Acquired immunodeficiency syndrome (AIDS) is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus (HIV). By damaging your immune system, HIV interferes with your body's ability to fight infection and disease.

HIV is a sexually transmitted infection (STI). It can also be spread by contact with infected blood or from mother to child during pregnancy, childbirth or breast-feeding. Without medication, it may take years before HIV weakens your immune system to the point that you have AIDS.

Anemia (likewise spelled anaemia) is a lessening in the aggregate sum of red platelets (RBCs) or hemoglobin in the blood, or a brought capacity of the blood down to convey oxygen. When paleness goes ahead gradually, the indications are regularly obscure and may incorporate inclination tired, shortcoming, brevity of breath, and a poor capacity to exercise. When the pallor goes ahead rapidly, side effects may incorporate disarray, feeling like one is going to drop, loss of awareness, and expanded thirst. Anemia must be critical before an individual turns out to be recognizably pale. Additional manifestations may happen contingent upon the fundamental reason.

Angina is a type of chest pain caused by reduced blood flow to the heart. Angina (an-JIE-nuh or AN-juh-nuh) is a symptom of coronary artery disease.

Angina, also called angina pectoris, is often described as squeezing, pressure, heaviness, tightness or pain in your chest. Some people with angina symptoms say angina feels like a vise squeezing their chest or a heavy weight lying on their chest. Angina may be a new pain that needs to be checked by a doctor, or recurring pain that goes away with treatment.

Although angina is relatively common, it can still be hard to distinguish from other types of chest pain, such as the discomfort of indigestion. If you have unexplained chest pain, seek medical attention right away.

Types

There are several types of angina.

Stable or chronic angina

Stable angina occurs when the heart is working harder than usual, for instance, during exercise. It has a regular pattern and can be predicted to happen over months or even years. Rest or medication relieves symptoms.

Unstable angina

Unstable angina does not follow a regular pattern. It can occur when at rest and is considered less common and more serious because rest and medication do not relieve it. This version can signal a future heart attack within a short time ? hours or weeks.

Variant and microvascular angina

Variant or Prinzmetal?s angina and microvascular angina are rare and can occur at rest without any underlying coronary artery disease. This angina is usually due to abnormal narrowing or relaxation of the blood vessels, reducing blood flow to the heart. It can be relieved by medicine.

Arthritis is the swelling and tenderness of one or more of your joints. The main symptoms of arthritis are joint pain and stiffness, which typically worsen with age. The most common types of arthritis are osteoarthritis and rheumatoid arthritis.

Osteoarthritis causes cartilage ? the hard, slippery tissue that covers the ends of bones where they form a joint ? to break down. Rheumatoid arthritis is a disease in which the immune system attacks the joints, beginning with the lining of joints.

Uric acid crystals, which form when there's too much uric acid in your blood, can cause gout. Infections or underlying disease, such as psoriasis or lupus, can cause other types of arthritis.

Treatments vary depending on the type of arthritis. The main goals of arthritis treatments are to reduce symptoms and improve quality of life.

An autoimmune disease is a condition in which your immune system mistakenly attacks your body.

The immune system normally guards against germs like bacteria and viruses. When it senses these foreign invaders, it sends out an army of fighter cells to attack them.

Normally, the immune system can tell the difference between foreign cells and your own cells.

In an autoimmune disease, the immune system mistakes part of your body, like your joints or skin, as foreign. It releases proteins called autoantibodies that attack healthy cells.

Some autoimmune diseases target only one organ. Type 1 diabetes damages the pancreas. Other diseases, like systemic lupus erythematosus (SLE), affect the whole body.

A bleeding disorder is a condition that affects the way your blood normally clots. The clotting process, also known as coagulation, changes blood from a liquid to a solid. When you?re injured, your blood normally begins to clot to prevent a massive loss of blood. Sometimes, certain conditions prevent blood from clotting properly, which can result in heavy or prolonged bleeding.

Bleeding disorders can cause abnormal bleeding both outside and inside the body. Some disorders can drastically increase the amount of blood leaving your body. Others cause bleeding to occur under the skin or in vital organs, such as the brain.

Types of bleeding disorders

Bleeding disorders can be inherited or acquired. Inherited disorders are passed down through genetics. Acquired disorders can develop or spontaneously occur later in life. Some bleeding disorders can result in severe bleeding following an accident or injury. In other disorders, heavy bleeding can happen suddenly and for no reason.

There are numerous different bleeding disorders, but the following are the most common ones:

• Hemophilia A and B are conditions that occur when there are low levels of clotting factors in your blood. It causes heavy or unusual bleeding into the joints. Though hemophilia is rare, it can have life-threatening complications.
• Factor II, V, VII, X, or XII deficiencies are bleeding disorders related to blood clotting problems or abnormal bleeding problems.
• Von Willebrand?s disease is the most common inherited bleeding disorder. It develops when the blood lacks von Willebrand factor, which helps the blood to clot.

As its name suggests, this type of cancer affects the production and function of your blood cells. This type of cancer starts in bone marrow which is the integral source of blood production. Stem cells in your bone marrow mature and develop into three types of blood cells: red blood cells, white blood cells, or platelets. In case of cancer, the blood production process is interrupted due to the growth of an abnormal type of blood cell. The various types include Leukemia, Lymphoma and Myeloma.

Metabolic bone disease or MBD refers to a large spectrum of bone disorders, usually caused by mineral abnormalities such as calcium, phosphorus, magnesium or vitamin D. The most common metabolic bone diseases include osteoporosis, osteomalacia, rickets, renal osteodystrophy and osteitis deformans (Paget?s disease of bone).

Metabolic bone disease can be caused by a number of factors including vitamin D deficiency, hereditary hypophosphatemia, and hyperparathyroidism (over-activation of the parathyroid gland).

The most common form of metabolic bone disorder is osteoporosis. Osteoporosis is a bone disease characterized by a decrease in bone mass and density resulting in brittle, fragile bones that are more susceptible to fractures. The condition most commonly affects elderly women. Osteoporosis related fractures are more common at the hips, wrists, or vertebral bodies of the spine. Osteoporosis is called a ?silent disease,? because a majority of patients are unaware of their condition until they develop a bone fracture.

Metabolic bone disease in children can result in linear growth reduction, bone deformities, non-traumatic fractures, and impairment of motor development and function.

Bone marrow is the spongy tissue inside some of your bones, such as your hip and thigh bones. It contains stem cells. The stem cells can develop into the red blood cells that carry oxygen through your body, the white blood cells that fight infections, and the platelets that help with blood clotting.

With bone marrow disease, there are problems with the stem cells or how they develop:

In leukemia, a cancer of the blood, the bone marrow makes abnormal white blood cells In aplastic anemia, the bone marrow doesn't make red blood cells In myeloproliferative disorders, the bone marrow makes too many white blood cells Other diseases, such as lymphoma, can spread into the bone marrow and affect the production of blood cells

A brain tumor is a collection, or mass, of abnormal cells in your brain. Your skull, which encloses your brain, is very rigid. Any growth inside such a restricted space can cause problems. Brain tumors can be cancerous (malignant) or noncancerous (benign). When benign or malignant tumors grow, they can cause the pressure inside your skull to increase. This can cause brain damage, and it can be life-threatening.

Brain tumors are categorized as primary or secondary. A primary brain tumor originates in your brain. Many primary brain tumors are benign. A secondary brain tumor, also known as a metastatic brain tumor, occurs when cancer cells spread to your brain from another organ, such as your lung or breast.

Heart rhythm problems (heart arrhythmias) occur when the electrical impulses that coordinate your heartbeats don't work properly, causing your heart to beat too fast, too slow or irregularly.

Heart arrhythmias (uh-RITH-me-uhs) may feel like a fluttering or racing heart and may be harmless. However, some heart arrhythmias may cause bothersome ? sometimes even life-threatening ? signs and symptoms.

Heart arrhythmia treatment can often control or eliminate fast, slow or irregular heartbeats. In addition, because troublesome heart arrhythmias are often made worse ? or are even caused ? by a weak or damaged heart, you may be able to reduce your arrhythmia risk by adopting a heart-healthy lifestyle.

Types of arrhythmias

Doctors classify arrhythmias not only by where they originate (atria or ventricles) but also by the speed of heart rate they cause:

• Tachycardia (tak-ih-KAHR-dee-uh). This refers to a fast heartbeat ? a resting heart rate greater than 100 beats a minute.
• Bradycardia (brad-e-KAHR-dee-uh). This refers to a slow heartbeat ? a resting heart rate less than 60 beats a minute.

Cardiovascular disease (CVD) is a general term for conditions affecting the heart or blood vessels. It's usually associated with a build-up of fatty deposits inside the arteries (atherosclerosis) and an increased risk of blood clots. It can also be associated with damage to arteries in organs such as the brain, heart, kidneys and eyes. CVD is one of the main causes of death and disability in the UK, but it can often largely be prevented by leading a healthy lifestyle.