hydrocephalus, normal pressure Hydrocephalus that occurs because of a gradual blockage of CSF drainage pathways in the brain. Although the ventricles enlarge, intracranial pressure remains within normal range. Abbreviated NPH. NPH can occur as a complication of brain infection or bleeding (hemorrhage). In some patients, no predisposing cause can be identified. NPH is characterized by…
hydrocephalus, congenital Hydrocephalus that is present at birth. See also hydrocephalus.
hydrocephalus, communicating Hydrocephalus in which there is no obstruction to the flow of the cerebrospinal fluid (CSF). Specifically, there is no obstruction within the ventricular system of the brain or where the CSF passes into the spinal canal. Communicating hydrocephalus is due to overproduction of CSF or failure of the brain to reabsorb CSF normally.
hydrocephalus, acquired Hydrocephalus that is due to a postnatal cause, something that happened sometime after birth. See also hydrocephalus.
hydrocephalus An abnormal buildup of cerebrospinal fluid (CSF) in the ventricles and/or subarachnoid space of the brain. The fluid often increases intracranial pressure, which can compress and damage the brain. Hydrocephalus can arise before birth or at any time afterward. Causes can include birth defects (particularly spina bifida), hemorrhage into the brain, infection, meningitis, tumor,…
hydrocele Accumulation of fluid in the coat around the testis. Small hydroceles tend to disappear by 1 year of age. Larger hydroceles may persist and warrant surgery.
hydro- Prefix meaning related to water.
hydatidiform mole A tumor that forms in the uterus as a mass of cysts resembling a bunch of grapes. Hydatidiform moles occur during the childbearing years, and they do not spread outside the uterus. However, a malignancy called choriocarcinoma may start from a hydatidiform mole. In its early stages, a hydatidiform mole may look like…
hydatid mole See hydatidiform mole.
hybridoma A hybrid cell used as the basis for the production of antibodies in large amounts for diagnostic or therapeutic use. Hybridomas are produced by injecting a specific antigen into a mouse, collecting an antibody-producing cell from the mouse’s spleen, and fusing it with a tumor cell called a myeloma cell. The hybridoma cells multiply…
hybrid The result of a cross between genetically unlike parents. A hybrid is therefore the offspring of parents who differ in regard to the particular gene in question.
hyaline membrane disease Synonym for acute respiratory distress syndrome and respiratory distress syndrome. See acute respiratory distress syndrome; respiratory distress syndrome.