How do you tell if someone is bleeding internally?

1. Pale or unperfused conjunctiva
2. Cyanosis
3. Rigid, distended or acute abdomen
4. Nausea
5. Blood in stool -- black tarry stool (GI bleeds)
6. Vomiting blood -- "coffee grounds" (GI bleeds)
7. Hypo-tension
8. Low blood O2 saturation.
9. Thirst
10. Syncope
11. Hypovolemia
12. Cardiac arrhythmia
13. Slowed response
14. Loss of acuity
15. Atelectasis (chest bleeds)
16. Cardiac Tamponade (chest bleeds)

Note that many of these symptoms apply to hypovolemia in any form.