Sarcoidosis

27/05/2013 by admin | Respiratory

Sarcoidosis:

Definition

  1. Systemic (multi-system) granulomatous inflammatory disease characterized by non-caseating granulomas (small inflammatory nodules) on lung…
  2. Granulomas most often appear in the lungs or the lymph nodes, but virtually any organ can be affected. Normally the onset is gradual/insidious.
  3. Sarcoidosis may be asymptomatic or chronic and may cause death.

 

Epidemiology

  1. Cause = idiopathic! Some causes may include = genetics, propionibacterium acnes, vit D dysregulation, hyperprolactinaemia, thyroid disease, autoimmune.
  2. 19 in 100,000 in UK
  3. Uncommon in Japan

 

Clinical features

 

  1. Bilateral hilar lymphadenopathy
    1. o Often symptomless
    2. o Detected on routine chest xray
    3. o Associated with dull ache in chest, malaise, mild fever, and pulmonary fibrosis
    4. o Differential diagnosis:
    5. Lymphoma
    6. Pulmonary tuberculosis
    7. Carcinoma of the bronchus with malignant spread to the contralateral hilar lymph nodes
  2. Pulmonary infiltration
  3. Skin and eye lesions (erythema nodosum)
  4. Keratoconjunctivitis sicca
  5. Metabolic manifestations
  6. Central nervous system
    1. o Lead to severe neurological disease
  7. Bone and joint involvement
    1. o Arthralgia without erythema nodosum seen in 5% of cases
    2. o Bone cysts are found
  8. Hepatosplenomegaly
  9. Cardiac involvement
    1. o Ventricular dysrhythmias and sudden death
    2. o Conduction defects
    3. o Cardiomyopathy (dilated/restrictive) with congestive cardiac failure

 

Immunopathology

  1. Typical sarcoid granulomas consist of focal accumulations of epithelioid cells, macrophages and lymphocytes, mainly T cells.
  2. There is depressed cell-mediated reactivity to tuberculin.
  3. There is overall lymphopenia: circulating T lymphocytes are low but B cells are slightly increased
  4. Bronchoalveolar lavage shows a great increase in the number of cells; lymphocytes are greatly increased (particularly CD4 helper cells).
  5. The number of alveolar macrophages (=’Kupfer cells’) is increased but they represent a reduced percentage of the total number of bronchoalveolar lavage cells.
  6. Transbronchial biopsies show infiltration of the alveolar walls and interstitial spaces with leucocytes, mainly T cells, prior to granuloma formation.

 

Histopathology:

  1. Langhan’s cells
  2. Asteroid bodies
  3. Schaumann bodies
  4. Epitheloid macrophages
  5. Lymphopenia

 

Investigations

  1. Imaging
    1. o CXR
  2. Full blood count
    1. o Mild normochomic, normocytic anaemia with raised ESR
  3. Serum biochemistry
    1. o Serum calcium is raised
    2. o Hypergammaglobulinaemia
  4. Transbronchial biopsy
    1. o Most useful investigation
    2. o Positive results seen in 90% of cases
    3. o Pulmonary non-caeseating granulomas are found
  5. Serum level of ACE
    1. o Raised
  6. Lung function tests
  1. o Restrictive lung defect
  2. o Decrease in FEV1 and FVC

 

Treatment

  1. Prednisolone
  2. Severe symptoms are generally treated with steroids, and steroid-sparing immunomodulating agents such as azathioprine and methotrexate are often used.

 

Prognosis

  1. The disease can remit spontaneously or become chronic, with exacerbations and remissions. In some patients, it can progress to pulmonary fibrosis and death.
  2. Approximately half of the cases resolve or can be cured within 12–36 months and most within 5 years.
  3. Where the heart is involved, the prognosis is poor
  4. Much more severe in American blacks – death rates are 10%
  5. Disease remits in 2/3rds patients with hilar lymphadenopathy alone 
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