Sarcoidosis

Original article by Tom Leach | Last updated on 4/6/2014
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Introduction

Sarcoidosis is a multisystem granulomatous disorder of unknown aetiology. It most commonly affects the lungs (>90% of cases) and lymphatic system, but can affect any organ. Many cases are asymptomatic, although some patients can have very severe disease. Treatment may involve NSAIDs and less often, steroids, but often none is required as most cases resolve spontaneously.
 

Epidemiology and Aetiology

  • Affects 10-20 per 100 000, and rates vary between races. Black Africans, followed by Scandinavians are at highest risk
  • Thought to have a genetic component. The most widely accepted hypothesis describes how in susceptible individuals, environmental factors (e.g. organic or inorganic agents) lead to a cell-mediated immune response, resulting in the formation of granulomas.
  • The specific organs involved also vary between populations, with certain organs more common in certain populations.
 

Signs and Symptoms

  • Many patients are asymptomatic
  • Dry cough
  • Chest pain
  • Dyspnoea (usually progressive)
  • Lymphadenopathy
  • Crackles on auscultation
  • Fatigue
  • Malaise
  • Weight loss
  • Weakness
  • Sarcoidosis is often a differential for a patient with lots of non-specific signs!
  • Symptom and disease progression occurs in 10-20% of patients – this usually involves a decline in lung function.
  • It can also cause a whole range of other non-pulmonary symptoms, making sarcoidosis a differential diagnosis for almost any unidentifiable disease! Examples include, Hepatomegaly, splenomegaly, lymphadenopathy, Bell’s palsy, uveitis, conjunctivitis and cataracts.
 

Pathology

What is a granuloma?

  • A granuloma is a collection of WBC’s (mononuclear cells and macrophages) , surrounded by lymphocytes, plasma cells, mast cells, fibroblasts, and collagen. They can occur in any organ, but in sarcoidosis most commonly occur in the lung and lymphatics.
  • In the lung they tend to be distributed along the line of lymph nodes – Hence the association of sarcoidosis and hilar CXR changes
 

Investigations

Often discovered incidentally on CXR .the classical finding is hilar lymphadenopathy, where there are clear lung fields, with ‘fluffy’ opacities in the hilar region. Other changes may include lung infiltrates and fibrosis.
It can also cause non-specific CXR changes.

  • CXR is often used to stage the condition
  • Stage 0 – normal CXR
  • Stage 1 – BHL – bilateral hilar lymphadenopathy
  • Stage 2 – BHL + Infiltrates
  • Stage 3 – Peripheral pulmonary infiltrates alone
  • Stage 4 – Progressive pulmonary fibrosis ± bulla (honeycombing on CXR).

90% of patients with sarcoidosis will show CXR changes – thus an absence of CXR changes will all but exclude sarcoidosis from your differential diagnosis.
Pulmonary Function Tests may show a reduced lung volume and restrictive pattern
Should be suspected in:

  • Patients with unilateral pain, but bilateral CXR signs

Diagnosis may be confirmed by tissue biopsy which will show the presence of a non-caseating granuloma.

  • Suitable biopsy sites include lung and liver tissue, lymph nodes and lacrimal glands

Hand X-ray – sometimes shows punched out lesions in the peripheral phalanges
Broncheoaleolar lavage – can show increased lymphocytes and neutrophils
CT/MRI – useful in some cases to assess the extent of pulmonary involvement

 

Management

  • Stage 0 and 1 – usually resolve spontaneously
  • Stage 2+ and acute disease – may improve with NSAIDs and bed rest
  • Steroid Management – is in some circumstances (prednisolone 40mg for 4-6 wks, then gradually decline dose over 1yr depending on symptoms.  Indications for steroid use include:
    • Parenchymal lung disease – even if asymptomatic
    • Uveitis
    • Hypercalcaemia
    • Neurological involvement
    • Cardiac involvement
  • Very severe cases may require further intervention, including:
    • IV methyprednisolone
    • Immunosuprressants – e.g. cyclosporine, methotrxate, cyclophosphamide