PVL – what is it? 

Periventricular Leukomalacia, commonly referred to as PVL, is a form of injury to the white matter of a baby’s developing brain. PVL occurs most commonly in premature babies as it occurs between 28 to 34 weeks gestation, but in certain situations term babies can also be affected.

PVL can happen when there has been damage to the developing cells in the white matter of the brain. The white matter (leuko) surrounding the ventricles (fluid filled spaces) of the brain can be damaged, either due to being deprived of blood and oxygen (hypoxic ischaemia), or due to inflammation or infection. This causes a softening (malacia) of the brain tissues, sometimes leaving fluid filled cysts.

The white matter of the brain is responsible for transmitting messages from the nerve cells in the brain and so when it has been damaged, problems with movement and other bodily functions can occur.

What causes PVL? 

Whilst PVL normally happens in the premature stages of gestation, prematurity is not in itself a cause of PVL and being born premature does not mean that PVL is inevitable. There also has to have been a damaging event or ‘insult’ to the brain for PVL to occur. Sometimes it is thought this insult happens during the pregnancy but showing no outward signs of having occurred. The baby may go on to be born perfectly healthy and only later, when development is delayed, is PVL suspected.

In other cases, there is an obvious insult, which may or may not have been preventable.

The damaging insult is almost exclusively the result of one of two things: Hypoxic ischaemia and inflammation/infection:

Hypoxia ischaemia

A baby in the womb and during the birth process requires a continuous supply of blood to provide oxygen and nutrients vital to growth and survival. If the oxygen supply to the baby is completely or partially interrupted, hypoxia (lack of oxygen) ischaemia (lack of blood flow) can occur, which can result in damage to the brain tissues.

Hypoxia ischaemia can occur for a variety of reasons, and can happen before, during and after birth.    Common causes during pregnancy, labour and delivery include:

• Impaired function of the placenta
• Pre-eclampsia
• Placental abruption
• Umbilical cord compression or prolapse
• Hyperstimulation of the uterus during labour

Sometimes, it is the failure of the medical professionals responsible for the pregnancy in recognising and responding to these events that allows a hypoxic ischaemic insult to occur and cause PVL, which may well have been avoidable with better care.

Inflammation/infection

Another common cause of PVL is when there has been an inflammatory insult to the baby’s brain, often caused by infection. This can be an infection during the pregnancy which is passed from Mum to baby, or when the baby contracts an infection directly during birth or in the neonatal period. There are a number of infections that can be present in both mother and baby such as Group B Strep (GBS) or chorioamnionitis (infection of the placental membranes). The infection can cause the brain tissues to be exposed to damaging toxins (cytokines) if not prevented or treated early enough, again leading to PVL.

Maternal infection in itself can also result in premature birth. This may indirectly contribute to the baby developing PVL. Premature babies are also vulnerable to bleeding in the brain due to immature and fragile blood vessels within the brain. This bleeding can put pressure on the tissues of the brain or directly involve the tissues, leading to damage and PVL.

How is PVL diagnosed?

PVL does not usually result in clinical signs in the neonatal period.  It is usually diagnosed when a preterm baby has ultrasound scans of the brain in the new-born period. Ultrasound scans of the baby’s head are performed at the bedside in hospital, and often repeated at regular intervals, to check for the presence of bleeds or the development of PVL. It isn’t always apparent straight away and can then take anywhere from 1 – 6 weeks from the damaging insult for the PVL to be fully established.  When PVL is suspected on an ultrasound scan, a MRI scan of the baby’s brain will often be performed, which can confirm the diagnosis and the extent of the damage.

In some cases, PVL may not be diagnosed until the child is older and shows signs of developmental delay or a movement disorder, and a later MRI scan is performed to investigate.

The degree to which a child’s development is affected by PVL depends on the severity of the damaging event or ‘insult’ to the brain tissues and how widespread the damage has occurred.

The most common consequence of PVL is cerebral palsy, a disorder that affects movement and coordination.  Children with PVL may also experience learning disabilities, visual problems, seizures, hearing problems and/or speech impairments.

Where PVL is suspected, either at birth or at a later stage as developmental delay occurs, it is important to obtain a formal diagnosis to enable parents or carers to seek early intervention and support for the child to give them the best chance of improving their condition and maximising their potential.

Consequences of living with PVL

The overall outlook for a child with PVL depends of the severity and extent of the brain injury. Some children may only suffer mildly whereas others may experience more severe disabilities.

PVL in itself cannot be cured or treated. However, there is a lot that can be done to help improve the difficulties experienced by the child.

Often children with PVL may be advised that they would benefit from some or all the following;

• Physiotherapy and orthopaedic intervention: particularly when there is a diagnosis of cerebral palsy and there are difficulties with movement, pain and muscle tightness
• Occupational therapy: where adaptions, specialist equipment, assistive technology or other intervention is needed for day to day living activities
• Speech and language therapy: where they are experiencing difficulty with speech and language
• Vision therapy: where they are experiencing difficulty with vision and eye movements
• Special educational needs support, either via an Education, Health and Care Plan (EHCP) or privately sourced educational support

There is no prescriptive list of therapy and treatment which must be provided to a child with PVL and the needs of every child will be different. Provision from the NHS and local authorities can be variable so accessing additional support via charities, or investigating whether the PVL could be the result of medical negligence and obtaining compensation, can also be considered. 

Where to seek support

There are a number of organisations that provide information, help and support for the families of children with PVL and any associated conditions, including of course, Cerebra. Other sources of support include;

• Bliss – the Special Care Baby Charity will be able to give you advice and support. Call their family support helpline on 0500 618 140 or visit their website at bliss.org.uk.
• Scope – the main UK charity for people with cerebral palsy – call their helpline on 0808 800 3333 or visit their website at scope.org.uk.

There is also further information on our website – https://clmedilaw.co.uk/specialisms/birth-injury-claims/periventricular-leukomalacia-brain-injury/ around not only PVL, but also the associated conditions which can result from PVL, such as cerebral palsy.

Laura Cook is a Partner at CL Medilaw who work closely with many families with children who have an acquired brain injury or brain condition arising out of medical negligence or personal injury. CL Medilaw are dedicated to changing the lives of their clients by making legal matters as straight forward as possible and securing early provision of support to really make a difference to the families they represent.

Article reviewed and contributed to by Dr Chris Dewhurst, Consultant Neonatologist and Deputy Medical Director at Liverpool Women’s NHS Foundation Trust

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