Thyroid Tuberculosis in Children

Key Points

• Extremely rare form of extrapulmonary tuberculosis
• Thyroid resistance to TB due to high iodine content
• Can mimic thyroid malignancy
• Often associated with disseminated TB
• Better prognosis compared to other endocrine TB

Pathophysiology

• Modes of Spread:
  • Hematogenous dissemination
  • Lymphatic spread
  • Direct extension from adjacent structures
  • Military spread
• Pathological Changes:
  • Granulomatous inflammation
  • Caseating necrosis
  • Cold abscess formation
  • Fibrosis in chronic cases

Risk Factors

• Immunocompromised status
• Previous TB infection
• Endemic area residence
• Cervical lymphadenopathy
• Malnutrition
• Poor socioeconomic conditions

Clinical Manifestations

Common Presentations

• Local Symptoms:
  • Painless thyroid swelling
  • Thyroid nodules
  • Cervical lymphadenopathy
  • Dysphagia
  • Hoarseness
• Systemic Symptoms:
  • Low-grade fever
  • Weight loss
  • Night sweats
  • Fatigue

Thyroid Function Patterns

• Usually euthyroid
• Subclinical hypothyroidism
• Rare cases of thyrotoxicosis
• Thyroid function abnormalities in extensive disease

Physical Findings

• Thyroid Examination:
  • Firm to hard swelling
  • Single or multiple nodules
  • Sinus tract formation
  • Local tenderness
• Associated Findings:
  • Cervical lymphadenopathy
  • Skin changes
  • Fistula formation

Diagnostic Approach

Laboratory Studies

• Thyroid Function Tests:
  • TSH levels
  • Free T4
  • Free T3
  • Thyroid antibodies
• TB Workup:
  • ESR and CRP
  • Tuberculin skin test
  • Interferon-gamma release assay
  • PCR for MTB
• Other Tests:
  • Complete blood count
  • Calcium profile
  • HIV testing

Imaging Studies

• Ultrasound Features:
  • Hypoechoic lesions
  • Complex cystic areas
  • Calcifications
  • Associated lymphadenopathy
• CT/MRI Findings:
  • Extent of disease
  • Adjacent structure involvement
  • Enhancement patterns
• Nuclear Imaging:
  • Cold nodules on scan
  • Functional status assessment

Definitive Diagnosis

• FNAC:
  • Epithelioid granulomas
  • Caseous necrosis
  • Langhan's giant cells
• Core Biopsy:
  • Histopathological confirmation
  • Culture studies
  • PCR testing

Management Protocol

Anti-tubercular Therapy

• Initial Phase (2-3 months):
  • Isoniazid
  • Rifampicin
  • Pyrazinamide
  • Ethambutol
• Continuation Phase (4-7 months):
  • Isoniazid
  • Rifampicin
• Monitoring:
  • Clinical response
  • Drug side effects
  • Compliance

Surgical Management

• Indications:
  • Large abscess drainage
  • Diagnostic uncertainty
  • Pressure symptoms
  • Non-resolving disease
• Procedures:
  • Abscess drainage
  • Hemithyroidectomy
  • Total thyroidectomy
  • Lymph node excision

Supportive Care

• Thyroid hormone replacement if needed
• Nutritional support
• Regular monitoring
• Pain management

Outcomes and Follow-up

Monitoring Protocol

• Clinical Monitoring:
  • Symptom resolution
  • Size of thyroid swelling
  • Local complications
  • Growth parameters
• Laboratory Follow-up:
  • Thyroid function tests
  • Inflammatory markers
  • Treatment response
• Imaging Follow-up:
  • Ultrasound monitoring
  • Resolution of lesions
  • Structural changes

Prognosis

• Generally good with treatment
• Risk factors for poor outcome:
  • Delayed diagnosis
  • Extensive disease
  • Immunocompromised status
  • Drug resistance
• Long-term Considerations:
  • Thyroid function monitoring
  • Scar formation
  • Risk of recurrence
  • Growth monitoring