10.5 CNS Infections: Other Than Meningitis

Question 1

Tuberculoma / TB abscess
Def
Clinical manifestation

Answer 1

• Focal brain lesion
• Multiple or single

Clinical manifestations depend on location:
- Hemisphere: Seizures / hemiparesis / other focal neurological deficit
- Posterior fossa: ataxia, cranial nerve palsies
- Spinal cord: paraparesis / quadriparesis, sensory level, sphincter disturbance (less common location)

• Readily visible on neuroimaging

Question 2

Syphilis classification

Answer 2

Primary syphilis
- Chancre (usually on genitalia)
- shortly after infec

Sec syphilis
- Lympadenopathy
- Skin rash
- Numerous systemic manifestations
- Meningovascular

Tertiary syphilis
- CVS (aortitis)
- Gummatous syphilis
- CNS
➡️GPI /General paresis
➡️Tabes dorsalis

Question 3

Classify neurosyphilis
Early
Late

Answer 3

EARLY
- Meningovascular syphilis (invasion of meninges)
• Asymptomatic (mostly)
• Meningitis with headache, confusion etc.
• Stroke, spinal cord infarction
• Seizures (with no apparent pathology)

LATE
- Tabes dorsalis [20 years after infec]
- Delirium and dementia
• General paresis / “General paralysis of the insane” (GPI) [2-25 years after infec]

Question 4

Neurocysticercosis
Aetiology
What it causes
Pathogenesis

Answer 4

• Caused by the larval stage of the tapeworm Taenia solium
• Important cause of adult-onset seizures in endemic areas

NOTE:
Humans can ingest:
- Neurocysticerci in raw meat – develop adult tapeworm infection (GIT)
- Ova/eggs in feces – develop cysticercosis (brain, muscle etc.) ->neurocysticercosis

Question 5

Herpes Simplex encephalitis
General
Clinical presentation
Complication

Answer 5

• Caused by HSV-1
• Commonest viral encephalitis worldwide
• Fatal:
  • 70% of untreated die
  • 20-30% of treated die
• NB:The earlier treatment is started, the better the outcome!

Clinical:
- Fever
- Headache
- Confusion
- Seizures
- Less frequently
• Focal neurological signs, e.g. hemiparesis, aphasia
• Ataxia

Complications = very common
- Mortality 20-30% of treated
- Persistent cognitive impairment, amnesia, behavioral abnormalities, seizures
- Autoimmune encephalitis

Question 6

Toxoplasmosis - Focal lesions
Organism
Clinical manifestation

Answer 6

Organism
- Toxoplasma gondii
- Primary in cats (but in other animals too)

Clinical manifestations
- Healthy: minor flu / asym
- HIV Infected: toxoplasma encephalitis (single/multiple lesions in brain)

Question 7

CNS Lymphoma
Pathogenesis
Clinical manifestations

Answer 7

Pathogenesis
- Associated with EBV infection

Clinical
- Focal neurological deficits
- seizures
- headache

Question 8

PML (progressive multifocal leukoencephalopathy)
Aetiology
Clinical presentation

Answer 8

Caused by reactivation of the polyomavirus (JCV)
- Most people have latent infection, reactivates in context of profound cellular immunosuppression, e.g. HIV infection
- Infects oligodendrocytes (responsible for myelination in CNS)

Clinical presentation
- Motor deficits
- Ataxia
- Visual, e.g. hemianopia
- Seizures
- Confusion

Question 9

Meningitis - Cryptococcus neoformans
Pathogenesis
Clinical

Answer 9

• Fungus, ubiquitous in environment (Infection by inhalation)
• Other cause of meningitis; other than TB

Clinical
- Advanced immunosuppression (CD4+ < 100)
- Presents with neck stiffness, photophobia, vomiting
- Visual loss due to infiltration of optic nerves or due to raised ICP
- May have fulminant course with coma and death in a few days

Question 10

Infections of spinal cord
What is causes
Two groups

Answer 10

• causes myelopathy

Groups
1. Compressive lesions (epidural abscess, vertebral infec)
2. Intramedullary infec (Neurosyphilis, TB, HTLVI, Varicella Zoster, HIV, Schistosoma)