Erythrocyte Sedimentation Rate in Chronic Mountain Sickness

Chronic mountain sickness (CMS) is associated with a lack of adaptation to hypoxia and can be found at altitudes more than 2000 m (Zubieta-Castillo, 2006). The diagnosis of CMS is based on seven features of signs or symptoms (breathlessness and/or palpitations, sleep disturbance, cyanosis, dilatation of veins, paresthesia, headache, and tinnitus) and the presence of excessive erythrocytosis (León-Velarde, 2005). Although CMS is associated with excessive erythrocytosis, Gonzales et al. (2013) have shown that CMS scores are not very well correlated with hemoglobin concentrations, but more related to overall health status, some of which are known to increase plasma viscosity. As it is commonly accepted that some symptoms of CMS are related to blood hyperviscosity, plasma viscosity may be an important contributor. Since plasma viscosity increases in parallel with erythrocyte sedimentation rate (ESR), but is not influenced by hematocrit (Késmárky, 2008) and is highly significantly correlated with ESR (Crook et al., 1980), I hypothesize that there may be a correlation between ESR and CMS score.

To test my hypothesis, I searched previous phlebotomy procedures performed for hyperviscosity symptoms in our institution. Patients who met CMS criteria according to the Qinghai CMS score and residents of the Sarıkamış district at an altitude of 2200–2600 m were studied. Prephlebotomy ESR values were analyzed for correlation with CMS score. Of those undergoing phlebotomy, 53 of 130 were determined to have mild CMS and one had moderate CMS. Mean ESR and CMS score were 3.24 ± 2.17 mm/h and 7.33 ± 1.28, respectively (Fig. 1). Interestingly, I found that ESR is inversely correlated with CMS score (Table 1). Correlation of ESR with CMS score was equivalent to the correlation between hemoglobin concentration and CMS score. If my findings can be confirmed in patients with more severe CMS, ESR might be an additional useful parameter in future scoring systems.

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FIG. 1.

ESR (mm/h); CMS (based on “The Qinghai CMS Score”). CMS, chronic mountain sickness; ESR, erythrocyte sedimentation rate.