Table of Contents
Overview – Parasitic Brain Infections
Parasitic infections of the brain are uncommon but critical causes of neurological disease, especially in immunocompromised individuals and those in endemic areas. Caused by helminths (worms) and protozoa, these infections can lead to seizures, altered mental status, focal neurological deficits, or even death. Early recognition, imaging, and serological or PCR-based diagnostics are key. Common causative agents include Taenia solium (neurocysticercosis), Toxoplasma gondii, Plasmodium falciparum, and Trypanosoma species.
Aetiology
Helminths
- Tapeworm (Taenia solium)
- Transmission: Ingestion of undercooked pork (larval cysts)
- Causes neurocysticercosis → cyst formation in CNS
- Found in endemic regions (e.g. Latin America, Southeast Asia)
- Symptoms: Seizures, hydrocephalus, raised ICP
- Roundworm (Toxocara canis/cati)
- Transmission: Ingestion of eggs from contaminated soil (from dogs/cats)
- Causes visceral larva migrans and ocular larva migrans
- Symptoms: Seizures, vision loss (retinal detachment)
Protozoa
- Malaria (especially Plasmodium falciparum)
- Transmission: Anopheles mosquito
- Can cause cerebral malaria → coma, seizures, death
- Prevalent in Sub-Saharan Africa, Asia
- Toxoplasma gondii
- Transmission: Ingestion of oocysts from cat faeces or undercooked meat
- CNS involvement typically in immunocompromised patients (e.g. HIV/AIDS)
- Symptoms: Headache, confusion, seizures, hydrocephalus
- Imaging: Ring-enhancing lesions on CT/MRI
- Trypanosoma brucei (African Sleeping Sickness)
- Transmission: Tsetse fly bite
- Symptoms: Sleep disturbances, personality changes, gait abnormalities
- Chronic CNS involvement in late stage
Clinical Features
- General signs:
- Seizures
- Headache
- Focal neurological deficits
- Altered mental status
- Visual disturbances
- Hydrocephalus
Diagnosis
| Organism | Diagnostic Method |
|---|---|
| Taenia solium | MRI (cysts), serum/CSF antibody tests |
| Toxocara spp. | ELISA for serum antibodies |
| P. falciparum | Rapid antigen test (RDT), thick/thin blood smear |
| T. gondii | PCR, serology, immunostaining |
| Trypanosoma spp. | Microscopy (CSF, blood smear), RDT antibody test |
Management
| Organism | Treatment |
|---|---|
| Taenia solium | Albendazole or praziquantel + corticosteroids |
| Toxocara spp. | Antihelminthic agents (except in ocular disease) |
| P. falciparum | IV artesunate or oral artemisinin combination therapy |
| T. gondii | Sulfadiazine + pyrimethamine + folinic acid; atovaquone for cysts |
| T. brucei | Melarsoprol, eflornithine (late-stage) |
Summary – Parasitic Brain Infections
Parasitic brain infections are life-threatening but treatable conditions seen in immunocompromised or globally exposed patients. Diagnosis relies on imaging and targeted serological or molecular testing. Common culprits include Taenia solium, Toxoplasma gondii, and Plasmodium falciparum. For more, visit our Nervous System Overview page.
