PERIPHERAL circulatory failure is an important complication of Rocky Mountain spotted fever. Previous studies have shown that the collapse occurs usually in the second week of rash and that the disturbance can be alleviated by the administration of preformed protein.1 The mechanism responsible for the circulatory changes is obscure, but the peripheral collapse is accompanied with a drop in serum proteins and with the development of visible generalized edema.2 The resemblance of the clinical picture to "shock" suggests that a drop in the circulating blood volume occurs.
The present studies were undertaken to determine whether the blood volume is altered, to observe the time at which the changes develop and to correlate the magnitude of the alterations with the clinical picture and other pertinent laboratory data. Determinations of the plasma volume and the thiocyanate space were done serially in a group of patients with rickettsial spotted fever,
HARRELL GT, AIKAWA JK. PATHOGENESIS OF CIRCULATORY FAILURE IN ROCKY MOUNTAIN SPOTTED FEVERAlterations in the Blood Volume and the Thiocyanate Space at Various Stages of the Disease. Arch Intern Med (Chic). 1949;83(3):331-347. doi:10.1001/archinte.1949.00220320085007