Sporadic porencephaly is a rare disorder affecting the central nervous system. In porencephaly cysts or cavities form on the surface of the brain. These cysts or cavities may become filled with cerebrospinal fluid, a colourless fluid that normally surrounds the brain and spinal cord to provide protection and nourishment. The severity and associated symptoms of porencephaly vary dramatically from one person to another based upon the size and exact locations of the fluid-filled cavities or cysts.
Porencephaly may be classified as sporadic or familial. Sporadic porencephaly can have many different causes including infection just before or just after birth (perinatal infection), trauma, maternal disease or sickness, maternal diabetes, or maternal use of alcohol or drugs such as cocaine during pregnancy.
Causes of sporadic porencephaly
Sporadic porencephaly is caused by damage to the cerebral hemispheres of the brain, which results in the formation of fluid-filled cavities or cysts on the surface of the brain. Researchers believe that the damage or loss of brain tissue that characterizes porencephaly results from infection interrupted or obstructed blood flow (ischemia) to the brain, or bleeding (haemorrhaging
) in the brain.
A variety of different conditions can potentially cause the localized brain tissue degeneration that ultimately leads to sporadic porencephaly. Such conditions include infection just before or shortly after birth (perinatal infection), too little oxygen in the body just before or shortly after birth (perinatal asphyxia), birth trauma, drug or alcohol use by the mother during pregnancy, maternal sickness or infection, maternal diabetes
, or injury or trauma (particularly to the abdominal area) to the mother during pregnancy.
The symptoms and severity of sporadic porencephaly vary greatly from one individual to another based on the size and exact location of the fluid-filled cyst or cavity. Some individuals may only have minor physical complications and intelligence may be unaffected others can have severe, disabling complications.
Possible symptoms include delays in growth and development, diminished muscle tone (hypotonia), seizures, and microcephaly or macrocephaly, conditions in which head circumference is either smaller (micro) or larger (macro) than would be expected in a child based upon age and weight.
Diagnosis of sporadic porencephaly
A diagnosis of sporadic porencephaly can be made before or after birth through a variety of specialized imaging tests such as an ultrasound, computed tomography (CT) scan, or magnetic resonance imaging (MRI). During an ultrasound, reflected sound waves are used to make an image of the developing foetus. During CT scanning, a computer and x-rays are used to create a film showing cross-sectional images of certain tissue structures. An MRI uses a magnetic field and radio waves to produce cross-sectional images of particular organs and bodily tissues.
The treatment of sporadic porencephaly is geared toward the specific symptoms that are present in each individual. Treatment may include physiotherapy, speech therapy, anti-convulsant medications for seizures, and a shunt to treat hydrocephalus by draining excess fluid from the skull.
Early intervention is important in ensuring that children with sporadic porencephaly reach their highest potential. Services that may be beneficial for some affected individuals include medical, social or vocational services such as special remedial education.