Mechanism of upper gastrointestinal hemorrhage in Mediterranean spotted fever.

Gastrointestinal (GI) hemorrhage is not a common complication of Mediterranean spotted fever (MSF). We describe three MSF cases with upper digestive tract bleeding in patients from Salamanca (Spain) and the results of the histologic studies performed in two of them. Besides the classical clinical triad of the disease (fever, rash and lesion at the site of tick bite, 'tache noire'), these patients presented purpuric rash and hypoalbuminemia, previously identified in severe forms of the disease. The hemorrhagic complication occurred late in the course of the MSF (between 13 and 20 days after the onset of fever) and was the consequence of multiple acute superficial erosions of the gastric mucosa. The histologic substrate of these lesions was identified as a vasculitic process - characteristically lymphohistiocytic - affecting the small vessels of the gastric wall. Rickettsial vascular injury at this level of the digestive tract is histologically similar to that observed in other organs in patients with MSF and may manifest clinically as digestive tract bleeding.