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|SubCategory=Endocrine | |SubCategory=Endocrine | ||
|Prompt=A 5-year-old boy is brought by his mother to the physician's office for excessive urination. The mother also notes that her child is always complaining he has a dry mouth and is drinking water all the time. Upon further questioning, the physician notes that several members of the patient's extended family have a similar condition. Initial work-up of the patient demonstrates that the patient is normoglycemic and has high-normal levels of plasma osmolality. Water restriction test is performed. It shows an elevated urine osmolality, reaching 1000 mOsm/kg upon administration of antidiuretic hormone (ADH). Which of the following structures is derived from the same embryological origin as that responsible for the patient's condition? | |Prompt=A 5-year-old boy is brought by his mother to the physician's office for excessive urination. The mother also notes that her child is always complaining he has a dry mouth and is drinking water all the time. Upon further questioning, the physician notes that several members of the patient's extended family have a similar condition. Initial work-up of the patient demonstrates that the patient is normoglycemic and has high-normal levels of plasma osmolality. Water restriction test is performed. It shows an elevated urine osmolality, reaching 1000 mOsm/kg upon administration of antidiuretic hormone (ADH). Which of the following structures is derived from the same embryological origin as that responsible for the patient's condition? | ||
|Explanation=Central diabetes insipidus (CDI) | |Explanation=[[Central diabetes insipidus]] (CDI) is a heterogeneous disease characterized by [[arginine vasopressine]] ([[AVP]]) deficiency. The hallmark of CDI are [[polyuria]] and [[polydypsia]]. It is caused by the destruction of neurons of the supraoptic and paraventricular nuclei in the hypothalamus by inflammatory, autoimmune, vascular causes, and compressive lesions, such as [[germinoma]], [[craniopharyngioma]], and [[Langerhans-cell histiocytosis]]. Other causes of CDI include trauma or iatrogenic causes, such as surgery. CDI may also be familial; it may be caused by a genetic disease that may be inherited by X-linked recessive or autosomal dominant pattern. Nonetheless, approximately half of cases of CDI among children are idiopathic. | ||
Physiologically, AVP is produced in the [[hypothalamus]]. AVP is then transported and stored in the [[posterior pituitary gland]] (neurohypophysis). In CDI, AVP will not be produced by the hypothalamus, thus it will not be available for storage in the posterior pituitary. [[Water restriction test]] is an appropriate test to differentiate central vs. nephrogenic diabetes insipidus (NDI). In contrast to NDI, where AVP receptors in the kidneys are dysfunctional, the administration of AVP analog (DDAVP) in CDI will cause remarkable elevation in [[urine osmolality]], usually to more than 800 mOsm/kg. Of note, most cases of DI are mixed. | |||
The hypothalamus, the posterior pituitary, and the retina are all embryologically derived from the same origin, the [[neuroectoderm]]. | |||
|AnswerA=Retina | |AnswerA=Retina | ||
|AnswerAExp=Retina is derived from neuroectoderm. | |AnswerAExp=[[Retina]] is derived from [[neuroectoderm]]. | ||
|AnswerB=Dorsal root ganglia | |AnswerB=Dorsal root ganglia | ||
|AnswerBExp=Dorsal root ganglia are derived from the neural crest. | |AnswerBExp=[[Dorsal root ganglia]] are derived from the [[neural crest]]. | ||
|AnswerC=Schwann cells | |AnswerC=Schwann cells | ||
|AnswerCExp=Schwann | |AnswerCExp=[[Schwann cell]]s are derived from the [[neural crest]]. | ||
|AnswerD=Parafollicular cells of the thyroid | |AnswerD=Parafollicular cells of the thyroid | ||
|AnswerDExp=Parafollicular cells of the thyroid are derived from the neural crest. | |AnswerDExp=Parafollicular cells of the [[thyroid]] are derived from the [[neural crest]]. | ||
|AnswerE=Follicular cells of the thyroid | |AnswerE=Follicular cells of the thyroid | ||
|AnswerEExp=Follicular cells of the thyroid are derived from the endoderm. | |AnswerEExp=Follicular cells of the thyroid are derived from the [[endoderm]]. | ||
|EducationalObjectives=Central diabetes insipidus is caused by the destruction of supraoptic nuclei of the hypothalamus, which are derived from the neuroectoderm. Retina is also derived from neuroectoderm. | |EducationalObjectives=Central diabetes insipidus (CDI) is caused by the destruction of supraoptic nuclei of the hypothalamus, which are derived from the neuroectoderm. Retina is also derived from neuroectoderm. | ||
|References=First | |References=Maghnie M, Cosi G, Genovese E, et al. Central diabetes insipidus in children and young adults. N Engl J Med. 2000;343(14):998-1007.<br>First Aid 2014 page 553 | ||
|RightAnswer=A | |RightAnswer=A | ||
|WBRKeyword=retina, neuroectoderm, embryological, origin, derived, central, diabetes, insipidus, polyuria, polydipsia, water, restriction, test, ADH, antidiuretic, hormone, hypothalamus, posterior, pituitary | |WBRKeyword=retina, neuroectoderm, embryological, origin, derived, central, diabetes, insipidus, polyuria, polydipsia, water, restriction, test, ADH, antidiuretic, hormone, hypothalamus, posterior, pituitary | ||
|Approved=No | |Approved=No | ||
}} | }} | ||
Revision as of 16:48, 16 September 2014
| Author | [[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Yazan Daaboul, M.D.)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Embryology |
| Sub Category | SubCategory::Endocrine |
| Prompt | [[Prompt::A 5-year-old boy is brought by his mother to the physician's office for excessive urination. The mother also notes that her child is always complaining he has a dry mouth and is drinking water all the time. Upon further questioning, the physician notes that several members of the patient's extended family have a similar condition. Initial work-up of the patient demonstrates that the patient is normoglycemic and has high-normal levels of plasma osmolality. Water restriction test is performed. It shows an elevated urine osmolality, reaching 1000 mOsm/kg upon administration of antidiuretic hormone (ADH). Which of the following structures is derived from the same embryological origin as that responsible for the patient's condition?]] |
| Answer A | AnswerA::Retina |
| Answer A Explanation | [[AnswerAExp::Retina is derived from neuroectoderm.]] |
| Answer B | AnswerB::Dorsal root ganglia |
| Answer B Explanation | [[AnswerBExp::Dorsal root ganglia are derived from the neural crest.]] |
| Answer C | AnswerC::Schwann cells |
| Answer C Explanation | [[AnswerCExp::Schwann cells are derived from the neural crest.]] |
| Answer D | AnswerD::Parafollicular cells of the thyroid |
| Answer D Explanation | [[AnswerDExp::Parafollicular cells of the thyroid are derived from the neural crest.]] |
| Answer E | AnswerE::Follicular cells of the thyroid |
| Answer E Explanation | [[AnswerEExp::Follicular cells of the thyroid are derived from the endoderm.]] |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::Central diabetes insipidus (CDI) is a heterogeneous disease characterized by arginine vasopressine (AVP) deficiency. The hallmark of CDI are polyuria and polydypsia. It is caused by the destruction of neurons of the supraoptic and paraventricular nuclei in the hypothalamus by inflammatory, autoimmune, vascular causes, and compressive lesions, such as germinoma, craniopharyngioma, and Langerhans-cell histiocytosis. Other causes of CDI include trauma or iatrogenic causes, such as surgery. CDI may also be familial; it may be caused by a genetic disease that may be inherited by X-linked recessive or autosomal dominant pattern. Nonetheless, approximately half of cases of CDI among children are idiopathic.
Physiologically, AVP is produced in the hypothalamus. AVP is then transported and stored in the posterior pituitary gland (neurohypophysis). In CDI, AVP will not be produced by the hypothalamus, thus it will not be available for storage in the posterior pituitary. Water restriction test is an appropriate test to differentiate central vs. nephrogenic diabetes insipidus (NDI). In contrast to NDI, where AVP receptors in the kidneys are dysfunctional, the administration of AVP analog (DDAVP) in CDI will cause remarkable elevation in urine osmolality, usually to more than 800 mOsm/kg. Of note, most cases of DI are mixed. The hypothalamus, the posterior pituitary, and the retina are all embryologically derived from the same origin, the neuroectoderm. |
| Approved | Approved::No |
| Keyword | WBRKeyword::retina, WBRKeyword::neuroectoderm, WBRKeyword::embryological, WBRKeyword::origin, WBRKeyword::derived, WBRKeyword::central, WBRKeyword::diabetes, WBRKeyword::insipidus, WBRKeyword::polyuria, WBRKeyword::polydipsia, WBRKeyword::water, WBRKeyword::restriction, WBRKeyword::test, WBRKeyword::ADH, WBRKeyword::antidiuretic, WBRKeyword::hormone, WBRKeyword::hypothalamus, WBRKeyword::posterior, WBRKeyword::pituitary |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |