Disease Database - Page 197

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Cerebellar tonsillar herniation

Cerebellar tonsillar herniation is primarily caused by abnormal development of the midline structures of the posterior cranial fossa during the embryonic period, leading to the herniation of the cerebellar tonsils, cerebellar vermis, medulla oblongata, and the lower part of the fourth ventricle into the foramen magnum. Cerebellar tonsillar herniation is typically classified into four types: Type I: This is the most common type clinically, characterized by cerebellar tonsillar herniation below the foramen magnum (>5mm), which may be accompanied by hydrocephalus and syringomyelia. Type II: Based on Type I, this type also involves downward displacement and deformation of the brainstem, cerebellar vermis, and fourth ventricle, often accompanied by myelomeningocele and hydrocephalus. Type III: This is very rare. Based on Type II, it also involves occipital or cervical encephalocele and an enlarged foramen magnum. The encephalocele sac contains the medulla oblongata, cerebellum, fourth ventricle, and various pathological neural tissue components. Type IV: This is extremely rare, characterized by hypoplasia or absence of the cerebellar tonsils and tentorium cerebelli.

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Brain abscess

Brain abscess is a purulent cavity formed by pathogens invading the brain, which directly destroys brain tissue and is a severe intracranial infectious disease. The main symptoms include headache, fever, nausea, vomiting, and confusion.

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Intracranial cholesteatoma

Intracranial cholesteatoma is a slow-growing congenital tumor, commonly found in the cerebellopontine angle and sellar region, but also seen in the lateral ventricles, cerebrum, and cerebellum. It often grows slowly along the subarachnoid spaces and fissures of the brain at the skull base. There are no characteristic clinical symptoms. When the tumor grows large, it can cause symptoms such as hydrocephalus and aseptic meningitis. It can occur at any age, with a peak incidence around 40 years old.

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Moyamoya disease

Moyamoya disease is a rare, progressive vascular disease characterized by occlusion or stenosis of the intracranial carotid arteries, which reduces blood flow to the brain. To maintain blood flow to the brain, small blood vessels at the base of the brain begin to dilate. Japanese scholars first reported this disease. On cerebral angiography of patients, dense clusters of small blood vessels can be seen at the base of the brain, resembling a puff of smoke, hence the name Moyamoya disease (Moyamoya means "a puff of smoke" in Japanese). Moyamoya disease can occur at any age, but it is more common in children and young adults, with two peak ages of onset: 10-14 years old and around 40 years old.

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Arachnoid cyst

Arachnoid cysts are congenital benign brain cysts, mostly caused by abnormal arachnoid membrane division during development. They can occur in all age groups, but are more common in children and adolescents, and more prevalent in males. Common symptoms include headache, epilepsy, and hydrocephalus (abnormal accumulation of cerebrospinal fluid in the brain). Based on the location of the cyst, arachnoid cysts can be divided into two main categories: intracranial arachnoid cysts and spinal arachnoid cysts.

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Ependymoma

Ependymoma is a low-grade central nervous system tumor originating from ependymal cells of the ventricles and central canal of the spinal cord, or from ependymal cell nests in the cerebral white matter. It is a type of ependymal cell tumor. Ependymomas account for less than 10% of all central nervous system tumors. They are more common in children, with a peak incidence between 5 and 15 years of age.

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Skull defect

Craniosynostosis is caused by various factors such as head trauma and craniotomy. Due to the altered shape of the skull defect, it can easily indent and compress brain tissue, leading to craniosynostosis-related syndromes. Therefore, the area of the skull defect needs to be repaired and covered to restore its integrity.

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Carotid body tumor

The carotid body is a small, highly vascularized and innervated tissue located posterior to the bifurcation of the common carotid artery. It is an important peripheral chemoreceptor that senses changes in blood carbon dioxide levels, leading to alterations in respiration and heart rate. In some cases, the carotid body can undergo hyperplasia, eventually forming a carotid body tumor. Carotid body tumors are classified as both paragangliomas and chemodectomas. They can occur at any age, with a higher incidence in females than males.

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Arteriovenous fistula

An arteriovenous fistula (AVF) is an abnormal connection between an artery and a vein that bypasses the capillary bed. It can be caused by congenital developmental abnormalities or acquired factors.

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