how does csf drain from the brain

The fluid acts as a delivery system for nutrients that your brain needs, and it also takes away waste products. Normally, CSF flows through these ventricles to the base of the brain. The fluid then bathes the brain and spinal cord before it’s reabsorbed into the blood.

Full Answer

What is the route of CSF through the brain?

What is the route of CSF through the brain? CSF flows from the lateral ventricle to the third ventricle through the interventricular foramen (also called the foramen of Monro). The third ventricle and fourth ventricle are connected to each other by the cerebral aqueduct (also called the Aqueduct of Sylvius).

What part of brain makes most of CSF?

Review of the literature Anatomy and physiology of cerebrospinal fluid

• Summary. ...
• Keywords. ...
• Comparative anatomy. ...
• The development of cerebrospinal fluid spaces retraces the steps of phylogenesis. ...
• Volumes. ...
• Cerebrospinal fluid secretion. ...
• Cerebrospinal fluid circulation. ...
• Cerebrospinal fluid absorption. ...
• The role of extra-arachnoid absorption pathways remains poorly elucidated. ...

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How does CSF leave the brain?

How does CSF leave the brain? From the fourth ventricle, the CSF may exit through the foramen of Lushka laterally, or the foramen of Magendie medially to the subarachnoid space. Passing through the foramen of Magendie results in filling of the spinal subarachnoid space. Is CSF found in the epidural space?

What does CSF stand for in brain?

Symptoms of Adult-onset Hydrocephalus

• Headaches
• Nausea
• Difficulty focusing the eyes
• Unsteady walk or gait
• Leg weakness
• Sudden falls
• Irritability
• Drowsiness
• Change in personality and behavior
• Seizures

Where does the CSF drain?

The choroid plexus mostly synthesizes CSF. Arachnoid granulations are responsible for CSF resorption; they drain CSF into the dural venous sinuses. CSF drains into the lymphatic circulation, through lymph ducts contiguous to the olfactory duct as it passes through the cribriform plate.

How does cerebrospinal fluid drain from the brain?

The CSF then passes through the arachnoid villi into the superior sagittal sinus, a large vein, and is absorbed into the bloodstream. Once in the bloodstream, it is carried away and filtered by the kidneys and liver in the same way as other bodily fluids.

How do you know if you are leaking brain fluid?

What are the symptoms of a cerebrospinal fluid leak?Positional headaches, which feel worse when sitting upright and better when lying down; caused by intracranial hypotension.Nausea and vomiting.Neck pain or stiffness.Change in hearing (muffled, ringing in the ears)Sense of imbalance.Photophobia (sensitivity to light)More items...

What does a CSF leak feel like?

The most common symptom of intracranial hypotension from a CSF leak is a postural headache, which means a headache that changes depending on your posture. A postural headache with a CSF leak worsens when you sit up or stand and improves when you lie down.

What Are The Symptoms of CSF Leak?

Patients typically complain of clear, watery drainage usually from only one side of the nose or one ear. Drainage can increase with tilting the hea...

How Are CSF Leaks Diagnosed?

Your doctor will perform a history and physical exam. Often, the doctor will examine the nose with an endoscope. Your physician may also ask you to...

What Is The Treatment For A CSF Leak?

Treatment can be either medical or surgical. Conservative treatment is usually recommended first in cases of spontaneous CSF leak or head trauma. T...

How to repair cranial CSF leak?

Repair of cranial CSF leaks depend on the size and the location of the leak. CSF leaks from your nose can usually be repaired using nasal endoscopy (using a camera and a thin long lens through your nostril). CSF leaks into your ear will usually need the use of a microscope.

What causes a headache when you lose CSF?

The tear or hole allows the CSF to leak out. The loss of CSF causes the previously cushioned brain to sag inside the skull, which results in a headache. Loss of fluid also causes a lowering of pressure within the skull, a condition called intracranial hypotension. CSF leaks can occur in the brain ...

What is the best treatment for spinal CSF leaks?

Spinal CSF leaks. After conservative treatments have been tried, an epidural blood patch is the most common treatment for spinal CSF leaks. In this procedure, your own blood is injected into the spinal canal. The blood clot that forms creates a seal to stop the leak.

What causes cerebrospinal fluid to leak?

The following are other possible common causes: Head trauma or spine injury. Lumbar puncture (spinal tap) History of epidurals or spinal catheters. Certain head and spine surgeries.

What is the process of leaking cerebrospinal fluid?

Cerebrospinal fluid (CSF) leak occurs when CSF escapes through a small tear or hole in the outermost layer of connective tissue (called the dura mater) that surrounds the brain and spinal cord and holds in the CSF. The tear or hole allows the CSF to leak out.

What is high pressure intracranial hydrocephalus?

High pressure intracranial hydrocephalus (an abnormal buildup of CSF in the brain) Underlying and untreated intracranial hypertension (elevated pressure in the brain fluid) Underlying and untreated connective tissue diseases, such as Ehlers-Danlos and Marfan syndromes. Bone spurs along the spine.

What is the name of the hole in the brain that surrounds the brain and spinal cord?

Cerebrospinal fluid (CSF) leak occurs when CSF escapes through a small tear or hole in the tissue that surrounds the brain and spinal cord called the dura mater .

How does CSF protect the brain?

Protection: CSF protects the brain tissue from injury when jolted or hit, by providing a fluid buffer that acts as a shock absorber from some forms of mechanical injury. Prevention of brain ischemia: The prevention of brain ischemia is aided by decreasing the amount of CSF in the limited space inside the skull.

How is CSF produced?

Firstly, a filtered form of plasma moves from fenestrated capillaries in the choroid plexus into an interstitial space , with movement guided by a difference in pressure between the blood in the capillaries and the interstitial fluid. This fluid then needs to pass through the epithelium cells lining the choroid plexus into the ventricles, an active process requiring the transport of sodium, potassium and chloride that draws water into CSF by creating osmotic pressure. Unlike blood passing from the capillaries into the choroid plexus, the epithelial cells lining the choroid plexus contain tight junctions between cells, which act to prevent most substances flowing freely into CSF. Cilia on the apical surfaces of the ependymal cells beat to help transport the CSF.

What is the purpose of a CSF test?

Testing often includes observing the colour of the fluid, measuring CSF pressure , and counting and identifying white and red blood cells within the fluid; measuring protein and glucose levels; and culturing the fluid. The presence of red blood cells and xanthochromia may indicate subarachnoid hemorrhage; whereas central nervous system infections such as meningitis, may be indicated by elevated white blood cell levels. A CSF culture may yield the microorganism that has caused the infection, or PCR may be used to identify a viral cause. Investigations to the total type and nature of proteins reveal point to specific diseases, including multiple sclerosis, paraneoplastic syndromes, systemic lupus erythematosus, neurosarcoidosis, cerebral angiitis; and specific antibodies such as Aquaporin 4 may be tested for to assist in the diagnosis of autoimmune conditions. A lumbar puncture that drains CSF may also be used as part of treatment for some conditions, including idiopathic intracranial hypertension and normal pressure hydrocephalus.

What causes CSF to leak?

CSF can leak from the dura as a result of different causes such as physical trauma or a lumbar puncture, or from no known cause when it is termed a spontaneous cerebrospinal fluid leak. It is usually associated with intracranial hypotension: low CSF pressure. It can cause headaches, made worse by standing, moving and coughing, as the low CSF pressure causes the brain to "sag" downwards and put pressure on its lower structures. If a leak is identified, a beta-2 transferrin test of the leaking fluid, when positive, is highly specific and sensitive for the detection for CSF leakage. Medical imaging such as CT scans and MRI scans can be used to investigate for a presumed CSF leak when no obvious leak is found but low CSF pressure is identified. Caffeine, given either orally or intravenously, often offers symptomatic relief. Treatment of an identified leak may include injection of a person's blood into the epidural space (an epidural blood patch ), spinal surgery, or fibrin glue.

What is the cause of hydrocephalus?

Hydrocephalus is an abnormal accumulation of CSF in the ventricles of the brain. Hydrocephalus can occur because of obstruction of the passage of CSF, such as from an infection, injury, mass, or congenital abnormality. Hydrocephalus without obstruction associated with normal CSF pressure may also occur. Symptoms can include problems with gait and coordination, urinary incontinence, nausea and vomiting, and progressively impaired cognition. In infants, hydrocephalus can cause an enlarged head, as the bones of the skull have not yet fused, seizures, irritability and drowsiness. A CT scan or MRI scan may reveal enlargement of one or both lateral ventricles, or causative masses or lesions, and lumbar puncture may be used to demonstrate and in some circumstances relieve high intracranial pressure. Hydrocephalus is usually treated through the insertion of a shunt, such as a ventriculo-peritoneal shunt, which diverts fluid to another part of the body.

How much cerebrospinal fluid is produced in the brain?

The brain produces roughly 500 mL of cerebrospinal fluid per day , at a rate of about 25 mL an hour. This transcellular fluid is constantly reabsorbed, so that only 125–150 mL is present at any one time. CSF volume is higher on a mL/kg basis in children compared to adults.

What test is used to detect a CSF leak?

If a leak is identified, a beta-2 transferrin test of the leaking fluid, when positive, is highly specific and sensitive for the detection for CSF leakage. Medical imaging such as CT scans and MRI scans can be used to investigate for a presumed CSF leak when no obvious leak is found but low CSF pressure is identified.

Why is cerebrospinal fluid important?

The draining of cerebrospinal fluid is thought to be important for brain health. In conditions like Alzheimer’s disease, proteins such as amyloids can build up in the brain and may cause damage. Proulx says there may be several routes for the brain to drain fluids, including the spine.

Do older mice have less cerebrospinal fluid drainage?

The team found a significant decline in cerebrospinal fluid drainage in the brains of older mice. Animals who were 2 or more years old had about half the level of drainage through their basal meningeal lymphatic vessels than those aged 3 months.

What is the role of CSF in the brain?

Its role is to supply nutrients to these areas and to cushion the brain inside the skull. The brain is covered in thin layers of tissue collectively called the dura mater, and CSF can escape through a tear in this tissue.

How to identify CSF?

A healthcare professional can often identify CSF just by looking at a sample on a handkerchief or piece of gauze. Unlike mucus, which is thick and sticky, CSF is clear and watery.

What is a CSF leak that does not improve with conservative treatment?

a CSF leak that does not improve with conservative treatment. a severe CSF leak that is unlikely to heal on its own. blood clotting in the brain or spinal cord. herniated brain tissue that pushes into the ears or nose. meningitis. Surgery involves suturing — or stitching— any tear to prevent further CSF leakage.

What causes CSF leaks?

Blunt force head injuries can fracture bones in the face or the temporal bones on either side of the skull. These fractures can also tear the dura mater, causing a CSF leak. Other causes of a CSF leak. Trusted Source.

How to tell if CSF is leaking?

The symptoms of a CSF leak include fluid drainage from the ears or nose and a headache that worsens when the head is upright.

What does it mean when you have a CSF leak?

An individual with a CSF leak may also notice clear , watery fluid draining from their nose or ears when they move their head, especially when bending forward . CSF may also drain down the back of the throat. People describe the taste as salty and metallic. Other symptoms of a CSF leak include:

How to diagnose a CSF leak?

A doctor can use a number of tests to diagnose a CSF leak. One test involves placing a sample of what the doctor suspects to be CSF discharge on a piece of filter paper. Once in contact with the paper, any CSF will separate from any blood or mucus.

Why is CSF important for the brain?

Because CSF bathes and irrigates the brain, including those regions known to participate in endocrine functions, the suggestion has been made that CSF may serve as a vehicle for intracerebral transport of biologically active substances. For example, hormone releasing factors, formed in the hypothalamus and discharged into the CSF of the third ventricle, may be carried in the CSF to their effective sites in the median eminence. The CSF may also be the vehicle for intracerebral transport of opiates and other neuroactive substances (Davson and Segal, 1996; Fishman, 1992; Milhorat, 1987; Rosenberg, 1990).

What is the CSF-brain interface?

The extensive CSF-brain (and spinal cord) interface consists of the ependyma within the cavities of the central nervous system and the pia mater covering the central nervous system. These two layers are each composed of a single layer of cells joined by gap junctions. The ependyma and the pia mater are not important permeability barriers; the CSF (ventricular and subarachnoid) and the brain interstitial fluid are directly continuous (Davson and Segal, 1996; Milhorat, 1987).

What are the cell types in CSF?

Normal CSF consists of varying proportions of small lymphocytes and monocytes. The proportions are species and age dependent (Kjeldsberg and Knight, 1993). In dogs, monocytic type cells predominate (Jamison and Lumsden, 1988), although there is individual variation. In cats (Jamison and Lumsden, 1988; Rand et al.,1990b), (unreactive) macrophages also predominate, with a mean of 87%, whereas small lymphocytes have a mean of 9%. This same trend is observed in horses, with 73.6% monocytes (macrophages) and 26.2% lymphocytes (Furr and Bender, 1994). However, small lymphocytes predominate in cattle (Welles et al.,1992) and llamas (Welles et al.,1994). In the literature published before 1975 that focused on humans, any neutrophils present in the CSF were thought to be indicative of disease (Kjeldsberg and Knight, 1993). However, with the advent of techniques for concentrating CSF specimens, such as cytocentrifugation, it became clear that a very small number of neutrophils may be found in normal human CSF (Fishman, 1992; Kjeldsberg and Knight, 1993). Similar observations have been made in many veterinary species, and rare neutrophils may be a normal finding in the CSF of all domestic species. Eosinophils are not present in normal CSF, although a single cell is occasionally seen on cytocentrifuge slides in animals with normal total nucleated cell counts. Large foamy activated macrophages or phagocytes are not seen in normal CSF (Christopher et al.,1988; Fishman, 1992), and their presence is nonspecific evidence of an inflammatory disorder. Plasma cells are not seen in normal CSF (Fishman, 1992; Kjeldsberg and Knight, 1993; Pelc et al.,1981). Their presence indicates underlying inflammatory disease. In people, plasma cells are seen particularly in acute viral disease and various chronic inflammatory conditions including tuberculous meningitis, syphilis, multiple sclerosis, and the Guillain-Barré syndrome (Kjeldsberg and Knight, 1993; Pelc et al.,1981). In animals, plasma cells have been observed in various conditions including distemper (Vandevelde and Spano, 1977), other viral meningitis (Bichsel et al.,1984a; Vandevelde and Spano, 1977), rabies (Green et al.,1992), granulomatous meningoencephalomyelitis (Bailey and Higgins, 1986a; Vandevelde and Spano, 1977), neoplasia, and abscesses (W. Vernau, personal observations). Therefore, although they are abnormal, no specificity is associated with their presence in CSF. Similarly, reactive lymphocytes are not found in normal CSF, but their presence has no specificity. They can be seen in active or resolving infectious disease, immune mediated diseases, and neoplasia (Cook and DeNicola, 1988).

What is CSF analysis?

The analysis of cerebrospinal fluid (CSF) has been described as the central nervous system (CNS) equivalent of the complete blood count (Jamison and Lumsden, 1988), and the analogy is appropriate. CSF analysis is a general index of neurological health and often provides evidence of the presence of disease. Similar to a complete blood count, CSF analysis has reasonable sensitivity but low specificity. The possible alterations of CSF are relatively limited compared to the varieties of neurological diseases that exist (particularly if the analysis is restricted to total cell counts and total protein determination). Additionally, the type and degree of CSF abnormality seem to be related as much to the location of disease as to the cause or the severity of lesion; meningeal and paraventricular diseases generally produce greater abnormalities than deep parenchymal diseases. Previous therapy may affect the type, degree, and duration of CSF (Jamison and Lumsden, 1988) abnormalities as well. The CSF abnormalities identified are also dependent on the CSF collection site with respect to lesion location (Thomson, Kornegay, & Stevens (1989), Thomson, Kornegay, & Stevens (1990)). Lastly, the CSF of animals with neurological disease is not always abnormal (Tipold et al., 1995). Only occasionally does CSF analysis provide a specific diagnosis (Kjeldsberg and Knight, 1993)—for example, if infectious agents (bacteria or fungi) or neoplastic cells are observed. In most situations, the chief utility of CSF analysis is to assist in the diagnostic process by excluding the likelihood of certain disease processes being present. As is the case with all tests of relatively low specificity, examination of CSF is most useful when the results are correlated with the history, clinical findings, imaging studies, and ancillary laboratory studies. As stated by Fankhauser (1962), “It is futile to make a diagnosis based solely on the CSF findings and particularly on single alterations of it. Only the entire picture of all findings linked with the other clinical symptoms is of value in reaching a diagnosis.”

How does CSF absorption occur?

Absorption of CSF occurs by bulk absorption of the fluid and by absorption or exchange of individual constituents of the fluid (i.e., ions, proteins, and drugs). Bulk absorption occurs directly into the venous system and depends primarily on the CSF hydrostatic pressure; as the pressure rises, the absorption rate increases (Davson and Segal, 1996). If intracranial pressure falls below a critical point, bulk absorption decreases, a homeostatic response to stabilize the intracranial pressure and the CSF volume. The primary site of bulk absorption, at least in people, is the arachnoid villi that project into the dural sinuses. Two other routes are through lymphatic channels in the dura and through the perineural sheaths of cranial nerves (particularly the olfactory nerves) and spinal nerves. Perineural absorption may be through arachnoid villi projecting into perineural veins, lymphatics, or connective tissue (Davson and Segal, 1996; Milhorat, 1987). The importance of these various absorption routes varies with the species (Bell, 1995).

What is the role of cerebral fluid in the nervous system?

Cerebrospinal fluid has four major functions: (1) physical support of neural structures, (2) excretion and “sink” action, (3) intracerebral transport, and (4) control of the chemical environment of the central nervous system. Cerebrospinal fluid provides a “water jacket” of physical support and buoyancy. When suspended in CSF, a 1500-gm brain weighs only about 50 gm. The CSF is also protective because its volume changes reciprocally with changes in the volume of intracranial contents, particularly blood. Thus, the CSF protects the brain from changes in arterial and central venous pressure associated with posture, respiration, and exertion. Acute or chronic pathological changes in intracranial contents can also be accommodated, to a point, by changes in the CSF volume (Fishman, 1992; Milhorat, 1987; Rosenberg, 1990).

What is the function of CSF?

An essential function of CSF is the provision and maintenance of an appropriate chemical environment for neural tissue. Anatomically, the interstitial fluid of the central nervous system and the CSF are in continuity (see Section II.A); therefore, the chemical composition of the CSF reflects and affects the cellular environment. The composition of the CSF (and the interstitial fluid) is controlled by cells forming the interfaces, or barriers, between the “body” and the neural tissue. These semipermeable interfaces, the blood-brain barrier, the blood-CSF barrier, and the CSF-brain barrier, control the production and absorption of CSF and provide a fluid environment that is relatively stable despite changes in the composition of blood (Davson and Segal, 1996; Fishman, 1992; Milhorat, 1987; Rosenberg, 1990).

Where is CSF secreted?

The cerebrospinal fluid (CSF) is continuously secreted and circulating within the subarachnoid spaces of the brain. It provides for a fluid environment inside the skull within which the brain is floating.

Why is CSF drained out of the cistern?

In surgeries of the brain, to remove tumors for example, CSF is deliberately drained out from the cisterns to reduce the pressure and to allow easier access to the tumor. The opening in the layer around the brain (dura mater) is later closed with fine sutures with or without a graft to prevent leak.

How does CSF leak?

First, cerebral spinal fluid leak (CSF) results when the fluid around the brain (called cerebral spinal fluid) leaks through a hole through the skull bone. This fluid can either drain from the ear or the nose, depending on where the skull bone is damaged. Patients typically complain of clear, watery drainage usually from only one side of the nose or one ear. CSF leaks can be separated into two groups. Spontaneous leaks occur without any known cause (most common). Traumatic leaks are most commonly related to a history of head injury, surgery, or tumors. This was a common question a medical stud

What is cerebral spinal fluid leak?

First, cerebral spinal fluid leak (CSF) results when the fluid around the brain (called cerebral spinal fluid) leaks through a hole through the skull bone. This fluid can either drain from the ear or the nose, depending on where the skull bone is damaged. Patients typically complain of clear, watery drainage usually from only one side of the nose or one ear. CSF leaks can be separated into two groups. Spontaneous leaks occur without any known cause (most common). Traumatic leaks are most commonly related to a history of head injury, surgery, or tumors. This was a common question a medical student would be asked by a senior resident just to watch them squirm!

What is a ventriculoatrial shunt?

Ventriculoatrial shunt: In this case the drained cerebrospinal fluid goes directly into the heart and mixes with blood.

What is a shunt in the abdomen?

Ventriculoperitoneal shunt: the peritoneal cavity is a potential space in the abdomen (like a folded empty bag that has no space inside until you put something in it). It is one of the toughest topics of human anatomy to understand so there is very little chance I could explain it thoroughly here, but to speak easily it is the space between the abdominal wall (skin and muscles) and the internal organs. The cavity (organs too) is lined by a thin serosa called peritoneum which normally produces and reabsorbs a very little amount of fluid. The extra fluid coming from the shunt is easily reabsorbed by the peritoneum and enters blood circulation.

How much does the average brain weigh?

The average adult brain has a mass somewhere in the ballpark of 1400 grams. When it's floating in CSF, the buoyancy makes it weigh ~60 grams. That's more than a 20X reduction in perceived mass. Clinicians quickly discovered the drawback of tapping CSF with a lumbar puncture when they found that patients who didn't lie on their side until their CSF was replenished could suffer headaches caused by the overbearing weight of the brain tugging mercilessly at spinal nerve roots.

Overview

Physiology

CSF serves several purposes:
1. Buoyancy: The actual mass of the human brain is about 1400–1500 grams; however, the net weight of the brain suspended in CSF is equivalent to a mass of 25-50 grams. The brain therefore exists in neutral buoyancy, which allows the brain to maintain its density without being impaired by its own weight, which would cut off blood supply and kill neurons in the lower sections without C…

Structure

Development

Clinical significance

History

Other animals

See also