Collapse syndrome: causes, symptoms, diagnosis

Intracranial pressure is the pressure in the cranial cavity and ventricles of the brain, which is formed by the meninges, cerebrospinal fluid, brain tissue, intracellular and extracellular fluid, and blood circulating through the cerebral vessels. In a horizontal position, intracranial pressure is on average 150 mm H2O. A persistent increase in pressure in the cranial cavity above normal values (above 200 mm H2O) indicates the development of intracranial hypertension and is most often observed as a result of cerebral edema, an increase in the volume of intracranial contents, intracranial hemorrhages, and cerebrospinal fluid circulation disorders, provided that compensatory mechanisms aimed at maintaining cerebral perfusion pressure are disrupted. Intracranial hypertension can lead to dislocation of various parts of the brain and herniation syndromes.

The most common causes of intracranial hypertension are: increased tissue volume (tumor, abscess), increased blood volume (hypercapnia, hypoxia, venous sinus occlusion), cytotoxic edema (ischemia, brain tumor, hyperosmolar state, inflammation), interstitial edema ( hydrocephalus with transependymal CSF flow).

Causes of herniation syndrome

I. Intracranial space-occupying lesions

1. Tumors (primary and metastatic)
2. Hematomas (intracerebral, subdural, epidural)
3. Abscesses
4. Granulomas
5. Parasitic diseases of the nervous system

II. Hydrocephalus

III. Intracranial infections

1. Meningitis
2. Encephalitis

IV. Cerebral edema

1. Ischemic
2. Toxic
3. Radiation
4. When hydrating

V. Traumatic brain injury

VI. Acute vascular disorders (ischemia, hemorrhage, hypertensive crisis, vascular spasm)

VII. Developmental anomalies of the brain and spinal cord

VIII. Venous hypertension

1. Occlusion of the superior or lateral sinus
2. Internal jugular vein occlusion
3. Obesity
4. Superior vena cava obstruction
5. Obstructive pulmonary disease
6. Arteriovenous shunt

IX. Parainfectious and autoimmune disorders

1. Guillain-Barre syndrome
2. Infections (poliomyelitis, acute lymphocytic choriomeningitis, mononucleosis, HIV infection, Lyme disease)
3. Chorea
4. Systemic lupus erythematosus
5. Allergy and post-vaccination reactions

X. Metabolic disorders

1. Uremia
2. Diabetes
3. Anemia
4. Hypercapnia

XI. Endocrinopathies

1. Hypoparathyroidism
2. Addison's disease
3. Cushing's disease
4. Thyrotoxicosis
5. Menarche, pregnancy

XII. Nutritional disorders (hypervitaminosis A, hypovitaminosis A)

XIII. Idiopathic intracranial hypertension

XIV. Intoxications (including drug intoxications) (phenothiazines, lithium, diphenin, indomethacin, tetracycline, sinemet, corticosteroids, etc.).

I. Intracranial space-occupying lesions

Intracranial space-occupying lesions (tumors, hematomas, abscesses, granulomas, some parasitic diseases) are one of the common causes of increased intracranial pressure. Clinical manifestations depend on the mechanism of increased intracranial pressure and the rate of its development; processes that impede the outflow of cerebrospinal fluid (tumors, adhesions) can lead to paroxysmal increases in intracranial pressure and are manifested by occlusive-hydrocephalic syndrome. Typical symptoms: intense constant headache, nausea, vomiting, congestion of the optic nerve papillae during ophthalmoscopy, autonomic disorders in the form of disturbances in the frequency and rhythm of breathing, heart rate and blood pressure. In case of acute increase (traumatic brain injury, tumors, cerebral edema) of intracranial pressure, dislocation of the brain and infringement of some of its parts (most often in the area of the tentorial and large occipital foramina) is possible with the appearance of brainstem symptoms, disruption of cardiovascular activity and respiration up to its cessation.

Causes of obstructive (non-communicating) hydrocephalus: stenosis of the aqueduct of Sylvius; Arnold-Chiari malformation (with or without myelodysplasia); Dandy-Walker malformation; atresia of the foramen of Monroe; anomalies of the bones of the skull base; space-occupying lesions (tumors, cysts); inflammatory ventriculitis (infection, hemorrhage, chemical irritation, cyst rupture).

Causes of communicating hydrocephalus: Arnold-Chiari malformation or Dandy-Walker syndrome (without blockage of the cerebrospinal fluid pathways); benign cysts; inflammation of the pia mater (viral and bacterial infections, subarachnoid hemorrhage with vascular malformations or injuries, including surgical, drug-induced arachnoiditis); carcinomatous meningitis.

Diagnostic criteria for hydrocephalus

Ventriculomegaly with signs of increased intracranial pressure (headache, vomiting, drowsiness, changes in muscle tone). The main paraclinical methods for confirming and assessing intracranial hypertension: ophthalmoscopy, measuring cerebrospinal fluid pressure, CT or MRI, as a rule, easily detect processes that limit space in the cranial cavity, developmental anomalies, signs of intracranial hypertension. Echoencephalography, angiography, and skull radiography are also used for these purposes.

Other causes of intracranial hypertension: cerebral edema (ischemic, toxic, radiation damage to the nervous system; excessive hydration); venous hypertension (superior or lateral sinus occlusion; sinus thrombosis; unilateral or bilateral occlusion of the internal jugular vein; superior vena cava obstruction; arteriovenous malformation; obesity; obstructive pulmonary disease); acute vascular disorders (ischemia, hemorrhage, hypertensive crisis, vasospasm); parainfectious and immunological disorders (Guillain-Barré syndrome; infections such as poliomyelitis, lymphocytic choriomeningitis; mononucleosis; HIV infection, Lyme disease; Sydenham's chorea; systemic lupus erythematosus; post-vaccination reactions); metabolic disorders (uremia, diabetic coma, iron deficiency anemia; hypercapnia); endocrinopathies (hypoparathyroidism; Addison's disease; Cushing's disease; thyrotoxicosis; menarche; pregnancy); nutritional disorders (hypervitaminosis A, hypovitaminosis A); intraspinal tumors (rare).

The cause of intracranial hypertension can be idiopathic intracranial hypertension (benign intracranial hypertension, Pseudotumor cerebri).

Diagnostic criteria for idiopathic intracranial hypertension:

• Elevated cerebrospinal fluid pressure (>200 mmH2O in non-obese patients and >250 mmH2O in obese patients).
• Normal neurological status except for paralysis of the sixth cranial nerve (n. abducens).
• Normal composition of cerebrospinal fluid.
• Absence of intracerebral space-occupying lesions.
• Bilateral papilledema. Rarely, increased CSF pressure may occur without papilledema.

Typical complaints of these patients: daily headaches (often pulsating), visual disturbances; visual field changes are possible. Most patients are obese women. "Pseudotumor" can coexist with obstructive sleep apnea.

Along with idiopathic intracranial hypertension, secondary "pseudotumor" occurs as a consequence of venous blood flow disorder and venous hypertension (chronic ear diseases, craniocerebral trauma, meningioma, heart failure, chronic lung diseases contribute to venous blood circulation disorder). Compression of the cavernous sinus (empty sella turcica, pituitary adenoma) can be the cause of secondary "pseudotumor". Hypoparathyroidism, adrenal insufficiency, estrogen imbalance contribute to the disease.

Differential diagnosis with diseases that may resemble "pseudotumor": sinus thrombosis, infectious lesions of the nervous system, malignant neoplasms. Tension headaches, migraines, abuse headaches and depression may also coexist with "pseudotumor". Lumbar puncture with measurement of cerebrospinal fluid pressure, neuroimaging and ophthalmoscopy are important for the diagnosis of benign intracranial hypertension.

Finally, intoxications can sometimes lead to the development of intracranial hypertension (phenothiazines, lithium, diphenin, indomethacin, tetracycline, sinemet, corticosteroids, gonadotropins, lithium, nitroglycerin, vitamin A, as well as herbicides, pesticides and some other substances).

Complications of intracranial hypertension are manifested by syndromes of infringement (wedge, herniation) of certain parts of the brain. Intracranial hypertension, when it increases in conditions of inflexibility of the skull bones, can lead to a shift of parts of the brain from their normal location and cause compression of some areas of brain tissue. Such a shift is most often observed under the falx, at the edge of the tentorial notch and in the foramen magnum. In such cases, the lumbar function can cause dangerous wedging and death of the patient.

Lateral displacement of the brain under the greater falx process leads to compression of one cingulate gyrus under the falx, which can be observed if one of the hemispheres increases in volume. The main manifestations are compression of the internal cerebral vein and anterior cerebral artery, which causes an even greater increase in intracranial pressure due to a decrease in venous outflow and the development of cerebral infarction.

Displacements under the cerebellar tentorium can be unilateral or bilateral and are manifested by compression of the midbrain (the so-called secondary midbrain syndrome).

Unilateral transtentorial herniation occurs when the enlarged temporal lobe causes the uncus of the hippocampus to protrude into the tentorial notch. This picture often accompanies subfalx entrapment. Consciousness is usually reduced before entrapment and continues to deteriorate as brainstem compression increases. Direct pressure on the oculomotor nerve causes ipsilateral pupillary dilation (loss of parasitic innervation to the pupil). Sometimes the contralateral pupil also dilates because dislocation of the entire brainstem results in compression of the opposite oculomotor nerve at the edge of the tentorial notch. Contralateral homonymous hemianopsia develops (but it cannot be detected in an unconscious patient) due to compression of the ipsilateral posterior cerebral artery. With further compression of the midbrain, both pupils become dilated and fixed, breathing becomes irregular, blood pressure increases, the pulse slows, decerebrate seizures develop, and death may occur due to cardiorespiratory collapse.

Bilateral (central) transtentorial herniation is usually caused by generalized cerebral edema. Both hemispheres tend to move downwards: both the diencephalon and midbrain are displaced caudally through the tentorial opening. Clinical manifestations include impaired consciousness, constriction and then dilation of the pupils; impaired upward gaze (elements of the quadrigeminal syndrome); irregular breathing, impaired thermoregulation, decerebration or decorticate seizures, and death.

Increased pressure in the posterior cranial fossa may cause upward displacement of the cerebellum and its infringement at the edge of the tentorial notch or lead to downward displacement of the cerebellum (more common) and infringement of its tonsils in the foramen magnum. Upward displacement leads to compression of the midbrain (paresis of upward gaze, dilated or fixed pupils, irregular breathing).

The downward displacement of the cerebellum causes compression of the medulla oblongata (impaired consciousness is absent or occurs secondarily, there is pain in the occipital region, paresis of upward gaze, and paralysis of the caudal cranial nerves with dysarthria and swallowing disorder); weakness in the arms or legs with symptoms of damage to the pyramidal tract and impaired sensitivity of various modalities below the head (foramen magnum syndrome) are observed. One of the earliest manifestations of cerebellar herniation into the foramen magnum is rigidity of the neck muscles or tilting the head to reduce pressure in the foramen magnum area. Breathing stops suddenly.

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Variants and symptoms of herniation syndrome

Herniation of the medial surface of the cerebral hemisphere under the falx vertebrae (semilunar herniation)

In this case, part of the cingulate gyrus is displaced into the free gap formed below by the corpus callosum and above by the free edge of the falx corpora. As a consequence, there is compression of the small arterial vessels that feed the specified area of the brain, the anterior cerebral artery ipsilateral to the tumor focus, as well as the great cerebral vein. The cause of this type of dislocation is the presence of a volumetric pathological process in the frontal, parietal, and less often in the temporal lobe. Most often, dysfunction of the cingulate gyrus does not have pronounced clinical manifestations.

Temporotentorial herniation

Asymmetric displacement of the mediobasal structures of the temporal lobe (parahippocampal gyrus and its hook) into the Bandt's fissure between the edge of the notch of the tentorium cerebelli and the brainstem. Occurs as the next stage in the development of dislocation syndrome in tumors of hemispheric localization. Accompanied by compression of the oculomotor nerve, downward displacement of the posterior cerebral artery, and pressing of the midbrain tentorial opening to the opposite edge. In this case, the ipsilateral pupil initially narrows, then gradually expands to the state of fixed mydriasis, the eye deviates outward and ptosis develops. Later, gradual dilation of the pupil on the opposite side and impaired consciousness occur. Motor disorders such as central teme- and then tetraparesis develop. Alternating Weber syndrome is observed. Occlusive hydrocephalus develops. Decerebrate rigidity may occur.

Cerebellotentorial herniation

It occurs infrequently, with a marked increase in pressure in the posterior cranial fossa (in particular, with cerebellar tumors) and is characterized by the displacement of cerebellar tissue through a gap in the aperture of the tentorial opening into the middle cranial fossa. The superior cerebellar peduncles, the superior medullary velum, the midbrain roof plate, and sometimes the cerebral aqueduct and subarachnoid cisterns of the middle cranial fossa on the side of the herniation are subject to compression. Clinically, this is manifested by the onset of a comatose state, paralysis of upward gaze, narrowing of fixed pupils with preserved lateral oculocephalic reflexes, and signs of occlusive hydrocephalus.

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Herniation of the cerebellar tonsils into the cervicodural infundibulum

The herniation of the cerebellar tonsils into the cervicodural funnel most often occurs with volumetric processes in the subtentorial space. In this case, the cerebellar tonsils are displaced in the caudal direction and herniated between the edge of the foramen magnum and the medulla oblongata, which inevitably leads to ischemia of the latter, respiratory failure, cardiac regulation, and, as a consequence, the death of the patient.