Many things can affect how your body responds to a symptom and what kind of care you may need. These include:

• Your age. Babies and older adults tend to get sicker quicker.
• Your overall health. If you have a condition such as diabetes, HIV, cancer, or heart disease, you may need to pay closer attention to certain symptoms and seek care sooner.
• Medicines you take. Certain medicines, herbal remedies, and supplements can cause symptoms or make them worse.
• Recent health events, such as surgery or injury. These kinds of events can cause symptoms afterwards or make them more serious.
• Your health habits and lifestyle, such as eating and exercise habits, smoking, alcohol or drug use, sexual history, and travel.

Shock is a life-threatening condition that may quickly occur after a sudden illness or injury.

Adults and older children often have several symptoms of shock. These include:

• Passing out (losing consciousness).
• Feeling very dizzy or lightheaded, like you may pass out.
• Feeling very weak or having trouble standing.
• Not feeling alert or able to think clearly. You may be confused, restless, fearful, or unable to respond to questions.

Shock is a life-threatening condition that may occur quickly after a sudden illness or injury.

Babies and young children often have several symptoms of shock. These include:

• Passing out (losing consciousness).
• Being very sleepy or hard to wake up.
• Not responding when being touched or talked to.
• Breathing much faster than usual.
• Acting confused. The child may not know where he or she is.

Abnormal bleeding means any heavy or frequent bleeding or any bleeding that is not normal for you. Examples of abnormal bleeding include:

• Nosebleeds.
• Vaginal bleeding that is different (heavier, more frequent, at a different time of month) than what you are used to.
• Rectal bleeding and bloody stools.
• Bloody or pink urine.
• Gums that bleed easily when you eat or gently brush your teeth.

When you have abnormal bleeding in one area of your body, it's important to think about whether you have been bleeding anywhere else. This can be a symptom of a more serious health problem.

Many prescription and nonprescription medicines may reduce your blood's ability to clot and cause bruising or bleeding under the skin. A few examples are:

• Aspirin and other medicines (called blood thinners) that prevent blood clots. Also, taking a nonprescription medicine with a blood thinner may increase your risk of bruising and bleeding.
• Medicines used to treat cancer.
• Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen (for example, Advil or Motrin).
• Steroids, such as prednisone.

Symptoms of infection may include:

• Increased pain, swelling, warmth, or redness in or around the area.
• Red streaks leading from the area.
• Pus draining from the area.
• A fever.

Symptoms of serious illness may include:

• A severe headache.
• A stiff neck.
• Mental changes, such as feeling confused or much less alert.
• Extreme fatigue (to the point where it's hard for you to function).
• Shaking chills.

Symptoms of serious illness in a baby may include the following:

• The baby is limp and floppy like a rag doll.
• The baby doesn't respond at all to being held, touched, or talked to.
• The baby is hard to wake up.

Certain health conditions and medicines weaken the immune system's ability to fight off infection and illness. Some examples in adults are:

• Diseases such as diabetes, cancer, heart disease, and HIV/AIDS.
• Long-term alcohol and drug problems.
• Steroid medicines, which may be used to treat a variety of conditions.
• Chemotherapy and radiation therapy for cancer.
• Other medicines used to treat autoimmune disease.
• Medicines taken after organ transplant.
• Not having a spleen.