Childhood tb

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Childhood tuberculosis

• Dr. Salvatory .F.M
• Lecture
• PDCH

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Introduction

• One third of the worlds population is infected
  with Mycobacterium tuberculosis.
• In 2015,estimated of incidence cases were
  10.4millions,whereby 10 were children below 15
  years
• In 2015,WHO estimated 1.4m deaths due to TB
• Of these childhood cases, 75 occur annually in
  22 high-burden countries that together account
  for 80 of the worlds estimated incident cases.
• The magnitude of childhood TB in Tanzania is
  difficult to ascertain due to challenges in
  diagnosis and reporting

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• Which factors influence children to become
  infected?
• Mostly Environmental
• Exposure
• - Never exposed never
  infected
• Duration of exposure
• Bacterial load in source case
• Closeness of contact

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Only Adults Transmit TB

• Number of bacilli in sputum
• Adult Child
  108
  104
• Need about 105 organisms/ml for positive smear

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The key risk factors for TB are

• Household contact with a newly diagnosed
  smear-positive case.
• Age less than 5 years.
• HIV infection.
• Severe malnutrition.

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Natural history and pathogenesis

• Caused by Mycobacterium tuberculosis
• Inhalation of bacilli form a smear positive adult
  or adolescent
• Bacilli are deposited in the lungs and multiply
  in terminal alveoli(Ghon focus)
• Some bacilli are carried by macrophages through
  lymphatic channels to regional lymph nodes
  especially hillar lymph nodes

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• Lymphatic and haematogeneous spread the bacilli
  to other part of the body leading to
  disserminated TB
• In majority of infected children the immune
  system stops multiplication of bacilli and the
  infection remain latent for many years

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• gtReactivation of infection may occur in children
  with weak immune system eg malnutrition and
  HIV-AIDS

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Diagnosis of TB in children
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Key features suggestive of TB

• The presence of three or more of the following
  should strongly suggest a diagnosis of TB
• History of close contact with an infectious
  case(smear ve)
• Physical signs highly suggestive of TB
• A positive tuberculin skin test
• Suggestive findings of TB in X RAY,FNAC .

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Recommended approach to diagnose TB in children

1. Careful history
2. including history of TB contact and symptoms
   consistent with TB.
3. Coughgt 2 or more weeks
4. failure to thrive
5. night sweats
6. fevergt2 weeks or more
7. Wait loss or faltering

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• Clinical examination (including growth
  assessment).
• There are no specific features on clinical
  examination that confirm pulmonary TB.

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• Some signs are highly suggestive and requiring
  investigation to exclude extra-pulmonary TB
• gibbus, especially of recent onset (resulting
  from vertebral TB)
• non-painful enlarged cervical lymphadenopathy
  with sinus formation
• Meningitis not responding to antibiotic
  treatment, with a sub-acute onset or raised
  intracranial pressure with early affection of the
  cranial nerves.
• Pleural effusion
• Pericardial effusion
• Distended abdomen with ascites
• Non-painful enlarged joint
• Signs of tuberculin hypersensitivity (e.g.
  phlyctenular conjunctivitis, erythema nodosum).

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• 3.Tuberculin skin test
• A positive TST occurs when a person is infected
  with M. tuberculosis, but does not necessarily
  indicate disease.
• TST can be used as an adjunct in diagnosing TB in
  children with signs and symptoms of TB and in
  conjunction with other diagnostic tests.
• Use 5 tuberculin units (TU) / 0.1 ml of
  tuberculin PPD-S or 2 TU / 0.1 of tuberculin PPD
  RT23.
• The results should be read between 48 and 72
  hours after administration. A patient who does
  not return within 72 hours will probably need to
  be rescheduled for another TST.

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Interpretation of the test

• Diameter of induration of 5 mm is considered
  positive in
• HIV-infected children
• Severely malnourished children (with clinical
  evidence of marasmus or kwashiorkor).
• Diameter of induration of 10 mm is considered
  positive in
• Children more than 5 years or not vaccinated with
  BCG.

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TST
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Bacteriological confirmation whenever possible

• Among younger children, especially under 5 years,
  sputum is difficult to obtain.
• Most children are sputum smear-negative.
• Children who are able to produce a specimen, it
  is worth sending it for smear microscopy and
  mycobacterial culture if available.
• Bacterial yields are higher in older children
  (more than 5 years of age) and adolescents, and
  in children of all ages with severe disease.

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• Appropriate clinical samples include
• Sputum,
• Gastric aspirates
• Laryngeal swaps
• Certain other material e.g. lymph node biopsy or
  other biopsies.
• Fine-needle aspiration of enlarged lymph glands
  for both staining of acid-fast bacilli and
  histology has been shown to be a useful
  investigation, with a high bacteriological yield.

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• Role of culture
• Increase the yield of confirmed TB cases,
• Differentiate M. tuberculosis from other
  non-tuberculous mycobacteria.
• determine the resistance pattern.

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Chest radiography

• The commonest picture is that of persistent
  opacification in the lung together with enlarged
  hilar or subcarinal lymph glands.
• Adolescent patients with TB have CXR changes
  similar to adult patients..

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Extra-pulmonary TB
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• Other tests
• PCR
• Not currently recommended for routine diagnosis
  of childhood TB, as they have been inadequately
  studied in children and have performed poorly in
  the few studies which have been done.

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Scoring system
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SCORE SYSTEM FOR THE DIAGNOSIS OF TB IN CHILDREN

• Has been rarely evaluated or validated
• The basis of a score system is the careful and
  systematic collection of diagnostic information.
• A score of 7 or more indicates a high likelihood
  of TB.

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score 4 3 2 1 0 feature
General General General General General General General
4wlt 2-4w 2wgt Duration of illness
60gt 60-80 80lt Weight for age
Proved VE Reported -VE Family history
positive Tuberculin test
Not improving After 4 w Malnutrition
No response to nonspecific treatment Unexplained fever and night sweats
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Local Local Local Local Local Local Local
Lymph nodes
Joint or bone swelling
Abd. mass or ascites
CNS findings
Angle deformity of the spine
Total score Total score Total score Total score Total score Total score
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TB treatment
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• TB chemotherapy should be based on two important
  microbiological considerations
• The combination of drugs to avoid the development
  of resistance.
• The need for prolonged chemotherapy to prevent
  disease relapse.

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• All mono-therapeutic regimens (real or masked by
  combination with drugs to which bacilli are
  resistant) lead to treatment failure and to the
  development of resistance.
• When three or more drugs are administered, the
  risk of resistance is practically zero.

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Phases of treatment

• The intensive phase
• usually covers the first 2 months of treatment.
• During this phase, most of the bacilli will be
  killed.
• The sputum converts from positive to negative in
  more than 80 of the new patients within the
  first 2 months of treatment.
• The continuation phase
• usually lasts 4-6 months, depending on the
  treatment regimen.
• This phase is intended to eliminate the remaining
  dormant bacilli.
• These dormant bacilli decrease constantly as
  treatment intake progresses.
• Since it is not possible to identify which
  patients still have dormant bacilli, all patients
  should continue their treatment until the end of
  the prescribed period, to limit the number of
  relapses.

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First-line anti-tuberculosis drugs, action and
side effects
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DRUG RECOMMENDED DAILY DOSAGE (DOSE RANGE),mg/kg
Isoniazide (H) 5 (46)
Rifampicin (R) 10 (812)
Pirazinamide (Z) 25 (2030)
Ethambutol (E) 15 (1520)
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Treatment regimens
Continuation Initial Patient Category Treatment category
4/HR 2/SHRZ OR 2/EHRZ New smear ve PTB. New smear ve New forms of extra-Pulmonary TB. I
HRZE means isoniazid rifampicin pyrazinamide
ethambutol.
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Treatment regimens, cont
Continuation Initial Patient Category Treatment category
5/HRE 2/SHRZE then 1/HRZE Sputum smear ve Relapse. Treatment after failure. Treatment after interruption. II
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• Drug-resistant TB
• Drug-resistant TB is a laboratory diagnosis.
• However, drug-resistant TB should be suspected if
  any of the features below are present.

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• Features in the source case suggestive of
  drug-resistant TB
• contact with a known case of drug-resistant TB
• remains sputum smear-positive after 3 months of
  treatment
• history of previously treated TB
• History of treatment interruption.

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• Features of a child suspected of having
  drug-resistant TB
• Contact with a known case of drug-resistant TB
• Not responding to the anti-TB treatment regimen
• Recurrence of TB after adherence to treatment.

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THANK YOU