Cerebral venous sinus thrombosis (
CVST) is a rare form of
strokeA stroke is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by thrombosis or embolism or due to a hemorrhage...
that results from
thrombosisThrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot, because the first step in repairing it is to prevent loss of blood...
(a blood clot) of the
dural venous sinusesThe dural venous sinuses are venous channels found between layers of dura mater in the brain...
, which drain blood from the
brainThe brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as jellyfish and starfish have a decentralized nervous system without a brain, while sponges lack any nervous system at all...
. Symptoms may include
headacheIn medicine a headache or cephalalgia is a symptom of a number of different conditions of the head. Some of the causes are benign while others are medical emergencies.There are a number of different classification systems for headaches...
, abnormal vision, any of the symptoms of
strokeA stroke is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by thrombosis or embolism or due to a hemorrhage...
such as weakness of the face and limbs on one side of the body, and seizures. The diagnosis is usually by
computed tomographyComputed tomography is a medical imaging method employing tomography created by computer processing. Digital geometry processing is used to generate a three-dimensional image of the inside of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation.CT...
(CT/CAT scan) or
magnetic resonance imagingMagnetic Resonance Imaging , or nuclear magnetic resonance imaging , is primarily a medical imaging technique most commonly used in radiology to visualize the internal structure and function of the body...
(MRI) employing
radiocontrastRadiocontrast agents are a type of medical contrast medium used to improve the visibility of internal bodily structures in an X-ray based imaging techniques such as Computed tomography or Radiography...
to demonstrate obstruction of the venous sinuses by thrombus.
Treatment is with
anticoagulantAn anticoagulant is a substance that prevents coagulation; that is, it stops blood from clotting. A group of pharmaceuticals called anticoagulants can be used in vivo as a medication for thrombotic disorders...
s (medication that suppresses blood clotting), and rarely
thrombolysisThrombolysis is the breakdown of blood clots by pharmacological means. It is colloquially referred to as clot busting for this reason...
(enzymatic destruction of the blood clot). Given that there is usually an underlying cause for the disease, tests may be performed to look for these. The disease may be complicated by
raised intracranial pressureIntracranial pressure is the pressure in the cranium and thus in the brain tissue and cerebrospinal fluid ; this pressure is exerted on the brain's intracranial blood circulation vessels. ICP is maintained in a tight normal range dynamically, through the production and absorption of CSF and...
, which may warrant surgical intervention such as the placement of a
shuntIn cases of hydrocephalus , a silicone elastomer tube called a shunt is used to drain excess cerebrospinal fluid from the brain and carry it to other parts of the body. This tube goes from the affected area of the brain, connects to a one-way valve which sits outside the skull, but beneath the...
. There are several other terms for the condition, such as
cerebral venous and sinus thrombosis,
(superior) sagittal sinus thrombosis,
dural sinus thrombosis and
intracranial venous thrombosis as well as the older term
cerebral thrombophlebitis.
Signs and symptoms
Nine in ten people with sinus thrombosis have a headache; this tends to worsen over the period of several days, but may also develop suddenly (
thunderclap headacheA thunderclap headache is a headache that is severe and sudden . Because it may be a sign of a medical emergency, some sources recommend immediate medical attention....
). The headache may be the only symptom of cerebral venous sinus thrombosis. Many patients have symptoms of stroke: inability to move one or more limbs, weakness on one side of the face or
difficulty speakingAphasia is an acquired condition in which there is an impairment of any language modality. This may include difficulty in producing or comprehending spoken or written language....
. This does not necessarily affect one side of the body as in the more common "arterial" stroke.
40% of all patients have
seizureAn epileptic seizure is a transient symptom of excessive or synchronous neuronal activity in the brain. It can manifest as an alteration in mental state, tonic or clonic movements, convulsions, and various other psychic symptoms...
s, although it is more common still in women who develop sinus thrombosis peripartum (in the period before and after giving birth). These are mostly seizures
affecting only one part of the bodyPartial seizures are seizures which affect only a part of the brain at onset, and are split into two main categories; simple partial seizures and complex partial seizures...
and unilateral (occurring on one side), but occasionally the seizures are
generalisedTonic–clonic seizures are a type of generalized seizure that affects the entire brain. Formerly known as grand mal seizures or gran mal seizures, these terms are now discouraged and rarely used in a clinical setting...
and rarely they lead to
status epilepticusStatus epilepticus refers to a life-threatening condition in which the brain is in a state of persistent seizure. Definitions vary, but traditionally it is defined as one continuous unremitting seizure lasting longer than 30 minutes , or recurrent seizures without regaining consciousness between...
(persistent or recurrent seizure activity for a long period of time).
In the elderly, many of the aforementioned symptoms may not occur. Common symptoms in the elderly with this condition are otherwise unexplained changes in mental status and a depressed
level of consciousnessLevel of consciousness is a measurement of a person's arousability and responsiveness to stimuli from the environment. A mildly depressed level of consciousness may be classed as lethargy; someone in this state can be aroused with little difficulty. People who are obtunded have a more depressed...
.
The
intracranial pressureIntracranial pressure is the pressure in the cranium and thus in the brain tissue and cerebrospinal fluid ; this pressure is exerted on the brain's intracranial blood circulation vessels. ICP is maintained in a tight normal range dynamically, through the production and absorption of CSF and...
(pressure around the brain) may rise, causing
papilledemaPapilledema is optic disc swelling that is caused by increased intracranial pressure. The swelling is usually bilateral but can be unilateral which is extremely rare and can occur over a period of hours to weeks...
(swelling of the
optic discThe optic disc or optic nerve head is the location where ganglion cell axons exit the eye to form the optic nerve. There are no light sensitive rods or cones to respond to a light stimulus at this point. This causes a break in the visual field called "the blind spot" or the "physiological blind spot"...
) which may be experienced as visual obscurations. In severely raised intracranial pressure, the level of consciousness is decreased, the
blood pressureBlood pressure is the pressure exerted by circulating blood on the walls of blood vessels, and is one of the principal vital signs. During each heartbeat, BP varies between a maximum and a minimum pressure...
rises, the
heart rate fallsBradycardia , as applied to adult medicine, is defined as a resting heart rate of under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beat/min....
and the patient assumes an abnormal posture.
Risk factors
Cerebral venous sinus thrombosis is more common in particular situations. 85% of patients have at least one of these risk factors:
- Thrombophilia
Thrombophilia or hypercoagulability is the propensity to develop thrombosis due to an abnormality in the system of coagulation. Hereditary defects in one or more of the clotting factors can cause the formation of potentially dangerous blood clots . Approximately 5-8% of the U.S...
, a tendency to develop blood clots due to abnormalities in coagulation, e.g. factor V LeidenFactor V Leiden is the name given to a variant of human factor V that causes a hypercoagulability disorder. In this disorder the Leiden variant of factor V cannot be inactivated by activated protein C. Factor V Leiden is the most common hereditary hypercoagulability disorder amongst Eurasians...
, deficiency of protein CProtein C is a major physiological anticoagulant. It is a vitamin K-dependent serine protease enzyme that is activated by thrombin into activated protein C . The activated form degrades Factor Va and Factor VIIIa...
, protein SProtein S is a vitamin K-dependent plasma glycoprotein synthesized in the endothelium. In the circulation, Protein S exists in two forms: a free form and a complex form bound to complement protein C4b...
or antithrombinAntithrombin is a small protein molecule that inactivates several enzymes of the coagulation system. It is a glycoprotein produced by the liver and consists of 432 amino acids. It contains three disulfide bonds and a total of four possible glycosylation sites...
, or related problems
- Nephrotic syndrome
Nephrotic syndrome is a nonspecific disorder in which the kidneys are damaged, causing them to leak large amounts of protein from the blood into the urine....
, a kidney problem causing protein loss in the urine
- Chronic inflammatory diseases, such as inflammatory bowel disease
In medicine, inflammatory bowel disease is a group of inflammatory conditions of the colon and small intestine. The major types of IBD are Crohn's disease and ulcerative colitis..-Forms:...
, lupusLupus erythematosus is a connective tissue disease. Lupus is a chronic inflammatory disease that occurs when the body's immune system attacks its own tissues and organs. Inflammation caused by lupus can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs...
and Behçet's diseaseBehçet disease is a form of vasculitis that can lead to ulceration and other lesions. It can be interpreted as a chronic disturbance in the body’s immune system...
- Pregnancy
Pregnancy is the carrying of one or more offspring, known as a fetus or embryo, inside the uterus of a female. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets. Human pregnancy is the most studied of all mammalian pregnancies. Obstetrics is the surgical field...
and puerperium (the period after giving birth)
- Particular blood disorders, especially polycythemia vera
Polycythemia vera is a blood disorder in which the bone marrow makes too many red blood cells. Polycythemia vera may also result in the overproduction of white blood cells and platelets...
and paroxysmal nocturnal hemoglobinuriaParoxysmal nocturnal hemoglobinuria , sometimes referred to as Marchiafava-Micheli syndrome, is a rare, acquired, potentially life-threatening disease of the blood characterised by complement-induced hemolytic anemia , red urine and thrombosis...
- Use of estrogen-containing forms of hormonal contraception
Hormonal contraception refers to birth control methods that act on the endocrine system. Almost all methods are composed of steroid hormones, although in India one selective estrogen receptor modulator is marketed as a contraceptive. The original hormonal method—the combined oral contraceptive...
- Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...
and infections of the ear, nose and throat area such as mastoiditisMastoiditis is an infection of mastoid process, the portion of the temporal bone of the skull that is behind the ear which contains open, air-containing spaces. It is usually caused by untreated acute otitis media and used to be a leading cause of child mortality...
and sinusitisSinusitis is a condition consisting of infection or inflammation of the paranasal sinuses, which may or may not be as a result of infection, from bacterial, fungal, viral, allergic or autoimmune issues...
- Direct injury to the venous sinuses
- Medical procedures in the head and neck area
Investigations
The diagnosis may be suspected on the basis of the symptoms, for example the combination of headache, signs of raised intercranial pressure and focal neurological abnormalities, or when alternative causes of headache and neurological abnormalities, such as a
subarachnoid hemorrhageA subarachnoid hemorrhage is bleeding into the subarachnoid space—the area between the arachnoid membrane and the pia mater surrounding the brain...
, have been excluded.
CT, MRI and angiography
There are various
neuroimagingNeuroimaging includes the use of various techniques to either directly or indirectly image the structure, function/pharmacology of the brain...
investigations that may detect cerebral sinus thrombosis.
Cerebral edemaCerebral edema is an excess accumulation of water in the intracellular and/or extracellular spaces of the brain.- Vasogenic cerebral edema:...
and venous infarction may be apparent on any modality, but for the detection of the thrombus itself, the most commonly used tests are
computed tomographyComputed tomography is a medical imaging method employing tomography created by computer processing. Digital geometry processing is used to generate a three-dimensional image of the inside of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation.CT...
(CT) and
magnetic resonance imagingMagnetic Resonance Imaging , or nuclear magnetic resonance imaging , is primarily a medical imaging technique most commonly used in radiology to visualize the internal structure and function of the body...
(MRI), both using various types of radiocontrast to perform a venogram and visualise the veins around the brain.
Computed tomographyComputed tomography is a medical imaging method employing tomography created by computer processing. Digital geometry processing is used to generate a three-dimensional image of the inside of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation.CT...
, with
radiocontrastRadiocontrast agents are a type of medical contrast medium used to improve the visibility of internal bodily structures in an X-ray based imaging techniques such as Computed tomography or Radiography...
in the venous phase (
CT venography or CTV), has a detection rate that in some regards exceeds that of MRI. The test involves injection into a vein (usually in the arm) of a radioopaque substance, and time is allowed for the bloodstream to carry it to the cerebral veins - at which point the scan is performed. It has a sensitivity of 75-100% (it detects 75-100% of all clots present), and a specificity of 81-100% (it would be incorrectly positive in 0-19%). In the first two weeks, the "empty delta sign" may be observed (in later stages, this sign may disappear).
Magnetic resonance venographyMagnetic Resonance Angiography is a group of techniques based on Magnetic Resonance Imaging to image blood vessels. Magnetic Resonance Angiography is used to generate images of the arteries in order to evaluate them for stenosis , occlusion or aneurysms...
employs the same principles, but uses MRI as a scanning modality. MRI has the advantage of being better at detecting damage to the brain itself as a result of the increased pressure on the obstructed veins, but it is not readily available in many hospitals and the interpretation may be difficult.
Cerebral angiographyCerebral angiography is a form of angiography that visualizes the arterial and venous supply of the brain. This medical imaging technique was pioneered by Dr. Egas Moniz in 1927, and is now the gold standard for detecting vascular problems of the brain....
may demonstrate smaller clots than CT or MRI, and obstructed veins may give the "corkscrew appearance". This, however, requires puncture of the
femoral arteryThe femoral artery is a large artery in the muscles of the thigh. It is a continuation of external iliac artery where it enters the femoral triangle at the mid inguinal point behind the inguinal ligament. It leaves femoral triangle through apex beneath the sartorius muscle...
with a sheath and advancing a thin tube through the blood vessels to the brain where radiocontrast is injected before X-ray images are obtained. It is therefore only performed if all other tests give unclear results or when other treatments may be administered during the same procedure.
D-dimer
A 2004 study suggested that the
D-dimerD-dimer is a fibrin degradation product, a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis.D-dimer concentration may be determined by a blood test to help diagnose thrombosis. Since its introduction in the 1990s, it has become an important test performed...
blood test, already in use for the diagnosis of other forms of thrombosis, was abnormal (above 500 μg/l) in 34 out of 35 patients with cerebral sinus thrombosis, giving it a sensitivity of 97.1%, a
negative predictive valueThe negative predictive value is the proportion of patients with negative test results who are correctly diagnosed.-Worked example:In the following example, the terms predictive value positive and predictive value negative are valid as shown assuming the data come from a cross-sectional study, or...
of 99.6%, a specificity of 91.2%, and a positive predictive value of 55.7%. Furthermore, the level of the D-dimer correlated with the extent of the thrombosis. A subsequent study, however, showed that 10% of patients with confirmed thrombosis had a normal D-dimer, and in those who had presented with only a headache 26% had a normal D-dimer. The study concludes that D-dimer is not useful in the situations where it would make the most difference, namely in lower probability cases.
Further tests
In most patients, the direct cause for the cerebral sinus thrombosis is not readily apparent. Identifying a source of infection is crucial; it is common practice to screen for various forms of
thrombophiliaThrombophilia or hypercoagulability is the propensity to develop thrombosis due to an abnormality in the system of coagulation. Hereditary defects in one or more of the clotting factors can cause the formation of potentially dangerous blood clots . Approximately 5-8% of the U.S...
(a propensity to form blood clots).
Pathogenesis
The
veinIn the circulatory system, veins are blood vessels that carry blood toward the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood...
s of the brain, both the superficial veins and the deep venous system, empty into the dural venous sinuses, which carry blood back to the
jugular veinThe jugular veins are veins that bring deoxygenated blood from the head back to the heart via the superior vena cava.-Internal and external:There are two sets of jugular veins: external and internal....
and thence to the
heartThe heart is a muscular organ found in all vertebrates that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
. In cerebral venous sinus thrombosis, blood clots usually form both in the veins of the brain and the venous sinuses. The thrombosis of the veins themselves causes venous
infarctionIn medicine, an infarction is the process of tissue death caused by blockage of the tissue's blood supply. The supplying artery may be blocked by an obstruction , may be mechanically compressed , ruptured by trauma , or vasoconstricted In medicine, an infarction is the process of tissue death...
–damage to brain tissue due to a
congestedBack pressure usually refers to the pressure exerted on a moving fluid by obstructions or tight bends in the confinement vessel along which it is moving, such as piping or air vents, against its direction of flow. For example, an automotive exhaust muffler with a particularly high number of twists,...
and therefore insufficient blood supply. This results in
cerebral edemaCerebral edema is an excess accumulation of water in the intracellular and/or extracellular spaces of the brain.- Vasogenic cerebral edema:...
(both
vasogenic and
cytotoxic edema), and leads to small
petechiaA petechia is a small red or purple spot on the body, caused by a minor hemorrhage ....
l haemorrhages that may merge into large haematomas. Thrombosis of the sinuses is the main mechanism behind the increase in intracranial pressure due to decreased resorption of cerebrospinal fluid (CSF). The condition does not lead to
hydrocephalusHydrocephalus , also known as "water on the brain", is a medical condition. People with hydrocephalus have an abnormal accumulation of cerebrospinal fluid in the ventricles, or cavities, of the brain. This may cause increased intracranial pressure inside the skull and progressive enlargement of...
, however, because there is no difference in pressure between various parts of the brain.
Any blood clot forms due to an imbalance between
coagulationCoagulation is a complex process by which blood forms clots. It is an important part of hemostasis , wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel...
(the formation of the insoluble blood protein
fibrinFibrin is a fibrous protein involved in the clotting of blood, and is non globular. It is a fibrillar protein that is polymerised to form a "mesh" that forms a hemostatic plug or clot over a wound site.Fibrin is made from fibrinogen, a soluble plasma glycoprotein that is synthesised by the liver...
) and
fibrinolysisFibrinolysis is the process wherein a fibrin clot, the product of coagulation, is broken down. Its main enzyme plasmin cuts the fibrin mesh at various places, leading to the production of circulating fragments that are cleared by other proteases or by the kidney and liver.-Physiology:Plasmin is...
. The three major mechanisms for such an imbalance are enumerated in
Virchow's triadVirchow's triad the three broad categories of factors that are thought to contribute to thrombosis.*Hypercoagulability*Hemodynamic changes *Endothelial injury/dysfunctionIt is named for German physician Rudolf Virchow...
: alterations in normal blood flow, injury to the blood vessel wall, and alterations in the constitution of blood (hypercoagulability). Most cases of cerebral venous sinus thrombosis are due to hypercoagulability.
It is possible for the clot to break off and migrate (
emboliseIn medicine, an embolism occurs when an object migrates from one part of the body and causes a blockage of a blood vessel in another part of the body. The term was coined in 1848 by Rudolph Carl Virchow...
) to the
lungThe lung or pulmonary system is the essential respiration organ in air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located in the chest on either side of the heart...
s, causing a
pulmonary embolismPulmonary embolism is a blockage of the main artery of the lung or one of its branches by a substance that has travelled from elsewhere in the body through the bloodstream . Usually this is due to embolism of a thrombus from the deep veins in the legs, a process termed venous thromboembolism...
. An analysis of earlier case reports concludes that this occurs in about 10% of cases, but has a very poor prognosis.
Treatment
Various studies have investigated the use of anticoagulation to suppress blood clot formation in cerebral venous sinus thrombosis. Before these trials had been conducted, there had been a concern that small areas of hemorrhage in the brain would bleed further as a result of treatment; the studies showed that this concern was unfounded. Clinical practice guidelines now recommend
heparinHeparin, a highly-sulfated glycosaminoglycan, is widely used as an injectable anticoagulant, and has the highest negative charge density of any known biological molecule. It can also be used to form an inner anticoagulant surface on various experimental and medical devices such as test tubes and...
or
low molecular weight heparinIn medicine, low-molecular-weight heparin is a class of medication used as an anticoagulant in diseases that feature thrombosis, as well as for prophylaxis in situations that lead to a high risk of thrombosis....
in the initial treatment, followed by
warfarinWarfarin is an anticoagulant. It was initially marketed as a pesticide against rats and mice and is still popular for this purpose, although more potent poisons such as brodifacoum have since been developed...
, provided there are no other bleeding risks that would make these treatments unsuitable. Some experts discourage the use of anticoagulation if there is extensive hemorrhage; in that case, they recommend repeating the imaging after 7–10 days. If the hemorrhage has decreased in size, anticoagants are commenced, while no anticoagulants are given if there is no reduction.
The duration of warfarin treatment depends on the circumstances and underlying causes of the condition. If the thrombosis developed under temporary circumstances (e.g. pregnancy), three months are regarded as sufficient. If the condition was unprovoked but there are no clear causes or a "mild" form of thrombophilia, 6 to 12 months is advised. If there is a severe underlying thrombosis disorder, warfarin treatment may need to continue indefinitely.
ThrombolysisThrombolysis is the breakdown of blood clots by pharmacological means. It is colloquially referred to as clot busting for this reason...
(removal of the blood clot with "clot buster" medication) has been described, either systemically by injection into a vein or directly into the clot during angiography. The 2006
European Federation of Neurological SocietiesThe European Federation of Neurological Societies is a body formed by 42 societies of neurology of European countries. As a result, it indirectly represents 12,000 neurologists. It was founded in 1991 in Vienna, Austria.-External links:* *...
guideline recommends that thrombolysis is only used in patients who deteriorate despite adequate treatment, and other causes of deterioration have been eliminated. It is unclear which drug and which mode of administration is the most effective. Bleeding into the brain and in other sites of the body is a major concern in the use of thrombolysis. American guidelines make no recommendation with regards to thrombolysis, stating that more research is needed.
Raised intracranial pressure, if severe or threatening vision, may require therapeutic
lumbar punctureIn medicine, a lumbar puncture is a diagnostic and at times therapeutic procedure that is performed in order to collect a sample of cerebrospinal fluid for biochemical, microbiological, and cytological analysis, or very rarely as a treatment to relieve increased intracranial...
(removal of excessive
cerebrospinal fluidCerebrospinal fluid , Liquor cerebrospinalis, is a clear bodily fluid that occupies the subarachnoid space and the ventricular system around and inside the brain. In essence, the brain "floats" in it....
), medication (
acetazolamideAcetazolamide, sold under the trade name Diamox, is a carbonic anhydrase inhibitor that is used to treat glaucoma, epileptic seizures, benign intracranial hypertension , altitude sickness, cystinuria, and dural ectasia...
), or
neurosurgicalNeurosurgery is the surgery discipline focused on treating the central nervous system, peripheral nervous systems and spinal column diseases amenable to surgical intervention....
treatment (optic nerve sheath fenestration or
shuntingIn cases of hydrocephalus , a silicone elastomer tube called a shunt is used to drain excess cerebrospinal fluid from the brain and carry it to other parts of the body. This tube goes from the affected area of the brain, connects to a one-way valve which sits outside the skull, but beneath the...
). In certain situations,
anticonvulsantThe anticonvulsants are a diverse group of pharmaceuticals used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of bipolar disorder, since many seem to act as mood stabilizers. The goal of an anticonvulsant is to suppress the rapid and...
s may be used to prevent seizures; these are focal neurological problems (e.g. inability to move a limb) and/or focal changes of the brain tissue on CT or MRI scan.
Prognosis
In 2004 the first adequately large scale study on the natural history and long-term prognosis of this condition was reported; this showed that at 16 months follow-up 57.1% of patients had full recovery, 29.5%/2.9%/2.2% had respectively minor/moderate/severe symptoms or impairments, and 8.3% had died. Severe impairment or death were more likely in those aged over 37 years, male, affected by coma, mental status disorder, intracerebral hemorrhage, thrombosis of the deep cerebral venous system, central nervous system infection and cancer. A subsequent
systematic reviewA systematic review is a literature review focused on a single question that tries to identify, appraise, select and synthesize all high quality research evidence relevant to that question. Systematic reviews of high-quality randomized controlled trials are crucial to evidence-based medicine...
of nineteen studies in 2006 showed that mortality is about 5.6% during hospitalisation and 9.4% in total, while of the survivors 88% make a total or near-total recovery. After several months, two thirds of the cases has resolution ("recanalisation") of the clot. The rate of recurrence was low (2.8%).
In children with CVST, the mortality averages 50%. Poor outcome is more likely if a child with CVST develops seizures or has evidence of venous infarction on imaging.
Epidemiology
Cerebral venous sinus thrombosis is rare, with an estimated 3-4 cases per million annual incidence in adults. While it may occur in all age groups, it is most common in the third decade. 75% are female. Given that older studies show no difference in incidence between men and women, it has been suggested that the use of oral contraceptives in women is behind the disparity between the sexes. A 1995 report from
Saudi ArabiaSaudi Arabia , is an Arab country and the largest country of the Arabian Peninsula. It is bordered by Jordan on the northwest, Iraq on the north and northeast, Kuwait, Qatar, Bahrain, and the United Arab Emirates on the east, Oman on the southeast, and Yemen on the south...
found a doubled incidence at 7 cases per 100,000; this was attributed to the fact that
Behçet's diseaseBehçet disease is a form of vasculitis that can lead to ulceration and other lesions. It can be interpreted as a chronic disturbance in the body’s immune system...
, which increases risk of CVST, is more common in the Middle East.
A 1973 report found that CVST could be found on
autopsyAn autopsy–also known as a post-mortem examination, necropsy , autopsia cadaverum, or obduction–is a medical procedure that consists of a thorough examination of a corpse to determine the cause and manner of death and to evaluate any disease or injury that may be present...
(examination of the body after death) in nine percent of all people. Many of these were elderly and had neurological symptoms in the period leading up to their death, and many suffered from concomitant heart failure.
In children, a Canadian study reported in 2001 that CVST occurs in 6.7 per million annually. 43% occur in the newborn (less than one month old), and a further 10% in the first year of life. Of the newborn, 84% were already ill, mostly from complications after childbirth and dehydration.
History
The first description of thrombosis of the cerebral veins and sinuses is attributed to the French physician Ribes, who in 1825 observed thrombosis of the saggital sinus and cerebral veins in a man who had suffered from seizures and delirium. Until the second half of the 20th century it remained a diagnosis generally made after death. In the 1940s, reports by Dr
Charles SymondsSir Charles Putnam Symonds KBE CB was an English neurologist.His initial medical training was at Guy's Hospital, followed by specialised training at the National Hospital for Neurology and Neurosurgery...
and others allowed for the clinical diagnosis of cerebral venous thrombosis, using characteristic signs and symptoms and results of
lumbar punctureIn medicine, a lumbar puncture is a diagnostic and at times therapeutic procedure that is performed in order to collect a sample of cerebrospinal fluid for biochemical, microbiological, and cytological analysis, or very rarely as a treatment to relieve increased intracranial...
.
Improvements on the diagnosis of cerebral venous sinus thrombosis in life were made with the introduction of
venographyVenography is a procedure in which an x-ray of the veins, a venogram, is taken after a special dye is injected into the bone marrow or veins...
in 1951, which also aided in the distinction from
idiopathic intracranial hypertensionIdiopathic intracranial hypertension , sometimes called by the older names benign intracranial hypertension or pseudotumor cerebri , is a neurological disorder that is characterized by an increased intracranial pressure in the absence of a tumor or other diseases...
, which has similar presenting signs and symptoms in many cases.
The British gynecologist Stansfield is credited with the introduction, in 1942, of the just recently introduced anticoagulant heparin in the treatment of CVST in 1942. Clinical trials in the 1990s finally resolved the concern about using anticoagulants in most cases of CVST.