Porencephaly
Encyclopedia
Porencephaly is a type of cephalic disorder
involving encephalomalacia. This is an extremely rare disorder of the central nervous system
involving a cyst
or cavity in a cerebral hemisphere
. The cysts or cavities are usually the remnants of destructive lesions, but are sometimes the result of abnormal development. The disorder can occur before or after birth.
An association with COL4A1
has been described.
of the skull in infancy. The diagnosis may be confirmed by CT
, MRI, or ultrasonography.
The diagnosis can be made antenatally with ultrasound.
paresis
(slight or incomplete paralysis), hypotonia
(decreased muscle tone), seizures (often infantile spasms), and macrocephaly
or microcephaly
.
Individuals with porencephaly may have poor or absent speech development, epilepsy
, hydrocephalus
, spastic contractures (shrinkage or shortening of muscles), and mental retardation
.
Cephalic disorder
Cephalic disorders are congenital conditions that stem from damage to, or abnormal development of, the budding nervous system...
involving encephalomalacia. This is an extremely rare disorder of the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
involving a cyst
Cyst
A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...
or cavity in a cerebral hemisphere
Cerebral hemisphere
A cerebral hemisphere is one of the two regions of the eutherian brain that are delineated by the median plane, . The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres has an outer layer of grey matter called the cerebral cortex that is...
. The cysts or cavities are usually the remnants of destructive lesions, but are sometimes the result of abnormal development. The disorder can occur before or after birth.
Causes
Porencephaly most likely has a number of different, often unknown causes, including absence of brain development and destruction of brain tissue.An association with COL4A1
COL4A1
Collagen alpha-1 chain is a protein that in humans is encoded by the COL4A1 gene.Mutations in COL4A1 exons 24 and 25 are associated with HANAC ....
has been described.
Diagnosis
The presence of porencephalic cysts can sometimes be detected by transilluminationTransillumination
Transillumination is the technique of sample illumination by transmission of light through the sample. Transillumination is used in a variety of methods of imaging.-Microscopy:...
of the skull in infancy. The diagnosis may be confirmed by CT
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
, MRI, or ultrasonography.
The diagnosis can be made antenatally with ultrasound.
Presentation
More severely affected infants show symptoms of the disorder shortly after birth, and the diagnosis is usually made before age 1. Signs may include delayed growth and development, spasticSpasticity
Spasticity is a feature of altered skeletal muscle performance in muscle tone involving hypertonia, which is also referred to as an unusual "tightness" of muscles...
paresis
Paresis
Paresis is a condition typified by partial loss of voluntary movement or by impaired movement. When used without qualifiers, it usually refers to the limbs, but it also can be used to describe the muscles of the eyes , the stomach , and also the vocal cords...
(slight or incomplete paralysis), hypotonia
Hypotonia
Hypotonia is a state of low muscle tone , often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases and disorders that affect motor nerve control by the brain or muscle strength...
(decreased muscle tone), seizures (often infantile spasms), and macrocephaly
Macrocephaly
Macrocephaly , occurs when the head is abnormally large; this includes the scalp, the cranial bone, and the contents of the cranium.-Causes:...
or microcephaly
Microcephaly
Microcephaly is a neurodevelopmental disorder in which the circumference of the head is more than two standard deviations smaller than average for the person's age and sex. Microcephaly may be congenital or it may develop in the first few years of life...
.
Individuals with porencephaly may have poor or absent speech development, epilepsy
Epilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
, hydrocephalus
Hydrocephalus
Hydrocephalus , also known as "water in the brain," is a medical condition in which there is an abnormal accumulation of cerebrospinal fluid in the ventricles, or cavities, of the brain. This may cause increased intracranial pressure inside the skull and progressive enlargement of the head,...
, spastic contractures (shrinkage or shortening of muscles), and mental retardation
Mental retardation
Mental retardation is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors...
.