Neurology · MU Sofia

54. Brain parasitic infections

Covers parasitic infections of the central nervous system, starting with a definition and a classification of the main protozoan and helminthic causes. It then goes through neurocysticercosis, cerebral toxoplasmosis, cerebral malaria and hydatid disease, giving for each the causative organism, clinical features, imaging and treatment where relevant. It closes with examination and CSF findings and a differential diagnosis list against tumour, abscess, tuberculoma and viral encephalitis.

Inside: 1 section · 3 labelled pictures · 16 flashcards · 2 min

Topic 54 of 88 in the MU Sofia syllabus for Neurology (Medicine, Year 4). The free AceMed note covers it in 1 section, about 256 words (2 min of reading), with 16 flashcards.

In this note

  1. Brain parasitic infeciton

Brain parasitic infeciton

Definition: Brain parasitic infections are infections of the central nervous system (CNS) caused by parasites, leading to meningitis, encephalitis, cysts, granulomas, hydrocephalus, seizures, and focal neurological deficits.

  • They are more common in tropical and developing regions but can occur worldwide.

Classification (Important Parasites): Protozoa. Toxoplasmosis. Cerebral Malaria. Amoebic encephalitis. Helminths (worms). Neurocysticercosis (most common worldwide). Echinococcosis (hydatid cyst). Schistosomiasis

1.Neurocysticercosis (Most Important)

Cause: Larval stage of Taenia solium (pork tapeworm).

Clinical Features

  • Most common presentation: Seizures (hallmark)
  • Other symptoms: Headache. Focal neurological deficits. Increased intracranial pressure. Hydrocephalus. Cognitive impairment
  • Imaging: Multiple cystic lesions. Ring-enhancing lesions. Calcifications (late stage)
  • Treatment: Albendazole ± praziquantel. Antiepileptic drugs. Corticosteroids

2.Cerebral Toxoplasmosis

Cause: Toxoplasma gondii

Risk Group: HIV/AIDS. Severe immunosuppression

Clinical Features: Headache. Fever. Confusion. Seizures. Hemiparesis. Altered consciousness

Imaging

  • Characteristic finding: Multiple ring-enhancing lesions, often in basal ganglia

Treatment: Pyrimethamine + sulfadiazine + folinic acid

3.Cerebral Malaria

Cause: Plasmodium falciparum

Clinical Features: High fever. Seizures. Coma. Delirium. Focal deficits

Complications: Brain edema. Death

4.Hydatid Disease (Echinococcosis)

Cause: Echinococcus granulosus

Features: Slowly growing intracranial cyst. Headache. Seizures. Raised intracranial pressure

Imaging: Large well-defined cystic lesion

Examination Findings

  • General: Fever (often). Signs of systemic infection
  • Neurological: Seizures. Focal deficits. Cranial nerve palsies. Meningeal signs (sometimes)

CSF Findings

Variable depending on parasite:

  • Common findings: Mild pleocytosis. ↑ protein. Normal or mildly reduced glucose. Eosinophilia may occur in some parasitic infections

Differential Diagnosis

  1. 1. Brain tumor: Similar focal deficits. No infectious signs
  2. 2. Brain abscess: Ring-enhancing lesion. Bacterial infection signs
  3. 3. Tuberculoma: Ring-enhancing lesions. TB history
  4. 4. Viral encephalitis: Diffuse rather than focal lesions

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