Shunt (medical)

In medicine, a shunt is a hole or a small passage that moves, or allows movement of, fluid from one part of the body to another. The term may describe either congenital or acquired shunts; acquired shunts (sometimes referred to as iatrogenic shunts) may be either biological or mechanical. TOC Cardiac shunts may be described as right-to-left, left-to-right or bidirectional, or as systemic-to-pulmonary or pulmonary-to-systemic. Cerebral shunt: In cases of hydrocephalus and other conditions that cause chronic increased intracranial pressure, a one-way valve is used to drain excess cerebrospinal fluid from the brain and carry it to other parts of the body. This valve usually sits outside the skull but beneath the skin, somewhere behind the ear. Cerebral shunts that drain fluid to the peritoneal cavity (located in the upper abdomen) are called ventriculoperitoneal (VP) shunts. Lumbar-peritoneal shunt (a.k.a. lumboperitoneal, LP): In cases of chronic increased intracranial pressure such as idiopathic intracranial hypertension and hydrocephalus, a tube or shunt with or without a one-way valve is used to drain the excess cerebrospinal fluid from the brain and transport it to the peritoneal cavity. Unlike the ventriculoperitoneal shunt, however, a lumbar-peritoneal shunt is usually inserted in between two of the vertebrae in the lumbar and punctures the cerebrospinal fluid sack or lumbar subarachnoid space, it then runs beneath the skin to the peritoneal cavity, where it is eventually drained away by the normal bodily fluid drainage system. A Peritoneovenous shunt: (also called Denver shunt) is a shunt which drains peritoneal fluid from the peritoneum into veins, usually the internal jugular vein or the superior vena cava. It is sometimes used in patients with refractory ascites. It is a long tube with a non-return valve running subcutaneously from the peritoneum to the internal jugular vein in the neck, which allows ascitic fluid to pass directly into the systemic circulation.