Posthaemorrhagic Hydrocephalus of Prematurity

Posthaemorrhagic hydrocephalus of prematurity is progressive ventricular dilatation with raised intracranial pressure following intraventricular haemorrhage in a preterm infant. It is caused by obstruction of CSF flow and reduced absorption by blood and debris.

About a quarter to a half of infants with grade III or IV haemorrhage develop progressive dilatation, and a proportion need a permanent shunt. Onset is usually 1 to 3 weeks after the bleed.

Outcome depends on the associated brain injury, particularly periventricular haemorrhagic infarction, and on shunt complications such as infection and obstruction.

Pathophysiology.

Blood clots obstruct the aqueduct and fourth ventricle outlets and cause an obliterative arachnoiditis of the subarachnoid space. Reduced CSF absorption follows.

Raised pressure impairs periventricular white matter perfusion and causes stretch injury, with ischaemic and inflammatory damage from blood breakdown products (free iron).

• Rapid head growth, more than 2 cm each week in head circumference, with a full or tense anterior fontanelle and widened sutures.
• Apnoea, bradycardia, vomiting, lethargy, poor feeding and sunsetting eyes.
• Ventricular dilatation may precede clinical signs by 1 to 2 weeks.

Red flags.

• Tense fontanelle with apnoea, bradycardia or seizures.
• Rapid increase in head circumference with sunsetting eyes.

• Cranial ultrasound at least twice weekly after severe haemorrhage until stable. Ventricular index on a centile chart (the anterior horn width is also used). Treatment is considered when the ventricular index exceeds the 97th centile by 4 mm, or earlier with clinical signs.
• Daily head circumference and fontanelle examination.
• MRI for parenchymal injury and obstruction site when planning surgery.
• CSF protein and cell count before permanent shunt placement.

Differential diagnosis. Ex vacuo ventricular dilatation from white matter loss (with a normal or small head), benign enlargement of the subarachnoid space, congenital hydrocephalus, infection and posterior fossa lesions.

Non-operative.

• Serial lumbar punctures, acetazolamide and furosemide are not advised because they do not reduce the need for a shunt and cause harm.

Temporising measures.

• Ventricular access device (reservoir) with CSF tapping of 10 to 15 mL/kg when clinical signs of raised intracranial pressure or progressive dilatation appear.
• Ventriculosubgaleal shunt or external ventricular drain are alternatives, especially if CSF protein is high.

Permanent treatment.

• Ventriculoperitoneal shunt when infant weight is about 2 to 2.5 kg, CSF protein is under 1.5 g/L, red cell count is low and there is no infection.
• Endoscopic third ventriculostomy with choroid plexus cauterisation is an option in selected infants.
• Treat shunt infection with IV antibiotics and externalisation of the shunt. Manage obstruction by revision.

Monitoring. Head circumference, ultrasound, neurodevelopment, vision and shunt function (headache, vomiting, drowsiness, or bulging fontanelle) throughout childhood.

Referral and escalation. Refer early to paediatric neurosurgery when ventricles are progressively enlarging.