Pediatric TB - Guidelines, Diagnosis And Management

Latest Terminology and IAP-NTEP 2020 Guidelines

• Latent tuberculosis infection (LTBI): When there is no sign of clinically active TB, a sustained immunological response to Mycobacterium tuberculosis antigen stimulation occurs.
• RR-TB: Resistance to rifampicin (R), either alone or in combination with medication resistance.
• Isoniazid resistance in HR-TB (H): However, it is susceptible to rifampicin.
• Multidrug-resistant tuberculosis (MDR-TB): Resistance to alternative first-line TB medications with or without resistance to both H and R.
• Pre-XDR TB: This type of TB is very resistant to drugs. MDR-TB/RR-TB is the kind. and unaffected by levo/moxi fluoroquinolones of any kind.
• XDR-TB is a combination of pre-XDR-TB and resistance to at least one group A medication, such as linezolid or bedaquiline.

Line Probe Assay = LPA

These multiplex-NAAT assays look for mutations linked to drug resistance using PCR and reverse hybridization techniques.
• FIRST LINE/FL LPA - it finds mutations in the katG, the inhA promoter area, and the rpoB gene for R and H resistance, respectively.
• SECOND LINE/SL LPA - identifies mutations in the FQ resistance genes gyrA and gyrB, and the SLID resistance genes rrs and eis (low level kanamycin resistance). 

NAAT V/S LPA

All patients who are suspected of having tuberculosis are first evaluated using the sensitive test NAAT. In addition, LPA is a multiplex-based NAAT used to assess DR-TB in patients with confirmed tuberculosis.
The turnaround time for NAAT is 2 hours, compared to 3–4 days for LPA.  LPA has a lesser sensitivity and is only helpful in smear-positive or culture-positive cases, whereas NAAT has a high overall sensitivity and is therefore utilized for diagnosis.

Also Read: Rapid Acquisition Of Key Concepts Infections

Diagnostic Algorithm For Pediatric TB: LAP- Ntep 2020 Guidelines

 If there has been an ongoing fever or constant cough for more than two weeks, it is suspected.  A weight loss of more than 5%, no weight gain in three months, or a SAM child's mishandling.  There is no guarantee that these problems are connected to a history of tuberculosis contact during the previous two years.  A screening examination, such as a chest X-ray, is completed. An X-ray of the chest can first be extremely suggestive, show non-specific shadows, or just be a regular X-ray.

 If the X-ray is normal, EPTB testing will be performed; if the issue worsens, CECT will be taken into consideration.  Patients are prescribed oral antibiotics for 5-7 days in non-specific shadows.  Sputum specimens are removed in strongly suspicious cases and used for NAAT.
NAAT is used if the shadows or symptoms don't go away after taking antibiotics. As seen in the graphic below, NAAT can have both positive and negative effects. 

If NAAT is positive, the patient is classified as a TB case with microbiologic confirmation. Rifampicin resistance is examined in this instance. Use the DR-TB guidelines if it's RR-TB.  Patients receive first-line ATT (2HRZE + 4HRE) if there is no RR-TB. To check for MTB, lymph node aspiration is considered if NAAT results are negative. 
For NAAT, different biological samples are taken into account.
Direct the patient to the more senior division. The trial can be administered as a clinically diagnosed probable tuberculosis case if the symptoms are persistent and no alternative diagnosis is possible.
In TB cases, HIV testing must to be provided as well.

Also Read: Anaerobic Bacterial Infections In Children

Key Points To Note

The most recent IAP-NTEP 2020 recommendations adhere to the Universal Drug Sensitivity Testing (U-DST) premise. It states that every patient should undergo microbiological examinations, such as NAAT, where a biological specimen can be collected. While NAAT is more sensitive than smears, certain paucibacillary instances may still go unnoticed. Therefore, TB is not ruled out by a negative NAAT. Prior to NAAT, CXR is still utilized as a screening test. As part of the first assessment of pediatric TB, ribampicin resistance testing is a standard procedure in all microbiologically proven NAAT +ve cases. 

Diagnostic Algorithm For Evaluation Of Suspected Pediatric DRTB

All drug-resistant tuberculosis (DRTB) cases that are resumed undergo either MGIT or NAAT culture.  Mycobacteria growth indicator tubes, or MGITs. Either RR-TB or RS-TB are possible.  An additional line LPA is carried out if it is RRTB. The patient will either be resistant to fluoroquinolone and second-line injectables or sensitive to them. The first line (FL-LPA) is executed if it is RSTB. As seen in the graphic below, the FL-LPA will provide information regarding H-sensitive or H-resistant.

Management Of Pediatric TB

Rifampicin Sensitive Pediatric TB

If patients have ever had TB treated in the past (relapse patients, treatment failure, lost to follow up of patients), or if they have clinically diagnosed pulmonary TB, extrapulmonary TB, microbiologically diagnosed pulmonary TB, or microbiologically diagnosed extrapulmonary TB. 

In these situations, a single medication regimen (2HRZE + 4HRE) is used.  When treating people with tuberculosis earlier, be aware of the potential for drug-resistant TB.

Exceptions

Rather than being 4 months, the consolidation period will now last 7 months for patients with disseminated tuberculosis.  The consolidation phase will take ten months for individuals with spinal, bone and joint, and central nervous system TB.

Management Of Resistant TB IAP-NTEP 2020 Guidelines

Drug Regimen for Pediatric DR-TB: IAP-NTEP 2020

This is the only regimen in pediatric TB where no distinct and rigorous consolidation periods are described; instead, a uniphasic regimen is employed for six months. RZE is used in conjunction with fluoroquinolone.

In the case of MDR -TB, MDR-TB + FQ resistance, and XDR-TB same regimen are followed, shown in the image below.

In the case of MDR-TB + FQ resistance, levofloxacin alone will not be useful along with all the regimens.
The MDR-TB ( extrapulmonary) regimen used is shown in the table below - 

With these modifications, in the case of young children(less than 6 years), this regime is slightly modified.

Additional Things To Remember Regarding

 As of right now, there is no Category I or II for first-line TB treatment.
Treatment response cannot be tracked using molecular techniques.
Therapy response: Initially, clinical visits should occur every 2-4 weeks, and subsequently, every 4–8 weeks.  You should consider getting a chest X-ray every 4–8 weeks after the initial 8-week examination.
All children on an INH-containing regimen should receive vitamin B6, or pyridoxine.

Role of Steroids in Childhood TB

Endobronchial TB with localized emphysema, segmental pulmonary lesions, or respiratory distress.Severe miliary TB (if alveolocapillary block is suspected)CNS TB - in this, steroids are used, and TB meningitis is an indicator.TB pericardial effusion will be indicated but not in TB pleural effusion.

Drug and Dosage

Prednisolone is used at 1-2 mg/kg/day for 4-6 weeks. For preventive therapy, no change is done in the regimen.

Also Read: Mumps : Virus Characteristics, Pathology and Pathogenesis, Investigations, Complications and Treatment

Hope you found this blog helpful for your NEET SS Pediatrics Infections preparation. For more informative and interesting posts like these, keep reading PrepLadder’s blogs.