Thursday, March 09, 2006

Diagnosing sarcoidosis

Mark H asks:

If a patient has hilar adenopathy and a biopsy shows noncaseating granulomas, we are taught that we must definitively rule out fungal (i.e. histoplasmosis) disease before settling on the diagnosis of sarcoid. What tests do you perform that will satisfy you prior to giving steroids (if the patient needs it clinically)? A serum test for IgM would only address active exposure. A urine test for antigen is low yield. Are you satisfied with the sarcoid diagnosis if special stains are negative?

2 comments - CLICK HERE to read & add your own!:

Jeff H said...

Mark, thank you for the question. I think it depends on the clinical scenario. Also, for clarification, I'm assuming that you mean transbronchial biopsies show non-caseating granulomas, as it can be quite difficlut to diagnose sarcoidosis or fungal infection based on transbronchial fine-needle aspiration (i.e. Wang needle biopsies), even if a 19g Wang is used.

If a patient has relatively symmetric, bilateral hilar lymphadenopathy, and is asymptomatic, then a bronchoscopy may not even be necessary. If a bronch is done, and the pathology shows non-caseating granulomas with negative special stains, and there is no evidence to support fungal disease (radiographic changes or sypmtoms), then an empiric diagnosis of sarcoidosis is reasonable. In fact, the primary fear in these patients is missing a lymphoma, and some experts recommend lymph node biopsies to rule out this possibility, although it is probably not necessary, as a lymphoma should declare itself...

If the patient is symptomatic, and has bilateral hilar LAD without other evidence of parenchymal disease, again I think that the pathology described is sufficient to treat for sarcoid. In that event, it's also important to check an EKG and look for opthamologic changes of sarcoid.

Fungal infection, mycobacterial infection, and lymphoma are always in the differential for a patient with bilateral hilar adenopathy. However, in most cases, other clinical information should lead you towared the infectious diseases or a lymphoma. Without those other findings, a biopsy with non-caseating granulomas should be sufficient.

Mendez said...

Ditto on what Jeff H said. If special stains are negative and the clinical scenario does not support fungal infection, a presumptive diagnosis of sarcoid is reasonable. If symptoms dictate the use of steroids then careful clinical follow-up is necessary (which you would do anyway).