Otitis media bacteria often enter the intracranial white matter with fewer blood vessels through bone destruction, forming abscesses. In acute otitis media, bacteria can also invade through thrombosed mucosal blood vessels, while hematogenous infections are rare. The cerebrum is more commonly affected than the cerebellum, with the temporal lobe being the most frequent site, followed by the occipital and parietal regions. Males are more susceptible than females, and adolescents are prone to the condition. Some individuals may develop multiple abscesses, with both the cerebrum and cerebellum being affected simultaneously, and in rare cases, bilateral brain abscesses may occur.

bubble_chart Clinical Manifestations

1. Toxic phenomena of abscess toxins such as headache, loss of appetite, and pale complexion, etc.

2. High intracranial pressure phenomena including headache, drowsiness, nausea, vomiting, etc., with 70% occurrence of fundus edema.

3. Space-occupying signs: The brain may exhibit monoparesis, hemiplegia, hemianopia, and aphasia, along with pathological reflexes. The cerebellum may show weakened muscle tone on the affected side, ataxia, dysdiadochokinesia, and multiple cranial nerve palsies, etc. Sometimes, symptoms of both the cerebrum and cerebellum may appear simultaneously, making the condition highly complex.

bubble_chart Diagnosis

In the past, special imaging techniques such as cerebral angiography, ventriculography, and pneumoencephalography were commonly used to diagnose conditions by observing the displacement of blood vessels and ventricles. These methods were cumbersome, had significant side effects, and offered limited diagnostic value. Since the advent of CT and MRI, these older techniques have largely been replaced.

(1) Conservative Treatment The infecting bacteria are mostly Proteus and Pseudomonas aeruginosa, followed by Staphylococcus aureus. Broad-spectrum antibiotics such as penicillin, chloramphenicol, and cephalosporins should be the first choice. Early medication during the cerebral membrane encephalitis stage can lead to complete cure, while for those who have already developed abscesses, the edema reaction can be significantly reduced. Small, frequent blood transfusions can enhance the body's resistance, and timely correction of electrolyte imbalances is necessary. Dehydration therapy with 20% mannitol should be applied.

(2) Surgical Treatment If the general condition permits, mastoid radical exploration should be performed first, preferably using an electric drill to remove bone tissue to avoid chisel-induced abscess rupture and infection spread. During the operation, sebaceous cysts, necrotic bone, and granulation tissue should be cleared, and the fistula through which the infection enters the cranial cavity should be identified. Through this opening, the abscess can be probed, followed by puncture and aspiration of pus, irrigation, and drug injection. A solution of 200,000 units of water-soluble penicillin or 0.5g of streptomycin in 5–10ml can be slowly injected into the abscess cavity, taking care not to inject outside the cavity to avoid stimulation such as epileptic seizures. Sometimes, a rubber tube with a diameter of 0.3–0.5cm can be inserted into the abscess cavity for drainage, with periodic drug irrigation. For puncture, a blunt-tipped trocar should be used to puncture the temporal lobe of the brain, directing the needle inward and upward, forward and upward, or backward and upward, with a depth not exceeding 3–4cm. Due to the narrow mastoid cavity, the puncture direction is somewhat limited, and sometimes larger abscesses may be missed. If multiple punctures fail, a cranial trephine puncture can be performed outside the mastoid, as the direction and angle are unrestricted, increasing the likelihood of success. The same irrigation and drug injection can then be applied. Generally, 2–3 punctures with pus aspiration and drug injection can cure the abscess. For multiloculated or multiple abscesses that do not heal after repeated punctures, craniotomy for abscess excision should be considered. Based on clinical experience, abscess incision and drainage have historically yielded the poorest outcomes and are rarely used except for superficial abscesses adherent to the dura mater. The drawbacks include deep abscess locations, inadequate drainage, and exposure of the wound, which can lead to complex infections. According to the author’s statistics on 251 cases of brain abscess treatment (1977), the overall mortality rate was 19.1%. The mortality rate for simple pus aspiration was 17.3%, for abscess excision it was 17.1%, and for incision and drainage it was 22.6%. This shows that simple puncture and aspiration yield similar results to abscess excision, both outperforming simple incision and drainage. Therefore, simple puncture and aspiration with drug injection should be the preferred surgical treatment method.