Definition of subarachnoid hemorrhage (SAH)
The surface of the human brain is covered by three membranes, from the inside to the outside: the soft meninges, the arachnoid membrane, and the dura mater. The cavity between the arachnoid and soft meninges is called the subarachnoid space, which is normally filled with colorless and transparent cerebrospinal fluid. When a cerebral blood vessel ruptures, blood flows into the subarachnoid space, which is called subarachnoid hemorrhage, or SAH for short.
Etiology of SAH
SAH is classified as traumatic or spontaneous according to the cause. Traumatic, as the name suggests, is related to head trauma and will not be discussed here. The most common cause of spontaneous SAH is rupture of intracranial aneurysm, accounting for about 75% of cases, followed by cerebrovascular malformation, accounting for about 5-10% of cases; other cerebrovascular diseases including cerebral atherosclerosis and smog (Moyamoya disease) can also cause SAH; and about 10% of patients have unknown causes.
Clinical manifestations of SAH
Patients show severe headache, neck straightening, self-perception of “tear-like” or “electric shock-like” headache, often accompanied by nausea, vomiting, and in severe cases, convulsions, unconsciousness, and even respiratory and cardiac arrest, and about 10-15% of patients die before reaching the hospital. About 10-15% of patients die before reaching the hospital. The diagnosis can be made by cranial CT, which shows a high density in the subarachnoid space; when the bleeding is small, CT may not be diagnostic, and sometimes lumbar puncture is required to confirm the diagnosis.
Treatment of SAH
The treatment of SAH is a combination of symptomatic and etiologic therapy. Symptomatic treatment includes dehydration medication to lower cranial pressure, hemostasis, sedation, analgesia, prevention and control of cerebrovascular spasm, nutritional support and functional rehabilitation. Etiological treatment is the most important, i.e., to understand what causes SAH first, and then give targeted treatment. The cause of SAH can be determined by non-invasive diagnostic means such as MRA (magnetic resonance angiography) and CTA (tomography angiography), but the gold standard for confirming the cause is still invasive digital subtraction cerebral angiography, the so-called DSA examination. This test requires a femoral artery puncture cannula to deliver a catheter into the aortic arch and then up into the cerebral artery, through which a contrast agent is injected into the cerebral artery, so that the vascular images of the brain are clearly and dynamically displayed on the X-ray fluoroscopy screen, and a negative film can be developed by intercepting the static image. Through DSA examination, doctors can clarify the nature, location, morphology and severity of the underlying cerebrovascular lesion causing SAH, and use it to formulate the next treatment plan.
If the SAH is caused by a ruptured intracranial aneurysm, emergency surgery is required to “destroy” the aneurysm. Why is emergency treatment necessary? According to statistics, 20% of patients with ruptured aneurysm SAH will have rebleeding within 2 weeks after the first bleeding, and the residual death rate is as high as 60-80% within one year, so we describe aneurysm as an “untimely bomb” in the brain, and removing this untimely bomb as soon as possible can effectively prevent its The removal of this untimely bomb as soon as possible can effectively prevent it from “re-exploding”. There are two surgical approaches for aneurysms: craniotomy and interventional embolization, which requires evidence-based medicine and doctor-patient communication.
If SAH is caused by rupture of cerebrovascular malformation, the cerebrovascular malformation can be treated surgically after the hemorrhage is absorbed and the condition is stabilized. Because the chance of rebleeding in the near future after bleeding from cerebrovascular malformation is not very high, the rebleeding rate is 4~18% within 1 year, so it is possible to operate electively without emergency surgery as in the case of aneurysm. Cerebrovascular malformation of the same surgical methods are craniotomy and interventional embolization, small vascular malformations less than 4cm in diameter can also choose gamma knife treatment – a gamma ray stereotactic radiation therapy. Large vascular malformations are difficult to eradicate at once with interventional embolization and often require multiple embolizations or a combination of Gamma Knife treatment.
If SAH is caused by smog, surgical treatment such as temporal muscle patching and vascular bypass can be considered later. Smoggy disease was first discovered by the Japanese and is also known as Moyamoya disease, a cerebrovascular disease with unexplained progressive occlusion of the cerebral arteries, so named because it appears on cerebral angiography as a smog-like compensatory proliferation of capillaries at the base of the skull. It does not fall under the scope of interventional treatment.
Some SAH cannot find an etiology, i.e., the cerebral angiographic findings are normal. These patients often have a benign course and are not prone to rebleeding later. However, it must be noted that occasionally false-negative cerebral angiography results occur, i.e., organic cerebrovascular lesions are missed due to inexperienced physicians, less advanced hardware equipment, or thrombosis within the aneurysm.
Finally, it is important to emphasize ruptured aneurysm SAH, which is the third most common cerebrovascular accident after cerebral infarction and hypertensive cerebral hemorrhage. The process of ruptured aneurysm bleeding is very brief and transient. The rupture of an aneurysm causes a rapid increase in brain pressure, and the pressure gradient inside and outside the aneurysm immediately reaches equilibrium, so that blood no longer flows outward and a thrombus soon forms at the rupture site, which provides an opportunity to treat the survivor as soon as possible. However, this thrombus is very unstable and will dissolve in a short period of time (about 2 weeks), causing rebleeding of the aneurysm, which will increase the mortality rate exponentially. Therefore, once aneurysmal SAH is clearly identified, surgery should be performed as soon as possible.
Definition of subarachnoid hemorrhage (SAH)
The surface of the human brain is covered by three membranes: the soft meninges, the arachnoid membrane, and the dura mater, in order from the inside to the outside. The cavity between the arachnoid and soft meninges is called the subarachnoid space, which is normally filled with colorless and transparent cerebrospinal fluid. When a cerebral blood vessel ruptures, blood flows into the subarachnoid space, which is called subarachnoid hemorrhage, or SAH for short.
Etiology of SAH
SAH is classified as traumatic or spontaneous according to the cause. Traumatic, as the name suggests, is related to head trauma and will not be discussed here. The most common cause of spontaneous SAH is rupture of intracranial aneurysm, accounting for about 75% of cases, followed by cerebrovascular malformation, accounting for about 5-10% of cases; other cerebrovascular diseases including cerebral atherosclerosis and smog (Moyamoya disease) can also cause SAH; and about 10% of patients have unknown causes.
Clinical manifestations of SAH
Patients show severe headache, neck straightening, self-perception of “tear-like” or “electric shock-like” headache, often accompanied by nausea, vomiting, and in severe cases, convulsions, unconsciousness, and even respiratory and cardiac arrest, and about 10-15% of patients die before reaching the hospital. About 10-15% of patients die before reaching the hospital. The diagnosis can be made by cranial CT, which shows a high density in the subarachnoid space; when the bleeding is small, CT may not be diagnostic, and sometimes lumbar puncture is required to confirm the diagnosis.
Treatment of SAH
The treatment of SAH is a combination of symptomatic and etiologic therapy. Symptomatic treatment includes dehydration medication to lower cranial pressure, hemostasis, sedation, analgesia, prevention and control of cerebrovascular spasm, nutritional support and functional rehabilitation. Etiological treatment is the most important, i.e., to understand what causes SAH first, and then give targeted treatment. The cause of SAH can be determined by non-invasive diagnostic means such as MRA (magnetic resonance angiography) and CTA (tomography angiography), but the gold standard for confirming the cause is still invasive digital subtraction cerebral angiography, the so-called DSA examination. This test requires a femoral artery puncture cannula to deliver a catheter into the aortic arch and then up into the cerebral artery, through which a contrast agent is injected into the cerebral artery, so that the vascular images of the brain are clearly and dynamically displayed on the X-ray fluoroscopy screen, and a negative film can be developed by intercepting the static image. Through DSA examination, doctors can clarify the nature, location, morphology and severity of the underlying cerebrovascular lesion causing SAH, and use it to formulate the next treatment plan.
If the SAH is caused by a ruptured intracranial aneurysm, emergency surgery is required to “destroy” the aneurysm. Why is emergency treatment necessary? According to statistics, 20% of patients with ruptured aneurysm SAH will have rebleeding within 2 weeks after the first bleeding, and the residual death rate is as high as 60-80% within one year, so we describe aneurysm as an “untimely bomb” in the brain, and removing this untimely bomb as soon as possible can effectively prevent its The removal of this untimely bomb as soon as possible can effectively prevent it from “re-exploding”. There are two surgical approaches for aneurysms: craniotomy and interventional embolization, which requires evidence-based medicine and doctor-patient communication.
If SAH is caused by rupture of cerebrovascular malformation, the cerebrovascular malformation can be treated surgically after the hemorrhage is absorbed and the condition is stabilized. Because the chance of rebleeding in the near future after bleeding from cerebrovascular malformation is not very high, the rebleeding rate is 4~18% within 1 year, so it is possible to operate electively without emergency surgery as in the case of aneurysm. Cerebrovascular malformation of the same surgical methods are craniotomy and interventional embolization, small vascular malformations less than 4cm in diameter can also choose gamma knife treatment – a gamma ray stereotactic radiation therapy. Large vascular malformations are difficult to eradicate at once with interventional embolization and often require multiple embolizations or a combination of Gamma Knife treatment.
If SAH is caused by smog, surgical treatment such as temporal muscle patching and vascular bypass can be considered later. Smoggy disease was first discovered by the Japanese and is also known as Moyamoya disease, a cerebrovascular disease with unexplained progressive occlusion of the cerebral arteries, so named because it appears on cerebral angiography as a smog-like compensatory proliferation of capillaries at the base of the skull. It does not fall under the scope of interventional treatment.
Some SAH cannot find an etiology, i.e., the cerebral angiographic findings are normal. These patients often have a benign course and are not prone to rebleeding later. However, it must be noted that occasionally false-negative cerebral angiography results occur, i.e., organic cerebrovascular lesions are missed due to inexperienced physicians, less advanced hardware equipment, or thrombosis within the aneurysm.
Finally, it is important to emphasize ruptured aneurysm SAH, which is the third most common cerebrovascular accident after cerebral infarction and hypertensive cerebral hemorrhage. The process of ruptured aneurysm bleeding is very brief and transient. The rupture of an aneurysm causes a rapid increase in brain pressure, and the pressure gradient inside and outside the aneurysm immediately reaches equilibrium, so that blood no longer flows outward and a thrombus soon forms at the rupture site, which provides an opportunity to treat the survivor as soon as possible. However, this thrombus is very unstable and will dissolve in a short period of time (about 2 weeks), causing rebleeding of the aneurysm, which will increase the mortality rate exponentially. Therefore, once aneurysmal SAH is clearly identified, surgery should be performed as soon as possible.
Definition of subarachnoid hemorrhage (SAH)
The surface of the human brain is covered by three membranes: the soft meninges, the arachnoid membrane, and the dura mater, in order from the inside to the outside. The cavity between the arachnoid and soft meninges is called the subarachnoid space, which is normally filled with colorless and transparent cerebrospinal fluid. When a cerebral blood vessel ruptures, blood flows into the subarachnoid space, which is called subarachnoid hemorrhage, or SAH for short.
Etiology of SAH
SAH is classified as traumatic or spontaneous according to the cause. Traumatic, as the name suggests, is related to head trauma and will not be discussed here. The most common cause of spontaneous SAH is rupture of intracranial aneurysm, accounting for about 75% of cases, followed by cerebrovascular malformation, accounting for about 5-10% of cases; other cerebrovascular diseases including cerebral atherosclerosis and smog (Moyamoya disease) can also cause SAH; and about 10% of patients have unknown causes.
Clinical manifestations of SAH
Patients show severe headache, neck straightening, self-perception of “tear-like” or “electric shock-like” headache, often accompanied by nausea, vomiting, and in severe cases, convulsions, unconsciousness, and even respiratory and cardiac arrest, and about 10-15% of patients die before reaching the hospital. About 10-15% of patients die before reaching the hospital. The diagnosis can be made by cranial CT, which shows a high density in the subarachnoid space; when the bleeding is small, CT may not be diagnostic, and sometimes lumbar puncture is required to confirm the diagnosis.
Treatment of SAH
The treatment of SAH is a combination of symptomatic and etiologic therapy. Symptomatic treatment includes dehydration medication to lower cranial pressure, hemostasis, sedation, analgesia, prevention and control of cerebrovascular spasm, nutritional support and functional rehabilitation. Etiological treatment is the most important, i.e., to understand what causes SAH first, and then give targeted treatment. The cause of SAH can be determined by non-invasive diagnostic means such as MRA (magnetic resonance angiography) and CTA (tomography angiography), but the gold standard for confirming the cause is still invasive digital subtraction cerebral angiography, the so-called DSA examination. This test requires a femoral artery puncture cannula to deliver a catheter into the aortic arch and then up into the cerebral artery, through which a contrast agent is injected into the cerebral artery, so that the vascular images of the brain are clearly and dynamically displayed on the X-ray fluoroscopy screen, and a negative film can be developed by intercepting the static image. Through DSA examination, doctors can clarify the nature, location, morphology and severity of the underlying cerebrovascular lesion causing SAH, and use it to formulate the next treatment plan.
If the SAH is caused by a ruptured intracranial aneurysm, emergency surgery is required to “destroy” the aneurysm. Why is emergency treatment necessary? According to statistics, 20% of patients with ruptured aneurysm SAH will have rebleeding within 2 weeks after the first bleeding, and the residual death rate is as high as 60-80% within one year, so we describe aneurysm as an “untimely bomb” in the brain, and removing this untimely bomb as soon as possible can effectively prevent its The removal of this untimely bomb as soon as possible can effectively prevent it from “re-exploding”. There are two surgical approaches for aneurysms: craniotomy and interventional embolization, which requires evidence-based medicine and doctor-patient communication.
If SAH is caused by rupture of cerebrovascular malformation, the cerebrovascular malformation can be treated surgically after the hemorrhage is absorbed and the condition is stabilized. Because the chance of rebleeding in the near future after bleeding from cerebrovascular malformation is not very high, the rebleeding rate is 4~18% within 1 year, so it is possible to operate electively without emergency surgery as in the case of aneurysm. Cerebrovascular malformation of the same surgical methods are craniotomy and interventional embolization, small vascular malformations less than 4cm in diameter can also choose gamma knife treatment – a gamma ray stereotactic radiation therapy. Large vascular malformations are difficult to eradicate at once with interventional embolization and often require multiple embolizations or a combination of Gamma Knife treatment.
If SAH is caused by smog, surgical treatment such as temporal muscle patching and vascular bypass can be considered later. Smoggy disease was first discovered by the Japanese and is also known as Moyamoya disease, a cerebrovascular disease with unexplained progressive occlusion of the cerebral arteries, so named because it appears on cerebral angiography as a smog-like compensatory proliferation of capillaries at the base of the skull. It does not fall under the scope of interventional treatment.
Some SAH cannot find an etiology, i.e., the cerebral angiographic findings are normal. These patients often have a benign course and are not prone to rebleeding later. However, it must be noted that occasionally false-negative cerebral angiography results occur, i.e., organic cerebrovascular lesions are missed due to inexperienced physicians, less advanced hardware equipment, or thrombosis within the aneurysm.
Finally, it is important to emphasize ruptured aneurysm SAH, which is the third most common cerebrovascular accident after cerebral infarction and hypertensive cerebral hemorrhage. The process of ruptured aneurysm bleeding is very brief and transient. The rupture of an aneurysm causes a rapid increase in brain pressure, and the pressure gradient inside and outside the aneurysm immediately reaches equilibrium, so that blood no longer flows outward and a thrombus soon forms at the rupture site, which provides an opportunity to treat the survivor as soon as possible. However, this thrombus is very unstable and will dissolve in a short period of time (about 2 weeks), causing rebleeding of the aneurysm, which will increase the mortality rate exponentially. Therefore, once aneurysmal SAH is clearly identified, surgical treatment should be performed as early as possible.