Arachnoid Yan

Yan means outlined arachnoid brain or spinal arachnoid in the etiology of some of the effects of a tissue reaction, arachnoid to the thickening, adhesion and cyst formation as the main feature. In essence, this is a pathological diagnosis, rather than a disease unit, was particularly prevalent in the young, middle-aged. Arachnoid cause congestion, edema, inflammatory reaction was, and vascular fibrous tissue hyperplasia, thickening caused arachnoid, Variable cloud or calcification, with soft arachnoid membrane, and subdural brain, spinal cord, cranial nerves, spinal nerve root adhesion, Cyst formation can, within the cyst had been wrapped in the cerebrospinal fluid. Because endometrial vascular adhesion and have inflammation and thickening or occlusion, can cause nerve near real ischemia, necrosis; Cysts can be nerve tissue secondary degeneration. If affected the adhesion of cerebrospinal fluid circulation, as of the fourth ventricle plug right in the middle of the hole, the side of the hole, the water can cause the brain. According to the main pathological findings can be divided into several arachnoid Yan type, simply type thickening, adhesion, cysts and mixed type. In the spinal cord, most more diffuse lesions, but the most serious changes can be found in only a small part of the spinal cord and brain lesions in more than its predecessor. Common causes of the following reasons : (a) an infection. Central nervous system infections : can be secondary to various types of cerebral spinal uveitis, encephalomyelitis, In particular virus infection caused serous meningitis. But for a clear diagnosis of diseases such as tuberculosis meningitis, purulent meningitis caused, usually called these directly in the aftermath of meningitis. 2. Outside the central nervous system infections : sepsis such as cold, flu, rheumatism, pneumonia, tuberculosis, sepsis, pelvic infection, are likely to cause of the disease. The head of the infected lesions such as pay otitis media and sinusitis. In particular, and the optic chiasm were likely and the posterior cranial fossa arachnoid Yan, may be microbial toxins through the blood-brain barrier caused. (2) Injury : Traumatic brain injury and spinal injury can occur, can be very minor injury, cranial muscle or spinal fractures can be no change. (3) foreign body into the subarachnoid : subarachnoid hemorrhage, antibiotics, anesthetics, the contrast agent. (4) the central nervous system of primary lesions : If tumor, syringomyelia, optic neuritis, multiple sclerosis and so on. (5), skull and spinal lesions : If basilar disease, spinal bone hyperplasia, disc herniation, spinal stenosis disease. (6) poisoning : If lead poisoning, alcoholism, and so on. (7) The etiology is unknown : it was probably not obvious clinical signs or identify the cause of non-suppurative meningitis, In particular infection caused.