Brain Tuberculosis (Intracranial Tuberculomas)
Key Points
- Most common form of CNS TB after meningitis in children
- Represents 5-30% of intracranial masses in children in endemic areas
- Peak incidence: 2-12 years age group
- Higher prevalence in immunocompromised children
- Can occur with or without evidence of TB elsewhere
Epidemiology
- More common in developing countries
- Male:Female ratio = 2:1
- Risk factors:
- Malnutrition
- HIV infection
- Recent TB contact
- Low socioeconomic status
- Immunosuppressive therapy
Detailed Pathophysiology
Formation Mechanism
- Rich Focus Formation:
- Hematogenous spread from primary focus
- Formation of microscopic tubercles
- Coalescence into tuberculomas
- Growth Stages:
- Early non-caseating granuloma
- Caseating granuloma with solid center
- Caseating granuloma with liquid center
Common Locations
- Frontal lobe (30%)
- Parietal lobe (25%)
- Cerebellum (20%)
- Brainstem (15%)
- Basal ganglia (10%)
Immunological Response
- Cell-mediated immunity activation
- Cytokine cascade:
- TNF-α production
- IFN-γ release
- IL-12 mediated response
- Formation of granulomatous inflammation
Clinical Manifestations
General Symptoms
- Fever (80-90% cases)
- Weight loss
- Night sweats
- Failure to thrive
- Behavioral changes
Neurological Symptoms
- Focal Neurological Signs:
- Hemiparesis
- Cranial nerve palsies
- Visual disturbances
- Speech disorders
- Ataxia (in cerebellar lesions)
- Features of Raised ICP:
- Headache (progressive)
- Vomiting
- Papilledema
- Altered consciousness
- Sixth nerve palsy
- Seizures:
- Focal seizures (60%)
- Generalized seizures (40%)
Age-Specific Presentations
- Infants:
- Irritability
- Poor feeding
- Developmental regression
- Bulging fontanelle
- Older Children:
- Academic decline
- Personality changes
- Focal neurological deficits
Diagnostic Approach
Neuroimaging
- MRI Findings:
- T1: Iso/hypointense with peripheral rim
- T2: Central hyperintensity with hypointense rim
- Contrast: Ring enhancement
- 'Target sign' - pathognomonic
- Perilesional edema
- CT Findings:
- Irregular hyperdense lesions
- Ring enhancement with contrast
- Calcification in chronic cases
- MR Spectroscopy:
- Elevated lipid peak
- Decreased N-acetylaspartate
- Elevated choline/creatine ratio
Laboratory Investigations
- CSF Analysis:
- Opening pressure
- Protein and glucose levels
- Cell count and differential
- AFB smear
- Gene Xpert MTB/RIF
- Culture
- Blood Tests:
- Complete blood count
- ESR and CRP
- HIV testing
- Liver function tests
- Immunological Tests:
- Mantoux test
- Interferon-gamma release assays
Treatment Protocol
Anti-tubercular Therapy
- Initial Phase (2-3 months):
- Isoniazid (H): 10-15 mg/kg/day
- Rifampicin (R): 10-20 mg/kg/day
- Pyrazinamide (Z): 30-35 mg/kg/day
- Ethambutol (E): 15-20 mg/kg/day
- Continuation Phase (9-12 months):
- Isoniazid + Rifampicin
- Total duration: 12-18 months
Adjunctive Therapy
- Corticosteroids:
- Prednisolone 2-4 mg/kg/day
- Duration: 4-8 weeks with tapering
- Indications:
- Significant edema
- Mass effect
- Paradoxical reactions
- Anti-epileptic Drugs:
- For seizure control
- Drug interactions with ATT considered
- Management of Raised ICP:
- Mannitol/hypertonic saline
- Head elevation
- Hyperventilation if needed
Surgical Intervention
- Indications:
- Large lesions with mass effect
- Hydrocephalus
- Failed medical management
- Diagnostic uncertainty
- Procedures:
- Stereotactic biopsy
- Excision of accessible lesions
- CSF diversion procedures
Complications and Monitoring
Disease-related Complications
- Neurological:
- Permanent neurological deficits
- Cognitive impairment
- Epilepsy
- Hydrocephalus
- Paradoxical Reactions:
- Development of new lesions
- Enlargement of existing lesions
- Usually occurs 2-3 months after ATT
Treatment-related Complications
- Drug-induced hepatitis
- Visual impairment (Ethambutol)
- Peripheral neuropathy (Isoniazid)
Monitoring Protocol
- Clinical Monitoring:
- Neurological examination every 2 weeks
- Visual acuity and fields monthly
- Growth and development monitoring
- Laboratory Monitoring:
- Liver function tests monthly
- Complete blood count
- Renal function tests
- Radiological Monitoring:
- MRI at 3, 6, and 12 months
- Earlier if clinical deterioration
Special Considerations
In HIV Co-infection
- Higher risk of dissemination
- Atypical presentations common
- Longer duration of therapy needed
- Drug interactions with ART
Prognostic Factors
- Good Prognosis:
- Early diagnosis
- Single lesion
- No hydrocephalus
- Good treatment compliance
- Poor Prognosis:
- Multiple lesions
- Brainstem involvement
- Associated meningitis
- HIV co-infection
Disclaimer
The notes provided on Pediatime are generated from online resources and AI sources and have been carefully checked for accuracy. However, these notes are not intended to replace standard textbooks. They are designed to serve as a quick review and revision tool for medical students and professionals, and to aid in theory exam preparation. For comprehensive learning, please refer to recommended textbooks and guidelines.
