Makindo Medical Notes

Related Subjects: |Idiopathic Pulmonary Fibrosis |Diffuse Parenchymal Lung disease |Asbestos Related Lung disease |Sarcoidosis |Coal Worker's Pneumoconiosis |Silicosis |Farmer's Lung |Cryptogenic Organising Pneumonia (COP-BOOP) |Extrinsic Allergic alveolitis (Hypersensitivity) |Byssinosis |Pneumoconiosis |Cor Pulmonale

Sarcoidosis is a systemic inflammatory disease characterized by the formation of non-caseating granulomas in various organs. The exact cause is unknown, but it is thought to result from an exaggerated immune response to an unknown antigen. The disease most commonly affects the lungs and lymph nodes but can involve any organ system.

About

• Non caseating granulomatous systemic disease
• Protean manifestations affecting many organs

Epidemiology

• Blacks > whites. Females >Males. Onset Age 20-40
• African-Americans and people of Northern European descent

The hallmark of sarcoidosis is the formation of non-caseating granulomas, which are clusters of immune cells, primarily macrophages and T lymphocytes. These granulomas can form in various organs, leading to tissue inflammation and damage. The exact trigger for this immune response is unknown, but it is believed to involve genetic susceptibility and environmental factors, such as infectious agents or occupational exposures

Aetiology

• Cutaneous anergy - lack of a skin reaction to various antigens e.g. tuberculin
• Diminished cell-mediated immune response to antigens
• Reduced lymphocytes and low circulating T cells as they are sequestered in lungs
• Mildly increased B cells in peripheral blood and increased bronchial CD4 cells

Clinical

Stages of Pulmonary Sarcoidosis

• Stage I: Bilateral hilar lymphadenopathy without pulmonary infiltrates.
• Stage II: Bilateral hilar lymphadenopathy with pulmonary infiltrates.
• Stage III: Pulmonary infiltrates without hilar lymphadenopathy.
• Stage IV: Pulmonary fibrosis with or without honeycombing.

Differential

• Tuberculosis - check smear for open TB and tuberculin testing
• Lymphoma - do HRCT
• Lung cancer with localised spread

Investigations

• The ESR and CRP may be elevated with active disease
• Raised serum ACE: from epithelioid cells of the granulomas
• Raised 1,25(OH)2 D3 and mild hypercalcaemia in only 10%
• Tuberculin tests are usually negative
• Bronchoscopy - Cobble stoning of mucosa and lavage shows an increased CD4:CD8 T cell ratio
• Transbronchial Biopsies - Non-caseating granulomata on biopsy
• Liver Biopsies - Non-caseating granulomata on biopsy
• ECG or 24 hr tape: heart blocks
• Kveim test: injection of splenic extract from a sarcoid patient injected intradermally and then biopsied but now cannot be done with risks of infections.
• Immunoglobulins: elevated hypergammaglobulinaemia
• Exclude open (smear-positive) TB before formal lung function tests or risks contaminating the equipment.
• Reduced transfer factor, Restrictive (small lung) PFT's and reduced DLCO
• High-resolution CT: BHL, fibrosis - ground glass appearance suggests active disease which may be steroid responsive
• Gallium-67 scan: The "panda sign" (localization in the lacrimal and salivary glands, giving a typical panda appearance to the face) is suggestive of sarcoidosis

Staging and Prognosis based on the CXR findings

• 0: CXR normal bit may have EN and arthralgia. Most cases resolve in 1 year
• I: BHL with no lung infiltrates 80% resolve spontaneously. EN and arthralgia.
• II: BHL + pulmonary infiltrate 50% resolve spontaneously. Breathlessness and cough.
• III: No BHL but Pulmonary infiltrates 10-25% resolve
• IV: Advanced fibrosis honeycombing, hilar retraction, bullae, cysts, emphysema. 0% resolve. Cor pulmonale

Prognostic indicators

• Good: younger, erythema nodosum
• Poor: Age > 40, Afro-Caribbean, Continuous symptoms over 6 months, Lupus pernio, Involvement of over 3 organs, CXR stages III-IV,

Management

When steroids are considered