Hydrocephalus

Volume of brain= 1400 ml Volume of CSF= 150ml (75+75) CSF in ventricles around 25 ml Volume of blood= 150 ml Total volume of CSF (adult) = 125-150 ml Total volume of CSF (infant) = 50 ml Monro-Kellie relation: the volume inside the cranium is CONSTANT.

CSF Secretion Cerebrospinal fluid is secreted by the epithelial cells of the choroid plexuses. These cells like those of other secretory epithelia are polarised so that the properties of their apical membrane (ventricle facing) differ from those of the basolateral membrane (blood facing).

Pink: Lateral Ventricles Green:3rd and 4th vent Red:Choroid plexi

CSF Circulation

Normally, CSF flows continually from the ventricles to the subarachnoid space that surrounds the brain and spinal cord.

The balance between production and absorption of CSF is critically important. Because CSF is made continuously, medical conditions that block its normal flow or absorption will result in an over-accumulation of CSF.  The resulting pressure of the fluid against brain tissue is what causes Hydrocephalus.

Causes Of CSF Obstruction

Definition Excessive accumulation of cerebrospinal fluid resulting in abnormal widening of ventricles.

Types of Hydrocephalus There are several different types of Hydrocephalus: Congenital hydrocephalus Acquired hydrocephalus Communicating hydrocephalus Non-communicating hydrocephalus Hydrocephalus ex-vacuo Normal Pressure Hydrocephalus

Congenital Hydrocephalus Congenital hydrocephalus is present at birth and may be caused by environmental influences during fetal development or by genetic factors. Causes are: Aqueduct Stenosis Colloid Cyst

Acquired Hydrocephalus Develops at the time of birth or at some point afterward. This type of hydrocephalus can affect individuals of all ages and may be caused by injury or disease.

Acquired Hydrocephalus is due to: Tumors Hemorrhage Ventriculitis

Communicating Hydrocephalus Communicating hydrocephalus occurs when the flow of cerebrospinal fluid (CSF) is blocked after it exits the ventricles. This form is called communicating, because the CSF can still flow between the ventricles, which remain open.

Causes are due to: Post-hemorrhage Bacterial Meningitis Malignant Meningitis Increased Venous Pressure

Non-Communicating Hydrocephalus Non-communicating hydrocephalus, also called "obstructive" hydrocephalus, occurs when the flow of CSF is blocked along one or more of the narrow pathways connecting the ventricles. Causes include: Congenital Acquired

Hydrocephaly is often suggested as the cause of the unusual parietal bossing (bulging of the bones at the rear sides of the skull) in the Starchild Skull.

Ex-Vacuo Occurs when stroke or traumatic injury damages the brain. In these cases brain tissue may actually shrink.

Normal Pressure Hydrocephalus More common among the elderly. It may result from a SAH, head trauma, infection, tumor or surgery complication. However many people develop normal pressure hydrocephalus when none of these factors are present for unknown reasons.

Symptoms Symptoms vary with age, disease progression and individual differences to tolerance to this condition. (infant vs adult) The infant skull can expand to accomodate the buildup of CSF because of sutures have not yet closed.

Infant In infancy the most obvious indication for hydrocephalus is a rapid increase in head size. Other symptoms: Vomiting Sleepiness Irritability Downward eye deviation(SUNSETTING) Seizures

Adults Older children and adults shows different symptoms since head cannot expand. Headache Vomiting Nausea Papilledema Blurred or double vision Sunsetting

Balance problems Poor coordination Gait disturbances Urinary incontinence Slowing or loss of developement Lethargy, drowsiness, irritability Personality or cognition changes Memory loss

Diagnosis Hydrocephalus is diagnosed through clinical neurological evaluation and by using cranial imaging techniques such as USG, CT, MRI and pressure monitoring techniques. Based on age, clinical presentation, and known abnormalities.

Aqueduct Stenosis on MRI-Sagittal

Treatment Hydrocephalus is often treated by surgically inserted shunt system. System diverts the flow of CSF from the CNS to another area where it can be absorbed. A limited number of individuals can be treated with Third ventriculostomy. By a neuroendoscope, a tiny hole is made on the floor of 3rd ventricle.

Complications Mechanical Failure Infections Obstructions Overdraining* Underdraining

Headache Subdural hematoma Slit-Ventricle Syndrome