Overview of Intracranial Hypertension
High cranial pressure (intracranial hypertension), also known as high cranial pressure syndrome, is a common syndrome in neurology, referring to the pressure in the cranial cavity, i.e., the pressure in the brain is increased, and the general intracranial pressure is often expressed by the cerebrospinal fluid pressure in the subarachnoid space of the lumbar vertebrae. Clinically, headache, vomiting and optic papilla edema are its main features. Normal intracranial pressure is the pressure measured by lumbar puncture when a normal person is lying horizontally, which is 80～180mmH2O in normal adults and 50～100mmH2O in children, and if the pressure is more than 200mmH2O, it is generally regarded as increased intracranial pressure. Active prevention and treatment of the primary disease is the main treatment measure.
Etiology
1. Increased brain volume
(1) Cerebrovascular diseases: cerebral embolism, cerebral thrombosis and hypertensive cerebral hemorrhage.
(2) Acute craniocerebral injury: cerebral contusion after craniocerebral trauma, intracerebral hemorrhage, craniocerebral surgery, etc. Edema of the surrounding tissues after brain cell injury can lead to increase in brain volume.
(3) Infections: various kinds of encephalitis (bacterial encephalitis, viral encephalitis, tuberculous encephalitis), brain abscess, sarcoidosis, and cerebral parasitic diseases (such as cerebral cysticercosis, schistosomiasis, and toxoplasmosis).
(4) Intracranial tumors: occupational effects of glioblastoma, meningioma, astrocytoma, and metastatic tumors.
(5) Others: such as febrile convulsions, especially severe and prolonged febrile convulsions, acute cerebral hypoxia, persistent epileptic status, as well as heatstroke and water intoxication. Systemic diseases such as hypertensive syndrome of pregnancy, uremia, nutritional and metabolic diseases, respiratory and cardiac arrest can lead to cerebral edema.
(6) Unknown cause: benign intracranial hypertension.
2. Cerebrospinal fluid increase
(1) Obstruction of cerebrospinal fluid circulation: common causes include congenital stenosis and atresia of cerebral aqueduct, congenital abnormality of cerebellar tonsils with excessive length or downward displacement, such as Arnold-Chiari malformation, abnormal development of the skull base, and tumors and cysts of cerebral ventricular system, as well as parasites, inflammatory adhesions, and so on.
(2) Impaired absorption of cerebrospinal fluid: common causes include meningitis, after subarachnoid hemorrhage and after traumatic brain injury, which can lead to occlusion of the arachnoid granules, thus affecting the absorption of cerebrospinal fluid, or affecting the absorption of cerebrospinal fluid by venous plexus of the spinal nerve roots, resulting in increased intracranial pressure.
(3) Excessive secretion of cerebrospinal fluid: it is seen in the lesions of the choroid plexus, which cause the secretory cells to secrete too much and the inflammatory reaction of the meninges.
(3) Increase in intracranial blood volume
It is mainly seen in venous sinus thrombosis, intracerebral phlebitis, thrombosis of large intracerebral veins and thrombosis of internal jugular vein.
Differential diagnosis
Increased intracranial pressure in infants and young children is manifested by skull enlargement and hydrocephalus, which should be distinguished from macrocraniosynostosis, subdural hematoma, cysts and tumors.
Examination
1. Physical examination
Physical examination includes: ① temperature, pulse, respiratory rate and depth, respiratory odor and respiratory secretion; ② blood pressure; ③ pupil size, whether both sides are equal and response to light; ④ eye movement; ⑤ fundus of the eye with or without papillary edema, hemorrhage and exudation; ⑥ motor, sensory and reflexes of the cerebral nerves and spinal nerves; ⑦ signs of meningeal irritation and so on.
2.Auxiliary examination
In addition to routine blood, urine, stool, electrocardiogram, chest radiographs and other examinations, patients with increased intracranial pressure should also selectively choose auxiliary examinations based on medical history and physical examination.
(1) Radiological examination: It is of great significance to the etiological diagnosis, such as brain tumor, cerebrovascular disease, hydrocephalus, cerebral parasitic disease, etc.. Generally speaking, patients who are suspected of having increased intracranial pressure should be examined by craniocerebral X-ray film, CT or MRI, and MRI is better for lesions in the posterior cranial fossa.
(2) Lumbar puncture examination: the diagnosis of increased intracranial pressure is mainly based on lumbar puncture, which measures the pressure of cerebrospinal fluid. If the pressure of cerebrospinal fluid is more than 1.96 kPa (200 mmH2O), it is considered increased intracranial pressure. Patients with increased intracranial pressure should be very careful when lumbar puncture, lumbar puncture if the release of cerebrospinal fluid is too much is very easy to induce cerebral hernia formation, especially in chronic occipital foramen magnum hernia, extremely dangerous. Therefore, the indications should be strictly controlled, and the operation should be very careful, and it is best to use a thin lumbar puncture needle. After successful lumbar puncture, the core of the needle should be withdrawn slowly. If the pressure of the cerebrospinal fluid is too high and the cerebrospinal fluid is seen to spurt out, the puncture needle should be withdrawn quickly. Retain the cerebrospinal fluid as long as enough for examination, do not put too much cerebrospinal fluid. And when doing the lumbar puncture, you should prepare 20% mannitol 250 ml, furosemide and hormone drugs, and be ready to give the treatment of lowering the cranial pressure.
Routine examination of cerebrospinal fluid as well as some special examinations are meaningful to clarify the etiology, such as when there is a large number of inflammatory cell changes in the cerebrospinal fluid, it supports that there is inflammation in the cranium; patients with a positive cysticercus test support that there is cysticercus infection in the cranium, i.e., cerebral cysticercosis. Positive tuberculosis antibodies mostly support the presence of intracranial tuberculosis infection. Positive oligoclonal zones are mostly suggestive of cerebral demyelinating disease.
Treatment principle
1. Active prevention and treatment of the primary disease is the main measure.
2. Benign intracranial pressure increase and congenital anomalies should be diagnosed promptly and treated early.
3. Epileptiform seizures often indicate a sharp increase in intracranial pressure.
4. If the pupil is dilated on one side, it is often the clinical manifestation of ipsilateral temporal lobe hernia of hook gyrus; bilateral pupil dilation is often the manifestation of cerebellar tonsil hernia; if accompanied by vital signs (increased blood pressure, slow heart rate, pulse flood, slow and deep breathing) and decreased consciousness, the patient is in an endangered state, and immediate first aid measures should be taken.
5. Dehydration to reduce cranial pressure treatment, the application of dehydration agents are mannitol, glycerol fructose, tachycardia, human albumin, etc..