A 2-year-old boy who recently immigrated to the United States with his family is brought to the office for irritability and excessive crying. The mother's pregnancy was uneventful, but the patient was delivered via cesarean section due to obstructed labor. His mother reports that he has developed more slowly than his brother in ability to lift his head, crawl, and walk. She has also noticed that the patient's head is larger than other children of the same age. His weight is at the 60th percentile, height is at the 50th percentile, and head circumference is at the 95th percentile. CT scan of the head is shown in the image below. Which of the following is the most likely diagnosis?

Question

A 2-year-old boy who recently immigrated to the United States with his family is brought to the office for irritability and excessive crying.  The mother's pregnancy was uneventful, but the patient was delivered via cesarean section due to obstructed labor.  His mother reports that he has developed more slowly than his brother in ability to lift his head, crawl, and walk.  She has also noticed that the patient's head is larger than other children of the same age.  His weight is at the 60th percentile, height is at the 50th percentile, and head circumference is at the 95th percentile.  CT scan of the head is shown in the image below.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec160b_39b8_1843_9249_2191df0a6e69_MD0001_00 This child likely has Dandy-Walker malformation, a developmental anomaly characterized by hypoplasia/absence of the cerebellar vermis (red arrow) and cystic dilation of the fourth ventricle with posterior fossa enlargement (blue arrow). Patients often present during infancy with developmental delay and progressive skull enlargement. Cerebellar dysfunction can result in unsteadiness and impaired muscle coordination. Non-communicating hydrocephalus may occur due to atresia of the foramina of Luschka and Magendie, resulting in symptoms of elevated intracranial pressure (eg, irritability, vomiting). Other associated features can include agenesis of the corpus callosum and malformations involving the face, heart, or limbs. (Choice A) Arnold-Chiari malformation, also known as Chiari II malformation, is characterized by downward displacement of the cerebellar vermis and tonsils below the foramen magnum. Patients also frequently have spinal myelomeningocele. (Choice B) Brain arteriovenous malformations are developmental vascular lesions that usually present at age 10-30 with intracranial hemorrhage, seizure, headache, or focal neurologic deficits. (Choice D) An encephalocele is a rare neural tube defect characterized by protrusion of the brain and meninges through an abnormal opening in the skull. (Choice E) Hypoxic-ischemic brain injury may occur with complicated deliveries (eg, emergency cesarean section), but it typically presents with altered consciousness and decreased spontaneous movements during the neonatal period. Neuroimaging classically shows watershed necrosis of the gray matter between perfusion zones of the major cerebral arteries. Educational objective: Dandy-Walker malformation is a developmental anomaly characterized by hypoplasia/absence of the cerebellar vermis and cystic dilation of the fourth ventricle with posterior fossa enlargement. Patients often present during infancy with developmental delay and progressive skull enlargement. Other features may include cerebellar dysfunction and non-communicating hydrocephalus. __________ References: Diagnosis and management of the Dandy-Walker malformation: 30 years of experience. (http://www.ncbi.nlm.nih.gov/pubmed/1472430)

A 2-Year-Old Boy Who Recently Immigrated to the United States