MEMBRANES OF THE BRAIN, CEREBROSPINAL FLUID, VENTRICLES OF THE BRAIN.MEMBRANES OF THE BRAIN, CEREBROSPINAL FLUID, VENTRICLES OF THE BRAIN. MENINGEAL AND HYPERTENSIVE SYNDROMES. HYDROCEPHALUSMENINGEAL AND HYPERTENSIVE SYNDROMES. HYDROCEPHALUS

Short anatomical data. Three membrane membrane the brain and spinal cord: dura mater (dura mater, or panchymeninx), arachnoid, or vascular sheath (arachnoidea) and pia (pia mater or leptomeninx). Dura mater and pia mater wrap nerves as they exit from the cranial cavity or spinal canal.

The outer layer of the dura mater adheres to the bone and periosteum the inner layer is the actual mater. Between the layers of dura mater are meningeal arteries supplying the bones of the skull. In certain parts of the inner layer of the dura mater is far behind from the outer one, forming the epidural (or rather intradural) space, within it; the venous sinuses of the skull, the spinal canal (loose connective tissue) and venous plexus. Arachnoidea consists of an outer cellular membrane and the inner layer of connective tissue, which is attached to a network of thin trabeculae, resembling a web, therefore its name. Arachnoidea is fixed to the dura mater with the villi, or pacchionian granulations. Arachnoid protects the brain against the penetration of various pathogenic agents.

Pia mater consists of a thin layer containing cells lining the entire surface of the brain and spinal cord, with the exception of the ventricles. It is fixed to the brain ectoderamal membrane, which accompanies all entering to the brain and exit from it are blood vessels.

Subarachnoid space (the space between the pia and the arachnoid) is filled with circulating cerebrospinal fluid (CSF). Areas where the subarachnoid space expands considerably, called cisterns. In a large cistern, located between medulla oblongata and cerebellar tonsils, goes through Majendie foramen, cerebrospinal fluid is formed in the ventricles of the brain. Subarachnoid space extends to the coccyx and from level L1or L2 of vertebra, which ends in the spinal cord is a hollow sac (terminal cystern), which roots of cauda equina pass until it exits from the spinal canal.

The system consists of two ventricles pair of lateral ventricle, III and IV ventricle. Each lateral ventricle is divided into anterior horn, body (middle part), dorsal and ventral horns. The lateral ventricles are connected to III through the interventricular foramen (foramen Monroe). III and IV ventricles are connected by running water. The entire ventricular system of the brain is associated with subarachnoid space through location in the IV ventricle paired foramen of Lyushka and Majendie. Ventricles of the brain are vascular or villiferous plexus (plexus choroideus), which are most pronounced in the lateral ventricles.

Cerebrospinal fluid is produced by choroid plexus of the ventricles, mainly lateral one. Endothelium of the capillaries, basement membrane and epithelium of the plexus form blood-brain barrier that protects the brain against the penetration of pathogenic agents. Cerebrospinal fluid is distributed to the brain via ventricular system and enters through Lyushka and Magendie foramen in the subarachnoid space, and which circulates around the brain and spinal cord.

Cerebrospinal fluid acts as a liquid buffer that protects the brain from mechanical injury of the head. In addition, it serves as a kind of "canalization" in which the products of metabolism of the brain (CO3, salt of lactic acid, NH2, hydrogen ions) pass into the bloodstream, and moves dissolved substances within the brain and spinal cord. Cerebrospinal fluid is colorless and transparent water; its pressure is on average 90 to 150 mm of water (6-11 mm Hg. Art.) contains protein - 25-40 mg/100 ml, number of cells - 1-5 in 1 microliter. Resorption (suction) of cerebrospinal fluid is through villi (Pacchionian bodies) in the venous sinuses of the

skull. Every day ventricles produces about 400-500 ml of CSF and in subarachnoid space is always about 130-150 ml of cerebrospinal fluid. Methods of Investigation.

To reveal the syndrome of irritation of the meninges (meningeal syndrome), examine the tone of certain muscle groups, which reflexively increases in pathological processes in membranes. Tonus cervical muscles investigated by passive tilt the head forward and bring the subject's chin to the chest, The inability of the passive motion in full volume due to the increase in muscle tone is regarded as the stiffness of the cervical muscles.

Test of Kernig symptom: lying on one’s back, ask subject to bent leg to the hip and knee joints at right angles, then unbend the knee; inability to fully straighten the leg at the knee because of the tonic muscle tension is regarded as a positive Kernig symptom. To study rigidity of the neck muscles, may involuntary flexion of the legs in the hip and knee joints (upper Brudzinski symptom), the study of symptom Kernig - involuntary flexion of the other leg in the hip and knee joints (lower symptom Brudzinskiy). Pressure on the area of the pubic symphysis may due to involuntary flexion of both legs in the hip and knee joints (medium symptom Brudzinski). Tapping on the zygomatic bone can increase and cause a headache on this pain side of a patients face (symptom Bechterev).

Cerebrospinal fluid is usually obtained by lumbar injection, or lumbar puncture - the introduction of a special needle into the space between the spinous processes of lower lumbar vertebrae (L or L) in the position of a patient lying on their sides. After outflow of cerebrospinal fluid begins, measure its pressure by manometer and collect it in sterile test tube at a few (5-8) ounces of liquid for microscope (the definition of cells), biochemical (protein, glucose, etc.) and bacteriological study. Before sending to the laboratory study carried out a visual assessment of cerebrospinal liquid (color, transparency). Normally, cerebrospinal fluid is colorless and transparent; its pressure is on average 90 to 150 mm of water. art. (6-11 mm Hg. art. in a horizontal position), protein content - 25-40 mg/100 ml, number of cells - 1-5 in 1 micro liter (usually lymphocytes), glucose - half than of blood (2,5 -3.9 mmol /l).

To identify the blockade of subarachnoid space in the spinal canal, liquor-dynamic samples can be used during lumbar puncture. Kvekkenshtedt Test: short (5-10s) pressure on the jugular vein causes an increase in liquor pressure by 2-3 times (due to increased venous pressure leading to increased intracranial pressure), and stopping of pressing leads to a rapid return of pressure of original liquor. Stukeya Test: pressure on the anterior abdominal wall causes an increase in liquor pressure is about 1,5 times, and cessation of pressing leads to rapid normalization of liquor pressure. If spinal subarachnoid space is blocked, increased liquor pressure is not observed or it is expressed insignificantly during Kvekenshtedt and Stukeya test.

In various neurological diseases, changes occur in the cerebrospinal fluid, so the lumbar puncture has a wide range of indications. Currently, however, lumbar puncture is used less often with the introduction of X-ray computed and magnetic resonance imaging, which allows diagnosis in many cases without a lumbar puncture. In stroke, traumatic brain injury and many other diseases, lumbar puncture is applied in cases when there is no possibility of CT or MRI.

It is important to study cerebrospinal fluid to diagnose subarachnoid hemorrhage. Absolute indication for lumbar puncture is when infectious disease of the nervous system, such as meningitis is suspected. Lumbar puncture is contraindicated in patients with inflammatory processes in the place to puncture. If you suspect a lengthy process (brain tumor, intracranial hematoma), lumbar puncture is dangerous because of the possibility of displacement and herniation of the brain structures, so it is only possible in the absence of signs of venous congestion of the optic disk using ophthalmoscopy. In some cases, cerebrospinal fluid is extracted through suboccipital puncture.

Cerebrospinal fluid changes in various neurological diseases, and therefore its study is of great diagnostic value. In intracranial (submembranous, intracerebral) hemorrhages, cerebrospinal fluid may become bloody; red blood cells and later developed xanthosis (yellow color) appears as a result of the degradation of hemoglobin from red blood cells disintegrated. In inflammatory diseases (encephalitis, meningitis), CSF shows pleocytosis (increase in the number of cells). Significant neutrophil pleocytosis (up to 1 thousand cells in 1mkl and more) are common in bacterial infection, if mainly lymphocytic - for viral, tubercular, and other infectious diseases. Increase protein content in cerebrospinal fluid significantly or prominent pleocytosis (protein-cell dissociation) occurs in tumors of the brain and spinal cord, carcinomatosis of membrane, some inflammatory diseases.

Meningeal syndrome. Increased intracranial pressure (hypertensive syndrome). Hydrocephalus

The syndrome of irritation of the meninges, or meningeal syndrome include stiffness in the muscles of the neck, positive Kernig and Brudzinski symptoms, Bechterev symptom. An important feature of irritation meninges are headache and general hyperesthesia: a painful reaction to any external stimuli (bright light, loud noise, touching the skin). In severe cases there may be a peculiar posture the patient: lie on side, head thrown back, hips pressed against her abdomen, legs to the hips.

Increased cerebrospinal fluid pressure at above 200 mm of water art. (14 mm Hg. Art.) is regarded as increased intracranial pressure, or intracranial hypertension. It may be asymptomatic with a gradual increase up to 20-30 mm Hg. art., in higher or a rapid increase in intracranial pressure, arise symptoms: headache, nausea, vomiting, oculomotor disorders (often defect of n. abducens), transient visual disturbances and the stagnation/congestion of the optic disk. The headache often is caused by stimulation of the meninges, nausea and vomiting - the excitation of the vagus nerve, visual disturbances - compression of the oculomotor nerve and venous stagnation in the fundus. In rapid and significant increase of intracranial pressure, blood supply to the brain decreases and possible impairment of consciousness up to coma. Intracranial hypertension can cause penetration - displacement of brain substance from one intracranial compartment to another, for example cerebellar tonsils to foramen magnum, which is associated with high risk of death of the patient.

Dropsy of the brain, or hydrocephalus, often develops because of obstacles the circulation of cerebrospinal fluid in any point between the main place of its formation in the lateral ventricles and subarachnoid space of the base of the brain. Because the obstacles, circulating cerebrospinal fluid accumulates in the ventricles, extending them, squeezing adjacently to the ventricles tissue and slightly widening the brain. Such hydrocephalus is manifested by symptoms of increased intracranial pressure (hypertensive hydrocephalus) in infants or young children (up to 2 years), who fontanelle and cranial suture are not completely closed, which increases the size of the head. Acute appearance of hypertensive hydrocephalus (eg, due to subarachnoid hemorrhage, or bleeding in the cerebellum, leads to the blockade of the ways of circulation of cerebrospinal fluid) leads to impairment of consciousness.

Hydrocephalus, which is well revealed by X-ray computed or magnetic resonance imaging of the head may not be accompanied by a significant increase in intracranial pressure (normotensive hydrocephalus). It happens when it bypass the acute pathological process that caused the hypertensive hydrocephalus (traumatic birth, meningitis, subarachnoid hemorrhage, tumor), or in cases where the ventricles and/or subarachnoid space passively increased due to atrophy of the brain (hydrocephalus exvasio). In these cases, it is possible that variety of neurological disorders is caused by atrophic process.

After the lumbar puncture, intracranial hypotension may develop due to continued expiration of cerebrospinal fluid. When sitting or standing, increased intracranial hypotension in a few minutes is

manifested by headache, combined with the pain and stiffness of the neck and sometimes nausea and vomiting. These symptoms usually go away within a few days. Causes of meningeal and hypertensive syndromes, treatment principles.

Meningeal syndrome is more often caused by meningitis, brain injury or hemorrhage in the subarachnoid space. Suspicion of meningeal syndrome requires immediate hospitalization of the patient.

The intracranial pressure increases due to increased intracranial contents (brain tumor, hemorrhage, extensive injury or cerebral infarction and other diseases), increased venous pressure (superior sagittal sinus thrombosis, or obstruction of superior vena cava), prevention of flow or absorption of cerebrospinal fluid (swelling, meningitis or subarachnoid hemorrhage), increased cerebrospinal fluid (choroid plexus papilloma). To reduce the swelling of the brain that causes intracranial hypertension, mannitol is usually used (for 0,25-1 g / kg / per every 6 h) or glycerol (250 ml 10% solution w / every 6 h) or dexazon (but 50-100 mg/s w/w or w/m), in critical situations - hyperventilation and neurosurgical intervention. In some cases, surgical removal of the pathological formation (intracranial hematoma, or tumor) or decompression for cerebral edema is the only chance to reduce intracranial pressure and save the life of the patient.

Congenital infantile hydrocephalus often is caused by a brain haemorrhage (premature infants), meningitis in the fetus or the newborn or congenital malformations of the brain, such as atresia or stenosis of the aqueduct. Acquired hypertensive hydrocephalus is caused by major process in the posterior cranial fossa (tumor, hemorrhage, or abscess) , subarachnoid hemorrhage or other diseases, leading to the blockade of the circulation of cerebrospinal fluid. Normotensive hydrocephalus is caused by the migrated meningitis or subarachnoid hemorrhage, in which impaired resorption of cerebrospinal fluid through villi (Pacchionian bodies) is filled with blood degradation products. In various degenerative processes (Alzheimer's disease, dementia with Lewy bodies, etc.) there is hydrocephalus ex vasio.

The treatment of hydrocephalus is aimed at the reasons if possible. If there is no occlusion within the ventricular system, a temporary therapeutic effect maybe provided by lumbar puncture with removal of a small amount of cerebrospinal fluid. Long-term effect is achieved with the imposition of a shunt between the ventricular system or subarachnoid space and, for example, the abdominal cavity (respectively ventriculoperitoneal and lyumboperitoneal bypass).

Meningeal and hypertensive syndromes

Syndrome Major manifestations

Meningeal Acute development of a severe headache, stiff/rigid muscles of the neck, symptom of Kernig, symptoms Brudzinskogo

Hypertensive Headache, nausea, vomiting, visual disturbances, impaired consciousness, increased liquor pressure above 200 mm of water art.