A woman is admitted with complains of low-grade fever of 6 weeks duration. Chest radiograph reveals bihilar adenopathy with clear lung fields. All of the following investigations will be useful in differential diagnosis except:
Answer is A (CD4/CD8 counts in the blood): The patient in question is suffering from sarcoidosis. `While there is marked enhancement of no. of TH cells at the sites of disease the number of TH cells in the blood are normal' - Harrison Where as TH cells in the involved organs are proliferating at an enhanced rate the T cells in other sites such as blood are quiescent' - Harrison It is the CD4 / CD8 counts in the affected organs which is an impoant ancillary aid in established the diagnosis of sarcoidosis and not the CD4 / CD8 count in the blood as specifically asked in the question. Active sarcoidosis results from an exaggerated cellular immune response resulting in accumulation of large no. of T4 cells in the affected organs, where the ratio of CD4 to CD8 cells may be as high as 10:1. Although CT of chest is also only rarely helpful, it may identify early fibrosis and active alveolitis and thus contribute to a diagnosis of sarcoidosis. Diagnostic tests for sarcoidosis have often been asked Diagnostic tests Ancillary Blood: ACEe - X ray cheste - Skin test for anergye - Gallium 67 etc.'' 1. X-Ray chest: * Bilateral hilar lymphadenopathy is the hallmark of disease * Parenchymal involvement may or may not be present (clear lung fields)e * Egg shell calcification of hilar nodes may be seene 2. Kveim siltzbach teste: Skin teste: * intradermal injection of a heat treated suspension of a sarcoidosis spleen extract. 3. Angiotensin conveing enzyme (ACE) in bloode: * ACE is elevated in 2/3 of patients with sarcoidosis Q (60%)Q * ACE levels indicate activity of disease * ACE levels provide an impoant method of monitoring the course of disease.deg (The cells in granuloma release angiotensin conveing enzyme into the serum) 4. Gallium 67 scan: Gallium 67 lung scan is usually abnormal showing a pattern of diffuse uptake 5. Bronchoalveolar large: Lavage fluid is characterized by * increase in Lymphocytes * high CD4 / CD8 cell ratioQ 6. Biopsy: * Biopsy is mandatory to make a definitive diagnosis of sarcoidosis * Characteristic finding is a typical non casseating granulomaQ 7. Lung function abnormalities: Typical for interstitial lung disease.
CD4/CD8 counts in the blood
Serum ACE levels
CECT of chest
Gallium scan