Damage around the aqueduct

Introduction The fourth ventricle is connected to the midbrain aqueduct, and the lower end is connected to the subarachnoid space by a side hole. The position is equivalent to the cerebral angle of the cerebellar bridge, and the middle hole is connected with the occipital pool. The fourth ventricle receives cerebrospinal fluid from the third ventricle through the midbrain aqueduct, and flows through the mesopores or lateral orifices into the subarachnoid space, and then enters the venous system through the arachnoid granules. The bottom of the fourth ventricle is rhomboid, and the nucleus of the pons and medulla are more adjacent to this, such as the sublingual nucleus of the medulla, the dorsal nucleus of the vagus nerve, the cochlea and the vestibular nucleus; the facial nucleus of the pons, the trigeminal nucleus and Trigeminal sensory nucleus, etc. Progressive damage to the gray matter around the aqueduct may be a prolongation of headache time and the conversion of paroxysmal migraine into a chronic migraine. When a tumor occurs in the fourth ventricle, the circulation of the cerebrospinal fluid is firstly blocked. When the tumor spreads to the periphery of the cerebral ventricle or the surrounding tissue is compressed, the corresponding clinical symptoms are generated, that is, the corresponding clinical symptoms are generated, mainly the cranial nerve damage. symptom.

Cause

When a tumor occurs in the fourth ventricle, the cerebrospinal fluid circulation is first blocked. When the tumor spreads to the periphery of the cerebral ventricle or the surrounding tissue is compressed, the corresponding clinical symptoms are generated, that is, the corresponding clinical symptoms are generated, mainly the symptoms of cranial nerve damage. . Most of the tumors originating in the fourth ventricle are choroidal papilloma. Tumors originating from the ventricular wall not only invade the fourth ventricle, but also often invade the brain stem or cerebellum, such as ependymoma and hemangioblastoma. Tumors at the top of the ventricles are mostly found in the cerebellum of the cerebellum, with medulloblastoma mostly. The fourth ventricle tumor occurs mostly in children and young people.

an examination

Related inspection

Brain ultrasound examination of brain CT

1. Increased intracranial pressure

The course of the fourth ventricle tumor is generally short, and intracranial hypertension can occur in the early stage. This is because the cerebrospinal fluid circulation is caused by obstruction of the tumor. The first symptom of almost all patients is headache caused by increased intracranial pressure, accompanied by nausea and vomiting, and some patients have dizziness at the same time. More headaches than the back of the occiput. Headache, vomiting and dizziness caused by the fourth ventricle tumor are mostly volatility, showing intermittent episodes, which can be induced by changes in head position and body position. Thus, the patient often maintains a special posture, the so-called compulsive head position, where the patient can flex the head forward or backward, or flex to the sides to reduce the onset. A small number of patients often stimulate the nerve nucleus at the end of the fourth ventricle due to changes in head position and position, resulting in corresponding clinical symptoms such as dizziness, headache, vomiting, diplopia, nystagmus and changes in vital signs, etc. coma. Intraventricular tumors have a large degree of activity. When the midbrain aqueduct, mesopore and lateral holes are not obstructed, the patient does not have symptoms of increased intracranial pressure such as headache and vomiting. When the head or body position changes, the tumor is in the ventricle. Movement, suddenly blocked the cerebrospinal fluid circulation pathway, so patients with episodes of increased intracranial pressure, severe intracranial pressure will lead to cerebellar crisis and cerebral palsy.

2. Chronic occipital foramen

Due to the compression and continuous growth of the tumor, the extrusion of the brain tissue is aggravated, and the long-term intracranial pressure is increased, which causes the cerebellar tonsils to swell out to the occipital foramen, and the corresponding clinical symptoms appear. However, the patient's condition is generally better. The cerebellar tonsils that are pulled out can be edema and edema, compressing the medulla and the upper cervical cord, but the patient's general symptoms are not obvious or only mild clinical symptoms. Due to the ciculus of the cerebellar tonsil, the fourth ventricle can be blocked, and the intracranial pressure is further increased, which in turn can exacerbate the degree of cerebral palsy. Most of the chronic occipital foramen occlusal adhesions are difficult to reset.

(1) Pain in the occipital region: The cerebral ventricle, the blood vessel, and the upper cervical nerve root are stimulated by the sputum, causing pain in the occipital region. This pain is a radiation pain from the upper neck to the occiput. There is often tenderness in the lower part of the patient's pillow.

(2) Neck stiffness and forced head position: Because the brain tissue that is pulled out oppresses the medulla and the upper cervical spinal cord, the neck muscles produce a protective reflex, causing paralysis and keeping the head in a fixed position. In order to avoid changes in the head position, the symptoms are aggravated. The rigidity of the neck is often on the side of the lesion or on the severe side of the sputum, but the degree of sputum sputum on both sides is generally almost equal, so most patients have the same degree of cervical muscle spasm.

(3) When the occipital foramen magnum, because the posterior group of cranial nerves are pulled, the patient has clinical manifestations of damage to the group of cranial groups, such as dysphagia and hearing loss.

(4) Acute exacerbations may occur on the basis of chronic occipital foramen magnum, resulting in a sharp increase in intracranial pressure, a change in vital signs in the medulla oblongata, and death from respiratory and circulatory failure.

3. Cerebellar symptoms

Cerebellar symptoms occur when the tumor grows backwards or invades the cerebellum or cerebellum. Due to the coordination function between the cerebellar muscles, the patient has an ataxia, which is characterized by walking squats, unstable gait, and often dumping to the side of the disease and the rear. The patient's muscle tone is reduced, the posture of the limb is abnormal, and the affected limb has a large and irregular tremor, that is, intentional tremor. In addition to the above symptoms, cerebellar damage is often accompanied by horizontal, vertical, and rotational tremors of the eyeball.

4. Brain stem symptoms

Brainstem symptoms refer to the symptoms of cranial nerves caused by tumors invading the fourth ventricle and causing stimulation or destruction of the cerebral nucleus of the medullary pons. The fourth ventricle tumor with brainstem symptoms as the first symptom is relatively rare. When the upper part of the fourth ventricle is damaged, the patient's intracranial pressure increases earlier, mainly manifested as dizziness, nystagmus, forced head position, and some patients have hearing loss. , facial paralysis, facial dysfunction, chewing weakness, abductor nerve paralysis. The lower part of the fourth ventricle is damaged, causing IX, X, XI, and XII to be involved in the cerebral nucleus. Patients may experience vomiting, hiccups, difficulty swallowing, hoarseness, and cardiovascular and respiratory disorders. The tumor in the lower part of the fourth ventricle, the symptoms of increased intracranial pressure appear earlier, and the long tract sign of the brain stem caused by the occipital foramen magnum, the patient feels and the movement is impaired, which is characterized by soft legs and easy fall. The sputum reflexes sometimes lead to pathological reflexes.

5. Optic nerve nipple changes

Because the tumor is easy to block the cerebrospinal fluid circulation pathway, the intracranial pressure is increased, resulting in optic nerve head edema, which shows that the boundary is unclear, the physiological depression disappears, and the optic nerve secondary atrophy occurs for a long time, and the patient's vision is reduced or even blind.

Differential diagnosis

Differential diagnosis of damage around the aqueduct:

(a) fourth ventricle colitis

Fourth ventricle cysticercosis occurs due to cystic obstruction of the mesopores or the lower mouth of the midbrain aqueduct, resulting in increased intracranial pressure. Cerebral cysticercosis is usually multiple, cysticercosis is not only located in the ventricles, but more in the cortex or subcortical structures. There are often seizures. Patients usually eat infected pork or go to endemic areas. Multiple nodules are often seen under the skin, and cysticercosis is often found in subcutaneous nodule resection. Both cerebrospinal fluid and blood complement fixation tests were positive. Ventricular angiography showed a uniform expansion of the ventricles, and soft tissue shadows or filling defects in the fourth ventricle.

(2) posterior fossa arachnoiditis

Patients often have brain adjacent parts, brain tissue or systemic infections, and patients with acute infection have increased body temperature and mild intracranial pressure. Generally, there is a long period of remission, and the symptoms may be aggravated by a cold or fatigue. In arachnoiditis, the midbrain aqueduct can be narrowed or occluded, and the fourth ventricle and the occipital pool are simultaneously cohesive, causing cerebrospinal fluid circulation disorder, and intracranial hypertension, clinical manifestations of headache, nausea, vomiting, and visual Nipple edema. If the brain stem is involved, there are often symptoms of cranial nerve involvement in the posterior group, but there are generally no symptoms of brain lesions. Most of the disease progresses quickly and severely, with a high mortality rate. Lumbar puncture examination increased the number of cerebrospinal fluid cells and increased intracranial pressure. The flat skull showed signs of increased intracranial pressure. The subarachnoid space and occipital pool of the cerebral ventricle were not filled. The ventriculography showed that the ventricular system above the midbrain was enlarged.

(c) cerebellar tuberculosis

Tuberculoma can be single or multiple, and is more common in children and young people. In addition to tuberculoma in the posterior cranial fossa, there are active tuberculosis lesions in the body. The patient is generally in poor condition and has symptoms of systemic tuberculosis, which is characterized by low fever, night sweats, flushing and wasting. Some patients may have tuberculous meningitis symptoms and meningeal irritation. Single tuberculosis, patients with obvious cerebellar symptoms, dysfunctional movement, nystagmus, cerebellar rigidity in severe cases, a small number of patients with symptoms of tuberculosis, most patients generally better. Lumbar puncture examination, cerebrospinal fluid pressure is high and contains protein, but the number of cells and sugar content is normal.

(four) cerebellar abscess

Often due to otitis media or mastoiditis caused by inflammation of the posterior wall of the tympanic cavity, and upward development led to cerebellar abscess, and less blood-borne. Patients with cerebellar abscess usually have symptoms of primary lesions and symptoms of systemic infection, which are characterized by fever, chills, increased white blood cells, and increased erythrocyte sedimentation rate. At the same time, the patient's intracranial pressure increased, headache, nausea and vomiting. Significant cerebellar signs, manifested as ataxia, gait sputum, decreased muscle tone and forced head position, sometimes can appear in the posterior group of cranial nerve symptoms. Ventricular angiography shows that the fourth ventricle deformation and displacement is of great value for diagnosis.

(5) Cerebellar hemisphere tumors

Most patients with cerebellar hemisphere tumors have increased intracranial pressure, and often have headache as the first symptom. The pain is often located in the posterior occipital region, accompanied by nausea and vomiting. The headache is more frequent, optic nerve head edema, vision loss, and some may appear double vision. . Ataxia (bomb upper and lower limbs), nystagmus, dizziness, etc. due to impaired cerebellar hemisphere. The tumor develops to the lateral side and causes damage to the cranial nerve. Common symptoms include trigeminal nerve, facial nerve, auditory nerve and glossopharyngeal nerve. Clinical symptoms appear as facial sensory disturbance, hearing loss and cough. The brain stem is invaded by a long bundle. Long-term high intracranial pressure and continuous growth of the tumor produce occipital foramen magnum, and the patient appears to be a forced head position. Ventricular angiography showed deformation, displacement, and filling defects in the fourth ventricle.

(6) cerebellar sac tumor

The cerebellar sac tumor tends to block the cerebrospinal fluid circulation pathway and cause increased intracranial pressure. The patient has headache, nausea and vomiting and optic nerve head edema, which is also the main symptom of cerebellar sac tumor. Due to the small volume of the cerebellar vermis, the cerebellar hemisphere is pushed to both sides when the tumor occurs, and the cranial nerve (IV, VI, VII, VIII to the cranial nerve) is damaged, and the ataxia after the cerebellar carcass is damaged is the trunk. Ataxia, sometimes nystagmus. The cerebellar sacral tumor is highly prone to occipital foramen magnum. The bilateral cerebellar tonsils are symmetrical into the occipital foramen. The patient has a forced head position, and the head is often tilted forward. Some patients often have a knee-chest position. Ventricular angiography can determine the diagnosis.

(7) Brain stem tumor

Brain stem tumors occur mostly in children, mostly in gliomas. Clinical manifestations include increased intracranial pressure, conscious and mental disorders, and focal lesions. Increased intracranial pressure usually occurs in the late stage, but the midbrain tumor is especially located in the covered part. Due to the compression of the midbrain aqueduct, the intracranial pressure may increase at an early stage. Due to damage to the brainstem network, the patient develops sleepiness, apathy, and even coma. The most prominent focal symptoms after brain stem injury are cross palsy, followed by cranial nerves, pyramidal tracts, and cerebellar damage. Patients with hearing loss, difficulty swallowing, paralysis, ataxia, and nystagmus. Cerebrospinal fluid examination has increased pressure and increased protein content. Occasionally, the bone of the skull is damaged by the internal auditory canal. The ventricle angiography shows a consistent enlargement of the ventricle, and the third ventricle often has a filling defect. The vertebral artery angiography shows the displacement of the posterior cerebral artery and the superior cerebellar artery.

(8) Cerebellar ganglion tumor

The cerebral ganglion tumors of the cerebral pons are mostly acoustic neuromas, followed by epithelioid cysts and meningioma. Clinical manifestations of cerebellar cerebral horn syndrome, dysfunction after trigeminal nerve, auditory nerve, facial nerve, abductor nerve, glossopharyngeal nerve, vagus nerve, hypoglossal nerve and cerebellar injury. There is a shift in the brain stem pressure and an increase in intracranial pressure in the late stage. The patient will have persistent tinnitus, progressive deafness, facial numbness, loss of corneal sensation, difficulty swallowing, hoarseness, etc. Hey, speech is unclear, ataxia, and intraocular tilt. A small number of patients may have mild hemiplegia and hemiplegia.

1. Acoustic neuroma: Acoustic neuroma occurs mostly in middle-aged and elderly people, and is mostly female. The first episode is the stimulation and destruction of the auditory nerve, which is characterized by high-pitched tinnitus, followed by hearing loss, dizziness, nausea, vomiting and nystagmus. Due to the compression and invasion of the tumor, patients V, VII, IX, X have dysfunction on the cranial nerve, which is characterized by corneal sensation, facial numbness, chewing weakness, difficulty in swallowing and hoarseness. A few patients have pain in the trigeminal nerve distribution area. Ataxia can occur in patients with impaired cerebellum. The X-ray skull shows an enlargement of the internal auditory canal or bone destruction.

2. The cerebellopontine angle epithelioid cyst: its incidence is second only to acoustic neuroma in the cerebellopontine angle tumor, which occurs in young and middle-aged people. Clinical manifestations of cranial nerve damage symptoms, which are more common in patients with trigeminal neuralgia, manifested as the second branch of the trigeminal nerve, the third branch of the area burning or electro-shock-like pain, there is a trigger point. Secondly, the patient may have tinnitus, deafness and unstable walking. A small number of patients have symptoms of pharyngeal and vagus nerve damage such as difficulty swallowing and hoarseness.

(9) large occipital tumor

Meningiomas and neurofibroma are more common, and the tumor originates from the periphery of the foramen magnum or the upper part of the spinal canal. Most of the patients are adults. After the early stage of the disease, the occipital and upper neck pains and radiate to the top. When the force or cough is aggravated, the patient has neck stiffness and forced head position. There may be physical activity disorders, which often start from one limb and develop to other limbs. Some begin with double upper limbs or lower limbs, and some may have spinal cord hemisection, which manifests different degrees of hemiplegia on the same side. Sensory disturbance of the lateral limbs and atrophy of the shoulder muscles. In the late stage, there is increased intracranial pressure and cranial nerve damage. Commonly, XI, IX, and X brain damage are common. Secondly, trigeminal nerve and facial nerve damage can be seen. Patients may have hiccups, nystagmus, ataxia, dizziness, and cervical sympathetic paralysis. The increase of protein content in cerebrospinal fluid examination is helpful for diagnosis. The X-ray film of the skull shows hyperplasia or destruction of the bone around the occipital foramen, and the lamina and vertebral arch of the upper cervical segment can also be destroyed. Brain CT examination is helpful for diagnosis.

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