Porencephaly is an extremely rare cephalic disorder involving encephalomalacia. It is a neurological disorder of the central nervous system characterized by cysts or cavities within the cerebral hemisphere. Porencephaly was termed by Heschl in 1859 to describe a cavity in the human brain. Derived from Greek roots, the word porencephaly means 'holes in the brain'. The cysts and cavities (cystic brain lesions) are more likely to be the result of destructive (encephaloclastic) cause, but can also be from abnormal development (malformative), direct damage, inflammation, or hemorrhage. The cysts and cavities cause a wide range of physiological, physical, and neurological symptoms. Depending on the patient, this disorder may cause only minor neurological problems, without any disruption of intelligence, while others may be severely disabled or die before the second decade of their lives. However, this disorder is far more common within infants, and porencephaly can occur both before or after birth.
The following text lists out common signs and symptoms of porencephaly in affected individuals along with a short description of certain terminologies.
Cause
Porencephaly is a rare disorder. The exact prevalence of porencephaly is not known; however, it has been reported that 6.8% of patients with cerebral palsy, or 68% of patients with epilepsy and congenital vascular hemiparesis, have porencephaly.
Cysts or cavities can occur anywhere within the brain and the locations of these cysts depend highly on the patient. Cysts can develop in the frontal lobe, parietal lobe, forebrain, hindbrain, temporal lobe, or virtually anywhere in the cerebral hemisphere. The mutation can weaken the blood vessels within the brain, elevating the probability of a hemorrhage, and eventually promoting internal bleeding then leading to porencephaly during neurodevelopment of infantile stage.
Another genetic mutation, factor V G1691A mutation, has been reported to show possible association to the development of porencephaly. A mutation in factor V G1691A increases the risk of thrombosis, blood clots, in neonates, infants, and children.
Diagnostics
The presence of porencephalic cysts or cavities can be detected using transillumination of the skull in infant patients. Porencephaly is usually diagnosed clinically using the patient's and family's history, clinical observations, or based on the presence of certain characteristic neurological and physiological features of the disorder. Advanced medical imaging such as computed tomography (CT), magnetic resonance imaging (MRI), or with ultrasonography can be used to exclude other possible neurological disorders. The diagnosis can also be made antenatally with ultrasound. Other assessments include memory, speech, or intellectual testing to help further determine the exact diagnosis of the disorder.