All parts of the jimsonweed plant are poisonous to horses and humans; toxicity is caused by tropane alkaloids. Symptoms of poisoning in horses include a weak, rapid pulse, dilated pupils, dry mouth, incoordination, diarrhea, convulsions, coma, and sometimes death.
Meningioma Causes. The causes of meningioma are not yet fully understood. In fact, several research studies suggest that many meningiomas develop spontaneously, or without a known cause. Sometimes, these tumors can disappear spontaneously as well. Meningiomas, like other solid tumors, develop when healthy cells undergo genetic mutations that cause them to replicate uncontrollably.
Symptoms of meningiomas are caused by pressure from the growing tumor on the surrounding tissue. Because these tumors can occur in a variety of places, symptoms vary, and tend to become more severe as the tumor grows in size.