[Enzymatic parameters in boutonneuse fever. II. Behavior and significance of lactic dehydrogenase].

Serum levels of Lactic dehydrogenase (LDH) were determined at weekly intervals, in 52 patients with Boutonneuse Fever: 33 adults (23 uncomplicated and 10 complicated cases) and 19 children (no complication occurred in these patients). In the first week of illness, LDH was increased in 86 and 100% of adults (uncomplicated and complicated cases respectively) and in 89% of children. Mean values were 419 and 472 U/l for adults (uncomplicated and complicated) and 423 for children (normal values until 240 U/l). In total (adults plus children), in the first week, pathological findings were observed in 90% of patients. In the second week, LDH was increased in 53 and 100% for adults, and 66% for children. Mean values were 252 and 306 for adults, and 291 U/l for children. The significance of this increase is related to the pathophysiology of rickettsial diseases. Rickettsiae cause endothelial injury with platelet aggregation, activation of inflammation as well as coagulation mechanisms and subsequently damage of various organ systems at various degree (from silent to evident forms). From a general point of view LDH increase appears in part of platelet origin, at first stage of illness, in part from other organ systems involved in the vasculitic process.