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Definition Arteriovenous malformation is a congenital disorder (present from birth) characterized by a complex, tangled web of arteries and veins in which there are a short circuit and high pressure due to arterial blood flowing rapidly in the veins. An AVM may occur in the brain, brainstem or spinal cord. …

What Is Apraxia? Apraxia is a poorly understood neurological condition. People who have it find it difficult or impossible to make certain motor movements, even though their muscles are normal. Milder forms of apraxia are known as dyspraxia. Apraxia can occur in a number of different forms. One form is …

Definition Amyloidosis is a rare and serious protein deposition disease. It is caused by an abnormal protein called amyloid that builds up in tissues or organs. As the number of amyloid protein deposits increase in a tissue or organ, they interfere with the tissue or organ’s healthy function. Eventually, amyloid …

Introduction – Acute Flaccid Myelitis Acute flaccid myelitis (AFM) is a rare disease that affects the spinal cord, the part of the nervous system that carries messages to and from the brain. Symptoms of AFM include sudden (acute) weakness in the arm(s) or leg(s), along with loss of muscle tone …

Definition Bones naturally grow and change as your child gets older. However, throughout a long process, abnormalities can sometimes occur. An aneurysmal bone cyst (which is often abbreviated ABC) is one such abnormality. ABCs are blood-filled, fibrous cysts that expand the bone and can cause pain, swelling, and fractures. They …

Definition Abdominal Aortic Aneurysm is an enlargement of the lower part of the aorta that extends through the abdominal area (at times, the upper portion of the aorta in the chest can be enlarged). The aorta is the main blood vessel that carries blood from the heart to the rest …

Overview – Actinomycosis Actinomycosis is a rare subacute or chronic bacterial infection that causes both suppurative and granulomatous inflammation. Characteristics include localized swelling with suppuration, abscess formation, fibrosis and sinus drainage of pus containing ‘sulfur granules’. Actinomycetes are normal colonizing organisms of the oral cavity and may also be present …

Overview Allergic rhinitis, also known as hay fever, is an allergic reaction. You have an allergy when your body overreacts to things that don’t cause problems for most people. These things are called allergens. Your body’s overreaction to the allergens is what causes symptoms. There are 2 forms of allergic …