DUHS CME - Ojha Institute of Chest Diseases

Tuberculosis

 

 

MODULE 9


TB in Children

Objectives

After going through this module we will understand

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Of the nine million cases of TB seen per year globally, 1.4 million are children. Children thus comprise 3-13%of all cases of TB. The mortality related to TB is high i.e.45,0000/year.
 According to WHO, a sensitive indicator to assess the impact of National Tuberculosis Control Programme, is the prevalence of less than 1% TB infection in children below 14 years, as it measures the current rate of transmission of infection rather than infections acquired in the past.
 In Pakistan though the exact prevalence of TB in children is not known, according to National Tuberculosis Control Programme 2009 data  3 647 were less than 15 years. This is less then the estimated number set by WHO.

Diagnosis  is based on  the combination of four criteria to diagnose TB in children:

  • Suggestive clinical history and examination
  • Evidence of close contact with an adult case of tuberculosis preferably smear positive
  • Tuberculin skin testing showing indurations of >10mm
  • Suggestive radiological findings.

 

1-CLINICAL HISTORY AND EXAMINATION
In children pulmonary TB could be

  • Asymptomatic and is detected after active contact investigation.
  • Present with nonspecific signs
    • Prolonged fever or Fever of unknown origin (FUO) duration?
    • Tiredness, night sweats.
    • Anorexia, weight loss, failure to thrive.
  • Minimal or no respiratory symptoms such as
    • Cough, respiratory distress or shortness of breath and chest pain
    • Sputum and hemoptysis is rare
  • pediatrician or physician should seek actively points in history and examination for a presumptive diagnosis

 

For extra-pulmonary TB, symptoms depend on the organ involved, for example:

  • Cough and shortness of breath in pleural or pericardial TB effusion.
  • Enlargement and swelling of lymph nodes, occasionally with pus discharge, in TB lymphadenitis
  • Headache, fever, neck stiffness and confusion when there is TB meningitis
  • Abdominal pain, diarrhea, mass or ascites with abdominal TB.
  • Backache with or without loss of function in lower limbs when TB spine occurs.
  • Pain and swelling of joints when TB arthritis occurs

 

2-EVIDENCE OF CLOSE CONTACT WITH AN ADULT CASE OF TUBERCULOSIS PREFERABLY SMEAR POSITIVE

Children acquire disease from adults who are in close contact with the child. Therefore, a history of close contact with an adult TB patient (AFB smear positive usually), mostly exposed at home, is the most important clue.

 

3-TUBERCULIN TEST
The Mantoux tuberculin skin test (TST) is an important value in pediatric TB and cannot be ignored. It is a delayed hypersensitivity reaction to M.TB and is the standard method for detecting infection by M. TB.
Purified protein derivative (PPD) with 5-tuberculin units (0.5 ml) is given intra dermally on the volar surface of the forearm by an experienced healthcare worker. The reaction should be measured accurately in millimeters of indurations after 48 to 72 hours. A positive reaction is considered ³ 10 mm induration in most circumstances in our setup. even if child had BCG which age group
Administering and reading MT


 

4-CHEST X-RAY
Chest x-ray has a very important diagnostic value in childhood TB. This is in contrast to adults where sputum for AFB smear is the primary method for diagnosis. However quality chest x-rays and variable interpretation may be a problem. Typical findings in children with TB include:

  1. Enlargement of hilar
  2. Mediastinal, or subcarinal lymph nodes
  3. lung parenchymal changes (atelactasis, consolidation, effusion).
  4. Miliary mottling may be seen in those with disseminated tb.
  5. Cavitation is more common in older children and adolescents.
  6. X-rays of other involved areas:
    1. Osteomylitis
    2. Fluid collections.

 

 

GASTRIC ASPIRATE FOR AFB

Confirmation of TB relies on detection (AFB smear) and isolation (AFB culture) of M. TB. Sputum microscopy by Ziel-nelson stain is easy, rapid and least costly as in adults. However in children sputum production and expectoration is minimal and poor. The standard of detection and isolation is gastric lavage for AFB smear and culture in children. It is generally recommended in cases with diagnostic difficulty

OTHER TESTS

  • A complete blood picture may be indicated in seriously ill patient or assessment of anemia but is not helpful in diagnosis.
  • ESR also should not be used as a screening or a diagnostic test for TB.
  • The rapid diagnostic tests for TB such as serology and polymerase chain reaction (PCR) are expensive and have variable sensitivity and specificity.

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DIAGNOSTIC CRITERIA
A number of scoring charts produced by WHO and others are also being used in different countries to improve the case detection rate. NTP guidelines have also included a scoring chart, which is a modification of the Scoring Chart used in India and Pakistan.

 

PAKISTAN PEDIATRIC ASSOCIATION SCORING CHART FOR DIAGNOSIS OF TB IN CHILDREN

HISTORY

 

 

 

 

 

 

Features

1

2

3

4

5

Score

Age

<2 yrs

-

-

 

-

 

Close contact in last 2 years

With TB patient

 

With sputum+ve
TB patient

 

 

 

BCG scar

Absent

-

 

 

 

 

History of measles and whooping cough

Between 3-6 months

< 3 months

 

 

 

 

Immuno-compromise /Immuno
suppressant*

Yes

-

 

 

 

 

PCM grade 3#

Yes

-

Not improving

 

 

 

EXAMINATION AND INVESTIGATION

Physical examination§

-

Suggestive of TB

 

Strongly suggestive

 

 

Radiological findings¶

Non specific

Suggestive of TB

 

 

 

 

Tuberculin skin test

5-10 mm

 

>10mm

 

 

 

Granuloma

Non
specific

 

 

 

Specific for TB

 

 

INTERPRETATION                
                                        

0-2 points             TB unlikely                                           
3-4 points             keep under observation for possible TB for three months
5-6 points             TB probable, investigations may justify therapy
7 or more points  TB “confirmed”          
*   Include children with malignancies (leukemias, lymphomas), immunodeficiencies, and immunosuppressive therapy such as chronic steroids more than 2 weeks
#        PCM grade 3: protein calorie malnutrition grade 3 not improving after 4 weeks of “adequate” caloric intake
§        Physical Examination suggestive of TB

  • Pulmonary findings (unilateral wheeze, dullness), hepatosplenomegaly, ascites
  • Extra pulmonary findings Matted lymphadenopathy, gibbus formation, chronic monoarthritis, CNS findings (bulging fontannele, irritability, papilledema)

¶        Radiological findings

  • Non-specific  (Ill defined opacity/infiltrates, marked broncho-vascular marking)
  • Suggestive of TB(Consolidation not responding to antibiotic therapy, paratracheal, tracheal or mediastinal lymphadenopathy, miliary mottling)

 

TREATMENT
Do not start TB treatment until a firm diagnosis has been made.
A trial treatment is discouraged

 However it may be prudent to start empirical therapy for those children in whom there is a strong index of suspicion or who are seriously ill. The requirements for adequate chemotherapy are:

  1. An appropriate combination of anti-TB drugs (with combined preparations preferred)
  2. Prescribed in the correct dosage
  3. Taken regularly as prescribed
  4. Taken for prescribed period

 

Dosage of antituberulosis drugs for Children (0-14 years old)

Initial Intensive Phase* Continuation Phase*
Daily during months 1 and 2 only

Daily during months 3-8

 

Weight of child (pretreatment weight)

H

(Isoniazid 100 mg)

R

(Rifampicin 150mg)

 

Z

(pyrazinamide) 500 mg tablet

 

S

(Streptomycin 1g/vial)

(H: Isoniazid 100 mg
T: Thioacetazone 50mg
R: Rifampicin 150 mg)

OP-1      OP-2

OP-1

OP-2

OP-3

 

HR H R*

 

 

HT
HR
H
R*

5-10 kg

½ ½ ½ ½ 250mg
 
½
 
½
 
½
 
½

11-20 kg

1 1 1 1 500 mg
2
1
1
1

21-30 kg

2 2 2 2 500mg
2
2
2
2

31-40 kg

750mg

 

* Additional ATT if required is given as tablets or syrup to complete dosages.
H=Isoniazid         R=Rifampicin    
Z=Pyrazinamide E=Ethambutol
S=Streptomycin  T=Thiacetazone   
FDC=Fixed drug combination       OP=option

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Study Questions

 

 

 

Objectives

After going through this module we will understand

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