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Hydrocephalus
A. Anatomy of the “Water” (CSF)
Cerebrospinal fluid is a clear colorless fluid that occupies the subarachnoid space and encloses the human brain. It is produced by the ependymal cells in the choroid plexus at a rate of 500milliliter/day. CSF serves as a cushion for the brain, thus, protects the brain from injury. Any condition that can obstruct its circulation and will eventually increase its volume can result to a condition called “Hydrocephalus”.
B. Dissection of the “Water-Head” (Hydrocephalus)
Hydrocephalus, from the Greek word Hydro - “water” and Cephalus -”head”, is a condition resulting from an imbalance between the
formation and drainage of CSF. The occurrence of hydrocephalus can be due to the obstruction of the CSF flow in the brain, decreased CSF absorption and decreased CSF production. This obstruction can be Congenital Hydrocephalus (obstruction in the cerebral aqueduct -aqueduct stenosis) or Acquired Hydrocephalus (obstruction may result from conditions such as spina bifida, intraventricular hemorrhage, meningitis, head trauma, tumors and cysts).
formation and drainage of CSF. The occurrence of hydrocephalus can be due to the obstruction of the CSF flow in the brain, decreased CSF absorption and decreased CSF production. This obstruction can be Congenital Hydrocephalus (obstruction in the cerebral aqueduct -aqueduct stenosis) or Acquired Hydrocephalus (obstruction may result from conditions such as spina bifida, intraventricular hemorrhage, meningitis, head trauma, tumors and cysts).
B.1 Types of Hydrocephalus
1. Noncommunicating Hydrocephalus
-reduced absorption occurs when one or more passages connecting the ventricles become blocked. This prevents the movement of CSF to its drainage sites in the subarachnoid space just inside the skull.
2. Communicating Hydrocephalus
- a reduction in the absorption rate is caused by damage to the absorptive tissue.
Both of these types lead to an elevation of the CSF pressure within the brain. This increased pressure pushes aside the soft tissues of the brain. This squeezes and distorts them. This process also results in damage to these tissues. In infants whose skull bones have not yet fused, the intracranial pressure is partly relieved by expansion of the skull, so that symptoms may not be as dramatic. Both types of elevated-pressure hydrocephalus may occur from infancy to adulthood.
B.2 Clinical Manifestations
-enlargement of the head
- bulging fontanelles
- separation of sutures
- vomiting
- irritability
- decreased mental function
- delayed development
- difficulty feeding
- lethargy
-headaches
-difficulty focusing the eye
-unsteady gait
- weakness of the legs
- dementia
B.3 Diagnostic Tools and Treatment
- Ultrasound, CT Scan, MRI
- Drugs (Mannitol, Furosemide, glycerol and Urea)
- Surgical Intervention (Ventricular Shunting)
B.4 Prognosis
Untreated hydrocephalus has a survival rate of 40–50%, with the survivors having varying degrees of intellectual, physical, and neurological disabilities. Prognosis for treated hydrocephalus varies, depending on the cause. If the child survives for one year, more than 80% will have a fairly normal lifespan. Approximately one-third will have normal intellectual function, but neurological difficulties may persist. Hydrocephalus not associated with infection has the best prognosis and hydrocephalus caused by tumors has a very poor prognosis. About 50% of all children who receive appropriate treatment and follow up will develop IQs in the near-normal or normal range.
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