Porencephaly/Cystic Encephalomalacia
Porencephaly/Cystic Encephalomalacia
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Author: Jaclyn Tencer, MDSonika Agarwal, MBBS, MD, Children’s Hospital of Philadelphia 
Reviewed: April 2021 


In porencephaly (or cystic encephalomalacia), a fluid-filled cyst develops in brain tissue. The fluid consists of cerebrospinal fluid (CSF). CSF is the clear fluid that normally bathes the central nervous system. The central nervous system is made up of the brain and the spinal cord. CSF helps cushion these important parts of our body. It can prevent injury to them. It also helps provide nutrients to the brain and clear its waste products.  

Porencephaly is a structural abnormality of the brain. It may manifest before or after birth. It has many causes. For instance, it can appear after a brain injury. Stroke, bleeding, or infection can cause the brain injury. In porencephaly, CSF fills the injured area. This creates the fluid-filled cyst.  

These cysts may also appear due to abnormal brain development. Abnormal brain development may have no clear cause. However, on rare occasions, it can be related to an inherited genetic condition. 


Disorder Overview


Symptoms of porencephaly vary widely. An individual with porencephaly may be asymptomatic. Some patients with very mild or no symptoms are not even diagnosed. Other patients may have severe symptoms. Those with severe symptoms are often diagnosed soon after birth. 

Symptom severity depends on a few factors. First, the location and size of the porencephalic cyst matters. A cyst that disrupts normal brain functions will likely cause symptoms. Different areas of the brain control different parts of the body. Therefore, a cyst affecting one area of the brain will cause symptoms in the corresponding part of the body.  

Symptom severity also depends on whether the porencephaly is associated with prior brain injury or with developmental abnormalities.  

Symptoms in one individual may be very different from those in another individual. The spectrum varies widely for each child. 

Common Symptoms of Porencephaly

Possible symptoms include: 

  • Motor delay (differences in muscle tone, movement, posture, or developmental milestones) 
  • Speech and language delay 
  • Learning challenges 
  • Cognitive or intellectual differences 
  • Slow overall growth 
  • Developmental delays in multiple areas (global delays) 
  • Seizures 
  • Spastic hemiplegia (stiffness and weakness in limbs)  
  • Hypotonia (low muscle tone) 
  • Macrocephaly (large head) 
  • Microcephaly (small head) 
  • Hydrocephalus (increased pressure in the brain) 
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Acute Symptoms of Porencephaly

Acute symptoms may require urgent attention and medical action. Acute symptoms may include: 

  • SeizuresSeizures are treated with medications. They require close follow up with a neurologist. 
  • Hydrocephalus. Hydrocephalus is raised pressure in the brain. A cyst that blocks CSF drainage areas can cause this pressure. It can further brain damage or be life threatening. A child may require urgent surgery to relieve this pressure. 

Acute symptoms may require using urgent neuroimaging. Two kinds of neuroimaging are considered in these cases. The first is computed tomography scans (CT scans). The second is MRI. Acute symptoms may also require an electroencephalogram (EEG). An EEG can test brain waves and electrical activity. 

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Porencephaly can be diagnosed during or after pregnancy. During pregnancy, it is diagnosed through one of two types of neuroimaging. The first option is an ultrasound. The second option is magnetic resonance imaging (MRI). Neuroimaging can look at the developing brain of a baby in the womb.  

Porencephaly can also be diagnosed in the first few years of life. Sometimes a primary care physician refers a baby with suspected neurological problems to a specialist. This specialist will likely be a child neurologist. Some child neurologists focus on babies with brain-related diseases.  

This specialist will check if the baby is meeting developmental milestones. Such milestones include sitting, crawling, walking, or speaking. The specialist will do a neurologic examination and look at the baby’s muscle tone, strength, reflexes, and more. After that, the specialist may order neuroimaging. The specialist may also order blood tests or refer the baby to other specialists. 


Porencephaly has a wide range of causes. Some of them can be identified. Many others remain unknown. Generally, however, prior injury to the brain causes porencephaly. These injuries are usually caused by blood clots, bleeding or abnormal vessel formation. The injuries can stem from either a medical condition or a genetic difference. 

Causes of brain injury associated with Porencephaly

Most often, porencephaly occurs following an injury to the brain during early development. This injury may take place before, during, or shortly after birth. A brain injury can cause an area of damaged brain tissue. Then, cerebrospinal fluid (CSF) can leak into that area. CSF can fill the area and form a fluid sac, or cyst.  

There are many medical causes of the initial brain injury: 

  • Lack of blood flow. A lack of blood flow or oxygen to part of the brain can cause injury. This is also called cerebral ischemia. 
  • Excessive bleeding. Excessive bleeding in an area of the brain can cause injury. 
  • Congenital infections. Congenital infections are infections that affect the fetus or newborn. They are usually due to viruses contracted during pregnancy. 
  • Physical trauma. Physical trauma to a fetus can cause of injury. 
  • Maternal diabetes. Maternal diabetes occurs when a mother’s sugar levels are too high. This can affect the development of the brain and make areas susceptible to injury.  
  • Maternal drug or medication use. Drug abuse and some medications, such as blood thinners, can lead to fetal brain injury. 
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Genetic Difference and Porencephaly

Porencephaly can be due to genetic abnormalities. The most common genes involved are the COL4A1 and COL4A2 genes.  

The COL4A1 and COL4A2 genes are involved in collagen formation. Collagen is an essential component of all tissues. It is very important for the stability of blood vessels. The disruption of collagen can lead to the breakdown of blood vessels. This, in turn, can lead to bleeding (or hemorrhaging). When the blood gets broken down and absorbed, an empty sac is left. This can then fill with cerebrospinal fluid (CSF). 

Scarring in surrounding brain tissue is called gliosis. It can cause seizures and developmental deficits. It can also be associated with eye problems in infants. (These can include cataracts and retinal blood vessel abnormalities.) It can also be associated with kidney problems.  

Some types of porencephaly are genetic and can be inherited. This means that a person only needs one abnormal gene copy to show symptoms. The abnormal gene can be inherited from a mother or father. A person with a COL4A1 or COL4A2 gene mutation has a 50 percent chance of passing on condition. Two people with the same mutation may have very different symptom severity.  

Often the COL4A1 or COL4A2 gene mutation is new, and not inherited. This means it formed randomly in a child’s DNA. This is called a “de novo” genetic mutation.  

There are other genetic mutations that can cause porencephaly. However, we still have a lot to learn about these variants.  

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Did Anyone Cause This?  


Nothing you may have done in pregnancy may directly cause this change in your baby. However, prenatal drug abuse and certain medications (such as blood thinners) are associated with a higher risk of brain bleeds. These brain bleeds can lead to porencephalic cyst formation.

Screenings during pregnancy can evaluate the risk factors associated with porencephaly and help manage these issues in a timely manner. Your doctor may advise regular screenings with ultrasound, as well.


Porencephaly is most commonly identified through brain imaging. Brain imaging methods include CT scans, ultrasounds, or MRIs. These tests are usually ordered after symptoms are first noticed. 

Once it is identified with imaging, doctors can evaluate the causes of the disease. These evaluations will take different forms depending on a patient’s symptoms. Following are two common routes for investigation. 

Blood Clot Investigation

Porencephaly may be thought to be related to a blood clot or bleeding. In these cases, doctors may look for conditions that can cause a blood clot or bleeding. This involves blood tests. The blood tests may look at: 

  • Platelet numbers 
  • Coagulation factors 
  • Other factors related to blood consistency  
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Genetic Porencephaly Investigation

Porencephaly may be thought to be related to abnormal brain or organ development. In these cases, a doctor may order genetic tests. Genetic tests can look for a common cause of the symptoms and the abnormal development. Sometimes, there is a family history of porencephaly. When there is a family history of the condition, COL4A1 and COL4A2 gene mutation tests may be used.  

Testing for the cause of porencephaly prior to birth is possible. It can be identified in a neuroimaging scan (US or MRI) during pregnancy. Porencephaly, when diagnosed in a developing fetal brain, can also be tested for genetic causes using amniotic fluid (fluid from the womb). 

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If There Is a Clear Cause… 

Sometimes, there is a clear cause of brain injury. This might include maternal physical trauma during pregnancy. Or it might include maternal drug use. In these cases, further evaluation of the cause may not be needed.  


There is no clear cure for porencephaly. This structural abnormality cannot be reversed. However, there are treatments that can help with symptoms arising in the aftermath of porencephaly. 

Symptoms and Available Treatments 

  • Cognitive, speech, language, or motor delays. Physical therapy, occupational therapy, special instruction, and speech therapy can be very effective. 
  • Learning challenges. Working closely with school systems to generate individualized educational plans and support can be helpful. Special education programs can also help. 
  • Seizures. Various medications can be used to treat seizures. There may be dietary and surgical options as well 
  • Spasticity. Medications can manage high tone or stiffness in muscles. For instance, injections of botulinum toxin can help loosen muscles or medications such as baclofen are commonly used.  
  • Adaptive equipment. Braces and adaptive equipment can significantly improve a child’s functioning and quality of life. 
  • Hydrocephalus. This is increased pressure in the brain. Depending on the specific location of the porencephaly, a resection or surgical shunt can relieve this pressure. 


The therapies and programs mentioned above work best when started at a younger age. They may be started as soon as symptoms are noticedEarly intervention can help achieve the best developmental outcome for child with this condition. 

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Outcomes can vary widely depending on the size and location of the fluid-filled cysts. Some children have mild or no symptoms. They may not even be diagnosed.  

Others may have some mild learning challenges. They may have treatable seizures or motor tone abnormalities. Children in this moderate category do very well with supportive treatment.   

Still others may have more severe secondary symptoms. They may have larger cysts. Their cysts may be in problematic brain locations. These children may have been diagnosed soon after birth. Supportive care, therapies, and special education programs can go a long way. They can improve the long-term outcomes of these children.  

Supports at school or in community settings may be available. They will likely be based on the abilities of an individual child. Therapies are likewise individualized. 



Pediatric Epilepsy Surgery Alliance
The Pediatric Epilepsy Surgery Alliance (formerly known as The Brain Recovery Project) enhances the lives of children who need neurosurgery to treat medication-resistant epilepsy. They empower families with research, support services, and impactful programs before, during, and after surgery. PESA’s programs include research-based, reliable information to help parents and caregivers understand when a child’s seizures are drug-resistant; the risks and dangers of seizures; the pros and cons of the various neurosurgeries to treat epilepsy; the medical, cognitive, and behavioral challenges a child may have throughout life; school, financial aid, and life care issues. PESA’s resources include a comprehensive website with downloadable guides, pre-recorded webinars, and virtual workshops; an informative YouTube channel with comprehensive information about epilepsy surgery and its effects; a private Facebook group (Education After Pediatric Epilepsy Surgery) with over 300 members; Power Hour (bi-monthly open forums and live virtual workshops on various topics); and free school training to help your child’s education team understand the impact of their epilepsy surgery in school. Their Peer Support Program will connect you with a parent who has been there. The Pediatric Epilepsy Surgery Alliance also hosts biennial family conferences and regional events that allow families to learn from experts, connect with other families, and form lifelong friendships. They also provide a travel scholarship of up to $1,000 to families in need to fund travel to a level 4 epilepsy center for a surgical evaluation.

In addition, PESA has resources for medical professionals to assist in helping clinicians help the parents of their patients find the resources they need after surgery. Educators and therapists will also find helpful resources and information, including videos, guides, and relevant research. Patients who have undergone surgery are encouraged to register with the Global Pediatric Epilepsy Surgery Registry to help set future research priorities.

Childhood Stroke 1

Warriors of Porencephaly (Facebook private group)

This group was created to help support parents, caregivers, and individuals who have been diagnosed with porencephaly. There are over 250 members in this online community, which shows you are not alone on this journey. Doctors, nutritionists, and therapists are welcome to join the group as well. All members are screened to protect privacy and ensure eligibility.  

Child Neurology Foundation (CNF) solicits resources from the community to be included on this webpage through an application process. CNF reserves the right to remove entities at any time if information is deemed inappropriate or inconsistent with the mission, vision, and values of CNF. 


ClincalTrials.gov for porencephaly (birth to 17 years) are clinical trials that are recruiting or will be recruiting. Updates are made daily, so you are encouraged to check back frequently.  

ClinicalTrials.gov is a database of privately and publicly funded clinical studies conducted around the world. This is a resource provided by the U.S. National Library of Medicine (NLM), which is an institute within the National Institutes of Health (NIH). Listing a study does not mean it has been evaluated by the U.S. Federal Government. Please read the NLM disclaimer for details.  

Before participating in a study, you are encouraged to talk to your health care provider and learn about the risks and potential benefits. 

The information in the CNF Child Neurology Disorder Directory is not intended to provide diagnosis, treatment, or medical advice and should not be considered a substitute for advice from a healthcare professional. Content provided is for informational purposes only.  CNF is not responsible for actions taken based on the information included on this webpage. Please consult with a physician or other healthcare professional regarding any medical or health related diagnosis or treatment options. 


1. National Institutes of Health,“Porecenphaly Information Page”

2. National Organization for Rare Disorders,“Sporadic Porecenphal”

3. Orphanet, “Porencephaly”

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