Autonomic and orthostatic dysfunction in primary Sjögren's syndrome

Exocrine function always is and autonomic nervous function may be impaired in primary Sjögren's syndrome (pSS). Since autonomic nervous signaling is a prerequisite for exocrine secretion we wanted to assess autonomic nervous function in pSS and relate it to diagnostic measures of exocrine function.

Autonomic nervous function was determined in 46 patients with pSS using the deep breathing test [expiration/inspiration (E/I) ratio], orthostatic test [acceleration index (AI), orthostatic systolic and diastolic blood pressure response (lSBP ratio and lDBP ratio)], and finger skin blood flow test [vasoconstrictory (VAC) score]. The results were corrected for age and expressed as z-scores by comparison with 3 control groups (E/I ratio and AI, n = 56; lSBP ratio and lDBP ratio, n = 238; and VAC score, n = 80). Exocrine gland function was determined in patients with pSS using the objective functional Schirmer-I test and rose-bengal staining (van Bijsterveld score) for the lacrimal glands and unstimulated whole sialometry for the salivary glands.

The E/I ratio and orthostatic systolic and diastolic blood pressures were significantly decreased and the VAC score was significantly increased in patients with pSS compared to controls, indicating both parasympathetic and sympathetic dysfunction. Autonomic and exocrine function measures were found to associate poorly.

Patients with pSS showed signs of both parasympathetic and sympathetic dysfunction. However, an association between cardiovascular autonomic and exocrine function in pSS was not detected.