With that in mind, we asked doctors what symptoms they would tell their friends to head to the ER for. Here are five times you shouldn't think twice.
What to do: Anytime you suspect a heart attack, "err on the side of caution and call 911," advises Dr. Rosen. Once the ambulance arrives, the paramedics can perform an EKG and give you aspirin or another treatment en route to the hospital. Don't go to urgent care or your family doctor; they won't be able to run the necessary tests to evaluate your heart.
You're doubled over with abdominal pain
Think about: Appendicitis or an ovarian cyst. Belly pain can be caused by anything from a bad fish taco to a chronic condition like ulcerative colitis, making it difficult to recognize a true emergency. Confusing matters more, appendicitis doesn't always start with the classic pain in the right lower quadrant of your abdomen. You might have pain around your belly button, be queasy, lose your appetite, or feel discomfort when you move, explains Dr. Fix. "These are all signs of an irritation of the lining of your abdomen, which can signal that something serious is going on," she says. The pain can feel smoldering but will usually get sharper and more severe—think pain you've never felt before.
A large ovarian cyst can create similar sensations in the abdomen. Other cyst-specific clues: pelvic pain on one side or general pelvic pain that radiates into your lower back or thighs. A large cyst ups your risk of ovarian torsion, in which the ovary twists, cutting off its own blood flow. The cyst can also rupture, causing internal bleeding.
What to do: Head to the ER if belly pain comes on suddenly or is getting worse; if it keeps you from sitting, walking, eating, or drinking; if it moves to the lower right quadrant of your abdomen; or if you also get a fever or start vomiting.
You were clocked in the head
Think about: A concussion or worse. Whether you fell and bumped your noggin or got beaned by a baseball, doctors don't mess around with head injuries. Depending on your symptoms, they'll want to rule out rare but serious possibilities like brain bleeding. They're also on the lookout for concussion: "Today, there's so much attention and focus on concussion," notes Shawn Evans, MD, emergency medicine physician at Scripps Health in San Diego. Loss of consciousness, repeated vomiting, and a worsening headache warrant immediate attention. But you should also be evaluated if you've hit your head and have any neurological symptoms, like dizziness, or issues with balance or vision -- no matter how insignificant they may seem.
What to do: Go to the ER if you were knocked out, regardless of how you feel afterward. And get examined if you have a severe headache or neck pain, fluid or blood is leaking from your nose, or you feel confused or very sleepy (all possible signs of serious injury). If you hit your head and develop dizziness or balance problems, you should suspect a concussion but don't have to rush to the ER—just see a doc within 12 hours, advises Dr. Evans.
You've got a cut and are bleeding like crazy
Think about: Needing stitches. One minute you're cutting up tomatoes for a salad, and the next minute your kitchen looks like a crime scene. Even small cuts can produce what appears to be a lot of blood. "It's hard for someone who's not a doctor to know which wounds need stitches and which don't, but the majority will heal without treatment," says Sean McGann, MD, an emergency medicine physician at Maimonides Medical Center in Brooklyn, N.Y. That said, an especially deep cut could result in damaged nerves or tendons, and, of course, heavy bleeding that won't stop is always an emergency. Stitches will also minimize scarring, and ER staff can clean out the wound to prevent infection -- and give you a tetanus shot if you haven't had one in the past five years.
What to do: Put direct pressure on the wound for at least 10 minutes (no peeking). Head to the ER if bleeding doesn't stop; blood is spurting out; the cut reaches the bone, muscle, or fat; or you don't have normal movement or sensation beyond the wound. You'll also need medical attention if the cut stops bleeding but the edges are jagged or gaping, it's on your face, or you can't get it clean. If you have a clean wound that's stopped bleeding but still aren't sure whether you need stitches, go to urgent care to save on waiting time. Or call your doc: You may be able to text a pic so he can make the call, says Dr. McGann.
You have the worst. headache. ever.
Think about: A ruptured aneurysm or stroke. People who've had a ruptured aneurysm (a burst blood vessel) in their brain often complain about feeling the worst headache of their life. The pain often starts suddenly. "That could signal bleeding within the brain," says Dr. Evans. You may also be unable to think clearly, fumble with speech, or have problems with vision, swallowing, or movement, symptoms that could indicate either a brain bleed or a blocked artery in the brain (aka ischemic stroke).
What to do: If any headache feels exceptional (it's more intense than normal, say, or it comes with dizziness or vomiting for the first time), book it to an ER. The faster you get treatment, the better. Don't be embarrassed if it's a false alarm. As Linda Regan, MD, assistant professor of emergency medicine at Johns Hopkins School of Medicine, puts it, "Telling patients it's nothing is what all ER doctors hope for."
How to be prepared for an emergency
Knowing what you'll do in an emergency is key to surviving one. Your ER plan:
Call 911: If you can't move, you're bleeding heavily, or you have symptoms of a heart attack or stroke, you need an ambulance. EMS personnel can provide lifesaving care en route and determine the best hospital for your needs.
Or (sometimes) get a ride: As long as you can walk to a car and do not have the symptoms listed above, someone -- a friend, a taxi -- can take you to the hospital. Don't drive yourself; and when in doubt, call 911.
Go to the closest hospital: When transporting yourself to the ER, your priority should be to get there as quickly as possible. They'll stabilize you and transfer you to another hospital if needed.
Make a list: "If you're unable to respond to EMS providers' questions, they'll look in your wallet for info," says Dr. McGann. "Keep a list there of meds you take along with emergency contacts." As a backup use an app, like the Health app in iOS or ICE Standard for Android, that can store info on your lock screen.