Sarcoidosis



Sarcoidosis


Xin Gu, MD










Sarcoidosis is often associated with hypercalcemia, which may cause azotemia, tubular dysfunction with polyuria, or rarely, nephrocalcinosis with calcification of nephron basement membranes image.






Renal involvement in sarcoidosis is often characterized by well-defined noncaseating granulomas. This granuloma is composed of epithelioid histiocytes, lymphocytes, and multinucleated giant cells image.


TERMINOLOGY


Definitions



  • Systemic granulomatous disease


ETIOLOGY/PATHOGENESIS


Etiology Unclear



  • Possibly multifactorial



    • Disordered immune regulation affecting T cells and histiocytes leading to tissue injury


    • Inflammatory cytokines stimulate synthesis of 1,25 OH vitamin-D3 leading to hypercalcemia


    • Genetic susceptibility &/or environmental factors


CLINICAL ISSUES


Epidemiology



  • Incidence



    • 1-40 per 100,000 population


  • Age



    • Most common in 2nd-4th decades


  • Gender



    • More common in males than females


  • Ethnicity



    • 3.5-10x higher in African-Americans than whites


Presentation



  • Nonspecific systemic symptoms



    • Lymphadenopathy


    • Cough, dyspnea, fever


  • Renal involvement in 15-45% of patients



    • Tubular dysfunction due to hypercalcemia



      • Urine concentration defect with polyuria


    • Acute or chronic renal failure


    • Hydronephrosis from retroperitoneal lymphadenopathy


Laboratory Tests



  • Hypercalcemia (50-60%)


  • Elevated angiotensin-converting enzyme (ACE) level


  • Azotemia


  • Hematuria &/or proteinuria, low grade to nephrotic


Treatment



  • Drugs



    • Steroids


Prognosis



  • Usually good, most patients respond to steroids



    • Worse outcome in African-Americans and elderly


  • Recurrent or resistant disease



    • Acute or chronic renal failure


    • Death


IMAGE FINDINGS


Radiographic Findings



  • Mediastinal lymphadenopathy

Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Sarcoidosis
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