Sarcoidosis- CT findings

By Dr Deepu

conglomerated micronodules and centrilobular
 nodules in both lungs

Enlarged mediastinal  lymph nodes

 Bilateral hilar lymph nodes

Chest CT scans show conglomerated micronodules and centrilobular nodules in both lungs. We can see the enlarged mediastinal and bilateral hilar lymph nodes.

Sarcoidosis is a multi-system disease of unknown etiology, usually affecting the respiratory tract and other organs, and is characterized by the formation of nonnecrotizing epithelioid granulomas. The diagnosis depends on a combination of a typical clinicoradiological presentation, the finding of nonnecrotizing epithelioid granulomas in a tissue biopsy, and exclusion of other possible diseases, especially those of infectious etiology.

 Sarcoidosis results from an uncontrolled cell-mediated immune reaction. Interactions between chemokines and receptors that activate mitogen-activated protein kinase pathways play a major role in inflammation and T-cell responses. Tumor necrosis factor (TNF)-[alpha] is an important player in granuloma formation, and recent clinical trials have investigated the efficacy of TNF-[alpha] inhibitors in sarcoidosis.

SARCOIDOSIS

A multisystem granulomatous disorder of unknown etiology.

Clinical manifestations

a.      Mostly young adults.

b.     Any organ may be involved with the lungs, lymphatics, skin, liver, eyes most commonly affected in decreasing order. Some manifestations to watch for:
- Myocardial involvement (possible conduction disturbances)
- Uveitis
- Cranial nerve VII involvement
- Erythema nodosa

c.      PFTs: Decreased volumes, compliance, DLCO, hypoxemia.

d.     BAL: Predominance of T-lymphocytes and macrophages.

e.      Immunology: Activated T-lymphocytes secrete IL-2 which, as a monocyte chemotactic factor, recruit monocytes and thus contribute to granuloma formation.

f.       CXR:
- Stage 0  Clear
- Stage I   Bilateral hilar adenopathy
- Stage II  Hilar adenopathy and parenchymal infiltrates
- Stage III Parenchymal infiltrates only
- State IV Extensive fibrosis and distortion of lung architecture

g.     Gallium-67 Imaging: increased pulmonary uptake with alveolitis.

h.     Hypercalcemia (10-15%), hypercalciuria (20-30%)

i.        Elevated ACE level (nonspecific); however, ACE may be followed for therapeutic response.

j.        Hyperglobulinemia, impaired delayed hypersensitivity.

Diagnosis: Transbronchial lung biopsy showing non-caseating granulomas with compatible clinical picture.

Therapy: Corticosteroids

a.      Indications for prednisone therapy: active alveolitis with severe symptoms, uveitis, liver disease (marked), cardiac disease, CNS disease, hypercalcemia.

b.     Secondary agent: methotrexate, antimalarial agents controversial.

Transplantation

a.      Recurrent sarcoid granulomata noted in allografts; immunosuppression for transplantation may attenuate granulomatous responses in patients having recurrent disease.