WBR263
| Author | [[PageAuthor::Ogheneochuko Ajari, MB.BS, MS [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Embryology |
| Sub Category | SubCategory::General Principles |
| Prompt | [[Prompt::A 12 month old female was brought to the physician’s office with complaints of fever, vomiting and difficulty with breathing. The mother is a chronic alcoholic and consumed alcohol excessively throughout the child’s pregnancy. A month ago, the child was diagnosed with fetal alcohol syndrome. Physical examination shows microcephaly, facial abnormalities, a heart murmur and developmental delay. Which one of the following errors most likely occurred in the embryonic period?]] |
| Answer A | AnswerA::Aplasia |
| Answer A Explanation | AnswerAExp::Incorrect. Aplasia is absent organ despite the presence of primordial tissue. |
| Answer B | AnswerB::Hypoplasia |
| Answer B Explanation | AnswerBExp::Incorrect. Hypoplasia is incomplete organ development with the presence of primordial tissue. |
| Answer C | AnswerC::Agenesis |
| Answer C Explanation | AnswerCExp::Incorrect. Agenesis is absent organ due to the absence of primordial tissue. |
| Answer D | AnswerD::Deformation |
| Answer D Explanation | AnswerDExp::Incorrect. Deformation is extrinsic disruption; it occurs after the embryonic period. |
| Answer E | AnswerE::Malformation |
| Answer E Explanation | AnswerEExp::Correct- See explanation |
| Right Answer | RightAnswer::E |
| Explanation | [[Explanation::The patient in this question has Fetal alcohol syndrome which is a leading cause of congenital malformations in the United States. Newborns of mothers that consumed significant quantities of alcohol during pregnancy have an increased incidence of congenital abnormalities present with features such as pre- and postnatal developmental retardation, microcephaly, holopresencephaly, facial abnormalities, limb dislocation, and heart and lung fistulas.
Malformation (Choice E) is said to have occurred during the embryonic period of development. Malformation is intrinsic disruption and occurs between the 3rd – 8th weeks (embryonic period – organogenesis) of pregnancy). Alcohol, a teratogen, exerts its effect during that stage of fetal development. Educational Objective Fetal alcohol syndrome is caused by the teratogen alcohol which causes congenital malformations, an error in organ morphogenesis in the embryonic period to organogenesis (3rd – 8th weeks). Reference: First AID for the USMLE Step 1, 2011 |
| Approved | Approved::Yes |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |