Myelofibrosis is a rare type of blood cancer where your bone marrow (the soft, spongy tissue inside of your bones) is replaced by fibrous scar tissue. It’s a form of chronic leukemia and a myeloproliferative disorder. Myeloproliferative disorders involve too many blood cells getting made in your bone marrow — where blood cells get made. Your bone marrow produces immature blood-forming cells called stem cells that may develop …

Agoraphobia is an anxiety disorder that causes an intense fear of becoming overwhelmed or unable to escape or get help. Because of fear and anxiety, people with agoraphobia often avoid new places and unfamiliar situations, like: Crowds. Places outside of their home. Public transportation. How common is agoraphobia? Researchers don’t know the exact cause of agoraphobia. However, it’s often associated with an …

Adult-onset Still’s disease (AOSD) is a rare type of inflammatory arthritis that affects your whole body. It causes joint and muscle pain, a daily fever and a rash. It can also cause other systemic (whole-body) symptoms. AOSD is an adult form of juvenile Still’s disease (juvenile idiopathic arthritis, JIA). It typically occurs in younger adults, between the ages of 16 and 35. …

Nicotine is a type of stimulant found in tobacco products. Nicotine dependence occurs when your body gets used to having some level of nicotine in your system. In physical and psychological ways, your body “depends” on constantly having the chemical. Physical dependence is when your body needs nicotine to avoid withdrawal symptoms — the unpleasant feelings that you get when you stop using …

Mesenteric lymphadenitis, also known as mesenteric adenitis, is inflammation (swelling) of the lymph nodes in the abdomen (belly). Lymph nodes are organs that are part of your body’s immune system. They filter harmful substances such as bacteria and viruses so that they don’t spread to other parts of your body. Lymph nodes are about the size of a pea, but …

Adenomyosis (pronounced “add-en-o-my-OH-sis”) is when tissue similar to the lining of your uterus (endometrium) starts to grow into the muscle wall of your uterus (myometrium). It causes your uterus to thicken and enlarge — sometimes, up to double or triple its usual size. Adenomyosis can cause painful periods, heavy or prolonged menstrual bleeding with clotting and abdominal/pelvic pain.

Frozen shoulder is a painful condition in which your shoulder movement becomes limited. Another name for frozen shoulder is adhesive capsulitis. Frozen shoulder occurs when the strong connective tissue surrounding your shoulder joint (called the shoulder joint capsule) becomes thick, stiff and inflamed. The joint capsule contains the ligaments that attach the top of your upper arm bone (humeral head) to your …

An adjustment disorder is a strong emotional or behavioral reaction to stress or trauma. It causes short-term symptoms that may make you react more than you typically would. You may cry easily or feel depressed and hopeless. You might overindulge in risky behaviors, or act recklessly or impulsively. The behaviors and feelings vary from person to person. Sometimes, one event can cause …

Adnexal tumors are growths of cells that form on the organs and connective tissues around the uterus. Adnexal tumors most often aren’t cancerous, but they can be cancerous. Adnexal tumors occur in the: Ovaries Fallopian tubes Connective tissue around the ovaries or fallopian tubes Diagnosis of adnexal tumors involves a careful physical exam, imaging tests and, sometimes, surgery. Treatment for …

Childhood schizophrenia is a very rare, severe psychiatric condition that begins before your child is 13. Psychiatric conditions affect people’s mental health and how they see the world around them. Symptoms of childhood schizophrenia include psychosis, and movement and thought (cognitive) disorders. Childhood schizophrenia interferes with things like your child’s: Thoughts. Memory. Senses. Behaviors. As a result, your child may struggle …