Glossary

Hydrocephalus glossary

Every term in the Hydrocephalus glossary — 265 plain-language definitions across 11 sections, each with its own page.

Core Terms & Classification

Hydrocephalus: Hydrocephalus is a condition in which excess cerebrospinal fluid builds up within the brain's ventricles, often raising pressure inside the skull and enlarging the ventricles.
Hydrocephaly: Hydrocephaly is an alternative term for hydrocephalus, referring to the same condition of excess cerebrospinal fluid in the brain.
"Water on the brain": "Water on the brain" is a common lay term for hydrocephalus, though the fluid involved is cerebrospinal fluid, not water.
Ventriculomegaly: Ventriculomegaly is enlargement of the brain's ventricles, which can be a sign of hydrocephalus or other conditions.
Communicating hydrocephalus: Communicating hydrocephalus is a type in which cerebrospinal fluid can still flow out of the ventricles but is not properly absorbed or circulated beyond them.
Non-communicating hydrocephalus: Non-communicating hydrocephalus is a type in which the flow of cerebrospinal fluid is blocked within the ventricular system.
Obstructive hydrocephalus: Obstructive hydrocephalus is another name for non-communicating hydrocephalus, caused by a blockage in the flow of cerebrospinal fluid.
Congenital hydrocephalus: Congenital hydrocephalus is hydrocephalus that is present at birth or develops during fetal development.
Acquired hydrocephalus: Acquired hydrocephalus is hydrocephalus that develops after birth as a result of another event or condition.
Primary hydrocephalus: Primary hydrocephalus refers to hydrocephalus that is the main condition, rather than a consequence of another identified disorder.
Secondary hydrocephalus: Secondary hydrocephalus is hydrocephalus that develops as a consequence of another identified condition.
Active (progressive) hydrocephalus: Active hydrocephalus is hydrocephalus that is ongoing and progressing, with continued fluid buildup or rising pressure that usually needs treatment.
Arrested hydrocephalus: Arrested hydrocephalus is hydrocephalus that has stabilized, with the fluid buildup no longer progressing.
Compensated hydrocephalus: Compensated hydrocephalus is hydrocephalus in which the body has reached a balance, so symptoms are minimal or absent despite enlarged ventricles.
Decompensated hydrocephalus: Decompensated hydrocephalus is when a previously balanced (compensated) state shifts, and symptoms or rising pressure return.
Hydrocephalus ex vacuo: Hydrocephalus ex vacuo is enlargement of the ventricles due to loss of brain tissue, rather than a buildup of fluid under pressure.
Internal hydrocephalus: Internal hydrocephalus refers to the accumulation of cerebrospinal fluid within the ventricles inside the brain.
External hydrocephalus: External hydrocephalus is the accumulation of cerebrospinal fluid in the spaces surrounding the brain, often a benign condition in infants.
Triventricular hydrocephalus: Triventricular hydrocephalus is enlargement of the two lateral ventricles and the third ventricle, typically due to a blockage at the cerebral aqueduct.
Tetraventricular hydrocephalus: Tetraventricular hydrocephalus is enlargement of all four ventricles, suggesting a problem beyond the ventricular outlets.
Unilateral hydrocephalus: Unilateral hydrocephalus is enlargement of one lateral ventricle, usually due to a blockage at the foramen of Monro on that side.
Acute hydrocephalus: Acute hydrocephalus is hydrocephalus that develops rapidly, causing a fast rise in pressure that is a medical emergency.
Chronic hydrocephalus: Chronic hydrocephalus is hydrocephalus that develops or persists slowly over a long period, sometimes with gradual or subtle symptoms.
Overt hydrocephalus: Overt hydrocephalus is hydrocephalus that is clearly causing symptoms or signs, as opposed to a hidden or subclinical form.
Occult hydrocephalus: Occult hydrocephalus is hydrocephalus that is present without obvious symptoms, sometimes discovered incidentally.
Multiloculated hydrocephalus: Multiloculated hydrocephalus is a complex form in which the ventricles are divided into multiple separate fluid compartments.

CSF, Ventricles & Brain Anatomy

Cerebrospinal fluid (CSF): Cerebrospinal fluid is the clear fluid that surrounds and cushions the brain and spinal cord and circulates through the ventricles.
Ventricular system: The ventricular system is the connected network of fluid-filled cavities within the brain that produce and circulate cerebrospinal fluid.
Lateral ventricle: A lateral ventricle is one of the two largest fluid-filled cavities in the brain, one in each cerebral hemisphere.
Frontal (anterior) horn: The frontal horn is the front portion of the lateral ventricle, extending into the frontal lobe of the brain.
Occipital (posterior) horn: The occipital horn is the rear portion of the lateral ventricle, extending into the occipital lobe of the brain.
Temporal horn: The temporal horn is the portion of the lateral ventricle that extends into the temporal lobe of the brain.
Body of the lateral ventricle: The body of the lateral ventricle is the central portion connecting the horns of the lateral ventricle.
Atrium (trigone) of the lateral ventricle: The atrium, or trigone, is the region where the body and horns of the lateral ventricle meet, containing a prominent tuft of choroid plexus.
Third ventricle: The third ventricle is a narrow, central cavity that connects the two lateral ventricles to the fourth ventricle.
Fourth ventricle: The fourth ventricle is the cavity near the brainstem and cerebellum that connects the ventricular system to the spaces around the brain and spinal cord.
Cerebral aqueduct (aqueduct of Sylvius): The cerebral aqueduct is the narrow channel connecting the third and fourth ventricles, and a common site of blockage in hydrocephalus.
Foramen of Monro (interventricular foramen): The foramen of Monro is the channel connecting each lateral ventricle to the third ventricle.
Foramen of Luschka: The foramina of Luschka are the two side outlets of the fourth ventricle, through which cerebrospinal fluid exits into the spaces around the brain.
Foramen of Magendie: The foramen of Magendie is the single midline outlet of the fourth ventricle, through which cerebrospinal fluid exits into the spaces around the brain.
Choroid plexus: The choroid plexus is the tissue within the ventricles that produces most of the cerebrospinal fluid.
Ependyma: The ependyma is the thin lining of cells that covers the inner surface of the ventricles and the central canal of the spinal cord.
Subarachnoid space: The subarachnoid space is the fluid-filled space around the brain and spinal cord where cerebrospinal fluid circulates and is absorbed.
Basal cisterns: The basal cisterns are wider pools of cerebrospinal fluid at the base of the brain within the subarachnoid space.
Cisterna magna: The cisterna magna is a large cerebrospinal fluid space behind the brainstem and below the cerebellum.
Arachnoid granulations (villi): Arachnoid granulations are small projections that absorb cerebrospinal fluid back into the bloodstream.
Meninges: The meninges are the three protective membranes — dura, arachnoid, and pia mater — that surround the brain and spinal cord.
Dura mater: The dura mater is the tough, outermost membrane covering the brain and spinal cord.
Arachnoid mater: The arachnoid mater is the thin, web-like middle membrane surrounding the brain, beneath which cerebrospinal fluid circulates.
Pia mater: The pia mater is the delicate innermost membrane that lies directly on the surface of the brain and spinal cord.
Septum pellucidum: The septum pellucidum is a thin membrane separating the two lateral ventricles, sometimes opened during endoscopic surgery.
Superior sagittal sinus: The superior sagittal sinus is a large venous channel along the top of the brain where much cerebrospinal fluid is absorbed.
Brain parenchyma: The brain parenchyma is the functional brain tissue itself, which surrounds the ventricles and can be affected by hydrocephalus.

CSF Physiology, Pressure & Dynamics

CSF production: CSF production is the continuous creation of cerebrospinal fluid, mostly by the choroid plexus within the ventricles.
CSF absorption (reabsorption): CSF absorption is the return of cerebrospinal fluid to the bloodstream, mainly through the arachnoid granulations.
CSF circulation (flow): CSF circulation is the movement of cerebrospinal fluid from the ventricles, through the brain's pathways, to the spaces where it is absorbed.
CSF turnover: CSF turnover is the replacement of the brain's cerebrospinal fluid several times per day through continuous production and absorption.
Bulk flow: Bulk flow is the net, directional movement of cerebrospinal fluid from where it is produced to where it is absorbed.
Glymphatic system: The glymphatic system is a brain-wide pathway, increasingly recognized, that helps clear fluid and waste from brain tissue.
Intracranial pressure (ICP): Intracranial pressure is the pressure inside the skull, which can rise when cerebrospinal fluid builds up in hydrocephalus.
Raised intracranial pressure: Raised intracranial pressure is abnormally high pressure inside the skull, a key concern in active hydrocephalus.
Opening pressure: Opening pressure is the cerebrospinal fluid pressure measured at the start of a lumbar puncture, reflecting the pressure in the CSF spaces.
Monro-Kellie doctrine: The Monro-Kellie doctrine is the principle that the skull is a fixed space, so the volumes of brain, blood, and CSF must stay in balance.
Intracranial compliance: Intracranial compliance is the brain's capacity to accommodate added volume, such as extra CSF, without a large rise in pressure.
Intracranial elastance: Intracranial elastance is the inverse of compliance — how much pressure rises for a given increase in volume inside the skull.
Pressure-volume curve: The pressure-volume curve describes how intracranial pressure changes as volume is added inside the skull, rising gently at first and then steeply.
CSF pulsatility: CSF pulsatility is the rhythmic, back-and-forth motion of cerebrospinal fluid driven by the heartbeat and breathing.
Transmantle pressure gradient: A transmantle pressure gradient is a pressure difference across the brain tissue between the ventricles and the surface, thought to contribute to ventricular enlargement.
Hydrostatic (siphoning) pressure: Hydrostatic pressure, in the context of shunts, is the pressure effect of gravity on the fluid column, which can cause overdrainage when a person is upright.
Cerebral perfusion pressure: Cerebral perfusion pressure is the pressure that drives blood flow to the brain, which can be reduced when intracranial pressure rises.
Lundberg pressure waves: Lundberg pressure waves are patterns of fluctuating intracranial pressure seen on pressure monitoring, some of which signal reduced reserve.
Blood-brain barrier: The blood-brain barrier is a protective barrier between the bloodstream and the brain, relevant to fluid balance and a small portion of CSF production.
CSF stasis: CSF stasis is a slowing or stagnation of cerebrospinal fluid movement, which can occur where flow is obstructed.
Capillary and parenchymal absorption: Capillary and parenchymal absorption refers to alternative routes by which cerebrospinal fluid may be absorbed, beyond the arachnoid granulations.
CSF volume: CSF volume is the total amount of cerebrospinal fluid present, normally about 150 mL, which increases when fluid accumulates in hydrocephalus.
CSF homeostasis (steady state): CSF homeostasis is the stable balance between cerebrospinal fluid production and absorption that keeps volume and pressure normal.
Compensatory reserve: Compensatory reserve is the brain's remaining capacity to accommodate added volume before intracranial pressure rises steeply.

Causes & Risk Factors

Aqueductal stenosis: Aqueductal stenosis is a narrowing of the cerebral aqueduct that blocks cerebrospinal fluid flow, a common cause of obstructive hydrocephalus.
Intraventricular hemorrhage (IVH): Intraventricular hemorrhage is bleeding into the brain's ventricles, a leading cause of hydrocephalus, especially in premature infants.
Germinal matrix hemorrhage: Germinal matrix hemorrhage is bleeding from a fragile region of the developing brain in premature infants, often the source of intraventricular hemorrhage.
Post-hemorrhagic ventricular dilation (PHVD): Post-hemorrhagic ventricular dilation is enlargement of the ventricles following bleeding into them, which may progress to hydrocephalus needing treatment.
Prematurity: Prematurity, or being born early, is a major risk factor for hydrocephalus, largely through intraventricular hemorrhage.
Low birth weight: Low birth weight is strongly associated with hydrocephalus, largely because it accompanies prematurity and the risk of brain hemorrhage.
Meningitis: Meningitis is infection or inflammation of the membranes around the brain, which can cause hydrocephalus by impairing CSF flow and absorption.
Ventriculitis: Ventriculitis is infection or inflammation of the ventricles' lining, which can scar the CSF pathways and cause complex hydrocephalus.
Subarachnoid hemorrhage (SAH): Subarachnoid hemorrhage is bleeding into the space around the brain, which can cause hydrocephalus by impairing CSF flow and absorption.
Brain tumor: A brain tumor can cause hydrocephalus by blocking the flow of cerebrospinal fluid through the ventricular system.
Posterior fossa tumor: A posterior fossa tumor is a tumor at the back of the brain that commonly causes hydrocephalus by blocking the fourth ventricle.
Colloid cyst: A colloid cyst is a benign cyst that can block CSF flow at the foramen of Monro, causing hydrocephalus.
Arachnoid cyst: An arachnoid cyst is a fluid-filled sac related to the arachnoid membrane that can sometimes obstruct CSF flow and cause hydrocephalus.
Chiari I malformation: Chiari I malformation is a condition where the lower cerebellum extends below the skull, sometimes affecting CSF flow.
Chiari II malformation: Chiari II malformation is a condition associated with spina bifida in which hindbrain structures are displaced downward, commonly causing hydrocephalus.
Dandy-Walker malformation: Dandy-Walker malformation is a condition affecting the cerebellum and fourth ventricle that is commonly associated with hydrocephalus.
Myelomeningocele (spina bifida): Myelomeningocele is the most significant form of spina bifida, commonly associated with Chiari II malformation and hydrocephalus.
Neural tube defect: A neural tube defect is a birth defect of the brain or spine, some forms of which (such as spina bifida) are commonly associated with hydrocephalus.
Congenital infection (TORCH): Congenital infections, sometimes grouped as TORCH infections, are infections passed during pregnancy that can cause hydrocephalus.
Cytomegalovirus (CMV): Cytomegalovirus is a common virus that, when passed during pregnancy, can affect the brain and cause hydrocephalus.
Toxoplasmosis: Toxoplasmosis is an infection that, when passed during pregnancy, can affect the brain and cause hydrocephalus.
Aqueductal web: An aqueductal web is a thin membrane within the cerebral aqueduct that can obstruct CSF flow and cause hydrocephalus.
Choroid plexus papilloma: A choroid plexus papilloma is a rare tumor of the choroid plexus that can cause hydrocephalus, sometimes by overproducing CSF.
Vein of Galen malformation: A vein of Galen malformation is a rare blood vessel malformation in the brain that can cause hydrocephalus among other effects.
Achondroplasia: Achondroplasia is a genetic condition affecting bone growth that can be associated with hydrocephalus, partly through skull-base narrowing.
Traumatic brain injury: Traumatic brain injury can lead to hydrocephalus, sometimes through bleeding that impairs CSF flow and absorption.
Idiopathic cause: An idiopathic cause means the underlying reason for the hydrocephalus is unknown despite evaluation.

Specific Types & Syndromes

Normal pressure hydrocephalus (NPH): Normal pressure hydrocephalus is a form, mainly in older adults, with enlarged ventricles and a classic triad of walking, thinking, and bladder problems, despite normal-range CSF pressure.
Idiopathic normal pressure hydrocephalus (iNPH): Idiopathic normal pressure hydrocephalus is NPH with no identifiable cause, occurring mainly in older adults.
Secondary normal pressure hydrocephalus: Secondary normal pressure hydrocephalus is NPH that follows an identifiable cause, such as prior hemorrhage, infection, or injury.
Hakim-Adams syndrome: Hakim-Adams syndrome is another name for normal pressure hydrocephalus, named after those who described it.
Fetal (prenatal) hydrocephalus: Fetal hydrocephalus is hydrocephalus identified in a baby before birth, on prenatal imaging.
Post-hemorrhagic hydrocephalus: Post-hemorrhagic hydrocephalus is hydrocephalus that develops after bleeding into or around the brain, a common cause in premature infants and after brain bleeds.
Post-infectious hydrocephalus: Post-infectious hydrocephalus is hydrocephalus that develops after an infection such as meningitis, by scarring the CSF pathways.
Post-traumatic hydrocephalus: Post-traumatic hydrocephalus is hydrocephalus that develops after a head injury, often through bleeding that impairs CSF flow and absorption.
X-linked hydrocephalus (L1 syndrome): X-linked hydrocephalus is an inherited form, affecting mainly boys, caused by changes in the L1CAM gene.
Bickers-Adams syndrome: Bickers-Adams syndrome is another name for X-linked hydrocephalus, an inherited form linked to the L1CAM gene.
HSAS (hydrocephalus with stenosis of the aqueduct of Sylvius): HSAS is hydrocephalus due to stenosis of the cerebral aqueduct, a feature of the L1 syndrome spectrum.
LOVA (long-standing overt ventriculomegaly in adults): LOVA is a form of long-standing hydrocephalus, present since childhood, that becomes apparent in adulthood with enlarged ventricles and a large head.
Benign external hydrocephalus (BEH): Benign external hydrocephalus is a usually self-resolving condition in infants with extra fluid around the brain and a large head.
Benign enlargement of the subarachnoid spaces (BESS): Benign enlargement of the subarachnoid spaces is another term for benign external hydrocephalus, describing widened fluid spaces around an infant's brain.
Entrapped (trapped) fourth ventricle: An entrapped fourth ventricle is an isolated, enlarging fourth ventricle that is cut off from the rest of the CSF pathways, often after shunting or scarring.
Isolated (trapped) lateral ventricle: An isolated lateral ventricle is a lateral ventricle cut off from the rest of the CSF pathways, which can enlarge on its own.
Hydranencephaly: Hydranencephaly is a rare, severe condition in which most of the brain's hemispheres are absent and replaced by fluid, distinct from hydrocephalus.
Idiopathic intracranial hypertension (pseudotumor cerebri): Idiopathic intracranial hypertension is raised intracranial pressure without a tumor or hydrocephalus, a distinct condition often affecting young adults.
Tumor-related hydrocephalus: Tumor-related hydrocephalus is hydrocephalus caused by a brain tumor obstructing or affecting CSF flow.
Communicating hydrocephalus of infancy: Communicating hydrocephalus of infancy is a form in babies where CSF flows out of the ventricles but is not properly absorbed or circulated.
Hydrocephalus in myelomeningocele: Hydrocephalus in myelomeningocele is the hydrocephalus that commonly accompanies this form of spina bifida, through its link to Chiari II malformation.
Hydrocephalus in Chiari II malformation: Hydrocephalus in Chiari II malformation is the hydrocephalus that frequently accompanies Chiari II, the malformation associated with spina bifida.
Hydrocephalus in Dandy-Walker malformation: Hydrocephalus in Dandy-Walker malformation is the hydrocephalus that commonly accompanies this condition of the cerebellum and fourth ventricle.
Walker-Warburg syndrome: Walker-Warburg syndrome is a severe genetic condition affecting the brain, eyes, and muscles that can include hydrocephalus.

Signs, Symptoms & Clinical Features

Macrocephaly: Macrocephaly is a larger-than-expected head size, which in infants can be a sign of hydrocephalus.
Increased head circumference: An increased head circumference, especially when growing rapidly, is a key early sign of hydrocephalus in infants.
Bulging fontanelle: A bulging fontanelle is a tense or outwardly swollen soft spot on a baby's head, which can indicate raised intracranial pressure.
Tense fontanelle: A tense fontanelle is a firm, full soft spot that can be a sign of increased pressure inside a baby's skull.
Suture diastasis (splayed sutures): Suture diastasis is widening or separation of the joints between a baby's skull bones, which can occur with raised pressure or rapid head growth.
Prominent scalp veins: Prominent scalp veins are enlarged, visible veins on a baby's head that can accompany raised intracranial pressure.
Sunsetting eyes (setting-sun sign): Sunsetting eyes are a downward deviation of a baby's eyes, a sign that can occur with raised intracranial pressure in hydrocephalus.
Frontal bossing: Frontal bossing is a prominent or protruding forehead, which can develop with hydrocephalus in infancy.
Irritability: Irritability is fussiness or distress in a baby that can be a nonspecific sign of raised intracranial pressure in hydrocephalus.
Poor feeding: Poor feeding is reduced or difficult feeding in a baby that can accompany raised intracranial pressure in hydrocephalus.
Vomiting: Vomiting, especially when persistent or associated with other signs, can be a symptom of raised intracranial pressure in hydrocephalus.
Lethargy: Lethargy is unusual drowsiness or reduced alertness that can be a sign of raised intracranial pressure in hydrocephalus.
Headache: Headache, particularly when worse in the morning or with other signs, can be a symptom of raised intracranial pressure in hydrocephalus.
Papilledema: Papilledema is swelling of the optic nerve heads from raised intracranial pressure, seen during an eye examination.
Sixth nerve palsy (abducens palsy): A sixth nerve palsy is weakness of the muscle that turns the eye outward, which can occur with raised intracranial pressure and cause double vision.
Diplopia (double vision): Diplopia is double vision, which can occur in hydrocephalus when raised pressure affects the nerves controlling eye movement.
Developmental delay or regression: Developmental delay or regression is a slowing or loss of developmental skills that can occur with hydrocephalus, especially if pressure is uncontrolled.
Gait disturbance: Gait disturbance is difficulty walking, a key feature of normal pressure hydrocephalus and a sign that can occur in other forms.
Cognitive impairment: Cognitive impairment is a decline in thinking abilities that is part of the normal pressure hydrocephalus triad and can occur with raised pressure.
Urinary incontinence: Urinary incontinence is loss of bladder control that is part of the normal pressure hydrocephalus triad.
NPH triad ("wet, wacky, wobbly"): The NPH triad is the classic combination of gait disturbance, cognitive impairment, and urinary incontinence in normal pressure hydrocephalus.
Parinaud syndrome (dorsal midbrain syndrome): Parinaud syndrome is a cluster of eye-movement findings from pressure on the upper brainstem, which can occur in hydrocephalus.
Macewen sign (cracked-pot sign): The Macewen sign is a hollow, "cracked-pot" sound on tapping the skull, which can occur with raised pressure and separated sutures in hydrocephalus.
Apnea and bradycardia (in infants): Apnea and bradycardia are pauses in breathing and a slowed heart rate that, in infants, can be serious signs of raised intracranial pressure.
Seizures: Seizures are episodes of abnormal brain electrical activity that can occur in some people with hydrocephalus, though they are not a universal feature.
Decreased level of consciousness: A decreased level of consciousness is reduced alertness or responsiveness, a serious sign of significant raised intracranial pressure requiring urgent attention.

Diagnosis & Imaging

Cranial ultrasound: Cranial ultrasound is an imaging test that uses sound waves to view a baby's brain through the soft spot, often used to detect hydrocephalus in infants.
Fetal (prenatal) ultrasound: Fetal ultrasound is prenatal imaging that can detect enlarged ventricles and hydrocephalus in a baby before birth.
Fetal MRI: Fetal MRI is a detailed prenatal imaging test that provides additional information about a baby's brain when hydrocephalus is suspected.
Computed tomography (CT): Computed tomography is an X-ray-based imaging test that can quickly show enlarged ventricles, often used in urgent situations.
Magnetic resonance imaging (MRI): Magnetic resonance imaging is a detailed, radiation-free imaging test that is a mainstay for evaluating hydrocephalus and its causes.
CSF flow study (cine phase-contrast MRI): A CSF flow study is a specialized MRI that visualizes the movement of cerebrospinal fluid, used to assess blockages and confirm flow through openings.
Head circumference measurement: Head circumference measurement is the routine measuring of the distance around a baby's head, a key way to monitor for hydrocephalus.
Occipitofrontal circumference (OFC): Occipitofrontal circumference is the formal term for head circumference, measured around the front and back of the head.
Growth chart (head circumference percentile): A growth chart plots a baby's head circumference against typical values for age, helping detect abnormal head growth.
Fontanelle examination: Fontanelle examination is the assessment of a baby's soft spot, which provides clues about intracranial pressure.
Fundoscopy (eye examination): Fundoscopy is an examination of the back of the eye that can reveal papilledema, a sign of raised intracranial pressure.
Evans index: The Evans index is a measurement on brain imaging used to assess whether the ventricles are enlarged.
Frontal and occipital horn ratio (FOHR): The frontal and occipital horn ratio is a measurement of ventricle size on imaging, often used to monitor hydrocephalus in children.
Ventricular index: The ventricular index is a measurement of ventricle size, including forms used in premature infants on ultrasound.
Lumbar puncture (spinal tap): A lumbar puncture is a procedure to sample cerebrospinal fluid and measure its pressure from the lower back, used in evaluating hydrocephalus in selected situations.
CSF opening pressure measurement: CSF opening pressure measurement is the recording of cerebrospinal fluid pressure at the start of a lumbar puncture.
CSF analysis: CSF analysis is laboratory testing of cerebrospinal fluid to look for infection, bleeding, or other findings.
Lumbar tap test (large-volume tap): The lumbar tap test is the removal of a larger volume of CSF to see if symptoms improve, used to help predict shunt response in normal pressure hydrocephalus.
External lumbar drainage trial: An external lumbar drainage trial is a temporary drainage of CSF over several days to assess whether a person with normal pressure hydrocephalus will benefit from a shunt.
Intracranial pressure (ICP) monitoring: Intracranial pressure monitoring is the direct measurement of pressure inside the skull over time, used in selected situations.
Shunt series (X-ray): A shunt series is a set of X-rays that traces the path of a shunt to check for breaks, disconnections, or other mechanical problems.
Radionuclide shuntogram: A radionuclide shuntogram is a test that tracks a small amount of tracer through a shunt to assess whether it is flowing properly.
DESH sign (disproportionately enlarged subarachnoid space hydrocephalus): The DESH sign is an imaging pattern associated with normal pressure hydrocephalus, showing tight and widened CSF spaces in characteristic locations.
Transependymal edema (periventricular lucency): Transependymal edema is fluid forced into the brain tissue around the ventricles under pressure, an imaging sign that can indicate active hydrocephalus.

Treatment: Shunts

CSF shunt: A CSF shunt is an implanted device that drains excess cerebrospinal fluid from the brain to another part of the body, the most common treatment for hydrocephalus.
Ventriculoperitoneal (VP) shunt: A ventriculoperitoneal shunt drains cerebrospinal fluid from a brain ventricle to the abdominal cavity, the most common type of shunt.
Ventriculoatrial (VA) shunt: A ventriculoatrial shunt drains cerebrospinal fluid from a brain ventricle to the heart, used when the abdomen is not suitable.
Ventriculopleural shunt: A ventriculopleural shunt drains cerebrospinal fluid from a brain ventricle to the space around the lungs, used as an alternative drainage site.
Lumboperitoneal (LP) shunt: A lumboperitoneal shunt drains cerebrospinal fluid from the lower spine to the abdomen, used mainly for communicating hydrocephalus and related conditions.
Ventriculosubgaleal shunt: A ventriculosubgaleal shunt is a temporary shunt draining CSF into a space under the scalp, used mainly in small or premature infants.
Ventricular catheter (proximal catheter): The ventricular catheter is the part of a shunt placed into a brain ventricle, where it collects cerebrospinal fluid for drainage.
Distal catheter: The distal catheter is the part of a shunt that carries cerebrospinal fluid to its destination, such as the abdomen.
Shunt valve: The shunt valve is the component that controls the flow of cerebrospinal fluid through a shunt.
Differential pressure valve: A differential pressure valve is a common type of shunt valve that opens when the pressure difference across it reaches a set level.
Programmable (adjustable) valve: A programmable valve is a shunt valve whose drainage setting can be adjusted non-invasively after surgery, allowing fine-tuning without another operation.
Fixed-pressure valve: A fixed-pressure valve is a shunt valve set to drain at a single, unchangeable pressure.
Antisiphon device: An antisiphon device is a shunt component that helps prevent overdrainage caused by gravity when a person is upright.
Flow-regulated valve: A flow-regulated valve is a shunt valve designed to maintain a relatively constant rate of CSF drainage regardless of pressure changes.
Gravitational valve: A gravitational valve is a shunt valve that adjusts drainage based on body position to help prevent overdrainage when upright.
Shunt reservoir: A shunt reservoir is a small component of a shunt that allows access to the system, for example to sample fluid or check function.
Burr hole: A burr hole is a small opening made in the skull through which a catheter or endoscope is passed during shunt or other neurosurgery.
Catheter tunneling: Catheter tunneling is the passing of shunt tubing under the skin from the head to the drainage site, such as the abdomen.
Peritoneal catheter: The peritoneal catheter is the end of a ventriculoperitoneal shunt placed in the abdomen, where cerebrospinal fluid is absorbed.
Valve pressure setting: The valve pressure setting is the level at which a shunt valve drains, chosen to balance adequate drainage against overdrainage.
Shunt dependence: Shunt dependence is a state in which a person relies on their shunt to control hydrocephalus, so a malfunction can quickly cause symptoms.
Shunt independence: Shunt independence is a state in which a person no longer relies on a shunt to control their hydrocephalus.

Treatment: ETV & Other Procedures

Endoscopic third ventriculostomy (ETV): Endoscopic third ventriculostomy is a procedure that creates a new opening in the floor of the third ventricle to let cerebrospinal fluid bypass a blockage, often avoiding a shunt.
Neuroendoscopy: Neuroendoscopy is the use of a small camera-equipped instrument to perform minimally invasive procedures inside the brain's fluid spaces.
Choroid plexus cauterization (CPC): Choroid plexus cauterization is a procedure that reduces cerebrospinal fluid production by treating the choroid plexus, often combined with ETV in infants.
ETV plus CPC (ETV/CPC): ETV/CPC is a combined procedure pairing endoscopic third ventriculostomy with choroid plexus cauterization, used especially in infants.
ETV Success Score (ETVSS): The ETV Success Score is a tool that estimates the likelihood that an endoscopic third ventriculostomy will succeed, based on age, cause, and prior shunt.
External ventricular drain (EVD): An external ventricular drain is a temporary catheter that drains cerebrospinal fluid from a ventricle to an external collection system, used in urgent or short-term situations.
Ventricular reservoir (Ommaya reservoir): A ventricular reservoir is an implanted device allowing access to a ventricle, used to drain or sample CSF, sometimes as a temporizing measure in infants.
Ventricular access device: A ventricular access device is a general term for an implanted device that provides access to a ventricle for draining or sampling CSF.
Septostomy (septum pellucidotomy): A septostomy is an endoscopic procedure that creates an opening in the membrane between the lateral ventricles, used to connect a trapped ventricle.
Aqueductoplasty: Aqueductoplasty is a procedure to reopen or widen a narrowed cerebral aqueduct, sometimes with a stent, to restore cerebrospinal fluid flow.
Endoscopic fenestration: Endoscopic fenestration is the creation of an opening in a membrane or cyst wall to connect fluid compartments and allow drainage.
Cyst fenestration: Cyst fenestration is the creation of an opening in a cyst wall to let its fluid drain into the normal cerebrospinal fluid spaces.
Lamina terminalis fenestration: Lamina terminalis fenestration is the creation of an additional opening in a thin structure at the front of the third ventricle, sometimes done to aid CSF flow.
Shunt revision: A shunt revision is surgery to repair or replace part or all of a malfunctioning shunt.
Shunt removal: Shunt removal is the taking out of a shunt, done when it is no longer needed or in situations such as infection.
Ventricular tap: A ventricular tap is the removal of cerebrospinal fluid from a ventricle through a needle, used to relieve pressure or obtain fluid, often in infants.
Temporizing measures: Temporizing measures are temporary treatments that control hydrocephalus until a permanent solution becomes appropriate, used especially in small infants.
ETV stoma: The ETV stoma is the opening created in the floor of the third ventricle during an endoscopic third ventriculostomy.
Antibiotic-impregnated catheter: An antibiotic-impregnated catheter is shunt or drain tubing treated with antibiotics to help reduce the risk of infection.
Shunt externalization: Shunt externalization is the temporary conversion of a shunt to drain outside the body, often done when treating a shunt infection.

Complications & Outcomes

Shunt malfunction (shunt failure): Shunt malfunction is any failure of a shunt to work properly, which can allow cerebrospinal fluid to build up again and cause symptoms.
Shunt obstruction (blockage): Shunt obstruction is a blockage in the shunt that stops cerebrospinal fluid from flowing, the most common cause of shunt malfunction.
Proximal catheter obstruction: Proximal catheter obstruction is a blockage of the ventricular catheter, the most common single cause of shunt failure.
Distal catheter obstruction: Distal catheter obstruction is a blockage of the tubing that carries cerebrospinal fluid to its destination, a recognized cause of shunt malfunction.
Shunt infection: Shunt infection is an infection of the shunt system, a serious complication that usually requires treatment of the infection and often removal of the shunt.
Overdrainage: Overdrainage is the draining of too much cerebrospinal fluid by a shunt, which can cause symptoms such as low-pressure headaches or fluid collections.
Underdrainage: Underdrainage is the draining of too little cerebrospinal fluid by a shunt, allowing pressure to remain high and symptoms to persist.
Slit ventricle syndrome: Slit ventricle syndrome is a condition of intermittent symptoms with very small, stiff ventricles, often related to long-term overdrainage.
Subdural hematoma: A subdural hematoma is a collection of blood over the brain's surface that can occur as a complication of overdrainage in shunted patients.
Subdural hygroma: A subdural hygroma is a collection of fluid over the brain's surface that can occur with overdrainage in shunted patients.
Shunt disconnection: Shunt disconnection is the separation of shunt components, interrupting cerebrospinal fluid flow and causing malfunction.
Shunt migration: Shunt migration is movement of a shunt component out of its proper position, which can cause malfunction.
Shunt fracture (breakage): Shunt fracture is a break in the shunt tubing or components, interrupting cerebrospinal fluid flow and causing malfunction.
Abdominal pseudocyst: An abdominal pseudocyst is a pocket of fluid that can form around the tip of a ventriculoperitoneal shunt in the abdomen, causing malfunction or symptoms.
Bowel perforation (rare): Bowel perforation is a rare complication in which a shunt's distal catheter erodes through the bowel wall, requiring prompt treatment.
ETV failure (stoma closure): ETV failure is the return of hydrocephalus after an endoscopic third ventriculostomy, often because the created opening closes.
Revision rate: The revision rate is how often shunts need surgical revision, reflecting that most people with shunts require one or more revisions over time.
Shunt survival: Shunt survival is how long a shunt continues to function before needing revision, varying widely among individuals.
Prognosis: Prognosis is the likely course and outcome of hydrocephalus, which depends heavily on the cause, associated conditions, and individual factors.
Neurodevelopmental outcome: Neurodevelopmental outcome is how a child's development and brain function progress over time, which varies depending on the cause and other factors.
Mortality: Mortality refers to the risk of death associated with hydrocephalus, which depends heavily on the cause and associated conditions and has improved with treatment.
Morbidity: Morbidity refers to the health problems and complications associated with hydrocephalus and its treatment, which vary widely among individuals.
Quality of life: Quality of life refers to a person's overall well-being and daily functioning with hydrocephalus, which many people maintain well with good management.
Outcome (overall): Outcome refers to the overall result of hydrocephalus and its treatment over time, which varies widely and is best understood individually.

Care Team, Therapy & Support

Neurosurgeon: A neurosurgeon is the surgeon who treats hydrocephalus, performing procedures such as shunt placement and ETV and managing the condition over time.
Pediatric neurosurgeon: A pediatric neurosurgeon is a neurosurgeon specializing in children, who treats hydrocephalus and related conditions in infants and children.
Neurologist: A neurologist is a doctor who diagnoses and manages conditions of the nervous system and may be involved in aspects of hydrocephalus care, such as seizures or NPH.
Neonatologist (NICU): A neonatologist is a doctor specializing in the care of newborns, including premature infants at risk for or with hydrocephalus in the NICU.
Maternal-fetal medicine specialist (MFM): A maternal-fetal medicine specialist is an obstetrician focusing on high-risk pregnancies, including those where the baby has hydrocephalus detected before birth.
Pediatrician: A pediatrician is a child's primary doctor, who monitors growth and development and helps coordinate care for a child with hydrocephalus.
Developmental pediatrician: A developmental pediatrician is a doctor specializing in children's development, who evaluates and supports developmental progress in children with hydrocephalus.
Ophthalmologist: An ophthalmologist is an eye doctor who can detect signs of raised intracranial pressure, such as papilledema, and monitor vision in hydrocephalus.
Neuropsychologist: A neuropsychologist evaluates thinking, memory, and other cognitive functions, helping assess the effects of hydrocephalus and guide support.
Physical therapy (PT): Physical therapy helps with movement, strength, balance, and motor skills, supporting children and adults affected by hydrocephalus.
Occupational therapy (OT): Occupational therapy helps with daily activities and fine motor skills, supporting independence in children and adults affected by hydrocephalus.
Speech-language therapy: Speech-language therapy helps with communication, language, and sometimes feeding, supporting children and adults affected by hydrocephalus.
Early intervention: Early intervention is a system of services for young children with developmental needs, supporting development in infants and toddlers with hydrocephalus.
Individualized Education Program (IEP): An Individualized Education Program is a plan providing special education services and supports for a school-age child with qualifying needs.
504 plan: A 504 plan provides accommodations in school for a child with a disability, supporting access to learning for some children with hydrocephalus.
Head circumference monitoring: Head circumference monitoring is the ongoing tracking of head size, a key way to detect and follow hydrocephalus in infants and young children.
Long-term follow-up: Long-term follow-up is the ongoing monitoring of a person with hydrocephalus over years, essential for managing the condition and any treatment.
Transition to adult care: Transition to adult care is the planned process of moving from pediatric to adult healthcare for a young person with hydrocephalus.
Care coordinator (case manager): A care coordinator helps organize and connect the various aspects of care for a person with hydrocephalus, easing navigation of a complex system.
Hydrocephalus Association (patient support): The Hydrocephalus Association is a patient organization that provides information, support, and community for people affected by hydrocephalus.
Caregiver support and education: Caregiver support and education provide caregivers with the knowledge and support to care for a person with hydrocephalus and sustain their own well-being.

Read the Hydrocephalus patient guides

All AURORA medical definitions

Not sure which page you need? Put words to it with the symptom navigator

Print a Hydrocephalus booklet to take to an appointment

What AURORA is building for Hydrocephalus