Pulmonary Tuberculosis in Children: Clinical Case and Viva QnA
Clinical Case: Pulmonary Tuberculosis in Children
Case Presentation
A 6-year-old boy presents with a 3-month history of persistent cough, intermittent fever, and weight loss. His mother reports night sweats and decreased appetite. The family recently immigrated from a high TB-endemic country.
Physical Examination
- Weight: Below the 5th percentile for age
- Temperature: 38.5°C
- Respiratory rate: 28 breaths/min
- Chest auscultation: Bronchial breathing in the right upper zone
- Palpable cervical lymphadenopathy
Investigations
- Chest X-ray: Right upper lobe infiltrate with hilar lymphadenopathy
- Mantoux test: 18mm induration
- IGRA (QuantiFERON-TB Gold): Positive
- Sputum microscopy: Acid-fast bacilli seen
- GeneXpert MTB/RIF: Mycobacterium tuberculosis detected, Rifampicin resistance not detected
- HIV test: Negative
Diagnosis and Management
Diagnosed with pulmonary tuberculosis. Started on standard four-drug regimen: Isoniazid, Rifampicin, Pyrazinamide, and Ethambutol. Contact tracing initiated for family members.
5 Varieties of Presentation of Pulmonary Tuberculosis in Children
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Primary Pulmonary TB
Most common in young children. Features include persistent non-remitting cough, low-grade fever, and failure to thrive. Chest X-ray may show hilar lymphadenopathy and/or lung infiltrates.
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Reactivation TB (Post-primary)
More common in adolescents. Presents with chronic cough, hemoptysis, weight loss, and night sweats. Chest X-ray often shows upper lobe infiltrates and cavitations.
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Miliary TB
Severe form seen in young or immunocompromised children. Presents with high fever, severe weight loss, respiratory distress, and sometimes meningeal signs. Chest X-ray shows diffuse miliary nodules.
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Endobronchial TB
Presents with persistent wheezing, cough, and sometimes atelectasis due to bronchial obstruction. May mimic foreign body aspiration or asthma.
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Pleural TB
More common in older children and adolescents. Presents with chest pain, dry cough, and sometimes fever. Chest X-ray shows pleural effusion, often unilateral.
Viva Questions and Answers: Pulmonary Tuberculosis in Children
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Q: What is the causative agent of tuberculosis and how is it transmitted?
A: Tuberculosis is caused by Mycobacterium tuberculosis. It is primarily transmitted through inhalation of airborne droplet nuclei containing the bacteria, usually from an adult with active pulmonary TB.
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Q: How does the pathogenesis of primary TB in children differ from post-primary TB in adults?
A: In children, primary TB typically results from initial infection, leading to the formation of a Ghon focus and lymph node involvement (primary complex). Progression to disease can occur rapidly. In adults, post-primary TB often results from reactivation of latent infection, typically affecting the upper lobes with cavitation.
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Q: What are the key risk factors for TB infection and disease progression in children?
A: Key risk factors include:
- Close contact with an infectious TB case, especially household contacts
- Age < 5 years
- HIV infection or other immunosuppressive conditions
- Malnutrition
- Living in high TB-endemic areas
- Poverty and overcrowding
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Q: What are the typical clinical features of pulmonary TB in children?
A: Typical features include:
- Persistent, non-remitting cough for > 2 weeks
- Low-grade fever
- Weight loss or failure to thrive
- Night sweats
- Fatigue and reduced playfulness
- Occasionally, hemoptysis in older children
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Q: How does the clinical presentation of TB differ between young children and adolescents?
A: Young children often present with primary TB featuring non-specific symptoms like failure to thrive, fever, and lymphadenopathy. Adolescents may present more like adults with reactivation TB, including productive cough, hemoptysis, and cavitary lesions on chest X-ray.
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Q: What is the role of tuberculin skin test (TST) in diagnosing TB in children?
A: TST is used to detect TB infection. In children, induration ≥10mm is considered positive (≥5mm in high-risk groups). However, TST has limitations including cross-reactivity with BCG vaccination and non-tuberculous mycobacteria, and false negatives in immunocompromised children or severe TB.
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Q: How do Interferon-Gamma Release Assays (IGRAs) compare to TST in pediatric TB diagnosis?
A: IGRAs, like QuantiFERON-TB Gold, are more specific than TST as they are not affected by BCG vaccination. They may be more sensitive in older children and adolescents. However, they may have reduced sensitivity in young children and may not distinguish between latent TB infection and active disease.
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Q: What imaging studies are commonly used in diagnosing pediatric pulmonary TB?
A: Common imaging studies include:
- Chest X-ray: Primary tool, may show hilar lymphadenopathy, lung infiltrates, or cavitations
- Chest CT: More sensitive, useful for detecting lymphadenopathy and early parenchymal changes
- Ultrasonography: Useful for guided procedures and evaluating pleural effusions
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Q: What are the challenges in obtaining bacteriological confirmation of TB in children?
A: Challenges include:
- Difficulty in obtaining good quality sputum samples, especially in young children
- Paucibacillary nature of pediatric TB, leading to low sensitivity of smear microscopy
- Need for invasive procedures like gastric aspirates or induced sputum
- Lower culture positivity rates compared to adults
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Q: What is the role of GeneXpert MTB/RIF in pediatric TB diagnosis?
A: GeneXpert MTB/RIF is a rapid molecular test that detects M. tuberculosis and rifampicin resistance. It has higher sensitivity than smear microscopy and provides results within hours. WHO recommends it as the initial diagnostic test in children suspected of having TB or multidrug-resistant TB.
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Q: What is the standard first-line treatment regimen for drug-susceptible pulmonary TB in children?
A: The standard regimen consists of:
- 2-month intensive phase: Isoniazid, Rifampicin, Pyrazinamide, and Ethambutol
- 4-month continuation phase: Isoniazid and Rifampicin
Ethambutol may be omitted in non-severe disease and where HIV prevalence is low.
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Q: How are drug doses calculated for children, and what are the recommended dosages?
A: Doses are calculated based on weight. WHO recommended dosages:
- Isoniazid: 10 mg/kg (range 7-15 mg/kg); maximum 300 mg/day
- Rifampicin: 15 mg/kg (range 10-20 mg/kg); maximum 600 mg/day
- Pyrazinamide: 35 mg/kg (range 30-40 mg/kg)
- Ethambutol: 20 mg/kg (range 15-25 mg/kg)
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Q: What is the approach to managing a child with suspected drug-resistant TB?
A: Management involves:
- Rapid molecular testing for rifampicin resistance
- Referral to a specialist experienced in managing pediatric drug-resistant TB
- Designing a regimen based on the resistance pattern, often including second-line drugs
- Longer treatment duration, typically 9-18 months or more
- Close monitoring for adverse effects and treatment response
- Addressing nutritional needs and providing psychosocial support
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Q: How is treatment response monitored in children with pulmonary TB?
A: Monitoring includes:
- Clinical assessment: Symptom resolution, weight gain
- Radiological follow-up: Chest X-rays at 2-3 months and end of treatment
- Microbiological follow-up in initially bacteriologically confirmed cases
- Monitoring for adverse drug reactions
- Adherence assessment
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Q: What are the potential adverse effects of first-line anti-TB drugs in children?
A: Potential adverse effects include:
- Isoniazid: Hepatotoxicity, peripheral neuropathy
- Rifampicin: Hepatotoxicity, gastrointestinal upset, orange discoloration of body fluids
- Pyrazinamide: Hepatotoxicity, arthralgia
- Ethambutol: Optic neuritis (rare in children at recommended doses)
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Q: What is the role of adjunctive corticosteroids in pediatric TB?
A: Corticosteroids are recommended in:
- TB meningitis
- Severe miliary TB
- Endobronchial TB with severe airway obstruction
- Pericardial TB
- Severe pleural effusions or ascites
They help reduce inflammation and prevent complications.
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Q: How is TB-HIV co-infection managed in children?
A: Management includes:
- Early initiation of antiretroviral therapy (ART)
- Attention to potential drug interactions between ART and anti-TB drugs
- Cotrimoxazole preventive therapy
- Close monitoring for immune reconstitution inflammatory syndrome (IRIS)
- Nutritional support
- Integrated care addressing both conditions
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Q: What is the approach to contact investigation when a child is diagnosed with pulmonary TB?
A: The approach involves:
- Identifying and screening all household contacts, especially children < 5 years and HIV-positive individuals
- Evaluating contacts for active TB
- Providing preventive therapy to eligible contacts without active TB
- Identifying the likely source case
- Extending investigation to other close contacts as needed
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Q: What is TB preventive therapy and when is it indicated in children?
A: TB preventive therapy involves giving anti-TB drugs to prevent progression from infection to disease. It's indicated for:
- Children < 5 years who are household contacts of pulmonary TB cases
- HIV-positive children of any age who are TB contacts or TST/IGRA positive
- Children on immunosuppressive therapy
Common regimens include 6-9 months of isoniazid or 3 months of isoniazid plus rifampicin.
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Q: How does BCG vaccination impact TB prevention and diagnosis in children?
A: BCG vaccination:
- Provides protection against severe forms of TB in young children (e.g., miliary TB, TB meningitis)
- Has variable efficacy in preventing pulmonary TB
- Can cause false-positive TST results, complicating interpretation
- Does not interfere with IGRA results
- Is recommended at birth in high TB burden countries
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Q: What are the key challenges in diagnosing and managing pediatric TB in resource-limited settings?
A: Challenges include:
- Limited access to diagnostic tools like GeneXpert and culture facilities
- Reliance on clinical diagnosis due to difficulties in bacteriological confirmation
- Shortage of pediatric drug formulations
- Difficulties in drug dosing and administration
- Limited capacity for managing drug-resistant TB
- Challenges in contact tracing and preventive therapy implementation
- Poor healthcare infrastructure and limited access to specialized care
- Socioeconomic factors affecting treatment adherence and follow-up
- Limited resources for addressing nutritional needs of TB-affected children
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Q: What are the long-term sequelae of pulmonary TB in children?
A: Potential long-term sequelae include:
- Bronchiectasis
- Chronic lung disease with restrictive or obstructive patterns
- Broncholiths from calcified lymph nodes
- Bronchoesophageal fistula
- Aspergilloma in healed cavities
- Growth impairment
- Psychological impacts from prolonged illness and treatment
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Q: How does extrapulmonary TB present in children, and what are the diagnostic approaches?
A: Common extrapulmonary presentations include:
- Lymph node TB: Cervical lymphadenopathy, diagnosed by fine-needle aspiration
- TB meningitis: Altered mental status, focal neurological signs; diagnosed by CSF analysis and neuroimaging
- Bone and joint TB: Chronic pain, swelling; diagnosed by imaging and biopsy
- Abdominal TB: Ascites, abdominal masses; diagnosed by ultrasound, CT, and ascitic fluid analysis
Diagnosis often requires a combination of clinical, radiological, and where possible, microbiological evidence.
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Q: What are the current research priorities in pediatric TB?
A: Current research priorities include:
- Developing more sensitive and child-friendly diagnostic tools
- Identifying biomarkers for disease progression and treatment response
- Developing shorter treatment regimens and child-friendly formulations
- Improving strategies for preventing TB in children
- Developing an effective TB vaccine for all age groups
- Optimizing management strategies for drug-resistant TB in children
- Understanding the long-term impacts of TB on child health and development
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Q: How does nutritional status impact TB in children, and what nutritional interventions are recommended?
A: Nutritional status impacts TB in children by:
- Increasing susceptibility to TB infection and disease progression in malnourished children
- Affecting treatment outcomes and risk of relapse
- Influencing immune response and drug metabolism
Recommended interventions include:
- Regular nutritional assessment during TB treatment
- Providing energy-dense and protein-rich foods
- Micronutrient supplementation, especially Vitamin D and Zinc
- Addressing underlying causes of malnutrition
- Integrating nutritional support into TB care programs
