Over the next several days, the individual petechiae may spread into each other, resulting in larger patches of hemorrhage. The most severe effects of RMSF occur due to damage to the blood vessels, which become leaky. This accounts for the production of petechiae. Breathing difficulties may arise as the lungs are affected. Heart rhythms may become abnormal.
Kidney failure occurs in very ill patients.
Liver function drops. The patient may experience nausea, vomiting, abdominal pain, and diarrhea . Brain injury can result in seizures, changes in consciousness, actual coma , loss of coordination, imbalance on walking, muscle spasms, loss of bladder control, and various degrees of paralysis . The clotting system becomes impaired, and blood may be evident in the stools or vomit. Complex tests exist to nail down a diagnosis of RMSF, but these are performed in only a few laboratories.