Hydrocephalus Flashcards
What is it?
Hydrocephalus is defined as a condition in which there is an excessive volume of cerebrospinal (CSF) fluid within the ventricular system of the brain and is caused by an imbalance between CSF production and absorption.
Symptoms?
Patients with hydrocephalus present with symptoms due to raised intracranial pressure, which include:
Headache (typically worse in the morning, when lying down and during valsalva)
Nausea and vomiting
Papilloedema
Coma (in severe cases)
Obstructive hydrocephalus ?
is due to a structural pathology blocking the flow of cerebrospinal fluid. Dilatation of the ventricular system is seen superior to site of obstruction. Causes include: tumours, acute haemorrhage (e.g. subarachnoid haemorrhage or intraventricular haemorrhage) and developmental abnormalities (e.g. aqueduct stenosis).
Non-obstructive hydrocephalus ?
is due to an imbalance of CSF production absorption. It is either caused by an increased production of CSF (e.g. choroid plexus tumour (very rare)) or more commonly a failure of reabsorption at the arachnoid granulations (e.g. meningitis or post-haemorrhagic).
Investigation
CT head is used as a first line imaging investigation since it is fast and shows adequate resolution of the brain and ventricles
MRI may be used to investigate hydrocephalus in more detail, particularly if there is a suspected underlying lesion
Lumbar puncture* is both diagnostic and therapeutic since it allows you to sample CSF, measure the opening pressure, but also to drain CSF to reduce the pressure
Treatment
An external ventricular drain (EVD) is used in acute, severe hydrocephalus and is typically inserted into the right lateral ventricle and drains into a bag at the bedside
A ventriculoperitoneal shunt (VPS) is a long-term CSF diversion technique that drains CSF from the ventricles to the peritoneum
In obstructive hydrocephalus, the treatment may involve surgically treating the obstructing pathology
