Sarcoidosis

Multisystem granulomatous (type IV) disorder to an unknown antigen

Aetiology

  • Unknown aetiology
  • May occur at any age but is usually seen in adults under the age of 50 years
  • Occurs more frequently in Afro-Caribbean patients, who are also more likely to develop extrapulmonary or chronic disease
  • Higher incidence in females

Pathophysiology

  • Inhalation of unknown antigen stimulates alveolar macrophages, CD4+ T cells, CD8+ T cells and B cells
  • Failure to clear antigen → persistent stimulation and granuloma formation → tissue damage and fibrosis

Clinical presentation

  • Typically presents with bilateral hilar lymphadenopathy, pulmonary infiltration and skin or eye lesions
  • Up to 50% of patients are asymptomatic and were diagnosed on the basis of routine CXR

Symptoms

  • Constitutional - fever, weight loss, fatigue
  • Respiratory - cough, dyspnoea, wheeze, chest pain
  • Wide range of other non-pulmonary signs e.g. hepatomegaly, splenomegaly, uveitis, erythema nodosum, skin infiltration

Signs

  • Lymphadenopathy
  • Crackles on lung auscultation

Investigations

  • Bloods - elevated serum ACE level, raised CRP, hypercalcaemia
  • CXR may show bilateral hilar or paratracheal lymphadenopathy
  • High-resolution CT scanning is often used to detect interstitial lung disease
  • Lung function tests show restrictive defect in severe, progressive cases
  • Transbronchial biopsy - non-caseating granulomata

Management

Acute

  • Self-limiting
  • NSAIDs
  • Oral steroids if vital organ affected

Chronic

  • Oral steroids usually needed
  • May need immunosuppression e.g. methotrexate, azathioprine

Monitoring

  • Monitor both acute and chronic disease with CXR and PFTs for several years - often relapses