LEARN Paediatrics EASY

Intestinal Tuberculosis (Abdominal TB)

Intestinal TB is a form of extrapulmonary tuberculosis caused by Mycobacterium tuberculosis. It most commonly affects the ileocecal region (terminal ileum and cecum) because of abundant lymphoid tissue and slow intestinal transit.

Symptoms

Symptoms usually develop gradually over weeks to months.

* Chronic abdominal pain (most common), often in the right lower abdomen
* Chronic diarrhea (may alternate with constipation)
* Weight loss
* Loss of appetite (anorexia)
* Low-grade fever, especially in the evening
* Night sweats
* Fatigue and weakness
* Abdominal bloating or distension
* Nausea and vomiting (if bowel obstruction develops)
* Blood in stool (uncommon but possible)

Signs

On examination, patients may have:

* Weight loss and cachexia
* Pallor (anemia)
* Fever
* Right lower quadrant tenderness
* A palpable mass in the right iliac fossa (ileocecal mass)
* Abdominal distension
* Ascites (fluid in the abdomen)
* Enlarged abdominal lymph nodes (on imaging)
* Generalized edema if severe malnutrition or protein-losing enteropathy causes marked hypoalbuminemia

Complications

If untreated, intestinal TB can lead to:

* Intestinal obstruction (from strictures)
* Intestinal perforation
* Fistula formation
* Gastrointestinal bleeding
* Severe malnutrition
* Protein-losing enteropathy with hypoalbuminemia and edema

Investigations

* CBC: anemia is common
* ESR and CRP: usually elevated
* Serum albumin: may be low
* Chest X-ray (pulmonary TB may coexist)
* CT abdomen: thickened ileocecal region, enlarged necrotic lymph nodes, ascites
* Colonoscopy with biopsy: ulcers, nodules, strictures, or a deformed ileocecal valve
* Histopathology: caseating granulomas (when present)
* TB PCR (GeneXpert) and mycobacterial culture from biopsy specimens
* Ascitic fluid analysis if ascites is present

Features that strongly suggest intestinal TB

* Chronic abdominal pain
* Weight loss
* Fever and night sweats
* Ileocecal involvement on imaging or colonoscopy
* Necrotic mesenteric lymph nodes
* Response to anti-tuberculous therapy (after diagnosis)

Distinguishing Intestinal TB from Crohn’s Disease

Feature Intestinal TB Crohn’s Disease
Fever Common Less common
Night sweats Common Rare
Pulmonary TB history/contact May be present Absent
Caseating granulomas Typical Rare
Necrotic lymph nodes Common Uncommon
Perianal disease Less common Common
Response to anti-TB therapy Improves No response

microbiological evidence rather than symptoms alone.

Miliary Tuberculosis (TB) in Children :

Miliary tuberculosis is a severe, life-threatening form of disseminated tuberculosis caused by widespread hematogenous (bloodstream) spread of Mycobacterium tuberculosis. It is most common in infants and children under 5 years, especially those with poor immunity or malnutrition.

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Definition

Miliary TB is characterized by the presence of numerous tiny (1–3 mm) granulomas throughout the lungs and often multiple organs, resembling millet seeds, hence the name “miliary.”

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Epidemiology

* Most common in:
* Infants (

Pulmonary Tuberculosis (PTB):

Pulmonary tuberculosis (PTB) is a chronic infectious disease of the lungs caused by Mycobacterium tuberculosis. It spreads through airborne droplet nuclei expelled when a person with active pulmonary TB coughs, sneezes, speaks, or sings.

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Epidemiology

* One of the leading infectious causes of death worldwide.
* Common in low- and middle-income countries.
* Children are at increased risk after close household exposure.
* Risk factors include:
* Close contact with an infectious TB case
* Malnutrition
* HIV infection
* Diabetes mellitus
* Immunosuppressive therapy
* Chronic kidney disease
* Smoking
* Overcrowded living conditions

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Etiology

Organism:

* Mycobacterium tuberculosis
* Acid-fast bacillus (AFB)
* Slow-growing aerobic bacterium

Transmission:

* Airborne inhalation of droplet nuclei
* Not spread through food, utensils, or handshakes

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Pathogenesis

1. Inhalation of bacilli
2. Bacilli reach alveoli
3. Phagocytosis by alveolar macrophages
4. Multiplication within macrophages
5. Cell-mediated immunity develops (2–8 weeks)
6. Granuloma formation
7. Infection may:
* Heal
* Remain latent
* Progress to active disease

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Types

Primary TB

* First infection
* More common in children
* Usually lower or middle lung zones
* Hilar lymphadenopathy common

Post-primary (Secondary) TB

* Reactivation of latent infection
* Common in adolescents and adults
* Upper lobe involvement
* Cavitation is common

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Clinical Features

General

* Fever (often evening rise)
* Weight loss
* Fatigue
* Loss of appetite
* Night sweats

Respiratory

* Cough >2 weeks
* Productive cough
* Hemoptysis
* Chest pain
* Breathlessness (advanced disease)

Children

* Persistent cough
* Failure to thrive
* Fever
* Weight loss
* Lethargy
* History of contact with an adult TB patient

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Physical Examination

* Fever
* Weight loss
* Cervical lymphadenopathy
* Reduced chest expansion
* Crackles
* Bronchial breath sounds
* Signs of pleural effusion (if present)

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Diagnosis

History

* Chronic cough
* Household TB contact
* Previous TB treatment
* HIV risk
* BCG vaccination history

Laboratory Tests

* CBC
* ESR (often elevated)
* CRP
* HIV test (where appropriate)

Microbiological Tests

* Sputum smear for AFB
* Sputum culture (gold standard)
* Nucleic acid amplification test (e.g., GeneXpert MTB/RIF) for rapid diagnosis and rifampicin resistance

Imaging

* Chest X-ray
* CT chest (selected cases)

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Chest X-ray Findings

Primary TB

* Hilar lymphadenopathy
* Segmental consolidation
* Pleural effusion
* Miliary pattern (disseminated disease)

Secondary TB

* Upper lobe infiltrates
* Cavitary lesions
* Fibrosis
* Volume loss

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Tuberculin Skin Test (Mantoux)

* Indicates TB infection, not necessarily active disease.
* May be false negative in immunocompromised patients, severe illness, or very recent infection.

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IGRA (Interferon-Gamma Release Assay)

* Detects TB infection.
* Useful in BCG-vaccinated individuals.
* Does not distinguish latent from active TB.

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Differential Diagnosis

* Bacterial pneumonia
* Lung abscess
* Bronchiectasis
* Fungal lung infections
* Lung malignancy (adolescents/adults)
* Sarcoidosis

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Treatment (Drug-Susceptible Pulmonary TB)

Intensive Phase (2 months)

* Isoniazid (H)
* Rifampicin (R)
* Pyrazinamide (Z)
* Ethambutol (E)

Regimen: 2HRZE

Continuation Phase (4 months)

* Isoniazid
* Rifampicin

Regimen: 4HR

Total duration: 6 months for most uncomplicated pulmonary TB.

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Common Adverse Effects

Drug Important adverse effect
Isoniazid Peripheral neuropathy, hepatitis
Rifampicin Orange discoloration of body fluids, hepatitis
Pyrazinamide Hyperuricemia, hepatitis
Ethambutol Optic neuritis (reduced visual acuity and red-green color discrimination)

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Complications

* Massive hemoptysis
* Bronchiectasis
* Pleural effusion
* Pneumothorax
* Fibrosis
* Respiratory failure
* Miliary TB
* Tuberculous meningitis

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Prevention

* Early diagnosis and treatment of infectious cases
* Contact tracing and screening
* BCG vaccination (reduces severe TB forms in children)
* Good ventilation and infection-control measures in healthcare settings
* Preventive therapy for eligible contacts and individuals with latent TB infection according to local guidelines

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Pediatric Pearls :

* Always ask about household contact in any child with chronic cough or weight loss.
* Young children are more likely to develop severe disseminated TB, including miliary TB and TB meningitis.
* Diagnosis in children often relies on a combination of history of exposure, symptoms, chest imaging, immunologic tests (Mantoux/IGRA), and microbiologic confirmation where possible, as sputum smears are frequently negative.
* GeneXpert is valuable for rapid diagnosis and detection of rifampicin resistance.

High-Yield MRCPCH Points

* Most common symptom: Persistent cough (>2 weeks)
* Most common risk factor in children: Close household contact with an infectious adult
* Gold standard for diagnosis: Mycobacterial culture
* Rapid molecular test: GeneXpert MTB/RIF
* Standard first-line regimen: 2HRZE followed by 4HR (for drug-susceptible pulmonary TB)
* Most serious complications in young children: TB meningitis and miliary TB

Influenza Vaccination:

The influenza vaccine (flu vaccine) is an annual vaccine that protects against infection caused by Influenza viruses. Because influenza viruses change frequently (antigenic drift), the vaccine composition is updated every year to match the circulating strains.

The vaccine:

* Reduces the risk of influenza infection.
* Prevents severe disease and complications.
* Decreases hospitalizations and mortality.
* Reduces transmission within the community.

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Why Influenza Vaccination is Important

Influenza is a contagious viral respiratory illness that may cause:

* Fever
* Cough
* Sore throat
* Runny nose
* Headache
* Muscle pain
* Weakness

Complications include:

* Viral pneumonia
* Secondary bacterial pneumonia
* Otitis media
* Sinusitis
* Myocarditis
* Encephalitis
* Myositis
* Exacerbation of asthma and COPD
* Respiratory failure
* Death

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Types of Influenza Vaccines

1. Inactivated Influenza Vaccine (IIV)

* Killed virus
* Given intramuscularly
* Cannot cause influenza
* Suitable for most people ≥6 months

Examples:

* Quadrivalent inactivated vaccine (QIV)
* Trivalent vaccine (used in some settings)

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2. Live Attenuated Influenza Vaccine (LAIV)

* Live but weakened virus
* Nasal spray
* Healthy people aged 2–49 years
* Avoid in:
* Pregnancy
* Immunocompromised patients
* Severe asthma
* Children receiving aspirin therapy

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3. Recombinant Influenza Vaccine (RIV)

* No egg proteins
* Produced using recombinant DNA technology
* Useful for adults with egg allergy (availability varies by country)

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4. High-dose Influenza Vaccine

Contains four times more antigen.

Recommended for:

* Adults ≥65 years

Provides:

* Better immune response
* Better protection against severe influenza

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5. Adjuvanted Influenza Vaccine

Contains an adjuvant to enhance the immune response.

Recommended for:

* Older adults

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Vaccine Composition

Most current vaccines are quadrivalent, containing four strains:

* Influenza A (H1N1)
* Influenza A (H3N2)
* Influenza B (Victoria lineage)
* Influenza B (Yamagata lineage may be omitted in newer formulations depending on current recommendations)

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Mechanism of Action

The vaccine stimulates the immune system to produce:

* Neutralizing antibodies (especially against hemagglutinin)
* Memory B cells
* T-cell responses

Protection develops in about 2 weeks.

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Indications

Annual vaccination is recommended for everyone aged ≥6 months unless contraindicated.

High-risk groups

* Children 6 months–5 years
* Adults ≥65 years
* Pregnant women
* Healthcare workers
* Residents of nursing homes
* Chronic lung disease
* Chronic heart disease
* Diabetes
* Chronic kidney disease
* Chronic liver disease
* Neurological disorders
* Obesity (BMI ≥40)
* Immunocompromised patients

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Timing

Vaccinate:

* Before the influenza season begins.
* Ideally 2–4 weeks before influenza circulation.

If missed, vaccinate at any time while influenza viruses are circulating.

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Dosage Schedule

Children 6 months–8 years

First influenza vaccination:

* 2 doses
* 0.5 mL each
* 4 weeks apart

If previously received ≥2 doses before:

* Only 1 annual dose

Children ≥9 years

* One dose annually

Adults

* One dose annually

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Route of Administration

Intramuscular injection:

* Infants: Anterolateral thigh
* Older children: Deltoid muscle
* Adults: Deltoid muscle

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Storage

* Store at 2–8°C
* Never freeze
* Protect from light
* Maintain the cold chain

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Contraindications

Absolute:

* Severe allergic reaction (anaphylaxis) after a previous influenza vaccine or to a vaccine component.

Relative:

* Moderate or severe acute illness (vaccinate after recovery).
* History of Guillain–Barré syndrome within 6 weeks after a previous influenza vaccine (individual risk assessment required).

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Side Effects

Common

* Injection-site pain
* Redness
* Swelling
* Mild fever
* Fatigue
* Headache
* Muscle aches

Rare

* Allergic reaction
* Febrile seizures (young children; uncommon)
* Guillain–Barré syndrome (very rare)

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Effectiveness

Influenza vaccine effectiveness varies each season because of:

* Matching of vaccine strains to circulating viruses
* Age
* Immune status

Average effectiveness:

* 40–60% against symptomatic influenza in seasons with a good match.

Even if infection occurs, vaccination significantly reduces:

* ICU admission
* Hospitalization
* Severe complications
* Death

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Influenza Vaccine in Special Populations

Pregnancy

* Recommended during any trimester.
* Protects both mother and infant during the first months after birth.

Breastfeeding

* Safe and recommended.

Egg Allergy

* Most people with egg allergy can safely receive any age-appropriate influenza vaccine under current recommendations.

Immunocompromised Patients

* Use inactivated influenza vaccine.
* Avoid live attenuated vaccine.

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Co-administration with Other Vaccines

Influenza vaccine can be given at the same visit as:

* COVID-19 vaccine
* Pneumococcal vaccine
* Routine childhood vaccines

Use different injection sites if multiple injectable vaccines are administered.

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Benefits

* Prevents influenza infection
* Reduces transmission
* Decreases absenteeism from school and work
* Prevents complications
* Reduces hospital admissions
* Lowers mortality
* Protects vulnerable populations through community immunity

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Frequently Asked Questions

Can the flu vaccine cause influenza?
No. Injected influenza vaccines do not contain live virus capable of causing influenza.

How long does protection last?
Approximately 6–12 months, which is why annual vaccination is recommended.

Why is it needed every year?
Because influenza viruses change frequently and vaccine-induced immunity decreases over time.

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Key Exam Points (MBBS/FCPS/MD)

* Annual vaccination for everyone ≥6 months.
* Protection begins about 2 weeks after vaccination.
* Children 6 months–8 years receiving influenza vaccine for the first time need 2 doses (4 weeks apart).
* Pregnant women should be vaccinated during any trimester.
* Store vaccine at 2–8°C; do not freeze.
* Inactivated vaccine is preferred for immunocompromised patients and is safe in pregnancy.
* Vaccine effectiveness is typically 40–60%, but it substantially reduces severe disease, hospitalization, and death.