CNS Tuberculosis

Question 1

What is the classification of TB according to site of infection?

Answer 1

1. Pulmonary TB

2. Extrapulmonary TB

Question 2

What is the classification of CNS TB?

Answer 2

1. Intracranial
   - TBM
   - Tuberculoma
2. Spinal
   - spinal tuberculous arachnoiditis
   - pott paraplegia

Question 3

What are the risk factors for CNS TB?

Answer 3

1. Prior infection
   - Pulmonary TB
2. Immunocompromised state
   - DM
   - HIV
   - malnutrition
   - alcoholism
   - malignancy
   - young age

Question 4

What is the pathogenesis of CNS TB?

Answer 4

Primary infection
Bacillemia
Hematogenous seeding
Dormancy
Immunocompromised 
Reactivation

Question 5

What is the pathogenesis of TBM?

Answer 5

Ruptured subependymal tubercle into subarachnoid space

Vasculitis
Proliferative arachnoiditis
Inflammatory exudates base of brain/spinal

Question 6

What are the complications of TBM?

Answer 6

Cerebral infarctions
Cerebral hemorrhage 
Hydrocephalus 
CN palsies
Tuberculomas
Focal seizures
Radiculopathy 
Myelopathy

Question 7

What is the clinical presentation of TBM?

Answer 7

3 phases

• prodromal
• meningitic
• paralytic

Prodromal

• insidious malaise, headache
• low grade evening pyrexia, night sweats
• LOA LOW

Meningitic

• meningism, protracted headache
• focal palsies
• long tract signs

Paralytic

• coma, seizures
• hemiparesis

Question 8

How do you diagnose TBM?

Answer 8

Clinical presentation 
Raised ESR CRP
Mantoux +
CXR TB
CSF +protein +lymphocytes -sugar (<2/3)
AFB 20% or Culture 40% or PCR 56%
Imaging 
-meninges enhanced
-hydrocephalus 
-suprasellar cistern exudates
-ring enhancing tuberculoma

Question 9

How do you prognosticate TBM?

Answer 9

British medical research council staging (MRC)

Stage 1 - alert, oriented, no focal deficits
<10% mortality

Stage 2 - GCS 14-11 or 15+focal deficits
55% mortality

Stage 3 - GCS =<10
87% mortality

Question 10

What are the features of intracranial tuberculoma?

Answer 10

+ICP
- headache, papilloedema

Focal deficits
- focal seizures and signs

Imaging
-ring enhancing lesion on CECT

Question 11

What are the features of spinal tuberculous arachnoiditis?

Answer 11

Subacute radiculopathy and myelopathy

Paresthesia

LMN paralysis

Bladder or bowel incontinence

Vasculitic infarction of spinal cord

Question 12

What are the features of Pott disease (spondylitis)?

Answer 12

Progressive increased local pain
In lumbar / lower thoracic

Constitutional symptoms

Imaging - bone destructions and vertebral collapse with cord compression

Question 13

How do you treat CNS TB?

Answer 13

Immediate ATT on high index of suspicion

Anti TB therapy

Intensive phase (4*2months) HRZE
Continuation phase (2*10 months) HR

Steroids
Prednisolone
1mg/kg/d * 3 weeks + 3 week taper off