Which of the following most likely causes a communicating (nonobstructive) hydrocephalus?
Correct Answer: Blockage of the arachnoid granulations
Description: Blockage of the arachnoid granulations would most likely cause a communicating, or nonobstructive, hydrocephalus. Hydrocephalus is an increase in cerebrospinal fluid (CSF) volume with distention of the ventricles. It may be caused by (1) overproduction of CSF, which is uncommon (e.g., in neoplasms of the choroid plexus); (2) decreased absorption of CSF from the arachnoid villi that is caused by an organizing meningitis with fibrosis blocking the arachnoid granulations, dural sinus thrombosis, or organization of blood clot in a subarachnoid hemorrhage; or (3) obstruction of CSF flow within the ventricles with distention of the ventricles proximal to the block, in conditions such as a colloid cyst of the third ventricle, stenosis of the duct of Sylvius, tumor (e.g., ependymoma, medulloblastoma) in the fouh ventricle, or the blockage of flow out of the foramina of Luschka and Magendie by pus (tuberculous meningitis) or blood. Blockage of CSF flow within the ventricles produces an obstructive, or noncommunicating hydrocephalus. Blockage of the resorption of CSF out of the subarachnoid space produces a communicating hydrocephalus, because there is still an open communication between the ventricles and the subarachnoid space. In any of these situations, the ventricles dilate under the increased pressure and are easily identified by computerized tomography scans or magnetic resonance imaging. Reference: GHAI Essential pediatrics, 8th edition
Category:
Pediatrics
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now