Pediatric Tuberculosis
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Transcript Pediatric Tuberculosis
Epidemiology
Pathophysiology
Clinical Presentations
Diagnostic Challenges
Treatment
Epidemiology TB in
st
21
Century
1/3 of world population infected w/ TB
9.4 M new cases & 1.8M deaths/ yr worldwide (2008)
15-20% global TB disease burden: children < 15 yrs
Indicates continued transmission in setting w/ poor epidemic control
4% reported cases, but 95% cases in <12yr age are smear -
80% in 22 highest burden countries
Increasing numbers developing world
HIV epidemic (> 34% co- infected)
Poverty, overcrowding, malnutrition. Travel
MDR-TB and XDR-TB /Incomplete treatments
Breakdown of TB control programs
Pediatric TB
Recent transmission from infected adult
Measure of TB control in community, rarely transmit TB
Higher risk & more rapid progression to active disease
95% of children who develop TB, w/in 12 mos (1ary infection)
Reflection of immature immune system
Innate (macrophages), DC (dendritic cells) & acquired T-cell (CD4)
immunity
EPTB more common
Infants: high morbidity and mortality
Disseminated TB/meningitis: 10-20%
Pulmonary TB: 30-40%
Pediatric TB stages
Exposure
Contact w/ infectious pulmonary TB
Child asymptomatic
TST -, CXR normal
Infection (LTBI)
Contact w/ infectious pulmonary TB (adult)
Child asymptomatic
TST +, CXR normal
Disease
Contact w/ infectious pulmonary TB
TST+/ Child symptomatic or CXR positive for TB
Pediatric TB – Epi challenges
Diagnosis TB childhood difficult
clinical presentation variable & nonspecific
confirmation by culture < 40%
absence productive cough , paucibacillary disease
contact investigation of adults w/ infectious pulmonary TB
60-80% children infected when exposed to AFB + sputum
30-40% children infected when exposed to AFB - sputum
most efficient method dx children w/ TB
Factors influencing Ped Epi in USA
Increasing rates of TB in foreign-born immigrants
Worldwide HIV epidemic & MRTB
Transmission of TB among undx individuals w/ limited
access to health care, poor housing/nutrition
80-87% childhood TB in USA among AA, Hispanics, Asians,
Native Americans
1 out of 4 children w/ TB is foreign born
Concentrated in cities w/ pop > 250,000
TB in HIV + children
Important factor contributing to persistence TB
HIV adults horizontally transmit TB to children
HIV exposed /infected children
TB incidence 100 x higher (underestimation)
HIV + children
Weaker cell mediated immunity (CD4+Tcells)
Increased risk progressing from TB infection to TB disease
Similar presentation but more severe/extensive/EPTB/CNS
Higher recurrence/reinfection rates
Higher TB mortality
Pathogenesis of Peds TB
1st 2 months post infection
Primary Complex: Ghon focus + adenopathy (usually hilar)
Cell mediated response TST +, TB antibodies formed
Febrile reaction w/ onset of delayed hypersensitivity
Hematogenous/lymphatic seeded areas
Massive dissemination 1-3% cases (miliary/meningeal TB)
10-15% live organisms persist (potential for reactivation)
Pathogenesis: Timetable
Symptomatic lymphohematogenous , miliary/meningitis
2-6 mos
Endobronchial TB w/ segmental pul changes
4-9 mos
Significant bone/joint lesions
1 yr
Renal lesions
5-25 yrs
Infants and young children
Rapid progression: 1 st yr/5yr post infection respectively
Reactivation of Pul TB
Function of age of primary infection
Cavitation, lung/bone/joint/renal lesions
HIV/measles/varicella co infection, malnutrition
Pregnancy & NN
Congenital Infection Rare (risk higher if mother HIV+)
Transplacental, hematogenous spead via UV/placenta
Bacille: fetal liver (primary focus w/ periportal lymph nodes) or wide
spread miliary disease.
Bacille: liver to main circulation (1ary focus in lung) active after birth.
Aspiration/ingestion infected amniotic fluid in utero
multiple 1ary foci (lung, gut, middle ear)
Postnatal infection by inhalation from TB + mother
Breastfeeding not CI if mother on treatment
NN needs treatment
Clinical Forms Peds TB
Endothoracic
Lymphohematogenous
CNS
Other Extrapulmonary Sites
Adolescents
Neonates
Clinical manifestations
Most infected children asymptomatic
Lymphadenopathy
w/in 6 mos infection, ant cervical/submandibular
Primary Pulmonary TB (PTB)
Most common presentation
Children > 10 yrs age more like adult disease
Intra thoracic adenopathy & parenchymal changes
Progressive Pulmonary disease
Common in young children: TB broncho-pneumonia
Chronic Pulmonary Disease/ reactivation
Most common in adolescents (1ary infection > 7 yrs age)
Cavitation, typically upper lobe
Endothoracic
Asymptomatic
80-95% infected children, 40-50% infected infants
Pulmonary
1ary pulmonary complex
Progressive pulmonary disease
Chronic pulmonary disease
Pleural effusion
Pericarditis
Endothoracic
Pulmonary
1ary pulmonary complex
Adenopathy large w/ small parenchymal foci
CXR
hilar adenopathy,
localized hyperaeration, atelectasis
localized pleural effusion
segmental infiltrate (foci)
Signs/symptoms infrequent (except in infants)
1ary complex: fever + cough
Fever, cough, night sweats, FTT
Localized wheeze, diminished BS
Dysphagia, edema hand/arm
Hilar Adenopathy
Endothoracic:
Progressive pulmonary disease
Rare but serious
CXR bronchopneumonia/lobar pneumonia w/ cavities
Signs/symptoms significant
Fever, night sweats, wt loss, cough
Diminished BS, rales, dullness, egophony
High fatality w/out treatment
Endothoracic:
Chronic pulmonary disease
“Adult reactivation” type/recent or reinfection
6-7% pediatric patients (TB acquired > 7yrs age)
Most common pul sites
original parenchymal focus, regional lymph nodes, or apical
seedings
Usually remains localized to lungs
Identical to Adult pulmonary disease
Endothoracic:
Pleural effusion
Subpleural 1ary pul focus /subpleural caseous lymph
nodes
Small, localized or generalized
4-30% of TB cases in young adults, rare children
Signs/symptoms abrupt
Fever, chest pain, SOB, dull percussion, decreased BS
Dx difficult
Acid fast stain pleural fluid-/cult + 30% biopsies
Prognosis good in treated children
Endothoracic
Pericarditis
Rare in children (0.4-4%)
Direct invasion from subcarinal lymph nodes
Can lead to constrictive pericarditis
Signs/symptoms nonspecific
Fever, malaise, fatigue, wt loss, chest pain
friction rub distant HS/pulsus paradoxus
Dx: acid fast stain -/cx + 30-70%
Pericardectomy
Lymphohematogenous
Clinical course acute/indolent/prolonged
Multiple organ involvement
HSM & adenitis (superficial/deep), Pulmonary, Meningitis
Papulonecrotic tuberculides
Miliary
Massive # organisms released, > 2 organs affected
Early complication 1ary infection (2-6 mos)
Common infants/children: explosive or insidious onset
Fever, wt loss, anorexia, malaise, HSM, gen. lymphadenopathy,
resp distress
CXR: tubercules
Dx difficult: TST -, liver/bone biopsy needed (33%+)
Prognosis w/ treatment excellent , resolution slow
CNS Manifestations
Rich focus, vessels infiltrated by exudate
Inflamation/infarction
Brain stem: CN III,VI,VII dysfunction
Basilar cisterns obstructed: hydrocephalus
TB meningitis
Children < 4 yrs age, most w/in 3-6 mos of 1ary infection
Gradual onset, rapid in infants Hydrocephalus
Tuberculomas (20-37%)
Mortality (<10% w/ Rx) Morbidity high (MR, Sz, hemiparesis)
TST – in 40%, CXR nl 50%
CSF: cell # 10-100, glucose low, protein high
Tuberculoma
Most common in < 10yrs age
Infratentorial: headaches, Seizures, increased ICP
Tuberculomas
CN palsy 3, 6, 7
Fever of Unknown Origin
Common in developing countries
Few clinical findings
Primary infection: cellular immune response
Reactivation old/hidden focus
Other Extrapulmonary Sites
More common, not infectious
Infants
HIV + children
Scrofula
Skeletal
Vertebrae most common: Pott’s Disease
Knee, hip, elbow, smaller joints
Abdominal/peritoneal TB
Adolescents
Eye, middle ear, sinuses, kidneys, skin
Rare in children
Osseous Clinical manifestations
TB osteitis
Synovitis/epiphysitis, destructive arthritis, fusion in deformed
positions
Abscesses may track through tissues (psoas)
TB arthritis (Ponchet’s Disease)
1-5% children if TB untreated
Knee/hip/elbow/dacylitis
Thick, inflammatory synovium, invades articular surface, w/
erosion and fibrosis joint
Pott’s Disease
TB osteitis
GI & GU Manifestations
Abdominal/peritoneal TB
Thickened gut, peritoneal lymph nodes
Obstruction, fistula formation, ascitis, perforation,
malapsorption
Palpation doughy abdomen w/ masses of adherent lymph
nodes
R/o malignancy (laparoscopic biopsy)
Poor prognosis, long term intestinal problems
Renal TB
Uncommon in children
Sterile pyuria
TB epididymitis and orchitis
GI TB
Adolescents
Acquired as initial infection during adolescence
Chronic pulmonary TB w/in 1-3 yrs
Acquired in early childhood
Rare if acquired as infant
More likely if acquired 1ary infection from 7-10 yrs age
Propensity to progress to contagious TB
Target group for TST & case finding
Neonates
Clinical symptoms 2-3wk
FTT, respiratory distress, fever, HSM, meningitis
lymphadenopathy, sepsis, lethargy
Dx difficult
TST -, CXR nl or miliary
AFB in gastric aspirate, urine, BM, liver biopsy, ear
TB in mother
Infants of + mother TB
INH & BCG to newborn, treat mother /contacts
Breastfeed if mother on Rx
Diagnosis TB in Children
General Principles
Triad
TST+
History of recent exposure to adult w/ probable /definitive TB
CXR abnormal
Symptom based scoring systems
Immunocompetent children
Definitive diagnosis
Acid fast smear of sputum/gastric secretions microscopy
Isolation of TB
Automated liquid culture systems (gold standard now)
Challenge of Childhood TB
diagnosis
Establishing accurate diagnosis
Challenges collecting adequate sample for micro
<15% of cases are sputum AFB smear + (paucibacillary)
Mycobacterial cx yields: 30-40%
Case detection & contact tracing not routine
Most individuals acquire infection childhood/adolescence
CXR nl in significant proportion of children w/ confirmed
pul TB
Most new Dx not validated in children
No widely available gold standard dx of TB in children
TST
Hallmark of 1ary TB infection
Appears 3wks-3mos after initial infection, lasts yrs
Infants less enduration, more anergy
Sensitivity/Specificity 95%
PPV – function of TB prevalence in community
AAP/CDC recommendations in USA
Screen w/ questionnaire
TST only for high risk children
BCG
<50% infants TST + at 9-12 mos post vaccination
80-90% TST- by 3-5yrs post vaccination
TST + interpretation
> 5 mm
Persons w/ contact w/ infectious persons
Persons w/ abnl CXR
HIV infected/immunocompromised
< 10mm
Infants
Children in contact w/ adults at high risk
Foreign born persons from hi prevalence countries, IVDU,
residents prisons, institutions
>15 mm
No risk factors
Specimen collection Methods
Sputum
Induced Sputum
Gastric aspirate
Nasopharyngeal aspiration
String Test
BAL
Urine/stool
Blood/BM
CSF
Find needle aspiration adenitis
Diagnosis TB in Children
Direct smears, acid fast stains & Cultures
Sputum smears
Sputum rarely produced <10yrs age, paucibacillary TB
Insufficient alone to dx or r/o TB
Induced sputum w/ 5% saline neb, serial collections in infants
Gastric washings (x3): acid fast stains/cultures
Sensitivity Cx: 30-50% children, 70% infants
Better than BAL
Other body fluids/tissue specimens
Sensitivity Cx: 30-50% children, 70% infants
Difficulty isolating TB in children should not greatly
influence approach to therapy
Attempt to isolate
no source case, source case MDR TB, child has suspected
extrathoracic TB
Diagnostics
Traditional direct smear microscopy
sputum
Solid culture
Chest radiography
Tuberculin skin testing (TST)
Traditional Approaches to
Diagnose TB in Children
TB culture
CXR
Symptom-based
TST
New diagnostic approaches
Organism – based
Colorimetric culture systems (TK-Medium)
Phage-based tests (FASTPlaque-TB)
Microscopic observation drug susceptibility (MODS)
Assay PCR based test
Antigen- based essays
LAM detection assay
Immune-based
Antibody-based assays
MPB-64 skin test
T-cell assays
T-Spot.TB (IGRA)
QuantiFERON-TB Gold
Symptoms-based: Refined symptom based diagnosis
TB Research Movement
initiated by the Stop TB Partnership & WHO
engaging TB researchers, programme
managers, & affected communities in a
collaborative & concerted strategic effort to
↑ scope, scale, & speed of TB research across
the continuum
linking basic research development of new
methods, & operational research
New Diagnostics since 2007
Liquid media for culture & DST
Def of a new sputum-smear-
positive TB case
one acid fast bacilli in at least one
sputum sample in countries
↓ of number of smears for
diagnosis of pul TB
WHO recommends the number
↓ from three to two
Molecular line-probe assays for
rapid screening pt at risk of MDR
TB
Same day dx by microscopy
LED-based microscopy
conventional fluorescence
microscopy replaced by LED
microscopy using auramine
staining
LED microscopy phased in as
alternative for conventional
Ziehl-Neelsen light microscopy
Non-commercial culture DST
methods
Microscopically observed drug
susceptibility
Nitrate reductase assay,
Colorimetric redox indicator
methods
New Diagnostics 2009
Xpert MTB/RIF
First automated molecular test for TB (NAAT assay)
Excellent performance in Smear + & - pts
Hi accuracy for determination rifampicin resistance
Simple to use system
Detects M tuberculosis directly from sputum in <2 hrs
IGRAs (interferon-γ release assays)
T-cell assays
T-Spot.TB (IGRA)
QuantiFERON-TB Gold
Blood test
Results in 24hr
TBDST: drug-susceptibility test
MODS: microscopic observation drug
susceptibility
NRA: nitrate reductase assay
CRI: colorimetric redox indicator assay
LPA: line-probe assay
NAAT: nucleic acid amplification test
LED: light-emitting diode
POC: point of care
LTBI: latent tuberculosis infection
Dx Active TB
Sputum-smear microscopy for pulmonary TB
FM, conventional, LED FM • When serial sputum specimens are examined, the mean
incremental yield and/or
A same-day-diagnosis approach (microscopy of two consecutive spot-spot sputum
specimens)
NAATs for pulmonary & EPTB
Serological antibody detection tests for pulmonary & EPTB
ADA for TB pleuritis, pericarditis, peritonitis
Measurement of ADA concentrations in pleural, pericardial, ascitic fluid
Interferon γ for TB pleuritis
Phage amplification assays for pulmonary TB
Automated liquid cultures for pulmonary TB
Automated liquid cultures are more sensitive than are solid cultures
time to detection is more rapid than for solid cultures.
Dx Latent TB
TST for latent TB infection
T-cell-based IGRAs for latent TB infection
IGRAs have excellent specificity (higher than the TST),
unaffected by previous BCG vaccination.
IGRAs cannot distinguish between latent TB infection & active
TB, &have no role for active TB dx in adults.
IGRAs correlate well with markers of TB exposure in lowincidence countries
IGRA sensitivity varies across populations & tends to be lower
in high-endemic countries & in HIV-infected individuals
Dx Drug Resistant TB
Phage amplification assays for rapid detection of rifampicin
resistance
Line-probe assays: INNO-LiPA Rif & GenoType MTBDR
assays for rapid detection of rifampicin resistance
CRI methods and NRA for rapid detection of rifampicin &
isoniazid resistance
MODS for rapid detection of rifampicin & isoniazid resistance
TLA for rapid detection of rifampicin & isoniazid resistance
Biomarkers
Predication of durable (non-relapsing) TB cure
Microbial markers in
sputum
2-month culture conversion
Serial colony counts or time to
culture positivitys
Other microbial markers
Urine M tuberculosis DNA,
lipoarabinomannan1
Volatile organic compounds
Mycobactericidal activity
Whole blood culture
TB-specific T-cell function
Interferon γ,interleukin 4δ2 splice
variant
Macrophage activation
markers
Neopterin, procalcitonin, C-reactive
protein
soluble intercellular adhesion
molecule soluble
urokinase plasminogen activator receptor,
monocyte
CDllc
Multiple host markers
Proteomics
Transcriptomics
Indication of reactivation risk & prediction of
eradication of latent infection
Tuberculosis-specific T-cell function
Interferon γ
Interferon-induced protein
Interleukin 4δ2 splice variant
Skin test
Macrophage activation
Neopterin
Procalcitonin
Prediction of vaccine efficacy
Tuberculosis-specific T-cell function
Interferon γ
Polyfunctional T cells
Mycobactericidal activity
Whole blood culture
Mononuclear cells
Treatment General Principles
Short treatments: key - intensive initial therapy
Most peds resistance is primary (paucibacillary TB)
Higher rates of disseminated /meningitis TB
Drugs that penetrate tissues/tissues/meninges well
Pharmacokinetics different in children
Young children w/ more severe disease, malnutrition
experience more hepatotoxic reactions
Formulations mainly for adults
Crushing pills/suspensions
Inadequate absorption, diarrhea
Treatment Anti TB drugs for
Children
First line drugs
INH, RIF, PZA, Streptomycin, Ethambutol
Second line drugs
Ethionamide
Kanamycin
Cycloserine
Para-amino salicylic acid
Fluoroquinolones (cipro, levofloxacin)
Treatment Specific Regimes
Exposure
INH alone in children < 5yrs age if exposed to
potentially infectious adults w/ pul disease
Regardless of TST result
If HIV infected
Exclude active TB
treat as if TB infection, 6-12 mos
After 3 mos treatment, TST repeated
If TST -: INH discontinued
If TST +: treat for total 9mos
Treatment Specific Regimes
Infection w/out Disease
TST + w/ known contact to infectious adult case
Highest risk of developing disease: always Treat
TST + w/out known contact to infectious adult case
Treat if < 5yrs age & adolescents
WHO
Min 6 mos with INH + regular follow up
AAP/CDC
9 mos with INH
Daily under self supervision or Twice weekly DOT
Rifampicin
If INH resistant TB
Treatment Specific Regimes
Pulmonary Disease
Most commonly used
INH + RIF + PZA x 2 mos (daily)
INH + RIF for total 6 mos DOT twice weekly
When source case risk factors for MDR TB
Add 4th drug: ethambutol, streptomycin
Continue 6 mos unless drug susceptibility available
PZA stopped after 2 mos
Treatment Specific Regimes
Extrapulmonary
INH, RIF & PZA
6 mos
Bone/Joint TB
9-12 mos
Meningitis/ disseminated TB
INH, RIF, PZA & ethionamide or streptomycin x 2 mos
INH & RIF x 9-12 mos total
Treatment Specific Regimes
MDR TB
Patterns of resistance reflect those found among adults
in same population
Treatment regimes guided by drug susceptibility
pattern of the isolate
At least 2 bactericidal drugs to which susceptible
Duration 9-12 mos if INH or RIF can be used
Duration 18-24 mos if resistance to INH+RIF
Usually 4-7 drugs daily DOT
Treatment Specific Regimes
HIV-related Tb
Principles same as those for non HIV + children
HIV+ children w/ exposure to TB
Exclude active TB
Treat as if infected w/ INH (or RIF if resistant)
HIV+ children w/ INH susceptible TB
4 drugs (INH,RIF, PZA, ethambutol/strepto) x2 mos
INH & RIG for total 9-12 mos (+pyridoxine)
HAART-TB drug interactions
Rifampicin CI w/ PI
IRIS
HIV + children w/MDR TB
4-6 drugs for 24mos
Second line anti TB drugs
HAART
Doses
INH
Faster elimination
Requires higher body wt dose
10mg/kg
RMP
10-20mg/kg
PZA
30mg/kg
EMB
20mg/kg (15-30mg/kg) day
30mg/kg given 3x/wk
Drug formulations
Individual & fixed drug combinations tabs
With good bioavailabiltiy
Liquids
Easy to administer to young children
Bulky
More expensive
Unacceptable toxicity
INH syrup → diarrhea (sorbitol based solution)
Treatment
Corticosteroids
When host inflammatory reaction creating tissue
damage/impairment in function
Always used w/ anti TB drugs
Meningitis
Mediastinal lymph nodes
Miliary disease
Pericardial effusion
Prednisone 1-2mg/kg x 4-6wk, taper 1-2 wks
Monitoring responses
Trend to lower cure rate w/ twice weekly regimens
Symptomatic improvement, weight gain
Regression of Radiographic findings
Months/years
F/u sputum examinations when possible
HIV and TB
Optimal timing of HAART yet to be defined
RMP lowers level of protease inhibitors (except ritonavir)
By > 75%
RMP lowers level of nevirapine
By 35%
RMP lowers level of efavirenz
By 17%
Doses for children <3yrs not established
Many physicians delay HAART until anti TB treatment completed
or use higher dose Nevirapin
Many other unknown factors impacting on antiretroviral blood
levels
Age, nutritional status, genetic polymophisms in cytochrome p450 enzymes
New TB Drugs
Fluoroquinolones
TMC207
OPC67683
PA824
Treatment of children laggs:
Difficulty confirming active TB
Concerns about ped specific adverse effects
Uncertainties about appropriate time to involve children in
drug dev
Optimal trial designs for drug dev
Complex regulatory requirements
Prevention
MDG
Improved living conditions
Improved Dx, contact tracing, treatment TB/LTBI
WHO guidelines for National TB programs
International standards TB care: Symptom bases screening
Global Drug Facility
WHO Stop TB Strategy
Stop TB Partnership’s Global Plan to Stop TB
Treatment HIV/AIDS
BCG
CI in HIV + infants
New vaccine development
Peds TB Cases
Meron 4 ½ months old
Evaluated in adoption clinic, from Haiti
Well appearing, Normal PE (wt in 10%) developmental
screen.
Screened for TB, Hepatitis, syphilis, HIV, parasites, lead
Vision/hearing screening: high frequency hearing loss
Received BCG at birth
TST 12 mm enduration, HIV –
Hx repeated respiratory infections in orphanage, treated w/
multiple antibiotics
Meron
CXR 2 views
Alert radiologist you are looking for TB
Meron
Laboratory testing
Microbiological testing
Sputum, sputum induction (?)
BAL (?)
Gastric aspirates
CBC, U/A & U/Cx, electrolytes & renal fct, LFT
LFT increased
Treatment? How many drugs?
Meron
Gastric aspirate positive Mtb on second aspirate
Started on 4 drug regime by DOT
Resistant to INH, RIF. Sensitive to PZA, EMB, SM
MAC also grew on purity plates
Meron
Use all first line drugs available (unless previously used &
associated w/ failing regime)
Use injectable drug (SM, amikacin, capreomycin,
kanamycin) by Broviac
Use fluroquinolone
Use additional second line drugs to have 4-6 drugs in the
regime
Meron
Treatment changed: aminoglycoside (by broviac x 4 mos),
PZA, EMB, ethionamide and levofloxacin, Vit B6 by DOT
2 negative gastric aspirates on therapy
Gained many pounds
CXR normalized
Normal growth and development
Resources
www.nationaltbcenter.edu
Pediatric on line course
WHO
CDC
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