed as an underlying etiology for pancytopenia in patients with GD. The clinical picture can be further confounded when these patients are treated with antithyroid drugs known to cause bone marrow suppression.
描述1例格雷夫斯病（GD）合并自身免疫性维生素B缺乏所致全血细胞减少的病例。虽然甲状腺毒症和抗甲状腺药物可导致全血细胞减少，但也可能出现其他自身免疫性疾病，如维生素B缺乏，进而导致严重贫血和全血细胞减少。
1例接受甲巯咪唑治疗的19岁GD女性患者出现甲状腺毒症及全血细胞减少迹象。诊断性检查包括全血细胞计数、外周血涂片、甲状腺功能检查及骨髓活检。
白细胞计数为2.4×10⁹/L（参考范围[RR]为3.4～9.6×10⁹/L），血红蛋白为7.9 g/dL（RR为11.6～15.0 g/dL），中性粒细胞计数为1.2×10⁹/L，血小板计数为84×10⁹/L（RR为157～371×10⁹/L）。促甲状腺激素<0.01 mIU/L（RR为0.50～4.30 mIU/L），游离甲状腺素为3.7 ng/dL（RR为1.0～1.6 ng/dL），总三碘甲状腺原氨酸为221 ng/dL（RR为91～218 ng/dL）。因怀疑药物性全血细胞减少，停用甲巯咪唑。3天后，她因晕厥发作住院，血红蛋白进一步降至6.7 g/dL，中性粒细胞降至0.68×10⁹/L，血小板降至69×10⁹/L。骨髓活检结果显示骨髓细胞增多和中性粒细胞核分叶过多提示维生素B缺乏。维生素B水平<70 ng/L（RR为180～914 ng/L）。开始肌内注射维生素B，全血细胞减少在1个月内得到缓解。
尽管文献中对此描述较少，但自身免疫性维生素B缺乏作为GD患者全血细胞减少的潜在病因可能被漏诊。当这些患者使用已知可引起骨髓抑制的抗甲状腺药物治疗时，临床表现可能会更加复杂。
