Abstract:
Objective: To shed light on the pathophysiology of water homeostasis in patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), classified by WHO as a neurological disease (ICD 10 code G933).
Background: The complex symptomatology of ME/CFS includes signs suggesting abnormal water homeostasis and hypovolemia. Since many patients report polyuria-polydipsia, we conducted an observational series of plasma and urine osmolality as well as plasma levels of vasopressin (VP) in consecutive patients diagnosed with ME/CFS according to the Canadian Consensus Criteria.
Design/Methods: Plasma and urine osmolality (P-Osm and U-Osm, respectively) and plasma VP levels were measured in 111 patients after overnight fasting and 10-hour fluid deprivation. The clinical routine also included brain MRI and blood chemistry.
Results: Following the fluid deprivation P-Osm was above normal (>292 mOsm/kg) in 61 patients (55.0%) and U-Osm below normal (< 750 mOsm/kg) in 74 patients (66.7%). VP-levels were below the level of detection (<1.6 pg/mL) in 91 patients (82.0%). A normal level of VP in relation to their P-Osm was found in 11 patients (9.9 %). The state resembling a central type of diabetes insipidus (cDI) would in the absence of hypophyseal imaging findings and blood chemistry consistent with any other hypophyseal hormonal defect be classified as idiopathic.
Conclusions: Our findings suggest that deficiency of vasopressin secretion is a fundamental measurable part of the disease mechanisms, which may underlie a number of symptoms in ME/CFS, including the common complaint of orthostatic intolerance.
Source: Helena Huhmar, Lauri Soinne, Per Sjögren, Bo Christer Bertilson, Per Hamid Ghatan, Björn Bragée, and Olli Polo. Low Vasopressin in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (P4-4.006) Neurology, April 9, 2024 issue 102 (17_supplement_1) https://doi.org/10.1212/WNL.000000000020576 https://www.neurology.org/doi/10.1212/WNL.0000000000205761