Chest Radiographic Screening for Sarcoidosis in the Diagnosis of Patients with Active Uveitis

Value of Chest X-Ray and Chest Computed Tomography for Systemic Sarcoidosis Diagnosis in Undifferentiated Uveitis

BACKGROUND

To evaluate the contribution of chest X-ray and chest CT for the diagnosis of sarcoid uveitis.

METHODS

Retrospective study on consecutive patients with uveitis of unknown etiology, who underwent both chest X-ray and CT during uveitis diagnosis workup in a tertiary French university hospital.

RESULTS

A total of 914 patients were included. Systemic sarcoidosis was identified in 23.1%. The probability of discordance between chest X-ray and CT increased with age at diagnosis (p < 0.001). In patients 30 years of age and younger, the probability of discordance was 5% or less, and 0.8% if the ACE level was normal. After 78.3 years of age, the probability of discordance was 20% or more.

CONCLUSION

We recommend not to perform CT in patients under 30 years of age with a normal chest X ray and ACE level, and suggest performing chest CT first in the elderly.

Rational laboratory testing in uveitis: A Bayesian analysis

Uveitis encompasses a heterogeneous group of clinical entities with the common feature of intraocular inflammation. In addition to patient history and examination, a focused set of laboratory investigations is frequently necessary to establish a specific diagnosis. There is limited consensus among uveitis specialists regarding appropriate laboratory evaluation for many distinct patient presentations. The appropriateness of a laboratory test for a given case of uveitis will depend on patient-specific as well as epidemiologic factors. Bayesian analysis is a widely used framework for the interpretation of laboratory testing, but is seldom adhered to in clinical practice. Bayes theorem states that the predictive value of a particular laboratory test depends on the sensitivity and specificity of that test, as well as the prevalence of disease in the population being tested. In this review we will summarize the performance of commonly-utilized laboratory tests for uveitis, as well as the prevalence of uveitic diagnoses in different geographic practice settings. We will propose a logical framework for effective laboratory testing in uveitic disease through rigorous application of Bayesian analysis. Finally, we will demonstrate that while many highly sensitive laboratory tests offer an effective means to rule out associated systemic disease, limited test specificity and low pretest probability often preclude the diagnosis of systemic disease association with any high degree of certainty, even in the face of positive testing.

Diagnostic Value of Serum-Soluble Interleukin 2 Receptor Levels vs Angiotensin-Converting Enzyme in Patients With Sarcoidosis-Associated Uveitis

Importance

New and improved diagnostic tests for sarcoidosis-associated uveitis are needed because the currently available laboratory diagnostic biomarkers (eg, lysozyme and angiotensin-converting enzyme [ACE]) are lacking in high sensitivity and specificity.

Objective

To compare the value of soluble interleukin 2 receptor (sIL-2R) with ACE as diagnostic biomarkers of sarcoidosis in patients with uveitis.

Design, Setting, and Participants

A cross-sectional retrospective study was conducted using data collected from 249 consecutive patients with uveitis at the Erasmus University Medical Center uveitis outpatient clinic, Rotterdam, the Netherlands, from April 3, 2013, through November 25, 2015. Measurements of sIL-2R and ACE in serum samples and data extraction from patient files were conducted from December 2016 through February 2017, and analysis from April to May 2017.

Main Outcomes and Measures

Serum levels of sIL-2R and ACE and chest radiographic findings were assessed. Receiver operating characteristics analysis was used to determine the probability that individual tests correctly identified patients with sarcoidosis. The Youden Index was used to determine the optimal cutoff points for serum sIL-2R and ACE levels to define sarcoidosis in patients with uveitis.

Results

Data were analyzed from 249 patients with uveitis who had their serum sIL-2R and ACE levels determined and underwent chest radiography. Mean (SD) age at the time of sampling was 51 (16) years, 161 patients (64.7%) were women, and 191 (76.7%) were white. Although patients with sarcoidosis-associated uveitis had the highest mean (SD) serum sIL-2R (6047 [2533] pg/mL) and ACE (61 [38] U/L) levels, elevated serum sIL-2R levels were also found in patients with HLA-B27–associated (4460 [2465] pg/mL) and varicella-zoster virus–associated (5386 [1778] pg/mL) uveitis. Serum sIL-2R and ACE levels were significantly correlated (Pearson correlation coefficient, 0.205; P = .001, 2-sided), but no association was found between uveitis activity and sIL-2R (Spearman rank correlation coefficient [ρ], 0.070, P = .27) nor uveitis activity and ACE (ρ, −0.071; P = .27). The highest Youden index for sIL-2R alone was 0.45, corresponding to an optimal cutoff of 4000 pg/mL and providing 81% (95% CI, 74%-89%) sensitivity and 64% (95% CI, 56%-72%) specificity alone but combined with chest radiography yielded 92% sensitivity and 58% specificity. Chest radiography combined with sIL-2R at a cutoff of 6000 pg/mL resulted in 77% sensitivity and 73% specificity. Combined chest radiography and serum ACE levels at the standard cutoff of 68 U/L resulted in 70% sensitivity and 79% specificity.

Conclusions and Relevance

This cross-sectional study demonstrates that sIL-2R is a useful marker for diagnosing sarcoidosis in patients with uveitis and has slightly better diagnostic value than ACE.

Lymphopaenia as a predictor of sarcoidosis in patients with a first episode of uveitis

Background/aims

The diagnostic properties of conventional diagnostic tests (ACE and chest radiography) for sarcoidosis-associated uveitis are not ideal. The diagnostic value of lymphopaenia for sarcoidosis-associated uveitis is investigated.

Methods

A retrospective study of 191 consecutive patients with a first uveitis episode visiting the ophthalmology department (Erasmus Medical Center, Rotterdam, The Netherlands). Receiver operating characteristics (ROC) analysis was performed and compared with known ROC values from literature of conventional diagnostic tests for sarcoidosis-associated uveitis. An ideal cut-off was determined for lymphopaenia by calculation of the highest Youden index.

Results

Out of all patients with first uveitis attack, 32/191 or 17% were subsequently diagnosed with biopsy-proven or radiological diagnosis of sarcoidosis. Lymphopaenia (<1.5×109/L) was significantly more often observed in patients with sarcoidosis-associated uveitis compared with patients with non-sarcoidosis-associated uveitis (p<0.05). The sensitivity and specificity of lymphopaenia was 75 % and 77 %, respectively. The optimal cut-off for lymphopaenia for diagnosing sarcoidosis-associated uveitis was 1.47 ×109/L. Lymphopaenia resulted in a 12.0 (95% CI 4.7 to 30.5 fold risk for having sarcoidosis, corrected for sex, race and age at onset of uveitis in patients with a first uveitis attack.

Conclusion

Lymphopaenia is a non-invasive and useful marker for diagnosing sarcoidosis-associated uveitis.