A rough guide to life-threatening emergencies is listed below. I have adapted and revised this list which has been published thanks to the American College of Emergency Physicians (ACEP), see this. This list is clearly not meant to be inclusive. At the same time, common sense should prevail: Not every cut needs stitches, nor does every injury or case of simple indigestion require advanced medical treatment:
1. Any chest pain lasting 2-5 minutes or more, especially unexplained frontal chest pain with or without radiation to the back, neck, head, shoulders or arms.*
2. Non-chest pain, particularly significant or severe unexplained abdominal pain lasting more than an hour. Significant steady abdominal pain lasting more than 4-6 hours generally indicates an acute surgical condition.*
3. Any uncontrolled bleeding.
4. Vomiting blood. Coughing blood, depending on amount and frequency, may or may not be an emergency, again depending on common sense assessment.
5. Severe or persistent vomiting or diarrhea.
6. Difficulty breathing, shortness of breath, persistent wheezing or uncontrollable cough.
7. Sudden dizziness, weakness, or change or blurring of vision lasting more than a few minutes.
8. Sudden onset of one-sided weakness of an arm and/or leg, or facial droop on one side.
9. The “worst headache ever.”
10. Change in mental status (e.g., confusion, difficulty arousing) or unexplained loss of consciousness. A brief episode of fainting does not qualify as an emergency, particularly if relieved by recumbency.
11. Sudden development of any symptoms, such as hives, wheezing, or generalized itching, either spontaneous or following an insect bite, ingestion of food, or exposure to an animal.
*As a general rule, every case of unexplained chest or abdominal pain, even if not obviously severe or acute, requires an urgent physician visit, preferably within 24 hours
Taking action can mean calling 911 for paramedics, or going directly to the nearest ER, obviously a choice depending on time and proximity. Other measures include applying direct pressure on a bleeding wound, performing CPR, or splinting an injury. Never perform a medical procedure unless you are competent to do so. For example, do not attempt to manipulate an acute back or a dislocation, or deal with a psychiatric emergency. A good idea for all of us: take a course in first aid and CPR.