Severe Symptoms. Severe symptoms of an ovarian cyst are rare, but they can occur. These severe symptoms will require immediate medical attention. If immediate medical attention is not sought, this can be life-threatening. The severe symptoms of an ovarian cyst are severe pelvic pain, fainting or dizziness, fever and rapid breathing. Symptoms like these can indicate that an ovarian torsion is possible or a ruptured cyst. Both these complications can result in the need for a complete hysterectomy, or even death. It is imperative that anyone with the symptoms go to their local emergency room as soon as possible.