A<unk>  (SDG) is a collection of cerebrospinal fluid (CSF), without blood, located under the dural membrane of the brain. Most<unk> s are believed to be derived from chronic<unk>  hematomas. They are commonly seen in elderly people after minor trauma but can also be seen in children following infection or trauma. One of the common causes of<unk>  is a sudden decrease in pressure as a result of placing a ventricular shunt. This can lead to leakage of CSF into the<unk>  space especially in cases with moderate to severe brain atrophy. In these cases the symptoms such as mild fever, headache, drowsiness and confusion can be seen, which are relieved by draining this<unk>  fluid.
Subdural hygroma
Cystic hygroma
Arachnoid cyst
Dandy–Walker malformation
Subependymoma
Choroid plexus cyst
Encephalocele
Porencephaly