Subdural hematoma is a limited intracranial accumulation of blood localized between the dura and arachnoid meninges. In most cases, it is a consequence of injury. It is manifested by variable in form and duration disorders of consciousness and psyche, headache, vomiting, focal neurological deficiency (mydriasis, hemiparesis, extrapyramidal disorders). CT or MRI data play a crucial role in diagnosis. In mild cases, conservative treatment (antifibrinolytic, decongestant, symptomatic) is sufficient, but surgical removal of the hematoma is more often required.
General information
Subdural hematoma is a local accumulation of blood located between the dura and arachnoid (arachnoid) cerebral membranes. It accounts for about 40% of all intracranial hemorrhages, which also include epidural and intracerebral hematomas, ventricular and subarachnoid hemorrhages. In the overwhelming majority of cases, subdural hematoma is a consequence of traumatic brain injury, the frequency of its occurrence in severe TBI reaches 22%. Subdural hematomas can occur at any age, but are more common in people over 40 years of age. Among patients, the ratio of men to women is 3:1.
Subdural hematomas are classified into acute (manifested in the first 3 days of TBI), subacute (manifested in the period from 3 days to 2 weeks from the moment of injury) and chronic (manifested later than 2 weeks). According to ICD-10, there are non-traumatic and traumatic subdural hemorrhage with the presence / absence of a wound penetrating into the skull. In clinical practice, subdural hematoma is a subject of study for specialists in the field of traumatology, neurosurgery and neurology.
Causes
Subdural hematoma is formed mainly due to the rupture of intracranial veins that occur as a result of TBI, passing in the subdural space. Much less often it occurs due to cerebral vascular pathology (arteriovenous malformations and cerebral vascular aneurysms, hypertension, systemic vasculitis) and blood clotting disorders (coagulopathy, anticoagulant therapy). The difference from an epidural hematoma is the possibility of bilateral formation of a subdural hematoma.
Subdural hematoma on the side of the damaging agent (homolateral hematoma) is formed with a sedentary head and a small area of contact with a traumatic object. The formation of a hematoma is possible without direct contact of the skull with a traumatic factor. This can happen when you stop abruptly or change the direction of movement. For example, while riding in transport, when falling on the buttocks or on the legs. The sudden shaking of the head that occurs in this case causes the displacement of the cerebral hemispheres inside the cranial box, which entails the rupture of the intracranial veins.
Subdural hematoma, the opposite side of the injury, is called contralateral. It is formed when the skull hits a massive sedentary object or when a traumatic object with a large contact area acts on a stationary head. Contralateral subdural hematoma is often associated with rupture of veins that flow into the sagittal venous sinus. Much less often, subdural hematomas are caused by direct injury to the veins and arteries of the cerebral cortex, which occurs when the dura mater is ruptured. In practice, bilateral subdural hematomas are often observed, which is associated with the simultaneous application of several injury mechanisms.
Acute subdural hematoma is formed mainly in severe TBI, subacute or chronic — in mild forms of TBI. A chronic subdural hematoma is enclosed in a capsule, which is formed a week after the injury due to the activation of fibroblasts of the dura mater. Its clinical manifestations are caused by an increasing increase in volume.
Subdural hematoma symptoms
General cerebral symptoms
Among the general cerebral manifestations, there are disorders of consciousness, mental disorders, cephalgia (headache) and vomiting. In the classical version, three-phase disorders of consciousness are characteristic: loss of consciousness after TBI, subsequent recovery for some time, designated as a light interval, then repeated loss of consciousness. However, the classical clinic is quite rare. If a subdural hemorrhage is combined with a brain injury, then there is no light gap at all. In other cases, it has an erased character.
The duration of the light interval is very variable: with acute hematoma — several minutes or hours, with subacute — up to several days, with chronic — several weeks or months, and sometimes several years. In the case of a long light interval of chronic hematoma, its termination may be triggered by changes in blood pressure, repeated trauma, and other factors.
Among the disorders of consciousness, disintegrative manifestations prevail: twilight state, delirium, amentia, oneiroid. Possible memory disorders, Korsakov syndrome, “frontal” psyche (euphoria, lack of criticism, ridiculous behavior). Psychomotor agitation is often noted. In some cases, generalized epiprimes are observed.
Patients, if contact is possible, complain of headache, discomfort when moving the eyeballs, dizziness, irradiation of pain in the back of the head and eyes, hypersensitivity to light. In many cases, patients indicate an increase in cephalgia after vomiting. Retrograde amnesia is noted. With chronic hematomas, vision may decrease. Acute subdural hematomas, leading to brain compression and mass effect (dislocation syndrome), are accompanied by signs of damage to the brain stem: arterial hypotension or hypertension, respiratory disorders, generalized disorders of muscle tone and reflexes.
Focal symptoms
The most important focal symptom is mydriasis (pupil dilation). In 60% of cases, acute subdural hematoma is characterized by mydriasis on the side of its localization. Mydriasis of the opposite pupil occurs when a hematoma is combined with a contusion focus in the other hemisphere. Mydriasis, accompanied by the absence or decrease in reaction to light, is typical for acute hematomas, with a preserved reaction to light — for subacute and chronic. Mydriasis can be combined with ptosis and oculomotor disorders.
Among the focal symptoms, central hemiparesis and insufficiency of the VII pair (facial nerve) can be noted. Speech disorders usually occur if a subdural hematoma is located in the shells of the dominant hemisphere. Sensory disorders are observed less frequently than pyramidal disorders, affecting both superficial and deep types of sensitivity. In some cases, there is an extrapyramidal symptom complex in the form of plastic muscle tone, oral automatism, the appearance of a grasping reflex.
Diagnostics
The variability of the clinical picture makes it difficult to recognize subdural hemorrhages. When diagnosing a neurologist, the following factors are taken into account: the nature of the injury, the dynamics of a violation of consciousness, the presence of a light gap, manifestations of the “frontal” psyche, neurological status data. Skull radiography is mandatory for all patients. In the absence of other methods, the recognition of a hematoma can be facilitated by Echo-EG. Ophthalmoscopy is an auxiliary method for the diagnosis of chronic hematomas. At the fundus, an ophthalmologist often determines the stagnant discs of the optic nerves with their partial atrophy. During angiography of cerebral vessels, a characteristic “symptom of the border” is revealed – a sickle-shaped zone of avascularization.
The decisive methods in the diagnosis of subdural hematoma are CT and MRI of the brain. In the diagnosis of acute hematomas, preference is given to CT of the brain, which in such cases reveals a homogeneous zone of increased density, having a crescent shape. Over time, the hematoma decompensates and blood pigments disintegrate, and therefore after 1-6 weeks. it ceases to differ in density from the surrounding tissues. In such a situation, the diagnosis is based on the displacement of the lateral parts of the brain in the medial direction and signs of compression of the lateral ventricle.
During MRI, there may be a reduced contrast of the acute hematoma zone; chronic subdural hematomas, as a rule, differ in hyperintensivity in the T2 mode. In difficult cases, MRI with contrast helps. Intensive accumulation of contrast by the hematoma capsule makes it possible to differentiate it from an arachnoid cyst or subdural hygroma.
Subdural hematoma treatment
Conservative therapy is carried out in patients without impaired consciousness who have a hematoma no more than 1 cm thick, accompanied by a displacement of cerebral structures up to 3 mm. Conservative treatment and dynamic follow-up with MRI or CT control is also indicated for patients in a coma or sopor with a hematoma volume of up to 40 ml and intracranial pressure below 25 mm Hg. The treatment regimen includes: antifibrinolytic drugs (aminocaproic acid, vikasol, aprotinin), nifedipine or nimodipine for the prevention of vasospasm, mannitol for the prevention of brain edema, symptomatic agents (anticonvulsants, analgesics, sedatives, antiemetics).
Acute and subacute subdural hematoma with signs of compression of the brain and dislocation, the presence of focal symptoms or severe intracranial hypertension are indications for urgent surgical treatment. With a rapid increase in dislocation syndrome, urgent endoscopic removal of a hematoma through a milling hole is performed. When the patient’s condition is stabilized, neurosurgeons perform a wide craniotomy with the removal of subdural hematoma and foci of crushing. Chronic hematoma requires surgical treatment with an increase in its volume and the appearance of stagnant discs during ophthalmoscopy. In such cases, it is subject to external drainage.
Prognosis and prevention
The number of deaths is 50-90% and is highest in elderly patients. It should be noted that mortality is caused not so much by subdural hematoma as by traumatic brain tissue damage. The cause of death is also: dislocation of brain structures, secondary cerebral ischemia, cerebral edema. The threat of death remains even after surgical treatment, since an increase in cerebral edema is possible in the postoperative period. The most favorable outcomes are noted during the operation in the first 6 hours from the moment of TBI. In mild cases, with successful conservative treatment, the subdural hematoma resolves within a month. Its transformation into a chronic hematoma is possible.
Prevention of subdural hemorrhages is closely related to the prevention of injuries in general and head injuries in particular. Safety measures include: wearing helmets when riding a motorcycle, bicycle, roller skates, skateboard; wearing helmets at a construction site, climbing in the mountains, kayaking and other extreme sports.