Hygroma

Last edit by Alaric Steinmetz on

A hygroma is a medical term for an accumulation of fluid that can occur in various parts of the body. In neurosurgery, the subdural hygroma is of particular importance. It is a collection of fluid that forms between the dura mater (dura mater) and the arachnoid membrane (arachnoid) of the brain. This type of hygroma often appears on imaging in a way that closely resembles a chronic subdural hematoma.

Cause

Hygromas can arise for various reasons.

  • One of the most common causes is traumatic brain injury. This can occur, for example, through a fall, a traffic accident, or even sports injuries[^1].

  • Another important factor in the development of hygromas is CSF dynamics. In some cases, complications can occur in patients with CSF diversion, such as a ventriculoperitoneal shunt (VP shunt). A VP shunt is a surgically implanted catheter that is used to divert excess cerebrospinal fluid from the ventricular system to other parts of the body in order to reduce intracranial cerebrospinal fluid pressure. If this shunt is not set correctly and drains too much cerebrospinal fluid, this can lead to underdrainage, which in turn can cause a hygroma[^2].

  • Hygromas can also develop postoperatively, especially after procedures involving the skull. Such surgeries can cause changes in cerebrospinal fluid dynamics that may lead to the formation of a hygroma[^3].

Imaging

On CT or MRI imaging, hygromas often appear as fluid-filled spaces that look similar to chronic subdural hematomas.

CT

On CT imaging, hygromas are typically visible as hypodense areas

MRI

On MRI, they present a somewhat different appearance, depending on the specific composition of the fluid and the sequences used. However, the exact distinction between a subdural hygroma and a chronic subdural hematoma can be difficult, since both conditions can look very similar on imaging.

Treatment

Treatment of a hygroma depends on its cause and size. In some cases, conservative treatment may be sufficient, in which the hygroma is reabsorbed on its own over time. In other cases, especially if the hygroma causes symptoms or increases in size, surgical intervention may be necessary.