Bleeds and Blockages: Post-Haemorrhagic Hydrocephalus

Dr Mark Butler, Paediatric Registrar, with consultant input from Dr Theo Dassios, Consultant Neonatologist.

Intraventricular haemorrhage (IVH) is a common consequence of prematurity, more common the more premature the baby. IVH in preterm infants is a huge topic, though this post focuses on a small subset of these patients: those with IVH who develop post haemorrhagic hydrocephalus (PHH). Children with post haemorrhagic hydrocephalus can be very challenging to manage. They often have significant comorbidity associated with prematurity and other pathologies, and are likely to have long term medical needs.

This article aims to explain the condition and its management, and will hopefully enable you to have some more fruitful conversations with your local neurosurgeons(!)

Epidemiology

Infants with PHH are managed with progressively more invasive treatments, ranging from serial lumbar punctures, temporary shunts, to permanent CSF diversion with shunts. Although continuing advances will hopefully reduce the occurrence of PHH in the future, the prevention and treatment of PHH in preterm infants remain challenging.

Over time, there may be spontaneous resolution of the hydrocephalus for some infants, while others will require permanent CSF diversion. The reported incidence of IVH and consequently PHH, varies enormously with time, geography, study population, imaging modality and diagnostic criteria.

Very approximately, 10% of preterm infants with any IVH and 20% of infants with severe IVH (grade 3-4) will ultimately require a shunt.

Pathophysiology

Preterm infants are vulnerable to cerebrovascular injury for many reasons. Many, particularly extremely preterm, infants suffer a combination of the following:

hypotension

poor cerebral perfusion (especially hypoperfusion/reperfusion)

impaired autoregulation

thrombocytopenia and coagulopathy

proinflammatory states

anatomical vulnerabilities, including incomplete arterial ingrowth into the deep white matter and a fragile germinal matrix vasculature.

These vulnerable infants undergo additional physiological stresses due to a range of factors; maternal or antenatal conditions (especially chorioamnionitis), and associated common problems such as RDS, invasive procedures, mechanical ventilation etc.

The reasons why some infants and not others develop PHH following IVH are complex and poorly understood. The nature and extent of the initial insult is a factor, and many processes interact and contribute, including fibrosis of arachnoid granulations, meningeal fibrosis, and subependymal gliosis, which combine to impair CSF resorption. There is some evidence that inflammatory signalling molecules such as TGF-β1 and 2 stimulate deposition of extracellular proteins which also impair CSF resorption.

Clinical Presentation

The clinical presentation of PHH is often subtle. Head circumference, examination of the fontanelle and splaying of sutures are not reliable when studied across practitioners, hence serial ultrasounds of the head (measuring ventricular dilation) are recommended.

Some infants will show signs of increased ICP, such as apnoea, bradycardia and decreased activity – though these signs are usually nonspecific and need to be interpreted in the context of examination findings and imaging.

Imaging

Cranial ultrasonography is the standard technique to diagnose and monitor PHH.

The Levene Ventricular Index (VI) is the horizontal measurement from the midline falx to the lateral aspect of the anterior horn of the lateral ventricle in the coronal plane obtained at the level of the third ventricle/foramen of Monro (Fig. 1). (it is referred to as an ‘Index’ as it is not a true measurement of the diameter of the ventricle, for technical reasons to do with the way the ultrasound displays an image, but correlates well with the true measurement.)

The threshold for intervention is usually taken as the 97th percentile + 4. Malcolm Levene’s charts produced in Hammersmith in the late 70s are still in use today.

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Ventricular Indices for the assessment of PHH: In the Coronal plane capture an image showing both the Lateral ventricles and the third ventricle at the level of the foramen of munro. Measure horizontally from the midline, to the lateral most border of each lateral ventricle.

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Treatment

Treatment decisions for children with PHH are complex and rely on close communication between the neurosurgical and neonatal team. The condition can evolve gradually or acutely, and it may resolve spontaneously at any stage of treatment – but a proportion of children will require permanent CSF diversion.

Once a diagnosis of PHH is suspected, the case should be discussed with your local neurosurgical centre. Infants will usually be monitored locally and transferred to a neurosurgical centre only when surgical intervention is required.

In older children or adults with CSF-related problems such as idiopathic intracranial hypertension, oral medications can be used effectively. However several RCTs and a Cochrane review showed acetazolamide and furosemide for preterm infants with IVH did not reduce the need for shunt insertion and increased the risks of death and neurological disability.

Treatment Options

Lumbar Puncture – This is the most straightforward treatment, as it can be performed by the neonatal team without the need for a neurosurgeon (although clearly would only be done on the advice of the neurosurgical team!) Usually 10ml/kg of CSF is removed over approximately 1ml/kg/min. This may be done as a one off or serially.  This method of drainage might not be successful if there is no communication between the spinal canal and ventricles.

Ventricular/ Trans-fontanelle taps – CSF can be drained directly from the ventricles. This is usually done only a limited number of times as a ‘bridge’ to surgery, or as a holding measure, as repeated taps cause intraparenchymal needle track injury.

Ventricular Access Devices (VADs, also known as Ommaya or Rickham reservoirs) – A flexible catheter inserted into the ventricle attached to a reservoir that sits subcutaneously. Once a VAD is in situ this can be used for repeated CSF tapping to control intracranial pressure and head growth.

 

 

 

Ventriculosubgaleal shunt – (VSGS) Usually a temporary measure used in infants who are too small or premature to tolerate other shunt types. A catheter is placed linking the ventricles to a  pocket formed beneath the epicranial aponeurosis (the subgaleal space), creating a fluid-filled swelling on the baby’s scalp, this may be converted to a more definitive shunt at a further procedure.

(Image: ventriculosubgaleal shunt)

 

External Ventricular Drainage – A catheter is placed into the ventricle, tunnelled under the skin and connected to an external drainage system. CSF drainage can be monitored and volume of fluid removed adjusted. This is a temporary measure, usually in place for around 7 days before removal or conversion to another system.

Endoscopic Third Ventriculostomy – (ETV) A procedure that has the advantage of not involving a foreign body. A neuroendoscope is introduced via the anterior fontanelle into a lateral ventricle. The scope is passed from the lateral ventricle through the foramen of Monro into the 3rd ventricle, where the floor of the ventricle is punctured to allow passage of CSF into the subarachnoid space.  This may be performed in isolation, or in combination with another shunt procedure.

Ventriculoperitoneal shunt – (VPS) This is the definitive procedure, which most of us are more familiar with seeing in older patients. A catheter (with valve) runs from within the ventricle to the peritoneal cavity, where drained CSF is reabsorbed. Extra lengths of catheter coils are left in situ to allow for growth.  This longer, more complex system is more prone to blockage and complications in the smallest babies, and when the CSF still contains significant amounts of blood and fibrin. Therefore this procedure is usually delayed until the patient weighs more than 2kg, and the CSF protein is less than 1.5g/L.

There has previously been a move towards more aggressive neurosurgical intervention with large IVHs, including clot removal, washouts and fibrinolytics. However the DRIFT trial (Drainage, Irrigation, and Fibrinolytic Therapy) showed that intraventricular fibrinolytics and CSF washing did not reduce shunt surgery or death – and was associated with significant rates of secondary intraventricular haemorrhage.

There is considerable variability in the approach taken by different neurosurgeons internationally and in the UK. A 2016 survey of UK neurosurgeons reported “Ventricular access device, trans-fontanelle tap, ventriculosubgaleal shunt and lumbar puncture were used by 33, 25, 17 and 17%, respectively, as the first temporising measure… Almost all respondents reported that VP shunting would be their preferred method of definitive cerebrospinal fluid (CSF) diversion.” So, although the definitive surgery is generally agreed upon, there is much less consensus as to the best approach to take before this.

Randomised controlled trials have failed to demonstrate a significant effect of serial lumbar puncture on morbidity, mortality or rates of permanent VPS. There have been a number of retrospective studies (mostly with small patient numbers), which give contradictory reports on the effectiveness of the various approaches and widely variable rates of complications. There is a need for high quality multicentre trials, but the small number of patients involved makes robust evidence difficult to come by.

Complications

Children with prematurity-associated PHH who have a shunt inserted are more likely than those with hydrocephalus from other causes to require shunt revisions and to develop complications such as shunt blockage, shunt infection, slit-ventricle syndrome and loculated hydrocephalus.

Shunt blockage – Shunts may become blocked or damaged at any stage. Typically early onset malfunctions are ‘ventricle end’ and the longer a shunt is in situ the more likely the problem is distal. The classical presentation of a shunt malfunction is the onset of symptoms and signs of raised intracranial pressure with enlarged ventricles on CT or MRI. Symptoms associated with raised ICP typically include headaches, vomiting, confusion and drowsiness while some children may develop diplopia or seizures. Signs on examination include bradycardia, hypertension, widened pulse pressure, papilloedema, bulging fontanelle, sluggish pupillary responses, focal neurological signs may develop though usually only at a late stage. If there is a suspicion of shunt blockage a CT of the brain as well as plain films of the course of the shunt (a shunt series) should be organised as a matter of urgency.  These images need to be linked or shared with your local neurosurgeon so they can be compared to previous imaging. It is important to note however that initial scans may be reported as negative and repeated discussions with the neurosurgeons or rescanning may be required.

Shunt infection – As with any indwelling device, infection is a risk. The highest risk is in the weeks following shunt placement. Patients may present with meningism, fever, headache, vomiting etc though presentation may be quite subtle initially and particularly in children with limited communication diagnosis may be difficult.  Skin flora, coagulase negative staphylococci and Staphylococcus aureus are the most common causative organisms. When a shunt infection is suspected, aspiration of the shunt reservoir is the key diagnostic test: these children should be discussed with the neurosurgical team for this to be considered. The standard treatment of shunt infection is intravenous antimicrobial therapy, removal of the infected shunt, placement of a temporary external ventricular drainage device and insertion of a new shunt once the CSF is sterile.

Slit ventricle syndrome – a syndrome where the shunt is not completely blocked but chronically partially occluded. The ventricles appear very thin on imaging and the intracranial pressure may be extremely high. It presents with symptoms of raised ICP, though the diagnosis is often difficult and may be delayed. It may require shunt revision, some cases respond well to ETV, all cases should be managed in conjunction with an experienced paediatric neurosurgeon.

 

Loculated hydrocephalus – If there is not communication between all CSF compartments this may be described as loculated hydrocephalus. This is most often the consequence of a pyogenic intracranial infection, usually in a patient who already has a shunt in situ. These patients may require multiple and complex shunt systems and repeated neurosurgical intervention, though neuroendoscopic approaches have improved treatment options in recent years.

 

Summary

Children with post haemorrhagic hydrocephalus can be very challenging to manage. They often have significant comorbidity associated with prematurity and other pathologies, and are likely to have long term medical needs.

Take home points

Though more severe IVH and lower gestational age are significant risk factors in the development of PHH, it is multifactorial and not easily predictable

Signs may be subtle; measure HC and perform regular cranial ultrasound scans in infants at risk

Liaise closely with neurosurgeons regarding monitoring and intervention, many cases may improve spontaneously

In ex-preterm infants with shunts in situ be especially aware of complications (blockage, infection etc). These children are at a high risk of complications

Have you been inspired to write something for PaediatricFOAM? Get in touch with us and join the team! Support, guidance and consultant input will be provided.

 

References/ further reading

Fountain DM, Chari A, Allen D, James G. Comparison of the use of ventricular access devices and ventriculosubgaleal shunts in posthaemorrhagic hydrocephalus: systematic review and meta-analysis. Child’s Nervous System. 2016;32:259-267. [free article] systematic review of the trials out there and the current state of practice

Kumar N, Al-Faiadh W, Tailor J, Mallucci C, Chandler C, Bassi S, Pettorini B, Zebian B Neonatal post-haemorrhagic hydrocephalus in the UK: a survey of current practice. Br J Neurosurg. 2016 Sep 30:1-5. [Epub ahead of print]

Levene MI. Measurement of the growth of the lateral ventricles in preterm infants with real-time ultrasound. Arch Dis Child. 1981;56:900–904. [free article] the original paper that includes the data for the chartson VI we continue to use today

Pettorini B., Keh R., Ellenbogen J.,Williams D., Zebian B. Intraventricular haemorrhage in prematurity. Infant 2014; 10(6): 186-90. [Free article] a very readable overview of the evidence

Robinson S. Neonatal posthemorrhagic hydrocephalus from prematurity: pathophysiology and current treatment concepts. J Neurosurg Pediatr. 2012;9:242–258. [free article] good free review article

 

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