A
subdural hygroma is a subdural body of
cerebrospinal fluid (CSF), without blood. Most hygromas are believed to be derived from chronic
subdural hematomas. It is commonly seen in elderly patients after minor trauma but can be seen in children after an infection. One of the common causes of subdural hygroma is a sudden decrease in pressure by
ventricular shunting. This can lead to leakage of CSF into the
subdural 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 subdural fluid.