bubble_chart Overview

This disease is a condition caused by the deposition of schistosome eggs in brain tissue.

bubble_chart Etiology

Adult schistosomes in the portal venous system and other blood vessels produce eggs that can invade the intracranial or spinal canal through the systemic circulation, intracranial venous sinuses, or vertebral venous system. The deposition of eggs in the brain or spinal cord can cause:

1. Specific inflammatory sexually transmitted disease changes, primarily occurring in the leptomeninges of the lesion area and the underlying cortex and white matter. These may manifest as egg granulomas, pseudosubcutaneous nodules, or scar nodules, accompanied by plasma cell infiltration and the formation of a capillary network around the lesion.
2. Non-specific sexually transmitted disease changes, presenting as glial cell proliferation, softening or edema of the brain (or spinal cord), and inflammatory changes in small blood vessels.

The infection leads to localized or widespread irregular granuloma formation in the meninges, with infiltration of lymphocytes, plasma cells, or multinucleated giant cells. The brain exhibits varying degrees of edema, with fungi aggregating around blood vessels and beneath the leptomeninges, forming multiple small cystic lesions. These lesions may show acute or chronic suppurative inflammatory reactions, and may even develop into brain abscesses or granulomas, mostly located within the brain parenchyma and occasionally in the ventricles. Large numbers of fungal bodies or hyphae can be observed in the abscesses and granulomas. Different types of fungal infections cause distinct pathological changes: Candida albicans often leads to small focal suppurations and granulomas; Cryptococcus initially forms gelatinous lesions without fibrous encapsulation, while in the advanced stage it forms granulomas; Actinomyces mainly causes multiple abscesses and granulomas, with yellowish abscess walls and pus containing "sulfur granules." Chronic sexually transmitted disease cases often exhibit widespread brain atrophy.

bubble_chart Clinical Manifestations

The course of the disease is often subacute, chronic, or insidious in progression, and may even persist or recur for decades, with most untreated cases resulting in death. The clinical presentation closely resembles that of intracranial tumors, featuring signs of increased intracranial pressure and focal neurological deficits. Spinal infections manifest as progressive transverse spinal cord damage. Fever may be present but is often not prominent. Communicating hydrocephalus due to adhesions of the basal arachnoid membrane is a common complication. Routine cerebrospinal fluid (CSF) analysis and biochemical tests may reveal increased pressure, protein levels, and cell counts, though these findings are nonspecific. Skull X-rays, isotope brain scans, and cerebral angiography only indicate the presence of an intracranial mass without specifying its nature. Brain CT findings resemble those of pyogenic brain abscesses, with possible ring enhancement of the capsule, while granulomas appear as isodense or slightly hyperdense lesions with moderate enhancement, with or without calcification. Perilesional edema is often minimal. Therefore, diagnosis based solely on clinical presentation and the aforementioned tests is challenging. The key diagnostic criteria include CSF smear staining, culture, inoculation, or pathological examination of brain or granuloma tissue samples to identify the causative organism. Positive fungal skin tests and evidence of fungal infection in other organs or tissues provide supportive diagnostic value. For instance, the presence of yellow, cream-colored, brown, or sometimes black "sulfur granules" in sinus tract secretions (which can be identified by diluting the discharge in saline, filtering the sediment, and examining it) strongly suggests actinomycosis infection.

bubble_chart Diagnosis

1. The acute type manifests with symptoms of acute diffuse encephalitis and corresponding signs of encephalopathic lesion damage, often gradually improving after body temperature subsides, with few sequelae.
2. The chronic type presents with epileptic seizures and corresponding signs of encephalopathic lesion damage.
3. Schistosome antigen intradermal test and blood moistening and tonifying body binding test are mostly positive.
4. Cerebrospinal fluid shows eosinophilia, and schistosome eggs can be detected in stool.
5. Head CT and MRI scans may reveal changes such as ventricular compression, displacement, and enlargement.
6. Differentiate from encephalitis, meningitis, other cerebral Chinese Taxillus Herb parasitic diseases, brain tumor, and epilepsy.

bubble_chart Treatment Measures

The main treatment is surgical removal of granulomas or abscesses, followed by adjuvant drug therapy. The drugs include:

1. **Amphotericin B**: Effective against Cryptococcus, Coccidioides, Candida, etc. The initial dose starts at 0.25 mg/kg, dissolved in 5% glucose solution for intravenous drip, gradually increasing to 1 mg/kg, with a total dose of 2–4 g over 3 months. The infusion rate should be slow, and light should be avoided. Since this drug does not easily cross the blood-brain barrier, intrathecal administration is often used concurrently. Method: Dissolve 0.25 mg of amphotericin B in 1 ml of isotonic saline, then further dilute with 5–10 ml of cerebrospinal fluid and slowly inject intrathecally in divided doses. The maximum single intrathecal dose is generally 1 mg, administered twice weekly. Dexamethasone and Phenergan can be given before administration to reduce drug reactions.
2. **Nystatin**: Effective against Cryptococcus, Candida, etc. Dose: Adults 2–4 million U/day, children 125,000–250,000 U/dose, divided into 2–4 oral doses.
3. **Clotrimazole (Triazole)**: Effective against Candida, Coccidioides, etc. Dose: Adults 50–60 mg/kg/day, children 20–60 mg/kg/day, divided into 3 oral doses.
4. **Trichomycin**: Effective against Cryptococcus, Blastomyces, Candida, etc. Dose: 200,000–400,000 U/day, divided into 3–4 oral doses.
5. **5-Fluorocytosine**: Similar in action to amphotericin B but can cross the blood-brain barrier. It may cause liver and kidney damage. Dose: 100–200 mg/kg/day, usually administered for 6–8 weeks.
6. **Antibiotics**: High-dose penicillin, lincomycin, and chloramphenicol are effective against actinomycosis infections.
7. **Ketoconazole**: Effective against Coccidioides and Histoplasma. Dose: 200–1200 mg/day.

The duration of drug use depends on the condition and should be determined based on cerebrospinal fluid routine tests, generation and transformation, smear examinations, and culture results to decide whether to discontinue the medication. During treatment, attention should be paid to drug side effects, and systemic conditions should be adjusted to enhance the body's resistance and eliminate the causes of fungal infection, thereby improving treatment efficacy.