Hypoplasia of the cerebral cortex

The brain is the most mysterious part of the human body. The brain dominates thinking and command. Any action of the human body is based on instructions issued by the brain. If the brain is not developed properly, a person may have mental disorders and develop illness. What impact does hypoplasia of the cerebral cortex have on people? Let’s understand the causes and mechanisms of cerebral cortical dysplasia, as well as treatment methods, and understand some manifestations of cerebral cortical dysplasia.

Focal cortical dysplasia is a disease caused by impaired migration or cell proliferation of cortical neurons. It is a type of cortical developmental malformation and the most common cause of refractory epilepsy. In epilepsy surgery, FCD accounts for approximately 40% to 50% of pediatric epilepsy surgery patients and about 20% of adult epilepsy surgery patients.

1. Causes and mechanisms

Factors that affect the development of the cerebral cortex, including genetic and environmental factors, may lead to FCD. Such as abnormal proliferation, migration defects, and abnormal differentiation of neuroblasts; blocked programmed cell apoptosis; abnormal synapse formation and cortical remodeling, etc. The influence of harmful factors in early pregnancy leads to the proliferation of abnormal cells and the formation of abnormal cortical structures.

The mechanism by which local cortical dysplasia leads to clinical epilepsy may be related to increased neural excitability and decreased inhibition. Glial cells may also play a role in the epilepsy mechanism in FCD patients. In the abnormal early epileptic tissue of FCD, the number of HLA-DR-positive cells and CD-68-positive macrophages increases and is confined to the perivascular area and around dysplastic neurons. The number of these active HLA-DR-positive microglia is positively correlated with the duration and frequency of epilepsy. Therefore, it is believed that inflammatory response and pro-inflammatory molecules play a certain role in the epilepsy of FCD.

2. Clinical manifestations

FCD generally develops early in children. The incidence ratio of FCD in boys and girls is roughly equal. Most cases occur within 10 years old, and are most common within 2-5 years old. The onset age of FCDII type is earlier than that of FCDI type. FCD can occur in any part of the brain, with the frontal and temporal lobes being the most common. About 30% of FCD involves more than 2 lobes of the brain. FCDI type is common in the temporal lobe, while FCDII type often occurs in cerebral lobes other than the temporal lobe, most commonly in the frontal lobe. FCD mainly affects the cortex and subcortical areas in a limited manner, but some FCDs involve the white matter extensively, and some involve the cortex to the lateral ventricles. FCD induces epilepsy more frequently than tumors, hippocampal sclerosis, etc.

FCD may be accompanied by developmental delay. 75%-90% of FCD patients will experience epileptic seizures. FCD can cause a variety of epileptic seizures. The type of seizure is often related to the site of the lesion. Patients with FCD and schizencephaly have the most difficult to control epilepsy and are often accompanied by intellectual disability. FCD located in the central area is often accompanied by partial status epilepticus.

Treatment

Epilepsy caused by FCD can be treated with drugs of choice, generally anti-epileptic drugs for partial seizures, such as carbamazepine, lamotrigine, levetiracetam, etc. FCD is often resistant to anti-epileptic drugs, and surgical resection of the epileptogenic focus and discharge area can achieve relatively satisfactory surgical results.

Because the FCD of imaging is often inconsistent with the area shown by pathology (smaller than the actual area), surgical operations are often recommended to expand the resection beyond the actual lesion area. In centers with sufficient technical conditions, if surgical resection can be performed after intracranial electrodes are placed to clearly define the scope of the epileptic focus, the effect will be more ideal.