I. Classification
According to the etiology and source of infection, it can be divided into four categories:
(1) Ear-nose-brain abscess: Ear-brain abscess is the most common, accounting for about 2/3 of brain abscess. It is secondary to chronic suppurative otitis media and mastoiditis. The infection system goes through two ways: (1) inflammation erodes the tympanic lid and the tympanic wall, and spreads to the brain through the dura blood vessels, often occurring in the temporal lobe, and a few in the parietal lobe or occipital lobe; (2) Inflammation invades the cerebellum through the top of mastoid cavity, petrosal posterior wall, dura mater or lateral sinus vessels. Nasal brain abscess is caused by purulent infection of adjacent sinuses invading the brain. Such as frontal sinusitis, ethmoid sinusitis, maxillary sinusitis or sphenoid sinusitis, the infected transcranial basal canal spreads to the brain, and abscesses mostly occur in the front or bottom of the frontal lobe.
(2) Hematogenous brain abscess: about 1/4 of brain abscess. Most of them are caused by infections in other parts of the body, and bacterial embolus spreads to the brain through arterial blood to form brain abscess. Primary infection focus is common in purulent infection of lung, pleura and bronchus, congenital heart disease, bacterial endocarditis, skin furuncle and carbuncle, osteomyelitis, infection of abdominal cavity and pelvic organs, etc. Brain abscesses are mostly distributed in the blood supply areas of middle cerebral artery, frontal lobe and parietal lobe, and some of them are multiple small abscesses.
(3) Traumatic brain abscess: mostly secondary to open brain injury, especially in wartime accompanied by penetrating brain injury or incomplete debridement. Pathogenic bacteria directly invade the skull through wounds or foreign bodies and bone fragments to form brain abscess. It can appear early after injury, or the symptoms of brain abscess can only appear months or years after injury because of the low toxicity of pathogenic bacteria.
(4) Cryptogenic brain abscess: When the primary infection focus is not obvious or hidden, and the body's resistance is weak, the hidden bacteria in the brain parenchyma gradually develop into brain abscess. Cryptogenic brain abscess is essentially a occult blood-borne brain abscess.
Second, the disease.
The formation of brain abscess is a continuous process, which can be divided into three stages:
(1) Acute meningitis and encephalitis stage: After the purulent bacteria invaded the brain parenchyma, the patients showed obvious systemic infection reaction and pathological changes of acute localized meningitis and encephalitis. The center of encephalitis is gradually softened and necrotic, and many small liquefaction areas appear, and the surrounding brain tissue is edema. When the lesion is superficial, meningitis may occur.
(2) purulent stage: the softening focus of encephalitis is necrotic, liquefied and fused to form an abscess, which gradually increases. If the fused small pus cavity is separated, it will become a multilocular brain abscess and the surrounding brain tissue will be edema. Signs of systemic infection in patients have improved and stabilized.
(III) Capsule formation period: Generally, after 1 ~ 2 weeks, granulation tissue around the abscess is initially formed by the proliferation of fibrous tissue and glial cells, and the abscess capsule is completely formed in 3 ~ 4 weeks or more. The speed of envelope formation is related to the type and toxicity of pathogenic bacteria, physical resistance and response to antibiotic treatment.
Third, clinical manifestations
Patients with brain abscess generally show three signs: acute systemic infection, increased intracranial pressure and localized lesions.
(1) Symptoms of systemic and intracranial infection: In addition to the symptoms of primary infection, the patient showed symptoms of systemic and intracranial infection such as fever, headache, vomiting, lethargy, general weakness and neck resistance at the initial stage of the lesion.
(2) Symptoms of increased intracranial pressure: The symptoms of clinical acute meningitis gradually subside, but with the formation of the capsule of brain abscess and the increase of abscess, the intracranial pressure increases again and intensifies, which may even lead to the formation of brain hernia or the rupture of abscess, which makes the condition deteriorate rapidly. Severe patients may die if they are not treated in time.
(3) Symptoms of focus: According to the nature and location of brain abscess, there are different symptoms of focus location. Due to the serious inflammation and edema of brain tissue around brain abscess, local symptoms often appear earlier and more obvious.
Fourth, diagnosis
(1) Clinical features: According to the patient's history of primary purulent infection and open craniocerebral injury, then acute purulent meningitis, encephalitis and limited symptoms accompanied by headache, vomiting or papilla edema should be considered.
(2) X-ray photograph: X-ray plain film can show the infected focus of skull, sinus and mastoid. Occasionally, the abscess wall is calcified or the calcified pineal gland shifts to the opposite side. Traumatic brain abscess shows intracranial bone fragments and metal foreign bodies.
(3) Ultrasonic examination: The method is simple and painless. Supratentorial abscess can move the midline wave to the opposite side, and infratentorial abscess can often be measured by ventricular wave expansion.
(4) Cerebral angiography: Carotid angiography is of great value in the location and diagnosis of supratentorial abscess. According to the displacement of cerebral vessels and the presence or absence of blood vessels in the abscess area, the abscess site can be judged.
(5) Computed Tomography (CT) and Magnetic Resonance Imaging (MRI): Since CT and MRI were applied in clinic, great breakthroughs have been made in the diagnosis of intracranial diseases, especially space-occupying lesions. CT can show high-density annular zone around brain abscess and low-density changes in the center. MRI is more accurate in showing the location, size and shape of abscess. Because MRI is not affected by bone artifacts, the accuracy of infratentorial lesions is better than that of CT. CT and MRI can accurately show multiple and multilocular brain abscesses and their surrounding tissues.
Verb (abbreviation of verb) processing
The management principle of brain abscess is: active anti-inflammatory and brain edema control treatment should be carried out before the abscess is completely limited. After abscess formation, surgery is the only effective treatment.
(1) Anti-infection: According to different kinds of pathogenic bacteria of brain abscess, we should choose the corresponding bacterial sensitive antibiotics. If the culture of bacteria in the primary focus is not detected or negative, antibiotics with broad antibacterial spectrum and easy to pass through the blood-brain barrier should be selected according to the condition. Commonly used penicillin, chloramphenicol and gentamicin.
(2) Treatment of reducing intracranial pressure: Intracranial pressure is increased due to brain edema, and mannitol and other hypertonic solutions are often used for rapid intravenous drip. Hormones should be used with caution to avoid weakening the body's immune ability.
(3) Operation
1. Puncture and aspiration of pus: This method is simple and easy, with little damage to brain tissue. It is suitable for patients with large abscess, thin abscess wall, abscess deeper than or located in important functional areas of the brain, infants, the elderly or the infirm who can't stand surgery, and patients with critical illness who take puncture and pus aspiration as emergency treatment measures.
2. Continuous catheter drainage: In order to avoid repeated puncture or inflammatory diffusion, a soft hose with an inner diameter of 3 ~ 4 mm was inserted into the abscess cavity for the first time, and pus was pumped, washed and injected with antibiotics or contrast agent regularly to understand the shrinkage of the abscess cavity. Generally, the tube is kept for 7 ~ 10 days. At present, CT stereotactic aspiration or catheter drainage technology has more advantages.
3. Incision and drainage: traumatic brain abscess, wound infection, difficult to remove abscess or foreign body remaining in the brain, often removing foreign body while draining abscess.
4. Abscess resection: the most effective surgical method. The abscess sac is well formed and located in the non-important functional area; Polylocular or multiple brain abscesses; Traumatic brain abscess containing foreign bodies or bone fragments is suitable for surgical resection. The operation method of brain abscess resection is similar to that of general brain tumor resection. During the operation, we should try our best to avoid abscess rupture and reduce pus pollution.