Lewandowski Krzysztof C, Dąbrowska Katarzyna, Basińska-Lewandowska Magdalena, Bolanowski Marek, Ruchała Marek, Lewiński Andrzej
1Department of Endocrinology and Metabolic Diseases, Medical University of Lodz, Rzgowska 281/289, 93-338 Lodz, Poland.
2Department of Endocrinology and Metabolic Diseases, Polish Mother's Memorial Hospital - Research Institute, Lodz, Poland.
Thyroid Res. 2020 May 18;13:5. doi: 10.1186/s13044-020-00079-6. eCollection 2020.
Levothyroxine (LT) pseudomalabsorption due to medication non-adherence results in significant costs for Health Service. High dose LT or LT/paracetamol absorption test is used in such cases. Hence, establishment of an optimal test protocol and timing of sample collection is of utmost importance.
A 34-year old woman was admitted to our Department because of severe hypothyroidism [on admission thyrotropin (TSH) > 100 μIU/ml, free thyroxine (FT) 0.13 ng/dl (ref. range 0.93-1.7)] despite apparently taking 1000 μg of LT a day. Autoimmune hypothyroidism had been diagnosed 4 years before during post-partum thyroiditis. Subsequently, it was not possible to control her hypothyroidism despite several admissions to two University Hospitals and despite vehement denial of compliance problems. There was no evidence of coeliac disease or other malabsorption problems, though gluten-free and lactose-free diet was empirically instigated without success. A combined paracetamol (1000 mg)/LT (1000 μg) absorption test was performed in one of these Hospitals. This showed good paracetamol absorption (from < 2 μg/ml to 14.11 μg/ml at 120 min), with inadequate LT absorption (FT increase from 5.95 pmol/l to 9.92 pmol/l at 0 and 120 min respectively). About 2 years prior to admission to our Department the patient was treated with escalating doses of levothyroxine [up to 3000 μg of T and 40 μg of triiodothyronine (T) daily] without significant impact on TSH (still > 75 μIU/ml, and FT still below reference range).After admission to our Department we performed a 2500 μg LT absorption test with controlled ingestion of crushed tablets, strict patient monitoring and sampling at 30 min intervals. We observed a quick and striking increase in FT from 0.13 to 0.46, 1.78, 3.05 and 3.81 ng/dl, at 0, 30, 60, 90 and 120 min, respectively. Her TSH concentration decreased to 13.77 μIU/ml within 4 days. When informed, that we had managed to "overcome" her absorption problems, she discharged herself against medical advice and declined psychiatric consultation.
Adequate patient supervision and frequent sampling (e.g. every 30 min for 210 min) is the key for successful implementation of LT absorption test. Paracetamol coadministration appears superfluous in such cases.
由于药物治疗依从性差导致的左甲状腺素（LT）假性吸收给医疗服务带来了巨大成本。在这种情况下会使用高剂量LT或LT/对乙酰氨基酚吸收试验。因此，建立最佳试验方案和样本采集时间至关重要。
一名34岁女性因严重甲状腺功能减退入住我科[入院时促甲状腺激素（TSH）>100 μIU/ml，游离甲状腺素（FT）0.13 ng/dl（参考范围0.93 - 1.7）]，尽管她显然每天服用1000 μg的LT。自身免疫性甲状腺功能减退在4年前产后甲状腺炎期间被诊断出来。随后，尽管多次入住两家大学医院且她强烈否认存在依从性问题，但仍无法控制她的甲状腺功能减退。没有乳糜泻或其他吸收不良问题的证据，尽管经验性地采用了无麸质和无乳糖饮食但未成功。在其中一家医院进行了对乙酰氨基酚（1000 mg）/LT（1000 μg）联合吸收试验。结果显示对乙酰氨基酚吸收良好（从<2 μg/ml在120分钟时升至14.11 μg/ml），而LT吸收不足（FT在0和120分钟时分别从5.95 pmol/l升至9.92 pmol/l）。在入住我科大约2年前，患者接受了递增剂量的左甲状腺素治疗[每天高达3000 μg的T和40 μg的三碘甲状腺原氨酸（T）]，但对TSH没有显著影响（仍>75 μIU/ml，且FT仍低于参考范围）。入住我科后，我们进行了2500 μg LT吸收试验，控制碾碎片剂的摄入，严格监测患者并每隔30分钟采样一次。我们观察到FT在0、30、60、90和120分钟时分别从0.13迅速显著升至0.46、1.78、3.05和3.81 ng/dl。她的TSH浓度在4天内降至13.77 μIU/ml。当得知我们成功“克服”了她的吸收问题后，她不听从医嘱自行出院并拒绝精神科会诊。
充分的患者监督和频繁采样（例如每30分钟采样一次，共210分钟）是成功实施LT吸收试验的关键。在这种情况下，联合使用对乙酰氨基酚似乎是多余的。
