INTRODUCTION: Respiratory involvement in Primary Sjogren’s Syndrome (pSS) ranges from 9-75%(1). Diffuse lung disease (DLD) is a common manifestation with non-specific interstitial pneumonia (NSIP) being most frequently identified. pSS DLD is typically diagnosed in clinical practice when sicca symptoms are present in conjunction with elevated titers of anti-SSA/SSB antibodies. However, situations arise when the suspicion for pSS DLD is high but the antibody titers are normal and the diagnosis remains elusive. We describe a case of a patient with a high clinical concern for pSS DLD but with normal antibody titers that required a minor salivary gland biopsy (MSGB) to confirm the diagnosis.
CASE PRESENTATION: A 37-year-old African American woman with a history of post traumatic stress disorder (PTSD) presented with a complaint of 3 months of an intermittent, non-productive cough and two years of progressive dyspnea on exertion. She was an active duty service member and deployed to Iraq three years prior to presentation, with symptoms beginning after she returned from deployment. While in Iraq, she was also in close proximity to a “burn pit”, but denied any specific exposures. She endorsed dry eyes and mouth, GERD related symptoms and dysphagia, as well as numerous dental cavities. She quit smoking 1 year prior to presentation. She was taking sertraline for PTSD. Her vital signs on initial evaluation showed a heart rate of 97 beats/min, BP of 104/64 mmHg, a temperature of 97.1°F, an oxygenation saturation of 100% on room air and a respiratory rate of 16. Her overall physical examination was normal. Her complete blood count, chemistry and liver studies were normal. Her anti-SSA, anti-SSBA, anti-dsDNA, anti-smith, anti-Jo1, anti-centeromere and anti-scl-70 antibiodies were negative. The anti-nuclear antibody (ANA) and rheumatoid factor (RF) were both positive at 1:1280 (<1:160) and 20.3 (<14 IU/ml), respectively. A chest x-ray was unremarkable. Spirometry with full lung volumes showed moderate restrictive lung disease (FVC 62%, FEV1 63%, FEV1/FVC 85%, TLC 54%). Her DLCO was reduced at 51%. A HRCT showed bilateral, lower lobe reticular and ground glass opacities. A surgical lung biopsy showed fibrosing NSIP. Due to the concern for pSS related NSIP but normal SS specific antibody titers, she underwent a MSGB that showed a lymphocytic focus score ≥ 1 which was consistent with a diagnosis of pSS. She had a moderate reduction in her 6 minute walk test but no evidence of pulmonary hypertension by a right heart catheterization. Given her functional impairment, she began treatment with prednisone and azathioprine but has not noticed a significant improvement to date in her functional status or spirometric values.
DISCUSSION: Primary Sjogren’s Syndrome (pSS) is described histopathologically as a lymphocytic infiltration of the exocrine glands leading to eventual mucosal dryness. Reports of respiratory involvement in pSS vary widely but NSIP is the most common diffuse lung disease. An updated diagnostic classification system for pSS includes a MSGB as a component of the diagnostic criteria(2). Sicca-related symptoms are common, but serologic studies might not be consistently elevated. As such, a MSGB might be needed in selected cases to confirm the diagnosis(3). The traditionally recommended treatment is prednisone and azathioprine with variable results. The prognosis of connective tissue disease-related DLD has been reported as more favorable than the idiopathic interstitial pneumonias and is one of the major reasons to confirm the etiology of the diffuse lung disease.
CONCLUSIONS: A MSGB should be considered in high pre-test probability cases of pSS even in the absence of positive serological studies. NSIP is the most common diffuse lung disease related to Sjogren’s syndrome. Sjogren’s NSIP may have a better overall survival than idiopathic NSIP. Prednisone and Azathioprine are recommended as initial treatment for NSIP causing clinical impairment.
Reference #1 Sarkar P, Patel N, Furie R, et al. Pulmonary manifestations of primary sjogren’s syndrome. Indian journal of chest diseases and allied sciences 2009 Apr-Jun;51:93-101
Reference #2 Vitali C, Bombardieri S, and Jonsson R et al. Classification criteria for Sjogren’s Syndrome: a revised version of the European criteria proposed by the American-European Consensus Group. Ann Rheum Dis 2002;61:554-558
Reference #3 Fishcer A, Swigris J, and du Bois R et al. Minor salivary gland biopsy to detect pSS in patients with ILD. Chest 2009;136:1072-1078
DISCLOSURE: The following authors have nothing to disclose: Matthew Aboudara, John Sherner, George Underwood, Russell Harley
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