In a trauma patient with an injury to the abdomen, the most common symptoms of a ruptured spleen are pain and tenderness of the abdomen, particularly on the left upper quadrant. As blood enters the abdominal cavity, it can lead to a symptom known as referred pain. This is pain that the patient feels somewhere other than where the injury is located.
Since the spleen is so rich with blood flow, bleeding from a rupture can be significant. If left untreated, bleeding from a ruptured spleen can very quickly lead to hypovolemia (when plasma portion of the blood is too low) and shock (a medical condition that decreases blood flow to the brain).
As the circulatory system struggles to get blood to important areas such as the brain, the patient can experience sweating, lightheadedness, fatigue, confusion, and eventually unconsciousness.