Cerebral arachnoiditis

Introduction to brain arachnoiditis Cerebral arachnoiditis, also known as serous meningitis, focal adhesion arachnoiditis, is caused by infection, trauma, foreign body stimulation and other factors leading to arachnoid inflammation, adhesions or cyst formation. More common in young adults, often insidious onset, slow progressive development, there may be multiple relief and aggravation, there are also acute or subacute onset. Brain inflammatory disease with clinical manifestations of increased intracranial pressure and localized localization. basic knowledge Sickness ratio: 0.0001% Susceptible people: no special people Mode of infection: non-infectious Complications: septic shock

Causes of brain arachnoiditis

Infection (40%):

(1) Intracranial infection: various types of meningitis caused by infections such as bacteria, viruses and parasites, meningitis, abscess, etc. may cause arachnoiditis, of which tuberculous meningitis is the most common cause .

(2) extracranial infection: otitis media, mastoiditis, paranasal sinusitis is a common cause, in addition, facial infection, pelvic inflammatory disease, stomatitis, etc. can also become a causative factor.

Pathogenesis (20%):

The main lesions are localized or multiple thickening and adhesion of arachnoid and soft membrane. Some brain tissue, cerebrovascular, ependymal membrane, etc. can be combined with local arachnoiditis, which can be divided into three types:

1. Spotted arachnoid membrane is thickened, turbid, with white spots or patterns. The arachnoid membrane does not adhere to adjacent brain tissue, and the subarachnoid space is unobstructed. This type is common in arachnoiditis.

2. Adhesive arachnoid not only has irregular thickening, but also has a cord-like or flaky adhesion between the adjacent pia mater, cerebrovascular, brain surface and cranial nerve. Adhesion can be widely confined, so that the subarachnoid space is not Unobstructed or occluded.

3. Cyst-type arachnoid adhesions form cysts, containing clear or yellow-green cystic fluid, sometimes forming a gap or gradually increasing, easy to oppress brain tissue and cranial nerves.

The common histological changes of these three types are: small round cells and inflammatory cell infiltration, arachnoid endothelial cell proliferation, and fibrosis of the reticular layer, which destroys the normal structure of the arachnoid membrane.

Head injury or surgery (10%):

Head injury or surgery is also an important cause of brain arachnoiditis.

Some intrathecal drugs (10%):

Antibiotics, antitoxins, anesthetics, contrast agents and subarachnoid hemorrhage may be pathogenic factors.

Primary intracranial lesions (10%):

Such as brain tumors, demyelinating diseases and cerebral arteriosclerosis can be associated with local arachnoiditis.

Brain arachnoiditis prevention

Control intracranial and extracranial infections, actively prevent and treat various brain injury, and reduce intrathecal injection of drugs, all help to prevent brain arachnoiditis.

Cerebral arachnoiditis complications Complications septic shock

Because arachnoiditis itself is an inflammatory reaction, therefore, ventricular-peritoneal shunt surgery, there may be infection, infection may be surgical infection, postoperative infection, and most infections around 6 months after surgery, a small number can occur After 1 year, the infection may be caused by the distal abdominal cavity, retrograde infection in the chest, blood-borne infection or inflammation in the brain. In short, once the infection occurs, the shunt tube must be temporarily removed for anti-inflammatory treatment, and the cerebrospinal fluid in the tube is taken out. Bacterial culture and drug susceptibility test and centrifugation for smear, as the basis for future treatment, the bacteria infected by the shunt are mostly Staphylococcus, followed by Staphylococcus aureus, others such as Gram-negative bacilli, Streptococcus and so on.

Cerebral arachnoid inflammation symptoms common symptoms sensory disorder hydrocephalus intracranial pressure increased urine collapse hemianopia partial sensation disorder arachnoid adhesion dull pain focal symptoms chronic headache

Can be expressed as acute, subacute or chronic disease, patients with varying degrees of fever and systemic symptoms, because the main site of brain arachnoiditis is posterior cranial fossa, chiasm and cerebral hemisphere convex, etc., have the following clinical features:

1. Acropititis of the optic chiasm is the most common type of arachnoiditis at the base of the brain. Inflammation mainly invades the intracranial segment of the optic nerve and around the optic chiasm, forming a dense or fine connective tissue network that surrounds it, often showing paleness and ischemia. Atrophic state, difficult to separate from the surrounding structure, it is not uncommon to form arachnoid cysts with oppressed nerves at the optic chiasm. Patients often have a history of paranasal sinusitis, and a few have a history of anterior cranial fossa fractures. Obviously, the earliest and main symptoms are chronic headache and visual impairment. The headache is mostly in the forehead, ankle or eyelids, often accompanied by a slow progressive vision loss. After a few months, it affects the contralateral side, and a few sides are simultaneously reduced. Most of the optic nerves involved are less, and most of the visual acuity declines early and develops rapidly. It is often repeated. After treatment with anti-inflammatory drugs, it can be improved. In the case of fatigue, cold, paranasal sinusitis, and excessive drinking, Gradually worsened, severe cases of blindness within 1 to 2 weeks, visual defects, due to adhesions damage to the location and extent of the optic nerve, the field of vision can appear diversified and atypical changes, It is characterized by early dark spots in the center or dark spots in the center, irregular peripheral vision, such as a narrowing of the centripetal field of vision, atypical changes such as hemianopia on both sides and narrowing of the nasal field. The fundus examination may be unchanged in the early stage, and the primary appears gradually. Sexual or secondary optic atrophy, optic discitis and one side of the primary optic atrophy and the other side of the optic disc edema, the wider brain arachnoiditis, there may be signs of I ~ VI cranial nerve damage, a few Patients with thalamic involvement may have symptoms such as diabetes insipidus, narcolepsy, obesity, and sexual dysfunction.

2. Posterior fossa arachnoiditis This area of arachnoid adhesion is very common, accounting for about one-third of all arachnoiditis, and the ratio of the posterior fossa tumor is about 7:1, posterior fossa arachnoiditis is easy to make Cerebrospinal fluid circulatory disorders, causing symptoms of increased intracranial pressure, according to different parts of the lesion, can be divided into three types:

(1) midline type: the most common in the posterior fossa, the main adhesion lesions in the median hole, lateral hole, occipital pool and occipital macropore area, the most likely to cause obstructive hydrocephalus and early intracranial hypertension symptoms, patients Early headache is significant, followed by vomiting and vision loss, neurological examination in addition to optic disc edema or secondary atrophy, nerve palsy, neck stiffness and other symptoms and signs of increased intracranial pressure, limited symptoms are not obvious, but the incidence It is faster, the condition is heavier, and there is less relief.

(2) Cerebellar convex type: the course of disease is slow, generally about 1 to 3 years. The cyst formed by arachnoiditis can oppress the cerebellar ataxia and nystagmus in the cerebellar hemisphere, but not as significant as the cerebellar tumor.

(3) Cerebellar pons: The main lesions are in the ventral region of the brainstem, often with different degrees of cranial nerve damage, including trigeminal nerve, facial nerve, auditory nerve insufficiency paralysis and hemifacial spasm, ipsilateral cerebellar ataxia and eyeball The tremor is mild or absent. The symptoms of increased intracranial pressure appear later. When the inflammation sticks to the jugular foramen, there may be signs of ipsilateral pharyngeal, vagus and accessory nerve damage. This type of disease develops slowly, symptoms It can be relieved in a longer period of time, and the course of disease can last for several years.

3. Cerebral hemispherical convex arachnoiditis inflammatory lesions often around the lateral cerebral palsy, a few between the cerebral hemisphere, anterior or upper cerebral surface, the earliest main symptoms are headache, seizures or mental symptoms, headaches are persistent Diffuse dull pain, the degree is mild, epilepsy is mostly localized seizures, rarely hemiplegia, partial sensory disturbances, aphasia and other symptoms, even if it is present, optic disc edema is less common, the general course is longer, the development is slow, When the time is good or bad, for months to years, the increase in intracranial pressure appears slower and is much lighter than the posterior cranial fove.

Examination of brain arachnoiditis

The lumbar puncture can be normal in the early stage. Most patients have mildly elevated cerebrospinal fluid pressure. The pressure of hydrocephalus is significantly increased. The number of cerebrospinal fluid cells in the acute phase is slightly increased (50×106/L or less). The chronic phase can be normal, and the protein quantification can be slightly increased.

1. Skull X-ray film can show signs of chronic intracranial hypertension or normal.

2. CT scan can show local cystic low-density changes, ventricular system shrinkage, normal or consistent expansion, scanning can exclude other intracranial space-occupying lesions.

3. MRI scan on the skull base, posterior cranial fossa showed clearer than CT, and can exclude other intracranial space-occupying lesions.

Diagnosis and differentiation of brain arachnoiditis

Diagnostic criteria

Cerebral arachnoid encephalitis often has different causes, different causes, clinical manifestations, and atypical. It is not easy to diagnose according to clinical manifestations. It is necessary to rely on auxiliary examination to confirm the diagnosis, but it also has its characteristics and is helpful for diagnosis.

1. Patients often have primary causes of arachnoiditis such as intracranial, extracranial infection, craniocerebral injury and surgery, subarachnoid hemorrhage.

2. The onset can be acute, subacute, gradually becoming chronic, or chronic, with a long course of disease, repeated, relieved, can be induced by colds, infections, fatigue, etc.

3. The focal symptoms are mild or multifocal, and can also be diffuse, so the symptoms are variable.

Differential diagnosis

1. The posterior cranial fossa midline arachnoiditis must be differentiated from the tumor in this area. The posterior cranial fossa midline tumors include cerebellar sac tumors, fourth ventricle tumors, children are common, and often malignant medulloblastoma, the symptoms develop rapidly. The condition is serious, and there may be signs of brain stem compression and bilateral pyramidal tract signs.

2. Arachnoiditis of the cerebellopontine angle and the tumors in this area. The tumors in this area are mostly acoustic neuromas. In addition, there are meningioma and epidermoid cysts, such as acoustic neuroma and meningioma. Early symptoms of auditory nerve damage can occur, followed by facial nerves. Trigeminal nerve and cerebellar damage symptoms, epidermal cysts often appear in the early symptoms of trigeminal neuralgia, skull X-ray film, acoustic neuroma can occur in the internal auditory canal destruction and expansion, meningioma can have rock bone destruction and calcification, CT or MRI scan can be Determine the diagnosis.

3. Arachnoiditis at the intersection of the gods and the tumors in this area. The most common tumors in this area are pituitary adenomas and craniopharyngioma. Most of the pituitary adenomas have early endocrine disorders, and the fundus and visual field changes are typical. Craniopharyngioma More common in children, X-ray plain saddle may have calcification, there are saddle nodular meningioma in this area, manifested as optic nerve chronic compression of vision loss and visual field disorder, late appearance of primary optic atrophy, these lesions by CT and MRI scans can display their unique lesions and can be used for identification and definitive diagnosis.

4. Cerebral hemispherical convex arachnoiditis and cerebral hemisphere superficial glioma, hemangioma, metastasis and tuberculosis and other lesions. Most of these lesions can be diagnosed by CT or MRI scan.

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