Mandl T et al. (2007) Autonomic and orthostatic dysfunction in primary Sjögren's syndrome. J Rheumatol 34: 1869–1874

Exocrine gland dysfunction in patients with Sjögren's syndrome does not always correlate with the extent of gland destruction; it has therefore been suggested that disturbances in other mechanisms, in particular the autonomic nervous system (ANS) that controls the exocrine glands, might be involved. A study by Mandl et al. has found evidence of sympathetic and parasympathetic neuropathy in patients with primary Sjögren's syndrome (pSS).

The study population consisted of 46 patients diagnosed with pSS according to the American–European Consensus Criteria. ANS function was tested by a deep breathing test, an orthostatic heart rate and blood pressure test, and a finger skin blood flow test. Compared with healthy controls, patients with pSS had significantly impaired sympathetic and parasympathetic nervous function. Surprisingly, however, when the exocrine function of patients with pSS was tested (by the unstimulated whole sialometry test, Schirmer-I test, and van Bijsterveld score), no correlation was found between ANS and exocrine function. The authors speculate that a lack of variability in exocrine function in the study population—most of whom had maximal exocrine dysfunction—might explain this finding. In addition, the present study measured cardiovascular ANS function; the authors suggest that tests specifically of exocrine ANS function might help to establish the relationship between exocrine and ANS function in patients with pSS.