A blood clot is a mass of blood that forms when platelets, proteins, and cells in the blood stick together. When you get hurt, your body forms a blood clot to stop the bleeding. After the bleeding stops and healing takes place, your body usually breaks down and removes the blood clot. But sometimes the blood clots form where they shouldn't, your body makes too many blood clots or abnormal blood clots, or the blood clots don't break down like they should. These blood clots can be dangerous and may cause other health problems.

Blood clots can form in, or travel to, the blood vessels in the limbs, lungs, brain, heart, and kidneys. The types of problems blood clots can cause will depend on where they are:

• Deep vein thrombosis (DVT) is a blood clot in a deep vein, usually in the lower leg, thigh, or pelvis. It can block a vein and cause damage to your leg.
• A pulmonary embolism (PE) can happen when a DVT breaks off and travels through the bloodstream to the lungs. A PE, especially if it is large, can damage your lungs and prevent your other organs from getting enough oxygen.
• Cerebral venous sinus thrombosis (CVST) is a rare blood clot in the venous sinuses in your brain. Normally the venous sinuses drain blood from your brain. CVST blocks the blood from draining and can cause a hemorrhagic stroke.
• Blood clots in other parts of the body can cause problems such as an ischemic stroke, a heart attack, kidney problems, kidney failure, and pregnancy-related problems.

Certain factors can raise your risk of developing blood clots:

• Atherosclerosis
• Atrial fibrillation
• Being overweight or having obesity
• Cancer and cancer treatments
• Certain genetic disorders
• Certain surgeries
• COVID-19
• Diabetes
• Family history of blood clots
• Overweight and obesity
• Pregnancy and giving birth
• Serious injuries
• Some medicines, including birth control pills
• Smoking
• Staying in one position for a long time, such as being in the hospital or taking a long car or plane ride

The symptoms for blood clots can be different, depending on where the blood clot is:

• In the abdomen: Abdominal pain, nausea and vomiting
• In an arm or leg: Sudden or gradual pain, swelling, tenderness, and warmth
• In the lungs: Shortness of breath, pain with deep breathing, rapid breathing, and increased heart rate
• In the brain: Trouble speaking, vision problems, seizures, weakness on one side of the body, and sudden severe headache
• In the heart: Chest pain, sweating, shortness of breath, and pain in the left arm

To find out if you have one or more blood clots, your health care provider:

• Will do a physical exam.
• Will take your medical history, which includes asking about your symptoms.
• May order blood tests, including a D-dimer test.
• May order imaging tests, such as
  • Ultrasound.
  • X-rays of the veins (venography) or blood vessels (angiography) that are taken after you get an injection of special dye. The dye shows up on the x-ray and allows the provider to see how the blood flows.
  • CT Scan.

Treatments for blood clots depend on where the blood clot is located and how severe it is. Treatments may include:

• Blood thinners.
• Other medicines, including thrombolytics. Thrombolytics are medicines that dissolve blood clots. They are usually used where the blood clots are severe.
• Surgery and other procedures to remove the blood clots

You may be able to help prevent blood clots by:

• Moving around as soon as possible after having been confined to your bed, such as after surgery, illness, or injury
• Getting up and moving around every few hours when you have to sit for long periods of time, for example if you are on a long flight or car trip
• Wearing compression stockings after surgery or during a long flight
• Regular physical activity
• Not smoking
• Staying at a healthy weight

Some people at high risk may need to take blood thinners to prevent blood clots.

Your bones help you move, give you shape and support your body. They are living tissues that rebuild constantly throughout your life. During childhood and your teens, your body adds new bone faster than it removes old bone. After about age 20, you can lose bone faster than you make bone. To have strong bones when you are young, and to prevent bone loss when you are older, you need to get enough calcium, vitamin D, and exercise. You should also avoid smoking and drinking too much alcohol.

Bone diseases can make bones easy to break. Different kinds of bone problems include:

• Low bone density and osteoporosis, which make your bones weak and more likely to break
• Osteogenesis imperfecta makes your bones brittle
• Paget's disease of bone makes them weak
• Bones can also develop cancer and infections
• Other bone diseases, which are caused by poor nutrition, genetics, or problems with the rate of bone growth or rebuilding

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

Like other parts of the body, bones can get infected. The infections are usually bacterial, but can also be fungal. They may spread to the bone from nearby skin or muscles, or from another part of the body through the bloodstream. People who are at risk for bone infections include those with diabetes, poor circulation, or recent injury to the bone. You may also be at risk if you are having hemodialysis.

Symptoms of bone infections include:

• Pain in the infected area
• Chills and fever
• Swelling, warmth, and redness

A blood test or imaging test such as an x-ray can tell if you have a bone infection. Treatment includes antibiotics and often surgery.

Caffeine is a bitter substance that occurs naturally in more than 60 plants including:

• Coffee beans
• Tea leaves
• Kola nuts, which are used to flavor soft drink colas
• Cacao pods, which are used to make chocolate products

There is also synthetic (man-made) caffeine, which is added to some medicines, foods, and drinks. For example, some pain relievers, cold medicines, and over-the-counter medicines for alertness contain synthetic caffeine. So do energy drinks and "energy-boosting" gums and snacks.

Most people consume caffeine from drinks. The amount of caffeine in different drinks can vary a lot, but it is generally:

• An 8-ounce cup of coffee: 95-200 mg
• A 12-ounce can of cola: 35-45 mg
• An 8-ounce energy drink: 70-100 mg
• An 8-ounce cup of tea: 14-60 mg

Caffeine has many effects on your body's metabolism. It:

• Stimulates your central nervous system, which can make you feel more awake and give you a boost of energy
• Is a diuretic, meaning that it helps your body get rid of extra salt and water by urinating more
• Increases the release of acid in your stomach, sometimes leading to an upset stomach or heartburn
• May interfere with the absorption of calcium in the body
• Increases your blood pressure

Within one hour of eating or drinking caffeine, it reaches its peak level in your blood. You may continue to feel the effects of caffeine for four to six hours.

For most people, it is not harmful to consume up to 400mg of caffeine a day. If you do eat or drink too much caffeine, it can cause health problems, such as:

• Restlessness and shakiness
• Insomnia
• Headaches
• Dizziness
• Fast heart rate
• Dehydration
• Anxiety
• Dependency, so you need to take more of it to get the same results

Some people are more sensitive to the effects of caffeine than others.

Energy drinks are beverages that have added caffeine. The amount of caffeine in energy drinks can vary widely, and sometimes the labels on the drinks do not give you the actual amount of caffeine in them. Energy drinks may also contain sugars, vitamins, herbs, and supplements.

Companies that make energy drinks claim that the drinks can increase alertness and improve physical and mental performance. This has helped make the drinks popular with American teens and young adults. There's limited data showing that energy drinks might temporarily improve alertness and physical endurance. There is not enough evidence to show that they enhance strength or power. But what we do know is that energy drinks can be dangerous because they have large amounts of caffeine. And since they have lots of sugar, they can contribute to weight gain and worsen diabetes.

Sometimes young people mix their energy drinks with alcohol. It is dangerous to combine alcohol and caffeine. Caffeine can interfere with your ability to recognize how drunk you are, which can lead you to drink more. This also makes you more likely to make bad decisions.

You should check with your health care provider about whether you should limit or avoid caffeine if you:

• Are pregnant, since caffeine passes through the placenta to your baby.
• Are breastfeeding, since a small amount of caffeine that you consume is passed along to your baby.
• Have sleep disorders, including insomnia.
• Have migraines or other chronic headaches.
• Have anxiety.
• Have GERD or ulcers.
• Have arrhythmia (a problem with the rate or rhythm of your heartbeat).
• Have high blood pressure.
• Take certain medicines or supplements, including stimulants, certain antibiotics, asthma medicines, and heart medicines. Check with your health care provider about whether there might be interactions between caffeine and any medicines and supplements that you take.
• Are a child or teen. Neither should have as much caffeine as adults. Children can be especially sensitive to the effects of caffeine.

If you have been consuming caffeine on a regular basis and then suddenly stop, you may have caffeine withdrawal. Symptoms can include:

• Headaches
• Drowsiness
• Irritability
• Nausea
• Trouble concentrating

These symptoms usually go away after a couple of days.

Metabolism is the process your body uses to make energy from the food you eat. Food is made up of proteins, carbohydrates, and fats. Chemicals in your digestive system (enzymes) break the food parts down into sugars and acids, your body's fuel. Your body can use this fuel right away, or it can store the energy in your body tissues. If you have a metabolic disorder, something goes wrong with this process.

Carbohydrate metabolism disorders are a group of metabolic disorders. Normally your enzymes break carbohydrates down into glucose (a type of sugar). If you have one of these disorders, you may not have enough enzymes to break down the carbohydrates. Or the enzymes may not work properly. This causes a harmful amount of sugar to build up in your body. That can lead to health problems, some of which can be serious. Some of the disorders are fatal.

These disorders are inherited. Newborn babies get screened for many of them, using blood tests. If there is a family history of one of these disorders, parents can get genetic testing to see whether they carry the gene. Other genetic tests can tell whether the fetus has the disorder or carries the gene for the disorder.

Treatments may include special diets, supplements, and medicines. Some babies may also need additional treatments, if there are complications. For some disorders, there is no cure, but treatments may help with symptoms.