Miliary Tuberculosis

Definition & Pathogenesis

• Disseminated form of TB characterized by tiny millet seed-sized (1-2 mm) lesions
• Results from massive lymphohematogenous dissemination of M. tuberculosis
• Higher incidence in children under 5 years and immunocompromised

Risk Factors

• Age <5 years
• Malnutrition
• Immunodeficiency states
  • HIV infection
  • Primary immunodeficiencies
  • Immunosuppressive therapy
• Recent TB contact
• Absence of BCG vaccination

Clinical Manifestations

Systemic Symptoms

• Fever (>80% cases)
  • Prolonged duration
  • Evening rise pattern
• Weight loss/failure to thrive
• Night sweats
• Anorexia
• Fatigue

Organ-Specific Symptoms

• Respiratory
  • Cough (non-productive)
  • Dyspnea
  • Hemoptysis (rare)
• Neurological
  • Irritability
  • Meningeal signs
  • Altered consciousness
  • Focal deficits
• Hepatosplenic
  • Hepatomegaly
  • Splenomegaly
  • Jaundice

Physical Examination

• General appearance
  • Toxic look
  • Wasting
  • Pallor
• Respiratory findings
  • Crackles
  • Decreased breath sounds
  • Respiratory distress
• Lymphadenopathy
• Choroid tubercles (pathognomonic)

Diagnostic Approach

Laboratory Studies

• Hematological
  • Complete blood count
    • Pancytopenia
    • Leukemoid reaction
  • ESR (typically elevated)
  • CRP
• Biochemical
  • Liver function tests
  • Renal function
  • Serum electrolytes
  • Blood gases

Microbiological Tests

• AFB microscopy and culture
  • Sputum/gastric aspirate
  • CSF
  • Blood
  • Bone marrow
• GeneXpert MTB/RIF
• Drug susceptibility testing

Imaging Studies

• Chest X-ray
  • Classic miliary pattern
  • 1-2mm nodules
  • Uniform distribution
• CT Chest
  • Higher sensitivity
  • Random nodular pattern
  • Interstitial thickening
• Brain imaging (if CNS symptoms)
  • CT/MRI brain
  • Look for tuberculomas
  • Hydrocephalus

Other Investigations

• Fundoscopy (choroid tubercles)
• Bronchoscopy (selected cases)
• Bone marrow examination
• HIV testing

Treatment Protocol

Anti-tubercular Therapy

• Initial Phase (2 months)
  • Isoniazid (H)
  • Rifampicin (R)
  • Pyrazinamide (Z)
  • Ethambutol (E)
• Continuation Phase (7-10 months)
  • Isoniazid
  • Rifampicin
• Duration: 9-12 months total

Supportive Care

• Respiratory support
  • Oxygen therapy
  • Mechanical ventilation if needed
• Nutrition
  • High protein diet
  • Micronutrient supplementation
  • TPN if needed
• Corticosteroids
  • CNS involvement
  • Severe systemic symptoms
  • ARDS

Critical Aspects

• CNS Involvement
  • Early recognition crucial
  • Longer treatment duration
  • Steroids mandatory
• ARDS Management
  • Protective ventilation
  • Prone positioning
  • ECMO in selected cases
• Immune Reconstitution
  • Monitor for IRIS
  • Adjust therapy accordingly

Monitoring

• Clinical response
  • Daily in acute phase
  • Weekly during recovery
• Laboratory monitoring
  • LFTs monthly
  • CBC weekly initially
• Radiological follow-up
  • Chest X-ray every 2-4 weeks
  • CT as indicated

Outcome Predictors

• Poor Prognostic Factors
  • Age <1 year
  • CNS involvement
  • ARDS
  • Multiple organ dysfunction
  • HIV coinfection
• Mortality Risk
  • 15-20% overall
  • Higher in delayed diagnosis
  • Up to 50% with CNS involvement

Long-term Follow-up

• Growth monitoring
• Neurodevelopmental assessment
• Pulmonary function tests
• Prevention of reactivation