Subdural hygroma is a local excessive accumulation of clear or blood—impurity cerebrospinal fluid in the gap between the dura and arachnoid cerebral membranes. Hygroma can be traumatic, spontaneous and iatrogenic. General cerebral symptoms prevail in the clinic, focal deficiency is moderately pronounced. Diagnosis includes X—ray of the skull, assessment of neurological status, MRI or CT of the brain; in the absence of the latter – Echo-EG and lumbar puncture. Subclinical hygromas of small size are subject to observation. In other cases, drainage of the hygroma is carried out. With relapse, a hygromo-peritoneal shunt is installed.
ICD 10
S06.8 Other intracranial injuries
General information
Subdural hygroma (Greek “hygros” — moist) is an accumulation of cerebrospinal fluid between the subarachnoid (arachnoid) and the dura mater. In severe traumatic brain injury (TBI), it is combined with subdural hematoma and brain contusion. A subdural space hygroma differs from a hematoma of the same localization by the absence of a capsule and the transparency of its contents, which may contain only a small admixture of blood. There are cases of transformation of a hygroma into a subdural hematoma of a chronic course due to hemorrhage into a hygroma with subsequent encapsulation.
Subdural hygroma can form in any age period. However, the risk of its occurrence increases with age and in the presence of atrophic changes in cerebral tissues. The most frequent localization of subdural hygroma is the supra—temporal regions. Clinical manifestations of hygroma are caused by an increase in its volume and compression of adjacent cerebral tissues by it. With a small volume of contents, subdural hygroma has a subclinical course and can become an unexpected find when examined for other cerebral pathology. Due to its localization, subdural hygroma is in the sphere of interests of specialists in the field of neurology and neurosurgery.
Causes
It is believed that the most common subdural hygroma is the result of head injuries, not only severe, but also mild, even minor. However, hygroma can occur for other reasons, including spontaneously. The main reasons include:
- TBI. Various data indicate the diagnosis of hygroma in 5-20% of closed craniocerebral trauma. The time of hygroma formation can vary, and therefore acute, subacute and chronic traumatic hygromes are distinguished.
- Cyst rupture. Spontaneous or non-traumatic hygromas are usually based on the rupture of an arachnoid cyst. Since arachnoid cysts are often congenital, subdural hygromas formed as a result of their rupture are diagnosed mainly at a young age and in children. Cases of congenital hygroma of the cerebral membranes are described.
- Iatrogenia. A separate group consists of hygromas of iatrogenic genesis, formed after neurosurgical operations. More often, the formation of hygromas is observed after interventions for intracerebral tumors, arachnoid cysts and cerebral vascular aneurysms. The iatrogenic mechanism of the formation of hygromas is associated with the liquorrhea that occurs after surgery.
Pathogenesis
The question of the pathogenesis of hygroma of traumatic genesis still remains open. According to one theory, a hygroma is formed due to the rupture of the arachnoid cerebral membrane with the formation of a valve through which cerebrospinal fluid is injected into the subdural space. According to another theory of pathogenesis, hygroma is a consequence of the accumulation of exudate of the injured dura mater. A number of researchers believe that the subdural hygroma is formed due to the separation of the hard and arachnoid shell at the time of injury with the appearance of a cavity between them, into which the cerebrospinal fluid of the damaged basal cisterns is poured.
Symptoms
The clinical signs are largely similar to the symptoms of a hematoma of similar localization. These include: loss of consciousness and confusion, squeezing or bursting cephalgia, nausea and vomiting, visual impairment, speech disorders, memory loss, discoordination symptoms. Possible mental disorders: mood swings, aggressiveness, ridiculous behavior, elements of disorientation. As the hygroma increases in volume, signs of compression of the brain appear and increase. This process occurs more gradually than with subdural hematoma. Progressive mass effect leads to dislocation of cerebral structures and compression of the medulla oblongata with the occurrence of respiratory and cardiac disorders.
Focal neurological deficit has a milder severity than with subdural space hematoma. It is usually represented by anisocoria and hemiparesis. Shell symptoms in the form of rigidity of the occipital muscles are found only in 20% of patients. Approximately 40% have epiprimes, more often of a generalized nature. Chronic hygroma with a small volume may have a subclinical course. Its transformation into a chronic hematoma can be triggered by additional trauma.
Diagnostics
The diagnostic algorithm for head injury includes a thorough neurological and instrumental examination. The main diagnostic methods include:
- X-ray. At the first stage, an X-ray of the skull is performed. Angiography of cerebral vessels does not always contribute to the detection of hygroma, which, like a hematoma, is found in the form of a non-vascular band and is indistinguishable from it.
- Echoencephalography. It helps to determine the degree of increase in intracranial pressure and the presence of dislocation of cerebral structures.
- Lumbar puncture. (in the absence of contraindications). Examination of the cerebrospinal fluid gives a pronounced increase in the concentration of albumin, in the presence of subarachnoid hemorrhage, blood is detected.
- Tomography. To differentiate the subdural space hygroma from tumors of the cerebral membranes, arachnoid cyst and subdural hematoma, only an MRI or CT scan of the brain allows. Often, on tomography, you can see the so-called “path” connecting the hygroma with the cisterns of the base of the brain. Tomography allows you to accurately determine the localization and volume of the hygroma, identify other cerebral injuries during TBI, and optimally plan therapeutic measures.
Treatment
Conservative therapy with hygrom is carried out by neurologists, surgical treatment is carried out by neurosurgeons. Subdural hygroma of small size, which does not give clinical manifestations, needs dynamic observation, including tomographic. With an increase in its volume, surgical drainage is indicated.
Surgical aspiration of the contents of the hygroma is carried out under general anesthesia through a milling hole in the skull. Then a subdural drainage is installed, which is removed after 1-2 days. Subdural hygroma has a significant tendency to relapse. Many patients are forced to undergo the drainage procedure repeatedly. Numerous relapses are a reason to consider the possibility of performing a bypass operation with the creation of a hygromo-peritoneal shunt.
Forecast
The prognosis of hygroma largely depends on the accompanying circumstances: the presence of traumatic damage to the substance and membranes of the brain, the degree of development of cerebral angiospasm, the age of the patient, the existence of brain atrophy, etc. Cases when subdural hygroma is not combined with other brain pathology and drained in a timely manner have a favorable prognosis up to 100% of the reverse development of all neurological symptoms.