2. Tuberculosis 411
Caused by mycobacterium tuberculosis
Can cause latent TB or primary TB
Primary TB can be pulmonary or extrapulmonary TB
Spread by aerosolized particles during coughing,
sneezing, or speaking
Children less likely to spread
Extrapulmonary TB is not transmitted
Incubation period is 2-12 weeks
Time from infection to identification of a primary lesion on
TST
3. Worldwide TB Epidemiology
8.7 million NEW cases per year
490,000 pediatric cases
Low burden countries – 5% pediatric cases
High burden countries- 20% pediatric cases
Infants and young children are more prone to
develop life threatening forms
Disseminated TB
TB meningitis
1.4 million deaths
64,000 pediatric deaths
Top ten cause of pediatric death
6. Clinical Features
Bimodal presentation
Children < 5 y/o and adolescents >10 y/o
Most children asymptomatic
Most common symptoms:
Chronic cough (>21 days)
+/- wheezing
Dyspnea
Hemoptysis
Fever (>14 days)
Weight loss/FTT
Weakness/lethargy
Night sweats
7. Pulmonary TB
Pulmonary parenchymal disease and intrathoracic
adenopathy
Most common: 60-80% of cases
8. Extrapulmonary TB
Harder to diagnose
Symptoms highly suggestive of extrapulmonary TB
Gibbus from vertebral body
Enlarged or painless joints
Cervical lymphadenopathy with fistula
Meningitis or pleural effusion not responsive to antibiotics
Pericardial effusion
Abdominal ascites
9. TB meningitis
CNS involvement is common
Symptoms include:
Headache
Neck stiffness
Coma
Hemiplegia
Seizures
LP to diagnose
SIADH is common
10. Latent TB
Do not show any symptoms of the disease
Not infectious
Can transition from LTBI to active TB more
frequently and faster (within weeks)
Conversion rate is 5% in 2 years
11. Diagnosis
Must distinguish between latent TB (LTBI) or TB
Diagnostic tests include
TST/QFT-GIT
CXR
AFB/Sputum culture
Majority of case ( < 12y/o) are paucibacillary
Microscopically negative for AFB
Culture negative
Smear positive TB only 20-40% of pediatric cases
12. Diagnosis
TST- Mantoux method: 0.1ml dermal injection of
PPD into volar surface of forearm
Positive can mean current or future active TB
False positive in BCG vaccine and non tuberculosis
mycobacteria
Interferon-gamma release assays (IGRAs)
IGRAs can not distinguish between current or past
QuantiFERON-TB Gold in Tube (QFT- GIT) ELISA test
QFT- GIT and TST sensitivity: 38% and 35%
QFT- GIT and TST specificity: 81% and 84%
Nucleic acid amplification tests (NAATs)
Used in neg. AFB microscopy and to detect drug resistance
14. Laboratory tests
TST- Mantoux method: 0.1ml dermal injection into
volar surface of forearm
Positive can mean current or future active TB
False positive in BCG vaccine and non tuberculosis
mycobacteria
Interferon-gamma release assays (IGRAs)
IGRAs can not distinguish between current or past
QuantiFERON-TB Gold in Tube (QFT- GIT) ELISA test
QFT- GIT and TST sensitivity: 38% and 35%
QFT- GIT and TST specificity: 81% and 84%
Nucleic acid amplification tests (NAATs)
Used in neg. AFB microscopy and to detect drug resistance
15. Pulmonary TB on CXR
Primary TB- infiltrate usually in middle or lower lobe
Ipsilateral hilar adenopathy
Any lobe can be affected
25% multilobar
Endogenous TB- develops from LTBI
Infiltrate in upper lobes
Cavitation and collapse
Both can have atelectasis, pleural effusions,
pericardial effusion, or lymphadenopathy
16.
17. Primary TB Treatment
Initial phase for 2 months then continuation phase for 4
months
Isoniazid (INH) and rifampicin (RIF)
Bactericidal, decrease microbial loads
RIF and pyrazinamide (PZA)
Sterilizing drugs that eradicate slow- replicating organism
Ethambutol (EMB)
Protects against the emergence of drug resistant TB
Not used in <8 y/o’s due to concerns for optic neuritis
Disseminated TB and TB meningitis treatment is 12
months
LTBI treatment:
INH daily for 6-9 months or RIF for 4 months