Dictionary

hyperkeratosis Thickening of the outer layer of skin, which is composed of the protein keratin. Causes include normal wear and tear, inflammation of the skin, or genetic conditions.

hyperlipidemia Elevated lipid (fat) levels in the blood. Hyperlipidemia can be inherited and increases the risk of disease of the blood vessels leading to stroke and heart disease.

hypermagnesemia Excess magnesium in the blood. Kidney disease is one of the main causes of hypermagnesemia. Persons with impaired kidney function should be especially careful about their magnesium intake because they can accumulate magnesium, which is dangerous and sometimes fatal.

hypermobility syndrome A condition in which joints can move beyond the normal range of motion predisposing them to injury and pain. Symptoms of hypermobility syndrome can include pains in knees, fingers, hips, and elbows, and the affected joints may sprain or dislocate. Joint hypermobility can disappear with aging from childhood to adulthood. Some persons have…

hypernatremia Elevated sodium in the blood. Hypernatremia can be caused by medications or conditions such as dehydration or kidney disease. See also sodium.

hyperopia See farsightedness.

hyperostosis Overgrowth of bone.

hyperphenylalaninemia Elevated levels of the amino acid phenylalanine in the blood. See also phenylalanine; phenylalanine hydroxylase deficiency; PKU; PKU, maternal.

hyperphosphatemia An elevated level of phosphate in the blood. Higher-than-normal levels can be caused by ingestion of phosphate-rich foods, such as dairy products, or by kidney failure.

hyperpigmentation Dark spots on the skin. Hyperpigmentation is primarily a cosmetic concern that can be covered with makeup, although in some cases (such as the cafe au lait spots associated with neurofibromatosis) it can be a sign of an underlying medical problem.

hyperplasia An increase in the number of normal cells in a tissue or an organ. Hyperplasia can represent a precancerous condition.

hyperplasia, benign prostatic See benign prostatic hyperplasia.