Overactive bladder (OAB) is a condition characterized by a sudden, uncontrollable urge to urinate, often accompanied by frequent urination and, in some cases, urinary incontinence. OAB is caused by involuntary contractions of the bladder muscles and can affect adults of any age, though it is more common in older individuals. The condition can impact daily life, work, and social activities. …

Norovirus infection is a highly contagious viral illness that affects the stomach and intestines, causing inflammation and irritation. It is a common cause of gastroenteritis, leading to vomiting, diarrhea, and stomach cramps. Norovirus spreads easily through contaminated food, water, surfaces, or close contact with infected individuals. The infection can affect people of all ages and often occurs in crowded settings …

Noonan syndrome is a genetic disorder that affects normal development in various parts of the body. It is characterized by distinctive facial features, short stature, heart defects, and other physical and developmental differences. Noonan syndrome can affect people of all genders and ethnic backgrounds and is often diagnosed in infancy or early childhood, though mild cases may be identified later …

Nonmelanoma skin cancer refers to a group of skin cancers that develop from cells other than melanocytes, most commonly basal cell carcinoma and squamous cell carcinoma. These cancers typically arise on sun-exposed areas of the body, such as the face, ears, neck, scalp, and hands. Nonmelanoma skin cancers are the most common cancers worldwide and usually grow slowly. With early …

Nightmare disorder is a sleep disorder characterized by recurrent, vivid, and distressing dreams that typically involve threats to survival, safety, or physical integrity. These nightmares usually occur during rapid eye movement sleep and often cause abrupt awakenings with clear recall of the dream content. Nightmare disorder can affect both children and adults and may interfere with sleep quality, emotional well-being, …

Niemann-Pick disease is a group of rare inherited metabolic disorders that affect the body’s ability to break down and transport fats, particularly cholesterol and sphingomyelin, within cells. As a result, harmful amounts of these substances accumulate in organs such as the liver, spleen, lungs, bone marrow, and brain. The disease typically begins in infancy or childhood, although some forms may …

Peripheral neuropathy is a condition that occurs when the peripheral nerves, which carry signals between the brain, spinal cord, and the rest of the body, become damaged. These nerves control sensations such as touch and pain, muscle movements, and some automatic body functions. When peripheral nerves are injured or diseased, communication between the brain and the body is disrupted. This …

Neurofibroma is a benign tumor that develops from nerve tissue and is made up of a mixture of nerve cells, connective tissue, and supporting cells. These tumors commonly occur on or under the skin but may also develop along deeper nerves in the body. Neurofibromas can appear as isolated growths or as part of a genetic condition known as neurofibromatosis. …

Neuroendocrine tumors are a diverse group of cancers that develop from neuroendocrine cells, which have traits of both nerve cells and hormone-producing cells. These cells are found throughout the body, especially in organs such as the gastrointestinal tract, pancreas, and lungs. Neuroendocrine tumors may grow slowly or aggressively and can be functional, producing excess hormones, or nonfunctional, producing no hormones …

Schwannomatosis is a rare genetic disorder characterized by the development of multiple schwannomas, which are typically benign tumors that grow from Schwann cells surrounding peripheral nerves. Unlike neurofibromatosis type 2, schwannomatosis usually does not involve tumors on the hearing nerves and does not commonly cause hearing loss. Schwannomatosis often appears in adulthood and can cause chronic pain due to nerve …