Chronic overshunting

Case contributed by Chris O'Donnell
Diagnosis almost certain

Presentation

Headache, confusion and dysphagia post VP shunt for normal pressure hydrocephalus.

Patient Data

Age: 85 years
Gender: Male
ct

Bilateral convexity subdural collections of fluid without obvious internal membranes or acute blood suggesting hygroma rather than chronic hematoma. Note subtle effacement of both frontal lobe sulci suggesting mass effect. These findings contrast with the preoperative scans.

Pre-operative scan

ct

Ventriculomegaly out of keeping with sulcal pattern. No extra-axial collection. 

Case Discussion

One of the major issues associated with shunting the ventricles of elderly patients is the development of subdural collections due to a excessive reduction in ventricular volume ("overshunting") leading to a subdural "dead space" that can fill with acute blood (hematoma) from the stretching of vessels traversing the space, or bland fluid = hygroma. Differentiating hygroma from chronic hematoma is always difficult on CT. The presence of membranes (granulation tissue) in the fluid indicates old hematoma but they can be very hard to see.

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.