David S. Bell MD, FAAP
77 South Main Street
Vasopressin, Circulating Blood Volume and CFS
Chronic fatigue syndrome is a clinical disorder with numerous symptoms including disabling fatigue and cognitive deficits. Prominent theories concerning CFS include ongoing infection, immunologic upregulation, and decreased central nervous system perfusion.
Forty-five patients with CFS were evaluated for circulating blood volume using Cr51 and albumin125 in a standard manner. Thirty-one (68.9%) were shown to have decreased circulating blood volume compared to historic controls, with thirty two (71.1%) having decreased red call mass, and thirty (66.7%) having decreased plasma volume. Further studies were done to ascertain the cause of the decreased circulating blood volume on fifteen patients shown to be hypovolemic. Thirteen (86.7%) of these patients had a relatively elevated serum osmolarity (defined as >290mOsrm/ml), nine (60.0%) had decreased fasting urine osmolarity (defined as <600 mOsm/ml) and fourteen (93.3%) had ADH levels below 3.0. This degree of ADH deficiency is striking in the face of decreased circulating volume.
Thus it is likely that the decreased circulating blood volume seen in the majority of patients with CFS represents a partial diabetes insipidus due to lack of normal secretion of vasopressin. As ADH has both water retention and vasoconstrictor properties, lack of ADH may result in decreased CNS perfusion and the symptoms of the illness. An alternative possibility is that the ADH deficiency may be one of many neuroendocrine abnormalities and not central to the cause of the illness. Results of an open label treatment trial with desmopressin (V2 specific) and vasopressin (V1 and V2 specific) will be presented.
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