A mass of pus (yellowish-white fluid filled with dead white blood cells) from an infection that collects in spaces between the structures of the neck.

A blood infection common in preterm, low-birth-weight babies, can be caused by bacteria or virus, commonly Group B streptococcus but most dangerously by E. coli.

A group of symptoms affecting both kidneys, usually with no obvious cause, indicated by high albumin in the urine, high blood cholesterol and fluid retention throughout the body.

Any structural, chemical or electrical disturbances in the central nervous system can result in weakness, paralysis, lack of coordination or sensation, confusion or pain.

Plural of nevus, a skin marking present at birth or appearing within a few weeks of birth, occurring anywhere and very common in infants. Most are harmless.

Intervals of no airflow through the nose and mouth during sleep despite continued attempts to breathe in and out.

An assortment of congenital malformations that affect various parts of the head and upper body.

Inflammation of the middle ear, often occurring with a viral upper respiratory tract illness, and is one of the most common diagnoses for U.S. children.

When the ovary twists on its axis, twisting its venous and lymphatic vessels and thus shutting down its blood supply, causing severe abdominal pain, nausea and vomiting.

When the four pea-sized nodules located on or near the back of the thyroid gland are either overactive or underactive, releasing too much or too little parathyroid hormone.

A group of symptoms usually including tremor, slowness of movement, rigidity, and postural instability, similar to Parkinson's disease, but resulting from several causes.

Also known as sunken chest or funnel chest, when an abnormal growth of cartilage in the chest wall pushes the sternum and ribs inward, creating a caved-in appearance.