HYDROCEPHALUS

Issah J. kiswagala.

(M.B.B.S)

DEFINITION

• This is a condition that occurs due to disturbances of CSF flow and imbalance between CSF production and absorption resulting in the accumulation of CSF and dilatation of ventricles.

SURGICAL ANATOMY

CEREBROSPINAL FLUIDS (CSF).

• is a clear, colorless body fluid found around the brain and spinal cord. It is produced by the specialised ependymal cells in the choroid plexuses of the ventricles of the brain, and absorbed in the arachnoid granulations.
• There is about 125mL of CSF at any one time, and about 500 mL is generated every day.
• CSF acts as a cushion or buffer for the brain, providing basic mechanical and immunological protection to the brain inside the skull.
• CSF also serves a vital function in cerebral autoregulation of cerebral blood flow.
• CSF occupies the subarachnoid space (between the arachnoid mater and the pia mater) and the ventricular system around and inside the brain and spinal cord.

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CSF CIRCULATION

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• Lateral ventricle

↓via foramen of Monroe

• 3rd ventricle

↓via aqueduct of Sylvius

• 4th ventricle

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• CSF leaves the 4th ventricle by foramen of Luschka and Magendie to circulate over the convexity where it is finally absorbed over arachnoid granulations.

EPIDEMIOLOGY

• Hydrocephalus is one of the most common brain disorders.
• Generally, incidence is equal in males and females.
• Incidence of human hydrocephalus presents a bimodal age curve. One peak occurs in infancy and is related to the various forms of congenital malformations and premature birth. Another peak occurs in adulthood- adult hydrocephalus represents approximately 40% of total cases of hydrocephalus.
• Low- and middle-income countries incur the greatest burden of disease, particularly those within the African and Latin American regions. 

AETIOPATHOLOGY

Hydrocephalus occurs due to two reasons:

• If there is overproduction of CSF, or CSF circulation
• If there is decreased absorption

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1. A. Overproduction:
1. True overproduction is rare and occurs in cases of choroid plexus papilloma.
2. B. Decreased absorption:
1. Failure of CSF absorption is much more common due to infection and haemorrhage.
2. Other causes being: Structural abnormality occurring in CSF pathway-tumour, congenital malformation such as aqueduct stenosis.

CLASSIFICATION/TYPES

Classification I

• There are two types of Hydrocephalus
• Communicating: Due to obstruction in subarachnoid space but Ventricles communicate freely. Here there is defective absorption of CSF following any inflammation, subarachnoid haemorrhage or trauma.
• Non-communicating: Due to obstruction in ventricular system or its exit. Can be due to any tumours or any inflammatory process.

Classification II

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CLINICAL FEATURES

I. INFANTILE HYDROCEPHALUS

• Difficulty in delivery of large head
• Craniofacial disproportion
• Increase in head circumference more than 2 cm/month
• Scalp is thin, shiny and prominent veins
• Fontanelles: Bulging and tense especially on crying
• Sutures: Open, excessive irritability
• Macewen's sign--cracked pot sound on percussing over dilated ventricles.
• Inability to retain feeds, mental retardation, delayed milestones, hypothalamic disturbances. Vomiting, more significant in the morning
• Sun-set sign: Weakness of upward gaze

II. Childhood/adult hydrocephalus

• By this time fontanelles have closed.
• Features of increased intracranial pressure: Headache, nausea, vomiting.
• Irritability, indifference, apathy, drowsiness.
• Blindness is not the sign of papilloedema
• Blindness is due to ophthalmoplegia
• Bradycardia, systemic hypertension, altered respiratory rate is due to distortion of brainstem. Untreated cases also develop unilateral or bilateral abducens palsy or upward gaze palsy.
• Dementia (of varying degrees)
• Urinary incontinence: May present as urgency, frequency, or a diminished awareness of the need to urinate

DIFFERENTIAL DIAGNOSIS OF LARGE HEAD

DIAGNOSIS

• The diagnosis is suspected based on the history and the physical exam. It is confirmed with imaging studies of the head, such as CT, MRI, or ultrasound.

INVESTIGATIONS

• Hb% level
• CT scan, to assess size of ventricles and other structures
• Ultrasonography through anterior fontanelle in infants: To assess for subependymal and intraventricular hemorrhage; to follow infants for possible progressive hydrocephalus
• Skull radiography: To detect erosion of sella turcica, or "beaten copper cranium" (or "beaten silver cranium")—the latter can also be seen in craniosynostosis; (after shunt insertion) to confirm correct positioning of installed hardware
• Ventriculography,
• Air encephalography, or
• MRI, to measure CSF stroke volume (SV) in the cerebral aqueduct.

MANAGEMENT�

Aim

1. To decrease CSF production by using pharmacological agents:

• Acetazolamide
• Furosemide
• lsosorbide
• Glycerol

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2. Direct removal of cause of obstruction

3. Diversion of CSF to another viscous for reabsorption by means of various shunt procedures.

PRE- REFERRAL MANAGENT�

• Hb% level
• Carbonic anhydrase inhibitors (eg, acetazolamide) and loop diuretics (eg, furosemide) 
• Ventricular tap in infants
• Lumbar puncture (LP) in posthemorrhagic and postmeningitic hydrocephalus
• Then refer

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TREATMENT�

SURGERY

• Surgical treatment is the preferred therapeutic option in patients with hydrocephalus.  Most patients eventually undergo shunt placements, such as the following:
• Ventriculoperitoneal (VP) shunt (most common),
• Ventriculoatrial (VA) shunt (or "vascular shunt"),
• Lumboperitoneal shunt (Only used for communicating hydrocephalus, CSF fistula, or pseudotumor cerebri),
• Ventriculopleural shunt (second-line therapy): Used if other shunt types contraindicated.

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PROGNOSIS

• Long-term outcome is related directly to the cause of hydrocephalus.
• Up to 50% of patients with large intraventricular hemorrhage develop permanent hydrocephalus requiring shunt.
•  Patients have good prognosis with shunting.

COMPLICATION

Related to progression of hydrocephalus:-

• Visual changes
• Cognitive dysfunction
• Incontinence
• Gait changes

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Related to medical treatment:-

• Electrolyte imbalance
• Metabolic acidosis

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Related to surgical treatment

• Signs and symptoms of increased intracranial pressure (ICP) can be a consequence of undershunting or shunt obstruction or disconnection.
• Subdural hematoma or hygroma is secondary to overshunting. Headache and focal neurological signs are common.
•  seizures (Treat with antiepileptic drugs)
• Shunt infection
• VP shunt complications include peritonitis, inguinal hernia, perforation of abdominal organs, intestinal obstruction, volvulus, and CSF ascites.
• Ventriculoatrial (VA) shunt complications include septicemia, shunt embolus, endocarditis, and pulmonary hypertension.
• Lumboperitoneal shunt complications include radiculopathy and arachnoiditis.

PREVENTION

• Often it cannot be prevented. Preventing the underlying conditions that lead to hydrocephalus may be the most effective form of prevention.
• Prevent head injury by using appropriate safety equipment such as seat belts, child safety seats and bike helmets.
•  Prevent and promptly treat infections and other illnesses that can lead to Hydrocephalus.