✅ Model Answer:
• Diffuse, bilateral 1-2 mm nodules – "millet seed" appearance.
• Fine nodular opacities throughout both lung fields.
• Ground-glass opacification with discrete nodules.
• No cavitation (unlike reactivation TB).
• May have mediastinal lymphadenopathy.
• Diagnosis: Miliary tuberculosis.

✅ Model Answer:
• Miliary TB results from hematogenous dissemination of Mycobacterium tuberculosis.
• Mechanism: Rupture of a primary pulmonary focus (Ghon focus) or a caseous lymph node into a blood vessel → bacilli spread through the bloodstream to multiple organs.
• The name "miliary" comes from the millet seed-sized nodules (1-2 mm) that form in the lungs and other organs.
• Risk factors: Young age (<5 years), immunodeficiency (HIV, malnutrition), immunosuppressive therapy, and recent primary TB infection.
• Common sites of dissemination: Lungs (most common), liver, spleen, bone marrow, CNS (meningitis), kidneys, and eyes (choroid tubercles).

✅ Model Answer:
• Systemic: Prolonged fever, night sweats, weight loss, failure to thrive, lethargy, anorexia.
• Respiratory: Cough (often non-productive), tachypnoea, respiratory distress.
• Abdominal: Hepatosplenomegaly, abdominal pain, jaundice (hepatic involvement).
• Neurological: Tuberculous meningitis (headache, vomiting, altered consciousness, seizures, cranial nerve palsies).
• Ocular: Choroid tubercles – pale, yellow-white lesions on fundoscopy (pathognomonic for miliary TB).
• Hematological: Anemia, leukopenia, thrombocytopenia (bone marrow involvement).
• Lymphatic: Generalized lymphadenopathy.

✅ Model Answer:
• Choroid tubercles are small, pale, yellow-white lesions on the retina (fundoscopy).
• They are pathognomonic for miliary tuberculosis.
• Mechanism: Hematogenous spread of TB bacilli to the choroid plexus of the eye.
• Clinical significance:
- Confirms the diagnosis of miliary TB.
- Indicates disseminated disease and high risk of CNS involvement.
- If choroid tubercles are present, the patient is likely to have tuberculous meningitis and should receive corticosteroids.
- Fundoscopy should be performed in all children with suspected miliary TB.

✅ Model Answer:
• This is tuberculous meningitis – a complication of miliary TB.
• Management:
1. Lumbar puncture – CSF analysis (lymphocytic pleocytosis, elevated protein, low glucose, AFB smear/culture, TB PCR).
2. Start anti-TB therapy: HRZE (isoniazid, rifampin, pyrazinamide, ethambutol) – all drugs cross the blood-brain barrier.
3. Corticosteroids: Dexamethasone or prednisolone (to reduce inflammation and prevent complications like hydrocephalus).
4. CT/MRI brain: To assess for hydrocephalus, tuberculomas, or infarcts.
5. Monitor: Neurological status, seizure control, and ICP.

✅ Model Answer:
• Intensive phase (2 months):
- HRZE – Isoniazid (H), Rifampin (R), Pyrazinamide (Z), Ethambutol (E).
- Doses: H 10-15 mg/kg, R 10-20 mg/kg, Z 30-40 mg/kg, E 15-25 mg/kg (max 2 g).
• Continuation phase (4 months):
- HR – Isoniazid + Rifampin.
- Total duration: 6 months (minimum).
• If CNS involvement (meningitis):
- Continuation phase extended to 10-12 months.
- Add corticosteroids (dexamethasone or prednisolone) for 4-8 weeks.
• Directly Observed Therapy (DOT): Essential for adherence.

✅ Model Answer:
• This could be due to:
1. Hepatic involvement from miliary TB (granulomatous hepatitis).
2. Drug-induced liver injury (DILI) – especially from isoniazid, rifampin, and pyrazinamide.
• Management:
1. Rule out other causes: Viral hepatitis, biliary obstruction.
2. LFTs: Monitor ALT, AST, bilirubin, alkaline phosphatase.
3. If DILI is suspected:
- Stop hepatotoxic drugs (usually stop H or Z first).
- Consider desensitization or substitution (e.g., replace H with a fluoroquinolone).
4. If hepatic TB: Continue anti-TB therapy and manage with supportive care (if no DILI).
5. Monitor: LFTs weekly until stable.

✅ Model Answer:
• Miliary TB: Diffuse 1-2 mm nodules, fever, hepatosplenomegaly, choroid tubercles.
• Pulmonary fungal infections: Histoplasmosis, coccidioidomycosis (in endemic areas).
• Metastatic disease: Neuroblastoma, lymphoma, leukemia (uncommon in this pattern).
• Sarcoidosis: Bilateral hilar lymphadenopathy with reticular nodules (rare in children).
• Pneumoconiosis: Occupational exposure (rare in children).
• Viral pneumonia: Diffuse bilateral infiltrates (but usually not discrete miliary nodules).
• Pneumocystis jirovecii: Ground-glass opacities, usually in immunocompromised.

✅ Model Answer:
• IGRAs (QuantiFERON-TB Gold, T-SPOT.TB) are blood tests that detect T-cell responses to TB antigens.
• Advantages over TST:
- No cross-reaction with BCG vaccination.
- No boosting effect.
- Better specificity.
• Limitations in miliary TB:
- False-negative results are common due to immunosuppression (malnutrition, HIV, disseminated disease).
- A negative IGRA does NOT exclude TB.
• Role: May be used as an adjunct to TST and chest X-ray, but NOT as a sole diagnostic test.
• In miliary TB: If clinically suspected, start treatment even if IGRA is negative.

✅ Model Answer:
• Hydrocephalus is a common complication of tuberculous meningitis.
• Management:
1. CT/MRI brain: To assess the degree of hydrocephalus.
2. Corticosteroids: Dexamethasone (0.15-0.3 mg/kg/day) to reduce inflammation and CSF outflow obstruction.
3. Serial lumbar punctures: To reduce CSF pressure (if communicating hydrocephalus).
4. Ventriculoperitoneal (VP) shunt: If hydrocephalus is progressive or non-communicating.
5. Continue anti-TB therapy for 12 months.
6. Monitor: Neurological status, cranial nerve function, and visual acuity.

✅ Model Answer:
• This is likely a drug reaction – most commonly due to isoniazid or rifampin.
• Management:
1. Assess severity: If mild rash (no systemic symptoms), continue treatment and monitor.
2. If severe (fever, desquamation, mucosal involvement): Stop all anti-TB drugs and consider drug desensitization or substitution.
3. Alternative regimens:
- Replace H with a fluoroquinolone (levofloxacin, moxifloxacin).
- Replace R with a fluoroquinolone or streptomycin.
4. Monitor: Liver function, renal function, and clinical improvement.
5. Consult pediatric infectious disease specialist.