Bird flu, also known as avian influenza, is a viral infection that primarily affects birds but can sometimes spread to humans. It is caused by influenza A viruses, with certain strains such as H5N1 and H7N9 being more likely to infect people. Human infections are rare but can be serious when they occur. Most human cases are linked to close …

Atrioventricular septal defect is a congenital heart defect, meaning it is present at birth. It involves a combination of heart problems that affect the center of the heart. Children born with this condition have a hole in the wall that separates the heart’s chambers, along with abnormalities of the valves that regulate blood flow through the heart. Because of this …

Atrioventricular nodal reentry tachycardia, also called AVNRT, is a type of irregular heartbeat known as an arrhythmia. It is the most common form of supraventricular tachycardia, which means the abnormal rhythm starts in the upper part of the heart. In AVNRT, the heart suddenly begins to beat very fast, often at a rate higher than 100 beats per minute, and …

Atrioventricular septal defect is a congenital heart defect, meaning it is present at birth. It involves a combination of structural problems affecting the center of the heart. Children born with this condition have a hole in the wall that separates the heart chambers, along with abnormalities of the heart valves that regulate blood flow. Because of this defect, extra blood …

Vaginal atrophy, also known as atrophic vaginitis or genitourinary syndrome of menopause (GSM), is a condition caused by thinning, drying, and inflammation of the vaginal walls due to a decrease in estrogen levels. It most commonly affects postmenopausal individuals but can also occur during breastfeeding or after medical treatments that reduce estrogen. Lower estrogen levels reduce blood flow and elasticity …

Reactive attachment disorder is a childhood mental health condition that affects a child’s ability to form healthy emotional bonds with caregivers. It develops when a child’s basic emotional and physical needs for comfort, affection, and consistent caregiving are not adequately met during early development. The disorder is most often seen in children who have experienced severe neglect, abuse, or frequent …

Attention-deficit/hyperactivity disorder, commonly known as ADHD, is a long-term neurodevelopmental condition that affects millions of children worldwide and often continues into adulthood. The disorder is marked by an ongoing pattern of inattention, hyperactivity and impulsive behavior that interferes with daily functioning and development. Children with ADHD may struggle with focus, self-control and staying organized. These challenges can affect academic performance, …

Adult attention-deficit/hyperactivity disorder, commonly known as adult ADHD, is a mental health condition characterized by a persistent pattern of inattention, impulsivity and restlessness. Although often associated with childhood, ADHD begins early in life and may continue into adulthood. In many individuals, symptoms are not recognized or formally diagnosed until adult years. Adult ADHD can affect many areas of daily life, …

Atypical hyperplasia of the breast refers to the growth of abnormal, precancerous cells within breast tissue. In this condition, breast cells increase in number and show changes in their appearance when examined under a microscope, making them look different from normal breast cells. Atypical hyperplasia is not breast cancer. However, it is an important warning sign because it is linked …

Atrial tachycardia is a type of irregular heartbeat, also called an arrhythmia. It belongs to a group of heart rhythm disorders known as supraventricular tachycardias, which originate in the upper chambers of the heart, called the atria. During an episode of atrial tachycardia, the heart beats faster than normal, often exceeding 100 beats per minute. In many cases, the heart …