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During an asthma attack, also called an asthma exacerbation, your airways become swollen and inflamed. The muscles around the airways contract, causing your breathing (bronchial) tubes to narrow. During an asthma attack, you may cough, wheeze and have trouble breathing. An asthma attack may be minor, with symptoms that get better with prompt home treatment, Read more…

Asthma is a condition in which your airways narrow and swell and produce extra mucus. This can make breathing difficult and trigger coughing, wheezing and shortness of breath. For some people, asthma is a minor nuisance. For others, it can be a major problem that interferes with daily activities and may lead to a life-threatening Read more…

Aspergillosis is an infection caused by a type of mold. The illnesses resulting from aspergillosis infection usually affect the respiratory system, but their signs and severity vary greatly. The mold that triggers the illnesses, aspergillus, is everywhere, indoors and outdoors. Most strains of this mold are harmless, but a few can cause serious illnesses when Read more…

Ascariasis (as-kuh-RIE-uh-sis) is a type of roundworm infection. These worms are parasites that use your body as a host to mature from larvae or eggs to adult worms. Adult worms, which reproduce, can be more than a foot (30 centimeters) long. One of the most common worm infections in people worldwide, ascariasis is uncommon in Read more…

Asbestosis (as-bes-TOE-sis) is a chronic lung disease caused by inhaling asbestos fibers. Prolonged exposure to these fibers can cause lung tissue scarring and shortness of breath. Asbestosis symptoms can range from mild to severe, and usually don’t appear until many years after continued exposure. Asbestos is a natural mineral product that’s resistant to heat and Read more…

Arthritis is inflammation of one or more of your joints. The main symptoms of arthritis are joint pain and stiffness, which typically worsen with age. The most common types of arthritis are osteoarthritis and rheumatoid arthritis. Osteoarthritis causes cartilage — the hard, slippery tissue that covers the ends of bones where they form a joint Read more…

A brain (intracranial) arteriovenous malformation (AVM) is an abnormal tangle of arteries and veins in your brain. These are congenital lesions, meaning that they can develop before you’re born. Arteriovenous malformations can also occur in your spinal cord (spinal arteriovenous malformation). Oxygen-rich blood normally enters your brain through arteries, which branch into smaller arterioles and Read more…

An arteriovenous (AV) fistula is an abnormal connection between an artery and a vein. Normally, blood flows from your arteries to your capillaries to your veins. Nutrients and oxygen in your blood travel from your capillaries to tissues in your body. With an arteriovenous fistula, blood flows directly from an artery into a vein, bypassing Read more…