Sarcoidosis is a granulomatous multi-system disease of unknown etiology.
It usually affects younger no middle aged, with a the disease being more severe in African blacks.
The typical histopathological picture is non-caseating granulomas, with heroes the presence of epitheliod cells, T lymphocytes and macrophages.
Commonly affected organs are the lungs, skin, and eyes.
Symptoms of lung disease are non-productive cough and dyspnea. Cor pulmonale may develop.
There may be pulmonary infiltrates, an less commonly pulmonary fibrosis.
Chest examination is usually normal. Fine crepitations may be present. Finger clubbing is rare , and if present it should raise the suspicion of an alternative diagnosis.
The triad of arthralgias, bihilar lymphadenopathy, and erythema nodosum is known as Löfgren’s sindrome.
Diagnosis is suggested by symptoms and signs. Biopsy from enlarged lymph nodes, skin, or transbronchial biopsy are indicated.
Pulmonary function tests help assess the disease severity and to monitor response to treatment. Abnormalities may be a restrictive lung defect with decrease in gas transfer.
Serum angiotensin-converting enzyme (ACE) is usually raised, but it has low specificity, and is not of diagnostic value.
Treatment is not indicated with normal lung parenchyma (even if there is hilar lymphadenopathy), and pulmonary function tests.
Patients with affected lung parenchyma or abnormal pulmonary function tests require treatment with oral Prednisolone (30 mg) for 6 weeks and then tapered to a low maintenance dose for six months to one year.
Prednisolone is also indicated for other organs involvement.
Alternatively, methotrexate, cyclophosphamide, or azathioprine, may be used in patients needing long term steroid therapy.
The prognosis is better in Caucasians , than in African blacks , and the cause of death is mainly respiratory failure.