Cold extremities and difficulties initiating sleep: evidence of co-morbidity from a random sample of a Swiss urban population.

Difficulties initiating sleep (DIS) can frequently occur in psychiatric disorders but also in the general population. The primary vasospastic syndrome is a functional disorder of vascular regulation in otherwise healthy subjects complaining of thermal discomfort from cold extremities (TDCE). Laboratory studies have shown a close relationship between long sleep onset latency and increased distal vasoconstriction in healthy young subjects. Considering these findings, the aims of the Basel Survey were to assess the prevalence rates for DIS and TDCE and to determine whether both symptoms can be associated in the general population. In a random population sample of Basel-Stadt, 2800 subjects (age: 20-40 years) were requested to complete a questionnaire on sleep behavior and TDCE (response rate: 72.3% in women, n = 1001; 60.0% in men, n = 809). Values of DIS and TDCE were based on questionnaire-derived scores. In addition, TDCE was externally validated in a separate group of subjects (n = 256) by finger skin temperature measurements--high TDCE values were significantly associated with low finger skin temperature. A total of 31.1% of women and 6.9% of men complain of TDCE. In contrast, prevalence rates of DIS were only slightly higher in women in comparison to men (9.3% versus 6.7%, P < 0.1). Irrespective of gender, each seventh subject complaining of TDCE had concomitant DIS and the relative risk in these subjects was approximately doubled. Therefore, a thermophysiological approach to DIS may be relevant for its differential diagnosis and its treatment.

Extraocular blood flow and endothelin-1 plasma levels in patients with multiple sclerosis.

In order to evaluate whether plasma levels of the potent vasoconstrictor endothelin-1 (ET-1) are increased in patients with multiple sclerosis (MS) and whether these patients exhibit an ET-1-mediated vascular dysregulation, ET-1 plasma levels were measured in 30 patients with MS. Blood flow velocities in the ophthalmic artery, central retinal artery, central retinal vein, short lateral posterior ciliary artery, and short medial posterior ciliary artery were assessed in parallel. ET-1 plasma levels were significantly increased in MS patients when compared to sex- and age-matched healthy controls (2.0 +/- 0.4 pg/ml, range 1.1-2.8 vs. 1.5 +/- 0.2 pg/ml, range 0.9-2.0; p < 0.001). Moreover, the patients exhibited significant alterations of extraocular blood flow. The role of ET-1 in the inflammatory process remains to be clarified.

Elevated plasma endothelin-1 levels and vascular dysregulation in patients with rheumatoid arthritis.

BACKGROUND: Contradictory results on plasma endothelin-1 (ET-1) levels in patients with rheumatoid arthritis have been reported in previous studies. We therefore evaluated whether plasma ET-1 levels in patients with rheumatoid arthritis differ from those of normal controls. Since systemically increased levels of ET-1 are known to occur in tandem with primary or secondary vascular dysregulation, we also measured peripheral blood flow by means of nailfold capillaroscopy combined with a cold provocation test. MATERIAL/METHODS: We measured plasma levels of ET-1 in twelve patients with different stages of rheumatoid arthritis by means of a specific radioimmunoassay, and compared ET-1 values to those of healthy controls. Capillary blood flow and the frequency of cold-induced vasospasm were studied in parallel, using nailfold capillaroscopy combined with a cold provocation test. RESULTS: Plasma ET-1 levels were significantly increased in patients with rheumatoid arthritis (p = 0.01) when compared to controls (2.38+/-0.95 pg/ml vs. 1.53+/-0.38 pg/ml). Capillary blood flow was reduced when compared to our own normal values, and a cold-induced blood standstill was seen in 58% of the patients. CONCLUSIONS: Patients with rheumatoid arthritis exhibit significantly elevated levels of ET-1, which may be associated with the symptoms of vascular dysregulation observed in nailfold capillaroscopy. Even though the clinical conclusions should be drawn from this study with caution, additional therapy with calcium channel blockers or, possibly in the future, with ET-1 receptor blockers, may be beneficial in patients with rheumatoid arthritis.