Hydrocephalus in infants results from which mechanism?

Hydrocephalus in infants results from which mechanism?

• A. Overproduction of CSF
• B. Obstruction to CSF flow
• C. Increased absorption of CSF
• D. Decreased CSF production

Answer: (B)

Hydrocephalus in infants most often results from a blockage that prevents CSF from circulating and being absorbed properly. CSF is produced by the choroid plexus, travels through the ventricles, and drains into the subarachnoid space where it’s absorbed by the arachnoid granulations. If something creates an obstruction along this pathway—such as congenital narrowing of the cerebral aqueduct, intraventricular bleeding, or infection-related scarring—CSF backs up, the ventricles dilate, and intracranial pressure rises. In infants, the skull sutures are not yet fused, so the head can enlarge as the ventricles expand, leading to rapid head growth and a bulging fontanelle. Other mechanisms do not typically produce hydrocephalus. Overproduction of CSF is rare and not the usual driver, and increased CSF absorption would reduce CSF buildup rather than cause it. Decreased CSF production likewise would not cause the accumulation seen in hydrocephalus.

Hydrocephalus in infants most often results from a blockage that prevents CSF from circulating and being absorbed properly. CSF is produced by the choroid plexus, travels through the ventricles, and drains into the subarachnoid space where it’s absorbed by the arachnoid granulations. If something creates an obstruction along this pathway—such as congenital narrowing of the cerebral aqueduct, intraventricular bleeding, or infection-related scarring—CSF backs up, the ventricles dilate, and intracranial pressure rises. In infants, the skull sutures are not yet fused, so the head can enlarge as the ventricles expand, leading to rapid head growth and a bulging fontanelle.

Other mechanisms do not typically produce hydrocephalus. Overproduction of CSF is rare and not the usual driver, and increased CSF absorption would reduce CSF buildup rather than cause it. Decreased CSF production likewise would not cause the accumulation seen in hydrocephalus.