Characteristics of tuberculosis in childhood

Ghodiwala TossifMl-610

Moscow 2013

People’s Friendship University of Russia

• In early childhood tuberculosis has the greatest tendency to progression, and that leads to the development of the most severe forms of tuberculosis.

• Child deaths from tuberculosis predominantly observed at this age, most often in the first year of life.

• The epidemiological situation of tuberculosis in young children characterized by low infectivity relatively high morbidity and high mortality rate.

• Infant – generalized form of TB

• Preschool and school age – less generalized

and more particular to lymphatic system

• Adolescence- infiltrative and disseminated

form

Anatomical and physiological characteristics INFANTS

• Immature immunity• Slow immune response• URT -short and wide unlike. LRT -longer and

narrow• Relatively dry mucousa (insufficient number of

mucous glands)• Poor elasticity of acini• Insufficient surfactant• Not well developed pleura• Cough reflex not fully developed

Anatomical and physiological characteristics Adolescent period

• Metabolic changes• Neuro-endocrine imbalance• Increase in the functional needs of the

organism• Psychological changes

– Bad habits– Diet– Social status

Tuberculosis in different age categories has certain features, which consequently contributes to the formation of various degrees of residual changes after the disease.

TB by the Numbers

• One-third of the world’s population has TB.• 9 million people are infected each year.• Roughly 1.5 million people die each year from

the complications of TB.• 8.5 million children have been orphaned due to

TB.• 22 countries account for 80% of TB cases

worldwide.

Incidence

Percent of US Pediatric TB Cases by Age Group1993–2006N=15,946

Age 10-1418.2%

Age < 19.2%

Age 1-449.5%

Age 5-923.1%

CDC data

Distribution

High-risk Factors forChildhood TB

• Poverty- Poor children often live in overcrowded conditions and lack access to healthcare.• Young Age-Because of their weak immune systems, infants under one year of age have a 40 percent chance of contracting TB if they do not receive preventive therapy when exposed to an adult with infectious TB.

• Malnutrition - Weak immune systems and malnutrition go hand in hand and make children more susceptible to active TB.

• HIV- TB is the third leading killer of children with AIDS and kids with HIV are up to 20 times more likely to develop TB than healthy children.

• Maternal TB - Children often contract TB from their mothers or other primary caregivers who have TB.

Transitions in Childhood Tuberculosis

Contact with smear positive index case

Not infected (50-70%) Infected (30-50%)

Diseased (10-30%)

Within 2 years (50%) Lifelong (50%)

• Risk of progression to disease is increased when primary infection occurs particularly in the very young (0–4 years).

• Children who develop disease usually do so within 2 years following exposure and infection, i.e. they develop primary TB.

• A small proportion of children (generally older children) develop post-primary TB either due to:

– Reactivation, after a latent period, of dormant bacilli acquired from a primary infection or

– By reinfection.

Age at primary infection Risk of disease following primary infection.

< 1year No disease 50%

Pulmonary disease (segmental) 20-40%

TBM or miliary 10-20%

1-2 years No disease 70%

Pulmonary disease (segmental) 10-20%

TBM or miliary 5-10%

2-5 years No disease 95%

Pulmonary disease (segmental) 5%

TBM or miliary 0. 5%

5-10 years No disease 98%

Pulmonary disease (segmental, effusion or adult type) 2%

TBM or miliary <0. 5%

> 10 years No disease 80%

Pulmonary disease (adult type) 10-20%

TBM or miliary <0. 5%

“These kids are the reservoir for adult TB,”

Dr. David Manissero

Which factors influence children to become infected?

Mostly “Environmental” • Exposure

- Never exposed = never infected

- Duration of exposure • Bacterial load• Close contact with infected

Only Adults Transmit TB

Number of bacilli in sputum Adult Child

108 104

Need about 105 organisms/ml for positive smear

What are the chances of a child under the age of 12 being able to transmit TB?

•Only a fraction of 1%

But why?

• Paucibacillary disease (fewer organisms)• Cannot cough/spread infection as well

• In adults, the most common way to diagnose TB is to look at mucus coughed up (sputum) and test it for the TB germ through sputum cultures.

• Most children, however, have a dry cough and do not produce sputum. In the rare instance that the child does produce sputum.

Difficult to diagnose

• paucibacillary, rarely culture confirmed :

• Sputum smear positive in 10.3% (10-14yr), 1.8% (5-9) and1.6% (<5)

• Cultures positive 21% (10-14), 5% (5-9) and 4.2% (<5),

• Extrapulmonary TB

Severity

• TB in children is more severe than adults.• Infants have a particularly high morbidity and

mortality from TB.• It is likely that the high rate of progressive TB

seen in young children is largely a reflection on the immaturity of the immune response.

Every day, more than 200 children under the age of 15 die needlessly from TB – a disease that is preventable and curable.