HYDROCEPHALUS

Definition: Hydrocephalus is defined as abnormal accumulation of cerebrospinal fluid (CSF) within the ventricles and subarachnoid spaces. It is often associated with dilatation of the ventricular system and increased intracranial pressure (ICP). Hydrocephalus is defined as abnormal accumulation of cerebrospinal fluid (CSF) within the ventricles and subarachnoid spaces. It is often associated with dilatation of the ventricular system and increased intracranial pressure (ICP).

Physiology and circulation of CSF The normal volume of circulating CSF is about 150 ml. The normal volume of circulating CSF is about 150 ml. The daily production of the CSF is about 450 ml, so the CSF volume is replaced approximately three times daily. The daily production of the CSF is about 450 ml, so the CSF volume is replaced approximately three times daily. CSF is produced by an active process independent of inracranial pressure (ICP). CSF is produced by an active process independent of inracranial pressure (ICP). 80% of CSF is produced by the choroid plexus, and the rest is from the parenchyma 80% of CSF is produced by the choroid plexus, and the rest is from the parenchyma

Functions of the CSF 1. Protect and support the brain and spinal cord. 1. Protect and support the brain and spinal cord. 2. Maintain homeostasis by acting as a transport medium for transmitters and as a method of removing the end-products of metabolism. 2. Maintain homeostasis by acting as a transport medium for transmitters and as a method of removing the end-products of metabolism.

CSF Circulation lateral ventricles. lateral ventricles. foramen of Monro foramen of Monro third ventricle third ventricle aqueduct of Sylvius aqueduct of Sylvius fourth ventricle fourth ventricle two foramina of Luschka two foramina of Luschka foramen of Magendie foramen of Magendie subarachnoid space subarachnoid space arachnoid villi arachnoid villi venous blood venous blood blood stream. blood stream.

CSF Circulation

Classification of Hydrocephalus A.Non-communicating hydrocephalus (Obstructive): results from lesions that obstruct the CSF pathways from the lateral ventricles to the fourth ventricle. A.Non-communicating hydrocephalus (Obstructive): results from lesions that obstruct the CSF pathways from the lateral ventricles to the fourth ventricle. B.Communicating hydrocephalus: B.Communicating hydrocephalus: refers to circumstances in which the intracerebral CSF pathways are patent but there is accumulation of CSF, usually due to impaired CSF absorption.

Epidemiology of Hydrocephalus The incidence of infantile hydrocephalus is about 3 to 4 per 1000 live birth The incidence of infantile hydrocephalus is about 3 to 4 per 1000 live birth

Aetiologty of Hydrocephalus In patients with hydrocephalus, an imbalance has occurred between the normal physiological production of CSF and its absorption. In patients with hydrocephalus, an imbalance has occurred between the normal physiological production of CSF and its absorption. This imbalance can be as a result of overproduction of CSF, an obstruction, or impaired absorption. This imbalance can be as a result of overproduction of CSF, an obstruction, or impaired absorption.

Normal Lateral Ventricle Vs Hydrocephalus

Normal Ventricles Vs Hydrocephalus

Normal Brain Vs Hydrocephalus coronal section

Normal Brain Vs Hydrocephalus

Aetiologty of Hydrocephalus A.Non-communicating hydrocephalus (Obstructive): A.Non-communicating hydrocephalus (Obstructive): 1. Lateral ventricle obstruction by tumours, e.g. basal ganglia glioma, thalamic glioma. 1. Lateral ventricle obstruction by tumours, e.g. basal ganglia glioma, thalamic glioma. 2. Third ventricular obstruction, due to colloid cyst of the 3rd ventricle or glioma of the 3rd ventricle 2. Third ventricular obstruction, due to colloid cyst of the 3rd ventricle or glioma of the 3rd ventricle 3.Occlusion of the aqueduct of Sylvius (either primary stenosis or secondary to a tumour) 3.Occlusion of the aqueduct of Sylvius (either primary stenosis or secondary to a tumour) 4. Forth ventricular obstruction due to posterior fossa tumour, e.g. medulloblastoma, ependymoma, acoustic neuroma. 4. Forth ventricular obstruction due to posterior fossa tumour, e.g. medulloblastoma, ependymoma, acoustic neuroma.

Aetiologty of Hydrocephalus B. Communicating hydrocephalus: 1. Failure of absorption of CSF through the arachnoid granulations over the cerebral hemispheres. 1. Failure of absorption of CSF through the arachnoid granulations over the cerebral hemispheres. Sclerosis or scarring of the arachnoid granulations can occur after meningitis (bacterial or tuberculous), subarachnoid haemorrhage (either spontaneous, traumatic or postoperative), or trauma. Sclerosis or scarring of the arachnoid granulations can occur after meningitis (bacterial or tuberculous), subarachnoid haemorrhage (either spontaneous, traumatic or postoperative), or trauma. 2. Oversecretion of CSF (choroid plexus papilloma). 2. Oversecretion of CSF (choroid plexus papilloma).

Clinical Features of Hydrocephalus Neonatal Hydrocephalus (Infantile): Neonatal Hydrocephalus (Infantile): 1. Failure to thrive and feeding problems. 2. Enlargement of the head with increasing head circumference. 3. Craniofacial disproportion with expansion of the dome and "low set" ears and eyes. 4. The scalp is thin and glistening. 5. The veins of the scalp are distended. 6. The anterior fontanelle is enlarged, tense, and bulging.

Clinical Features of Hydrocephalus Neonatal Hydrocephalus (Infantile): Neonatal Hydrocephalus (Infantile): 7. Weakness of upward gaze (the setting-sun sign)(3 rd ventricular pressure on midbrain tectum). 8. Diastasis of the cranial sutures. 9. Transillumination of the head is usually positive (if cortical mantle is less than 1cm and the patient is under 9 months age). 10. Bradycardia can be seen in extreme cases.

Neonatal Hydrocephalus (Infantile)

Clinical Features of Hydrocephalus Hydrocephalus in older children and adults: Hydrocephalus in older children and adults: 1. Headache. 2. Nausea and vomiting. 3. Deterioration in the level of consciousness. 4. May be associated ataxia. 5. Visual disturbance.

Investigations of Hydrocephalus A. Skull x-ray: can show 1. Separation of sutures. 2. Features of increased intracranial pressure

Investigations of Hydrocephalus B. Ultrasound of the brain: can be done through opened anterior fontanelle to see the ventricular system. can be done through opened anterior fontanelle to see the ventricular system.

Ultrasound of the brain

Investigations of Hydrocephalus C. CT scan of the Brain: 1. Ventricular dilatation. 2. Can show the cause of obstruction as tumour. D. MRI of the brain: same as CT but no radiation so can be used for follow up.

CT scan of the Brain

Choroid Plexus Papilloma with Hydrocephalus

Third Ventricle Tumour with Hydrocephalus

MRI HYDROCEPHALUS

MRI Hydrocephalus

Investigations of Hydrocephalus E. Lumbar puncture: can be done in communicating hydrocephalus for both diagnostic and therapeutic aims. can be done in communicating hydrocephalus for both diagnostic and therapeutic aims.

Management of Hydrocephalus A. Medical management B. Surgical management

Medical management of Hydrocephalus By using methods to reduce CSF By using methods to reduce CSF production, but till now no definite medical treatment is satisfactory.

B. Surgical management 1. Removal of obstructing lesion e.g. removal of tumour will resolve hydrocephalus. 2. Bypassing obstruction: either by: a. Endoscopic third ventriculostomy b. External drainage of CSF c. Internal diversion (Shunting)

Endoscopic Third Ventriculostomy

Types of Internal Shunts 1. Ventriculo-Peritoneal Shunts. 2. Ventriculo-Atrial Shunts. 3. Ventriculo-Pleural Shunts.

Ventriculo-peritoneal Shunt

Shunted Hydrocephalus

The complications of shunting The complications of shunting 1. Shunt obstruction: 2. Shunt infection. 3. Intracranial haemorrhage either: a. Intracerebral haemorrhage, or b. Subdural haematoma.

Complications of Ventriculo-Atrial Shunts Infective Endocarditis Volume Overload (Heart Failure) Arrhythmias (SA node).

Complications of Ventriculopleural Shunts: Pneumothorax and Haemopneumothorax Pleural Effusion Pleural Empyema.

Benign intracranial hypertension Benign intracranial hypertension, also known as pseudotumour cerebri, is, as its name implies, a disease of raised intracranial pressure, which usually runs a self-limiting course. Although termed ‘benign’, this condition can cause blindness due to severe papilloedema. The pathogenesis is poorly understood. The condition usually occurs in obese females.

Aetiology Hypoparathyroidism Vitamin A excess (used to treat acne) Pernicious anaemia Drug reaction—tetracycline, nalidixic acid, sulfamethoxazole, indomethacin, danazole, lithium carbonate, oral contraceptive steroids A similar condition results from venous sinus thrombosis.

Clinical features: Headaches Visual disturbance. The headaches have the features of raised intracranial pressure in that they are worse in the morning and exacerbated by straining, stooping and coughing. The visual problems result from: Papilloedema Secondary optic atrophy Diplopia due to sixth cranial nerve palsy.

Investigations The CT and/or MRI scan will show no cause for the papilloedema and the ventricles will often be smaller than usual Digital subtraction cerebral angiography or magnetic resonance venography may be performed to exclude thrombosis of a venous sinus as the cause If the CT scan or MRI shows no mass or lesion a lumbar puncture is usually performed; the pressure will be raised. CSF examination is normal in benign intracranial hypertension but biochemistry and cytological investigations should be performed to exclude underlying pathology.

Medical (Conservative) Treatment Benign intracranial hypertension is usually a self-limiting disease and most cases respond to simple conservative treatment. The usual measures undertaken are: A. A. Conservative Treatment: Weight loss (the patients are usually obese) Stopping any medication that may have led to the disease, e.g. oral contraceptives, tetracycline Diuretic therapy Acetazolamide (reduces CSF production) If there is no improvement with the above measures, treatment with glycerol or steroids may be tried.

Surgical Treatment The major indications for surgical treatment are: Persistent severe papilloedema despite conservative measures Failing vision Intractable headaches despite conservative measures. The surgical procedures that can be performed are: Optic nerve sheath decompression Lumboperitoneal shunt.

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