Glossary of Medical Terms

A head injury caused by inflicted harm to a child. Hospital teams are required to ask careful questions and to run specific tests when the pattern of injury does not match the story given. The aim is always the safety of the child.

A medication that puts your child fully to sleep for the duration of an operation, so they feel nothing during the surgery. Given by a specialist doctor called an anaesthetist.

A weak point in the wall of a blood vessel that bulges outwards. In the brain, an aneurysm can leak or burst and cause a haemorrhagic stroke. Rare in children, but real.

A detailed scan of the blood vessels in the brain. A thin tube (catheter) is passed through an artery, usually in the groin, and contrast is injected to show the vessels. The most detailed test for moyamoya, AVMs, and aneurysms.

A narrow channel deep inside the brain that lets cerebrospinal fluid flow from one fluid space to another. If this channel is blocked, hydrocephalus can develop.

A tangle of abnormal blood vessels where arteries connect directly to veins, without the normal small vessels in between. Can bleed and cause a haemorrhagic stroke. Treated with surgery, embolisation, radiosurgery, or a combination of these.

Bruising behind the ear that appears in the day or two after a serious head injury. A possible sign of a fracture at the base of the skull.

Taking a small piece of tissue to examine under the microscope and to test in the laboratory. Used to confirm what kind of tumor or other tissue change is present.

A temporary condition that can occur after surgery in the back part of the brain (the posterior fossa). The child may have difficulty speaking, swallowing, or controlling movements for days to weeks. In most children it improves with rehabilitation over weeks to months.

The smaller part of the brain at the back, sitting behind the brainstem. It helps to control balance and smooth movement.

The clear, water-like liquid that surrounds the brain and the spinal cord and fills the internal fluid spaces of the brain. It cushions the brain and helps to keep it healthy.

Medications that target tumor cells. Used in many childhood cancers, including some paediatric brain tumors. Usually given in cycles over months and managed by the paediatric oncology team.

A condition where the lower part of the cerebellum (the cerebellar tonsils) sits below the foramen magnum, in the top of the spinal canal. Chiari I is the milder and more common form. Chiari II is the more complex form that occurs together with spina bifida (myelomeningocele).

An endoscopic procedure, often combined with ETV, in which parts of the cerebrospinal-fluid-producing tissue inside the brain are gently scarred to reduce CSF production. Used mainly in young infants with hydrocephalus.

A type of X-ray scan that takes detailed pictures of the brain within a few seconds. Useful in emergencies because it is fast. Uses a small dose of radiation.

A mild traumatic brain injury caused by a blow or by shaking to the head. Usually involves headache, dizziness, confusion, or simply feeling "not quite right" for days to weeks. Almost all children recover fully.

A bruise of the brain tissue from a head injury, visible on a scan as a small area of damage or bleeding.

The lower end of the spinal cord. A low-lying conus on a scan can be a sign of tethered spinal cord.

A benign but locally aggressive tumor that arises near the pituitary gland at the base of the brain. Treatment usually involves surgery and sometimes radiation. Can affect vision, hormones, and growth.

An operation in which the neurosurgeon temporarily opens part of the skull to reach the brain underneath. The piece of skull is put back at the end of the operation.

Leakage of cerebrospinal fluid through a hole in its protective covering (the dura). Can happen after some operations or after certain head injuries. The signs include clear watery fluid from the nose, the ear, or a wound, and a headache that gets worse on sitting up and better on lying flat.

An operation in which a piece of skull is temporarily removed to give a severely swollen brain room to expand and to reduce the pressure. The skull piece is replaced in a second operation later, once the swelling has settled.

A small tube-like tract that connects the skin (usually on the lower back or the back of the head) to deeper structures, sometimes into the spinal canal. Can tether the spinal cord and can let infection in.

Not the same as the more common diabetes. DI happens when the body cannot hold on to enough water, the child passes a large amount of urine and becomes very thirsty. Can occur after surgery near the pituitary gland, and is treatable.

A microscopic stretching injury to nerve fibres throughout the brain, seen in some severe head injuries. It does not bleed and can be hard to see even on MRI. Often the reason for a prolonged period of unconsciousness after severe trauma.

The thick, tough membrane that wraps around the brain and the spinal cord. The neurosurgeon may "open" or "close" the dura during certain operations.

Enlarging the dura with a patch (made from the body's own tissue, or from a synthetic material). Used in Chiari decompression surgery and in some other operations.

Blocking an abnormal blood vessel (such as an AVM or an aneurysm) from the inside, by passing a catheter through an artery and injecting a blocking material. Performed by an interventional neuroradiologist.

A small camera on a thin tube that the neurosurgeon uses to look inside the body, for example inside the fluid spaces of the brain, through a very small opening.

An operation for hydrocephalus that uses an endoscope to make a small opening in the floor of one of the brain's fluid spaces, so that the fluid can drain naturally without leaving any equipment inside.

A brain (and sometimes spinal cord) tumor that arises from the cells lining the ventricles. Treatment usually involves surgery and radiation.

A collection of blood between the skull and the outer covering of the brain (the dura). Usually caused by a head injury and can grow quickly, one of the most urgent reasons for emergency brain surgery in trauma.

A temporary tube that drains cerebrospinal fluid from the brain to a collection bag outside the body, used while the team monitors the situation. Removed when it is no longer needed.

The thin band of tissue at the very bottom of the spinal cord that attaches it to the bottom of the spinal canal. A "tight" or "thickened" filum is a common cause of tethered spinal cord.

A vitamin (B9) taken before and during early pregnancy. It lowers the risk of spina bifida and of other neural tube defects in the baby.

The soft area on top of a baby's head where the skull bones have not yet joined. Doctors feel and watch the fontanelle as a way to check the pressure inside the head. It closes naturally during the first two years.

The large opening at the base of the skull where the brainstem connects to the spinal cord.

A safe substance given through a vein during certain MRI scans to make blood vessels and certain tissues (such as tumors) stand out more clearly. "MRI with contrast" usually means that gadolinium was used.

A score doctors use to describe how awake and alert a person is, particularly after a head injury. Ranges from 3 (deeply unconscious) to 15 (fully awake).

A brain tumor that arises from the brain's supportive cells (the glia). Low-grade gliomas grow slowly and are often curable, high-grade gliomas grow faster and are harder to treat.

A collection of blood outside the blood vessels. In the brain, haematomas are named according to where they sit, epidural, subdural, or inside the brain itself (intracerebral).

Weakness or paralysis on one side of the body, often after a stroke or another one-sided brain injury.

A stroke caused by bleeding into or around the brain. Different from an ischaemic stroke, which is caused by a blocked blood vessel.

A condition where extra cerebrospinal fluid builds up in the fluid spaces of the brain. Treated by giving the fluid a new way to drain (a shunt or an ETV).

A specialised hospital ward where the most unwell children are closely monitored by a team of doctors and nurses. The "P" in PICU stands for paediatric (children's).

The pressure inside the skull. The team monitors and treats high ICP, which can damage the brain if it stays too high for too long.

A stroke caused by a blocked blood vessel, so that part of the brain does not receive enough oxygen. The most common type of stroke at all ages.

A fatty mass attached to the spinal cord or to its surroundings. A spinal lipoma can tether the cord and cause symptoms over time.

A condition in which a spinal lipoma is connected to a spina-bifida-like opening, the spinal cord, the fatty tissue and the skin are all involved. Usually requires surgery to release the tethering.

A scan that uses a strong magnet (with no radiation) to produce detailed images of the brain and the spine. The standard scan for most paediatric neurosurgical conditions. It takes longer than a CT, and young children may need light sedation.

A type of brain tumor that arises in the posterior fossa, most common in children. Malignant but treatable, treatment usually involves surgery, chemotherapy, and sometimes radiation.

Inflammation (usually an infection) of the layers around the brain and the spinal cord. A serious condition treated with antibiotics or antivirals.

A form of spina bifida in which a sac of cerebrospinal fluid pokes through a gap in the spine, but the spinal cord itself stays in its normal place inside the spinal canal. Surgery is usually needed.

A condition where the large arteries at the base of the brain narrow over time, and tiny new vessels grow to try to make up for it. Can cause repeated mini-strokes (TIAs) or larger strokes. Treated with revascularisation surgery to create a new blood supply to the brain.

An MRI scan focused on the blood vessels rather than on the brain tissue. Used to look for moyamoya, AVMs, aneurysms, and other vessel problems. No injection is needed for the basic version.

A care team made up of specialists from different fields, for example neurosurgery, neurology, oncology, urology, orthopaedics, rehabilitation, and social work, who work together on the care of a single child.

The most serious form of spina bifida. The spinal cord and the nerves come out through a gap in the spine and are exposed at birth, usually inside a sac. It affects how the legs, the bladder, and the bowel work, and often comes with hydrocephalus.

A group of birth conditions in which the developing spine or brain does not close fully early in pregnancy. Spina bifida is the most common type. Folic acid before and during pregnancy lowers the risk.

A bladder that does not work in the usual way because the nerves controlling it have been affected. Common in spina bifida and after some spinal cord problems. Managed by a paediatric urologist.

The medical speciality that diagnoses and treats brain and nervous-system conditions without surgery (medication, monitoring, follow-up). Different from neurosurgery.

The branch of psychology that focuses on how brain conditions affect thinking, memory, attention, and behaviour. A neuropsychological assessment maps out which abilities have been affected, and helps plan school and rehabilitation support.

The surgical speciality for operations on the brain, the spine, and the nerves.

Latin for "nothing by mouth." Your child will be NPO (no food or drink) for a number of hours before the surgery, so that the stomach is empty when they receive the anaesthesia. Your team will tell you the exact times.

The medical specialty that treats children with cancer, including most brain tumor care after the initial operation (chemotherapy, radiation, follow-up).

The sterile room where surgery takes place. In some countries also called the operating theatre. Family members wait in a separate waiting area.

Swelling at the back of the eye that the eye doctor can see when they shine a light into the eye. Can be a sign of high pressure inside the head.

Relating to the care of children. A paediatric neurosurgeon is a neurosurgeon specifically trained to operate on children.

An indirect revascularisation operation for moyamoya. A healthy scalp artery is laid gently onto the surface of the brain, over the following months the brain grows new tiny vessels into this new blood supply. Common in younger children with moyamoya.

A common type of low-grade glioma in children. Slow-growing, and often curable with surgery alone.

Flattening of one side or the back of a baby's head from spending a lot of time lying in one position. Very common, does not affect the brain, and does not need surgery, usually managed with positioning changes, more tummy time, and sometimes a helmet. Different from craniosynostosis.

The lower back part of the inside of the skull, where the cerebellum and the brainstem sit. Many paediatric brain tumors arise here.

A modern form of radiation that uses proton particles rather than X-rays. The focused dose spares more of the healthy tissue around the tumor. Used selectively in paediatric brain tumors where it is available.

Treatment that uses focused beams of energy to destroy tumor cells. Used carefully in young children because the developing brain is more sensitive to the long-term effects.

A highly focused, single (or very few) dose of radiation used to close some abnormal vessels (such as some AVMs) or to treat some tumors without an open operation. Names you may hear include stereotactic radiosurgery and Gamma Knife.

Therapies that help a child recover and adapt after a brain or spine injury, an illness, or an operation. Usually includes physiotherapy, occupational therapy, and speech-language therapy, sometimes also neuropsychology and mental health support.

Surgical removal, for example "tumor resection" means surgically removing the tumor.

A surgical operation to create a new blood supply to part of the brain. Used in moyamoya. Can be direct (a healthy artery sewn into a brain artery) or indirect (a scalp artery laid onto the surface of the brain).

A small dimple near the bottom of the back. Most sacral dimples are completely harmless and need no test. A dimple becomes worth investigating when it is large, deep, off-centre, high above the buttock cleft, hairy, or alongside another skin marker.

A sideways curvature of the spine. Can be related to several paediatric neurosurgical conditions, including spina bifida, tethered cord, Chiari, syringomyelia, and brain injury.

A sudden burst of abnormal electrical activity in the brain that can cause jerking movements, staring, or loss of awareness. Different from a "fit" in seriousness, and has many possible causes.

A small implanted system of tubes and a valve that drains excess cerebrospinal fluid from the brain to another part of the body where it can be absorbed (most commonly the abdomen). The standard treatment for most kinds of hydrocephalus.

An inherited condition of the red blood cells that can cause many problems, including stroke and moyamoya in children. Requires specialised haematology and neurology care.

A break in the skull bone. Most are simple (linear) and heal without surgery. Some, depressed, open, or basilar fractures, need specific treatment.

A neural tube defect in which the lower spine does not fully close during early pregnancy. There are several forms, ranging from the mild occulta (often no symptoms) to the severe myelomeningocele.

The bundle of nerves that runs down the back inside the spine, connecting the brain to the rest of the body.

A condition in which the spinal cord is divided into two halves by a piece of bone or fibrous tissue. Can tether one or both halves of the cord.

Sudden loss of brain function caused by an interruption to the brain's blood supply. Can be ischaemic (from a blocked vessel) or haemorrhagic (from a bleeding vessel). A medical emergency at any age, including in children.

Bleeding into the space between the brain and its thin inner covering. Can occur after a head injury, or because of a ruptured aneurysm or AVM.

A collection of blood between the brain and one of its protective coverings. Can develop after a head injury, including in babies after non-accidental trauma.

The flexible seam between two skull bones. Skull sutures allow the head to grow as the brain grows, they normally stay open for years. When a suture closes too early, the result is termed craniosynostosis.

A small fluid-filled cavity inside the spinal cord. Can develop with Chiari I and with some other spinal conditions, and can cause weakness, sensation changes, or scoliosis. Often improves once the underlying cause is treated.

A spinal cord that is anchored at the bottom and cannot move freely as the child grows. Stretching of the cord over time can lead to leg, bladder, or bowel problems. Treated by surgery to release the anchor.

A short episode (lasting minutes) of stroke-like symptoms that fully resolves. Sometimes called a "mini-stroke." A warning sign that a stroke could happen, and should be looked at urgently.

Any injury to the brain caused by trauma, from a concussion (mild) through to severe brain injury. A leading cause of childhood disability worldwide.

An abnormal growth of cells in the brain. Some tumors are benign (slow-growing, often curable with surgery) and some are malignant (cancerous, requiring additional treatment).

A scan that uses sound waves (with no radiation) to produce pictures. Used in babies through the soft spot, it is quick, painless, and very useful for following hydrocephalus.

A test that measures how the bladder fills and empties. Used in children with spina bifida, tethered cord, and other conditions to assess and to follow neurogenic bladder.

The part of a shunt that controls how much fluid drains and at what pressure. Some valves can be adjusted from outside the body using a small magnetic device.

The fluid-filled spaces inside the brain where cerebrospinal fluid is made and through which it flows. There are four ventricles in total.

The most common type of shunt, draining cerebrospinal fluid from the brain's ventricles to the peritoneum (the space inside the abdomen), where the body absorbs it.