Choanal atresia associated with prenatal methimazole exposure: Three new patients

Abstract

We report three patients with bilateral choanal atresia in children prenatally exposed to methimazole (MMI) in order to define a MMI embryopathy clinical pattern. The combination of choanal atresia and other specific malformations strongly resembles previously reported patients exposed to MMI in utero. At present, propylthiouracil is considered the best treatment in pregnancies. However in Argentina and some other countries MMI is the only antithyroid drug, possibly posing a significant risk to the unborn fetus.

Choanal atresia associated with maternal hyperthyroidism treated with methimazole: A case–control study

“…Several case reports suggested a possible relationship between prenatal exposure to MMI and choanal atresia [Greenberg, 1987;Hall, 1997;Johnsson et al, 1997;Wilson et al, 1998;Clementi et al, 1999; Gianantonio et al, 2001;Barwell et al, 2002;Ferraris et al, 2003;Barbero et al, 2004;Foulds et al, 2005;Myers and Reardon, 2005;Ozgen et al, 2006;Wolf et al, 2006]. However, two previous epidemiological studies have not found a significant association [Momotani et al, 1984;Di Gianantonio et al, 2001].…”

“…Nevertheless, the finding of thyroid nuclear receptors partially occupied by T3 in fetal brain tissue at the first trimester of gestation suggests a role of thyroid hormones at an early period of the embryogenesis [Iskaros et al, Patients 1, 2, and 3 were reported previously [Barbero et al, 2004].…”

“…Several case reports have associated prenatal use of MMI or CMZ with choanal atresia in the offspring [Greenberg, 1987;Hall, 1997;Johnsson et al, 1997;Barbero et al, 2004;Foulds et al, 2005;Myers and Reardon, 2005;Ozgen et al, 2006;Wolf et al, 2006]. However, two epidemiological studies did not find an increase in the frequency of congenital anomalies in children prenatally exposed to MMI [Momotani et al, 1984;Di Gianantonio et al, 2001].…”

Iridic and retinal coloboma associated with prenatal methimazole exposure

“…Reports by Greenberg [1987], Wilson et al [1998], and Barbero et al [2004] have provided strong evidence that choanal atresia is a relatively frequent feature. Lessfrequent malformations include aplasia cutis congenita [Mujtaba and Burrow, 1975;Milham, 1985], esophageal malformations [Ramirez et al, 1992;Karlsson et al, 2002], nipple anomalies [Greenberg, 1987;Wilson et al, 1998], cardiovascular defects [Sugrue and Drury, 1980;Johnsson et al, 1997] and a persistent vitelline duct [Milham, 1985].…”

Study of a Series of Choanal Atresia Patients: Presentation, Surgical Management and Outcome

“…Other wellknown syndromes having choanal atresia as a component are Crouzon syndrome, pfeiffars syndrome and treacher-colin syndrome. Alcohol, retinoic acid, methimazole, propranolol and antithyroid medication use, is thought to contribute to occurrence of choanal atresia by influencing neural crest cell migration [5] . The malformation may either be a bony plate or soft membranous tissue due to failed re-canalization of nasal fossae during fetal development.…”