Avascular necrosis Avian influenza (See: Bird flu (avian influenza)) AVNRT (See: Atrioventricular nodal reentry tachycardia (AVNRT)) Overview Avascular necrosis is the death of bone tissue due to a lack

Autonomic neuropathy Overview Autonomic neuropathy occurs when the nerves that control involuntary bodily functions are damaged. It can affect blood pressure, temperature control, digestion, bladder function

Autoimmune pancreatitis Overview Autoimmune pancreatitis, also called AIP, is a chronic inflammation that is thought to be caused by the body’s immune system attacking the pancreas and that responds

Autoimmune hepatitis Overview Autoimmune hepatitis is liver inflammation that occurs when your body’s immune system turns against liver cells. The exact cause of autoimmune hepatitis is unclear,

Autism spectrum disorder Overview Autism spectrum disorder is a condition related to brain development that impacts how a person perceives and socializes with others, causing problems in social interaction

Atypical hyperplasia of the breast Overview Atypical hyperplasia is a precancerous condition that affects cells in the breast. Atypical hyperplasia describes an accumulation of abnormal cells in the breast. Atypical

Atypical depression Overview Any type of depression can make you feel sad and keep you from enjoying life. However, atypical depression — also called depression with atypical features — means that

Attention-deficit/hyperactivity disorder (ADHD) in children Attention-deficit/hyperactivity disorder in adults (See: Adult attention-deficit/hyperactivity disorder (ADHD)) Overview Attention-deficit/hyperactivity

Supraventricular tachycardia Atrioventricular septal defect (See: Atrioventricular canal defect) Atrophic vaginitis (See: Vaginal atrophy) Attachment disorder (See: Reactive attachment disorder) Atrioventricular

Atrioventricular canal defect Overview Atrioventricular canal defect is a combination of heart problems resulting in a defect in the center of the heart. The condition occurs when there’s a hole

Supraventricular tachycardia Atrial tachycardia is the least common type of supraventricular tachycardia. It’s generally seen in children with underlying heart disorders such as congenital heart

Atrial septal defect (ASD) Overview An atrial septal defect (ASD) is a hole in the wall between the two upper chambers of your heart (atria). The condition is present at birth (congenital). Small defects

Atrial flutter Overview In atrial flutter, your heart’s upper chambers (atria) beat too quickly. This causes the heart to beat in a fast, regular rhythm. Atrial flutter is a type of heart rhythm

Atrial fibrillation Overview Atrial fibrillation is an irregular and often rapid heart rate that can increase your risk of stroke, heart failure and other heart-related complications. During atrial fibrillation,

Atopic dermatitis (eczema) Overview Atopic dermatitis (eczema) is a condition that makes your skin red and itchy. It’s common in children but can occur at any age. Atopic dermatitis is long lasting