Sarcoidosis: An FP’s primer on an enigmatic disease
Management includes ruling out alternate diagnoses, identifying occult/overt organ involvement, determining treatment, and recognizing worrisome features.
PRACTICE RECOMMENDATIONS
› Consider biopsy to aid in diagnosing sarcoidosis; it may be avoided with a high clinical suspicion for sarcoidosis (eg, Löfgren syndrome, lupus pernio, or Heerfordt syndrome). C
› Rule out alternative diagnoses such as infection, malignancy, collagen vascular disease, and vasculitis. C
› Identify extra-pulmonary organ involvement, as clinically indicated, by screening with a baseline eye examination; complete blood count; creatinine, alkaline phosphatase, and calcium levels; electrocardiogram, and other organ-specific studies. C
› Make a patient-centered decision whether to begin antiinflammatory treatment based on symptomatology and risk of organ failure or death. C
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
Laboratory studies
Multiple abnormalities may be seen in sarcoidosis, and specific lab tests may help support a diagnosis of sarcoidosis or detect organ-specific disease activity (TABLE 4).22,23,25,38 However, no consistently accurate biomarkers exist for use in clinical practice. An angiotensin-converting enzyme (ACE) level greater than 2 times the upper limit of normal may be helpful; however, sensitivity remains low, and genetic polymorphisms can influence the ACE level.25 Biomarkers sometimes used to assess disease activity are serum interleukin-2 receptor, neopterin, chitotriosidase, lysozyme, KL-6 glycoprotein, and amyloid A.21
Additional tests to assess specific features or organ involvement
Pulmonary function testing (PFT) is reviewed in detail below under “pulmonary sarcoidosis.”
Electrocardiogram (EKG)/transthoracic echocardiogram (TTE). EKG abnormalities—conduction disturbances, arrhythmias, or nonspecific ST segment and T-wave changes—are the most common nonspecific findings.30 TTE findings are also nonspecific but have value in assessing cardiac chamber size and function and myocardial involvement. TTE is indeed the most common screening modality for sarcoidosis-associated pulmonary hypertension (SAPH), which is definitively diagnosed by right heart catheterization (RHC). Further evaluation for cardiac sarcoidosis can be done with cardiac MRI or fluorodeoxyglucose PET in specialized settings.
Lumbar puncture (LP) may reveal lymphocytic infiltration in suspected neurosarcoidosis, but the finding is nonspecific and can reflect infection or malignancy. Oligoclonal bands may also be seen in about one-third of neurosarcoidosis cases, and it is imperative to rule out multiple sclerosis.28
Pulmonary sarcoidosis
Pulmonary sarcoidosis accounts for most of the morbidity, mortality, and health care use associated with sarcoidosis.39,40
Continue to: Pathology of early and advanced pulmonary sarcoidosis
