Pain is a signal from your nervous system that something may be wrong. It is an unpleasant feeling, such as a prick, tingle, sting, burn, or ache. Pain may be sharp or dull. You may feel pain in one area of your body or all over. Each person feels pain differently, even if the reason for the pain is the same.

Pain might be acute or chronic. The type of pain is based on how long and how often you have pain. Acute pain starts suddenly and goes away when the cause is treated or healed. This pain lets you know that you may be injured or have a problem you need to take care of. Chronic pain lasts longer than three months or the time in which you should have healed.

If you have chronic pain, it can occur most days or every day and may last for weeks, months, or even years. It can affect all aspects of daily life, including your mood and relationships. Treatment may not get rid of chronic pain, but it can help with your symptoms.

Sometimes, acute pain can become chronic pain. The original cause may have been an injury or infection, or you may have an ongoing cause of pain, such as arthritis or cancer. In some cases, there is no clear cause. Environmental factors and psychological factors such as mood and stress can make chronic pain worse.

Since people feel pain in different ways, two people could have the same issue, but each may have different symptoms. Chronic pain can occur anywhere in your body and may cause other symptoms such as fatigue, mood changes, or difficulty sleeping. If you have depression or stress, it may make chronic pain worse.

Many older adults have chronic pain. Women also report having more chronic pain than men, and they are at a greater risk for many pain conditions. Some people have two or more chronic pain conditions. You may be more likely to have chronic pain if you have certain medical conditions such as:

• Headaches or migraines
• Cancer
• Fibromyalgia
• Arthritis
• Nerve damage
• Back problems

Chronic pain lasts three months or longer or when pain continues after your body has healed. If the cause of your pain is unknown, your health care provider may:

• Ask you about your medical history
• Ask you to describe the pain and how it affects your life
• Do a physical exam
• Order blood tests or other medical tests

Chronic pain is not always curable, but treatments can help. Treatments may include medicines, including pain relievers. There are also non-drug treatments, such as acupuncture, physical therapy, and sometimes surgery.

Depending on the cause of your pain and your symptoms, your provider may also recommend lifestyle changes which may include suggestions for:

• Improving mental health
• Managing stress
• Getting to and staying at a healthy weight
• Adding low-impact exercise

Complex regional pain syndrome (CRPS) is a chronic pain condition. It causes intense pain, usually in the arms, hands, legs, or feet. It may happen after an injury, either to a nerve or to tissue in the affected area. Rest and time may only make it worse.

Symptoms in the affected area are:

• Dramatic changes in skin temperature, color, or texture
• Intense burning pain
• Extreme skin sensitivity
• Swelling and stiffness in affected joints
• Decreased ability to move the affected body part

The cause of CRPS is unknown. There is no specific diagnostic test. Your doctor will diagnose CRPS based on your signs and symptoms.

There is no cure. It can get worse over time, and may spread to other parts of the body. Occasionally the symptoms go away, either temporarily or for good. Treatment focuses on relieving the pain, and can include medicines, physical therapy, and nerve blocks.

NIH: National Institute of Neurological Disorders and Stroke

Congenital heart defects (CHDs) are problems with the structure of the heart. "Congenital" means that that the problems are present at birth. These defects happen when a fetus's heart doesn't develop normally during pregnancy. Congenital heart defects are the most common type of birth defect.

Congenital heart defects can change the way the heart pumps blood. They may make blood flow too slowly, go the wrong way, or block it completely.

There are many types of congenital heart defects. They can happen in one or more parts of the heart. The most common types are:

• Septal defects ("hole in the heart") - openings in the wall between the left and right sides of the heart
• Heart valve defects - problems with the valves that control the flow of blood through the heart
• Defects in the large blood vessels that carry blood in and out of the heart

Congenital heart defects can range from very mild problems that never need treatment to life-threatening problems at birth. The most serious congenital heart defects are called critical congenital heart disease. Babies with these defects usually need surgery in the first year of life. But the symptoms of milder heart defects may not show up until childhood or adulthood.

Researchers often don't know what causes congenital heart defects. They do know that changes in a baby's genes sometimes cause a heart defect. The changed genes may come from the parents, or the changes may happen during pregnancy.

Several things may increase the chance that your baby has a congenital heart defect, such as:

• Your health before and during pregnancy, including:
  • Having diabetes before pregnancy or developing it in the first 3 months of pregnancy (diabetes that develops later in pregnancy isn't a major risk for heart defects). Carefully controlling your blood glucose, also called blood sugar, before and during pregnancy can lower your baby's risk of congenital heart defects.
  • Having phenylketonuria (PKU), a rare inherited disorder that affects how the body uses a protein in foods. If you have PKU, eating a low-protein diet before getting pregnant can lower your baby's risk of having a congenital heart defect.
  • Having rubella (German measles) during pregnancy.
• Your contact with certain substances during pregnancy, including:
  • Smoking or secondhand smoke (breathing smoke from another smoker).
  • Certain medicines, such as angiotensin-converting (ACE) inhibitors for high blood pressure and retinoic acids for acne. If you're pregnant or plan to get pregnant, talk with your health care provider about all the medicines you take.
• Your family history and genetics. In most cases, congenital heart defects don't run in families. But your chance of having a baby with a congenital heart defect does go up if you or the other parent has a congenital heart defect, or if you already have a child with a congenital heart defect.

Congenital heart defects don't cause pain. The signs and symptoms are different, depending on the type and number of defects and how serious they are.

Common signs and symptoms of congenital heart defects include:

• Cyanosis - a bluish color to the skin, lips, and fingernails. It happens when there isn't enough oxygen in the blood.
• Fatigue - your baby may be unusually sleepy and may become very tired during feedings.
• Poor blood flow.
• Fast or difficult breathing.
• Heart murmur - an unusual sound between heartbeats.

Congenital heart defects don't always cause other problems. If they do, which problems you have would depend on the type and number of defects and how serious the defects are.

Children with congenital heart defects are more likely to:

• Be smaller than other children
• Have problems or delays in mental, and emotional growth, and behavior, such as:
  • Speech and language problems
  • Attention deficit hyperactivity disorder (ADHD)

People with congenital heart defects may develop other health conditions, including:

• Endocarditis - an infection of lining of the heart and valves
• Arrhythmia - a problem with the rate or rhythm of your heartbeat
• Heart failure - when your heart can't pump enough blood to the body
• Pulmonary hypertension - high blood pressure in your lungs
• Kidney and liver disease

• Before a baby is born, your provider may use ultrasound pictures of the fetus's heart to look for heart defects. This is called a fetal echocardiogram. It's done between weeks 18 and 22 of pregnancy.
• During the first few days after birth, all newborns are checked for congenital heart defects. A pulse oximeter is clipped to your baby's hands or feet to measure blood oxygen. If it shows low levels of blood oxygen, more tests will be needed to find out if your baby has a heart defect.
• To diagnose congenital heart defects in babies, children, and adults, a provider may use many tools, including:
  • A physical exam.
  • Certain heart tests to see how the heart is working.
  • Genetic testing to see if certain gene problems caused the defect.

Treatment depends on the type of congenital heart defect and how serious it is. Possible treatments include:

• Cardiac catheterization to repair simple defects, such as a small hole in the inside wall of the heart. A catheterization uses a thin tube guided through a vein and into the heart.
• Heart surgery may be needed to:
  • Repair defects in the heart and blood vessels.
  • Repair or replace a heart valve.
  • Place a device in the chest to help the heart pump blood.
  • Do a heart transplant
• Medicine is often used if your baby has a specific type of congenital heart defect called patent ductus arteriosus.

All children and adults who have congenital heart defects need regular follow-up care from a cardiologist (a doctor who specializes in heart diseases) throughout their life, even if their defect was repaired.

Some people may need several heart surgeries or catheterizations over the years. They may also need to take medicines to help their hearts work as well as possible.

NIH: National Heart, Lung, and Blood Institute

Coronary artery bypass surgery creates a new path for blood to flow to your heart. This surgery is sometimes called a coronary artery bypass graft (CABG) or heart bypass. It's the most common heart surgery in adults. You may need this surgery if you have a blocked or partially blocked artery in your heart.

This surgery is often used to treat coronary artery disease (CAD). Your coronary arteries supply blood to your heart. If you have coronary artery disease, a sticky material called plaque builds up in your coronary arteries. This can cause them to harden and narrow. When this happens, some parts of your heart don't get enough blood.

Before recommending surgery, your health care provider may try other treatments. These could include lifestyle changes, medicines, or angioplasty, a procedure to open your arteries. If these treatments don't help, you may need coronary artery bypass surgery.

Your provider may recommend surgery if you have obstructive coronary artery disease to help lower your risk of a heart attack. They will consider your overall health before deciding if surgery is your best option.

You may benefit from surgery if you have:

• Coronary heart disease with angina (chest pain)
• Diabetes
• Multiple blocked coronary arteries
• Serious heart failure

You might need emergency coronary artery bypass surgery to treat a severe heart attack.

During surgery, the surgeon takes healthy blood vessels from another part of your body. These blood vessels are attached to blood vessels above and below the blocked artery to let blood bypass (get around) the blockage. You might need more than one bypass if you have a few blocked arteries.

Methods to perform coronary artery bypass surgery include:

• Traditional CABG. The chest is cut open to reach the heart. A machine pumps blood through your body during the surgery. This is the most common type of CABG surgery.
• Off-pump CABG. The chest is cut open to reach the heart. A machine for pumping blood is not used.
• Minimally invasive CABG methods. Small cuts are made in the chest. A machine for pumping blood is not used.
• Robotic-assisted surgery. This is a type of minimally invasive surgery. The surgeon uses a computer to control tools on the arms of a robot. A machine for pumping blood may be used.

Like all surgery, CABG has risks even though the results are often excellent. The risks can include:

• Arrhythmia
• Bleeding
• Heart attack
• Infection
• Kidney failure
• Stroke

After coronary artery bypass surgery, many people remain symptom-free for years. You may need surgery again if blockages form in the grafted arteries or veins. Or if blockages happen in arteries that weren't blocked before. Lifestyle changes and medicines may help stop your arteries from becoming clogged again.

NIH: National Heart, Lung, and Blood Institute

Critical care is medical care for people who have life-threatening injuries and illnesses. It usually takes place in an intensive care unit (ICU). A team of specially-trained health care providers gives you 24-hour care. This includes using machines to constantly monitor your vital signs. It also usually involves giving you specialized treatments.

You need critical care if you have a life-threatening illness or injury, such as:

• Severe burns
• COVID-19
• Heart attack
• Heart failure
• Kidney failure
• People recovering from certain major surgeries
• Respiratory failure
• Sepsis
• Severe bleeding
• Serious infections
• Serious injuries, such as from car crashes, falls, and shootings
• Shock
• Stroke

In a critical care unit, health care providers use lots of different equipment, including:

• Catheters, flexible tubes used to get fluids into the body or to drain fluids from the body
• Dialysis machines ("artificial kidneys") for people with kidney failure
• Feeding tubes, which give you nutritional support
• Intravenous (IV) tubes to give you fluids and medicines
• Machines which check your vital signs and display them on monitors
• Oxygen therapy to give you extra oxygen to breathe in
• Tracheostomy tubes, which are breathing tubes. The tube is placed in a surgically made hole that goes through the front of the neck and into the windpipe.
• Ventilators (breathing machines), which move air in and out of your lungs. This is for people who have respiratory failure.

These machines can help keep you alive, but many of them can also raise your risk of infection.

Sometimes people in a critical care unit are not able to communicate. It's important that you have an advance directive in place. This can help your health care providers and family members make important decisions, including end-of-life decisions, if you are not able to make them.