Hydrocephaly

Introduction

The word Hydrocephalus is derived from Greek words, 'hydro' means water, and 'cephalus' means head. It simply refers to a condition of excess cerebrospinal fluid in the head. Cerebrospinal fluid (CSF) is found around central nervous system. It flows into the subarachnoid space and functions as a cushion. The CSF is absorbed by arachnoid villi.

The CSF contains essential nutrients necessary to provide nourishment to brain and carries waste material away from brain. The fluid circulates in brain through ventricles. In each ventricle, there is a tuft like structure called the choroid plexus, which produces CSF. The brain maintains a CSF balance between its production and absorption. Hydrocephalus occurs due to imbalance between CSF production and absorption. This is caused by a disturbance of absorption system or overproduction of CSF. This causes enlargement of ventricles and increased pressure inside the skull, which cause pressure symtoms (Cinalli, Maixner, & Sainte-Rose, 65). In the United States, 1 in 500 children has hydrocephalus, and 50 % of these cases have congenital hydrocephalus, it means that 1 in 1,000 babies has congenital hydrocephalus (Cinalli, Maixner, & Sainte-Rose, 65).

Discussion

Aetiology

Hydrocephalus can be caused by two factors

Congenital.

Acquired (Cinalli, Maixner, & Sainte-Rose, 65).

Congenital Factors

Congenital Hydrocephalus is present at birth and occurs due to genetic and environmental factors. It is does not mean that it is hereditary. It can be diagnosed in prenatal period by routine ultrasound, which shows dilated ventricles of fetus (Cinalli, Maixner, & Sainte-Rose, 65).

Acquired Factors

Acquired Hydrocephalus occurs after birth due to neurological disorders. This type can affect people of all ages and is caused by brain tumour, large hematoma in head, cyst, and hemorrhage or CNS infection. It may occur as communicating or non-communicating. Communicating type occurs when the blockage is outside the ventricles. Non-communicating occurs when the blockage is inside the ventricles (Cinalli, Maixner, & Sainte-Rose, 65).

Causes of Hydrocephalus

Aqueductal Stenosis

Aqueductal stenosis is the cause of congenital Hydrocephalus, it is associated with narrowing or blockage of passage between the ventricles due to infection, tumour

or haemorrhage (Cinalli, Maixner, & Sainte-Rose, 65).

Neural Tube Defect

The neural tube defect such as Spina Bifida, causes leaking of CSF, and pushes the fourth ventricle and the cerebellum downward through the base of skull, blocking CSF's flow and produces Hydrocephalus (Cinalli, Maixner, & Sainte-Rose, 65).

Arachnoid Cysts

Arachnoid Cysts in children are located in the vicinity of third ventricle. They are

lined by arachnoid membrane. Some cysts are connected with subarachnoid space or the ventricles. These cysts may block the CSF pathways (Cinalli, Maixner, & Sainte-Rose, 65).

Dandy-Walker Syndrome

In this syndrome, the fourth ventricle outlets are blocked causing enlargement of fourth ventricle. Dandy-Walker syndrome is associated with inadequate development of cerebellum and other parts of the brain. (Cinalli, Maixner, & Sainte-Rose, 65).

Arnold-Chiari Malformation

This causes the brain to push down into the spinal column at the base of brain, causing blockage in CSF flow(Cinalli, Maixner, & Sainte-Rose, 65).

Intraventricular Hemorrhage

This affects premature infants. When blood vessels in the ventricular membrane rupture cause blockage of ventricles or villi, which results in ...