Overview

Porencephaly is an extremely rare condition that is present at birth and affects the central nervous system (the brain and spinal cord).^1,2,3 It involves the growth of a fluid-filled sac (a cyst or cavity) in the brain.^1,3,4  This will often prevent healthy brain development after birth, or cause the part of the brain near the growth to die, resulting in brain damage.^1,3,4 Porencephaly is caused by bleeding on the brain, not enough oxygen supply to the brain, or abnormal development in the womb.^1,2,3,5 

When porencephaly occurs during pregnancy or just after birth, there can be long term effects on brain tissue. Cysts can occur in different areas of the brain, and depending on the area, they can cause different symptoms or outcomes to sufferers of porencephaly.³ The seriousness of symptoms can vary, and can include learning and information processing problems, movement disorders, and seizures.^1,2 

Types of porencephaly

There are two different types of porencephaly: congenital porencephaly and acquired porencephaly.⁶ Congenital porencephaly is present at birth and occurs due to brain development problems in the womb, often due to genetics.⁶ Acquired porencephaly happens during or after birth because of brain injury, infection or blood vessel issues in the brain.⁶

Causes of porencephaly

There are a few things that can cause porencephaly, including brain trauma, genetics, infection, bleeding of the brain, or a lack of oxygen supply to the brain.^2,4,5 These can occur during pregnancy, as well as during or after birth.

Some causes of porencephaly that are present before birth include:

• Genetic factors: Porencephaly can be caused by a gene mutation when one parent is a carrier of the gene, meaning in some cases it is a hereditary condition.¹ The gene is called type IV collagen alpha-1 (COL4A1) and can cause blood vessels in the brain to form incorrectly and cause brain development issues.¹ This is called familial porencephaly and is a type of congenital porencephaly.^1,7 This gene results in a much higher chance that a baby will have a brain bleed during late pregnancy or birth, causing porencephaly and the growth of a cyst.¹ However, porencephaly and other conditions relating to the gene can be completely absent.¹
• Pregnancy complications: Complications can be a cause of porencephaly. Infections of the baby’s brain during pregnancy can cause porencephaly, as can diseases that a mother may contract while she is pregnant.⁷ A condition called oligohydramnios can also affect the growth of the baby.¹ This is when the fluid surrounding the baby in the womb is too low.¹
• Alcohol exposure: If a mother consumes alcohol while she is pregnant, this can put the baby at risk of brain injury and porencephaly.⁸

Other causes of porencephaly occur during or after birth:

• Birth trauma: Brain injuries can occur when a birth is difficult or complicated.⁷
• Haemorrhage: Trauma or genetic factors can result in brain injury in children with porencephaly. Bleeding on the brain is caused by the rupture of a blood vessel.^1,3,4
• Oxygen deprivation: Another cause of porencephaly is a lack of blood supply to an area of the brain which in turn causes a lack of oxygen supply, resulting in brain tissue dying.^2,4 This is called ischemia.^2,4

Symptoms of porencephaly

Symptoms of porencephaly will more commonly occur shortly after birth; however, sometimes symptoms will not appear early childhood.⁵ Very rarely, when genetic factors are the cause of porencephaly, symptoms can go undetected until adulthood.¹ As a result of the causes we have just discussed, infants or young children develop porencephaly and can potentially present with some of the following symptoms.

• Motor impairments are the loss or partial loss of functions of a body part or group of muscles and can be a symptom of porencephaly. These kinds of symptoms include:
  • Hemiparesis: the loss of movement and weakness on one side of the body.¹
  • Spasticity: muscle spasms or stiffness causing uncontrollable and imprecise movements of limbs.^1,5
  • Tetraplegia/quadriplegia: paralysis or inability to control movement of the limbs and sometimes the neck and shoulder area.⁷
  • Diplopia: double vision.⁵
• Seizures are a common symptom of porencephaly.^4,5,9 Seizures often occur suddenly, causing jerky movements of the limbs, frothing from the mouth, and children will be unresponsive.^5,9
• Symptoms can also present as cognitive impairments that vary in severity, including:
  • Mild to severe intellectual disabilities^1,3,4
  • Severe mental retardation^3,7
  • Mild to severe speech impairments: impaired development of speech and conversational language can be mildly to severely impaired.¹

Diagnosis

The diagnosis of porencephaly involves both imaging techniques such as MRI or CT scans, as well as neurological examinations.^3,4

Imaging techniques

The most suitable way to diagnose porencephaly in a child is through imaging techniques. This involves taking images of the brain, either with magnetic resonance imaging (MRI) or computed tomography (CT) scans.^3,5,9 This gives specialists a clear picture of the brain to determine if there is pressure due to porencephalic cysts and their location.^1,3,9 Ultrasounds are another type of imaging technique used in follow-up appointments to track any progress or changes.¹ They can sometimes be used for diagnosis during pregnancy.⁵

Neurological examinations

Neurological examinations allow specialists to determine the presence or severity of any neurological impairments affecting your child’s nervous system. In infants, this involves assessing their blinking, crawling, grasping, and how they react to loud noises.¹⁰ In older patients, this involves motor function and balance tests, touch perception, and mental status.¹⁰ Both may have assessments of reflexes and cranial nerves (the 12 main nerves in the brain).¹⁰

Surgical Intervention

One option when porencephaly growths are causing, or will cause, brain damage, is surgery. This will prevent cysts from causing irreversible brain damage, or remove already damaged areas to prevent them causing further brain injury.

Doctors will perform electrical technology assessments before surgery, to help specialists make important decisions on the best approach for surgeries. This involves recording brain activity from electrodes that are stuck to the scalp.⁴ This is called intracranial electroencephalography or intraoperative electrocorticography, and can be particularly helpful for children experiencing seizures.⁴

One surgical option is something called a shunt placement, which removes excess fluid that is putting pressure on the brain.⁴ This relieves pressure on the brain and prevents further damage and brain development issues in the future.⁴

A brain surgery called a hemispherectomy can be performed on children who suffer from seizures due to porencephaly.⁴ These surgeries are performed when porencephaly has caused a region of brain tissue to die. The brain surgery involves half of the brain being completely or partially removed or disconnected, preventing the dead tissue from affecting healthy parts of the brain.⁴ Studies have measured the outcomes of hemispherectomies performed on children and found that they are often successful in curing seizures and preventing further brain damage.⁴

Treatment and Management

Unfortunately, in many cases, only the symptoms of porencephaly can be treated and managed, as by the time symptoms are present, the porencephaly has already caused irreversible damage.³ There are currently no medical interventions that can improve brain growth.³ There are, however, medical interventions, medications, and other therapies that can help alleviate symptoms and improve quality of life.^4,5 

• Medication: anticonvulsant medications can prevent or at least reduce seizures.^4,5 Sometimes it requires a cocktail of medications to get the seizures under control.⁴ 
• Physical therapy: helps improve motor skills and functional abilities.
• Speech therapy and education support: help improve communication skills and intellectual development.
• Occupational therapy: helps patients be more independent.

Prognosis

Sadly, many cases of porencephaly result in early mortality within a few weeks or months of diagnosis, and in many cases the impact on quality of life is severe.² The extent and location of brain damage greatly influence the prognosis and the impairments that need to be managed.^2,4

Support and resources

Due to the rarity of porencephaly, there is limited research into the disorder due to a lack of patient observation. However, there are many case studies that contribute imperative information to the practice of doctors and surgeons when treating patients with porencephaly.

Patient organisations play an important role in supporting patients and families that are affected by specific diseases. They play a vital role in facilitating connections among patients and families, raising public awareness, ensuring information accessibility, and supporting research. They also provide resources to enhance the quality of life for patients. Currently, there is a Facebook group aimed at connecting families touched by porencephaly.

Warriors of Porencephaly – Support Group: https://www.facebook.com/groups/171005069540/

Other parent support groups can be found at: https://birthdefects.org/parent-services/ 

Summary

Porencephaly, a very rare disorder affecting the central nervous system, causes fluid-filled cysts to cause brain damage and disrupt development. There are factors, including genetic mutation and trauma, that contribute to the occurrence of porencephaly and cause symptoms of cognitive impairments, motor impairments, and seizures. We have reliable imaging techniques for diagnosis as well as some early interventions involving surgery to reduce the negative impact of porencephaly on brain development. Ongoing research into case studies provides hope for the progress of therapy and treatments.