Qualitative evaluation of tuberculin test responses in childhood tuberculosis

1. Qualitative Evaluation of
Tuberculin Test Responses in
Childhood Tuberculosis
Soumya Ranjan Parida
Basic B.Sc. Nursing 4th
year
Sum Nursing College

2. Tuberculin test
• Tuberculin test is still a valuable tool for
diagnosis of acquired immunity against
tuberculosis in children
• Olivier et al observed that qualitative analysis of
Tuberculin skin test responses (LTS) is useful in
the diagnosis of childhood tuberculosis
• The qualitative assessment of Koch (turgid) and
Listeria (non turgid) type of reactions

3. Koch’s type
• 1. Hard induration.
• 2. Well delineated.
• 3. Painful
• 4. Skin changes – vesiculation or bullae,
necrosis

4. Listeria type
• 1. Soft induration.
• 2. Not well delineated.
• 3. Not painful

5. Objective
• To study if different forms of clinical
presentation of tuberculosis in children are
associated with a different type of
tuberculin reaction.

6. MATERIALS AND METHODS
• This cross sectional study, describing Tuberculin skin testing (TST) responses in 268
children (134 cases and 134 controls) less than 12 yr of age was carried out over a
period of 18 months at JIPMER, a tertiary care referral hospital in Pondicherry, India.
The qualitative and quantitative TST responses in various clinical forms of
Tuberculosis were analysed
• children from low income families
• Height in cm and weight in Kg were measured in all children; Quetelet's index (weight
in Kg/ ht. in m2) x 100 was obtained as a measure of nutritional status. A Quetelet
index of < 15 was indicative of malnutrition
• both sexes aged 2 month to 12 yr. Children were randomly selected and then divided
into 2 study groups – cases and controls
• CASES-children who had fulfilled the IUATLD criteria for high possibility of
tuberculosis and subsequently investigated for definitive diagnosis by standard
methods.
• CONTROLS- were BCG vaccinated children with acute upper respiratory tract
infection but otherwise healthy on clinical examination

7. IUATLD CRITERIA
• Criterion Score points in Age group
0-4 yr. 5-14 yr.
• Close contact with a known case of TB 1 1
• Mantoux skin test positive 2 3
• Persistent cough 2 1
• Low weight for age/weight loss 2 2
• Unexplained/prolonged fever 3 3
• Total score must equal/exceed 6 6

8. • Tuberculin tests were carried out by one of the authors.
• All the children in the study were given 0.1 ml of 1 TU (PPD RT-
23) with Tween 80 (manufactured by the BCG vaccine laboratory,
Chennai) intradermally on the volar surface of the left forearm
• Readings of the transverse diameter of induration were taken at
24 hr, 48 hr and 72 hr with a transparent plastic ruler using the
ball point pen technique and recorded meticulously in mm by the
same observer.
• A transverse diameter reading of 10mm was designated as
Tuberculin positive and < 10mm was taken as negative reading
• The qualitative assessment of Koch (turgid) and Listeria
(nonturgid) type of reactions was carried out according to the
criteria of Stanford et al
• Out of 134 cases, 116 children were followed up for a period of 12
months while on standard antituberculous therapy. 18 cases were
lost to follow-up.

9. RESULTS
• Among the 134 controls 128 had negative response to TST. Listeria
type of response was seen in 6 of the controls. These 6 children had
no evidence of tuberculous disease on further evaluation.
• The distribution of cases by tuberculous disease and tuberculin reaction is
presented in Table
Distribution of Cases by Type of Tuberculous Disease and Tuberculin
Reaction
S. Diagnosis Type of Tuberculin Reaction
No Tuberculin positive Tuberculin
Listeria Koch Total negative
1. Pulmonary TB 53 16 69 0
(64.6%) (40%) (56.5%) (0%)
2. TB lymphadenitis 8 13 21 0
(9.7%) (32.5%) (17.2%) (0%)
3. Neurotuberculosis 11 5 16 10
(13.4%) (12.5%) (13.1%) (83.3%)
4. DisseminatedTB 10 6 16 2
(12.1%) (15%) (13.1%) (16.6%)
Total 82 40 122 12

10. •Listeria variant of tuberculin reaction was more common (61%) than
Koch (29%) Among children with Tuberculous lymphadenitis Koch’s
reaction was more common
•Negative tuberculin response (10%) was seen predominantly in children
with neurotuberculosis
•There was no significant association between the BCG scar status and
the type of tuberculin reaction
•Koch's reaction was never seen in children with severe malnutrition
•Only 6% of well nourished children among the cases (QI>15.0) had
negative TST whereas 40% of malnourished children (QI<10.0) had
negative response
•There was significant association between the nutritional status of
children and the type of tuberculin reaction among the entire study group
(c2=6.295 df=2 p= 0.04)
•The grade of disease according to increasing severity and type of
tuberculin reaction ranging from negative to Listeria to Koch’s type were
found to have a strong negative correlation with a correlation coefficient of
-0.245 which was notably significant ( p value 0.004).

11. It is believed that Koch type reactions are related to hypersensitivity and Listeria
type to protective immunity of BCG vaccination.1 The positive TST (Listeria
type) response among 6 control healthy study children could mean cross
reaction to unclassified mycobacteria or related to protective immunity of
intracutaneous BCG. But the distribution of Listeria type response among cases
who had BCG scar and proven disease does not support this view point
The greaterdegree of cutaneous reaction observed in Koch type could mirror
extensive destruction of tissue and spread of infection.
The state of activation and probably sensitization of local macrophages and
lymphocytes influence the clinical picture of the disease
A genetically determined modulation of release of inflammatory mediators as
a possible cause of variation in different individuals was considered by van
Eden et al.5
Many descriptions of childhood tuberculosis refer to the malnourished
condition of the children. The observations on Quetelet index and tuberculin
test support this impression.
In conclusionqualitative TST responses are non-homogeneous among
the various clinical types of childhood tuberculosis. They are not a correlate of
protective immunity with little or no prognostic significance.