Subarachnoid hemorrhage

The subarachnoid hemorrhage (from Greek ἀραχνοειδής, " the spider-like meningitis ," derived, see Spiderskin; SAB ) is a pathological events in the central nervous system. It is characterized by free blood in the brain with fluid ( CSF) -filled subarachnoid space.

Cause of this special form of stroke is in most cases the bursting of an arterial vessel due to a deformity. The state of the free circulation leads to irritation of the blood vessels of the brain and meninges. A build-up of cerebrospinal fluid with increase in pressure in the skull ( hydrocephalus ) is typical of a complicated course.

The subarachnoid hemorrhage is associated with sudden heaviest headache and neck stiffness. It can cause short-term disturbance of consciousness, but also to severe permanent brain dysfunction.

• 3.1 Warning bleeding
• 3.2 classification of severity

• 4.1 Computed Tomography
• 4.2 angiography
• 4.3 sonography
• 4.4 lumbar puncture

• 5.1 First Aid
• 5.2 Prevention of rebleeding
• 5.3 Prevention and treatment of vasospasm
• 5.4 Treatment of Hydrocephalus

Disease incidence, prognosis

The subarachnoid hemorrhage belongs to the sphere of apoplexy (stroke). She is responsible for 6 to 10 percent of strokes. According to the latest situation one can assume that in developed countries about 10 people per 100,000 population per year suffer a subarachnoid hemorrhage (incidence). This corresponds to approximately 10,000 new patients per year in Germany. Worldwide, the incidence varies quite widely between 2 (China ) and 22 ( Finland) persons per 100,000 population per year.

The age distribution of spontaneous subarachnoid hemorrhage differs from the age distribution of ischemic stroke. Most commonly SAH occurs at the age of 50 years. However, it can occur at any age.

Women are affected slightly more often than men.

40 percent of patients die within the first 30 days after the event. Of the survivors, 25 to 50 percent remain severely disabled. The mortality rate of recurrent bleeding (see " clinical picture and classification of severity " ) is 50 to 70 percent.

Definition

Anatomical bases

The subarachnoid space ( cavum subarachnoid ) surrounds the brain and spinal cord as a fluid- filled cushion, in which the brain literally in the cerebrospinal fluid, cerebrospinal fluid, floats. The brain is thus supported so that it is largely protected from damage due to vibration.

The walls of the subarachnoid space outside form the spider skin (Latin: arachnoid ) and inside the soft meninges ( pia mater ).

The arachnoid is the dura mater ( dura mater ) on the inside. It extends across the surface of the brain, but draws, with the exception of the interhemispheric gap ( longitudinal cerebral fissure ), not in the individual brain furrows ( sulci ) into it. From the arachnoid off small vascularized outgrowths evert ( arachnoid granulations, Pacchioni granulations ) into the filled with venous blood sinus of the dura mater. They serve the regulation of cerebrospinal fluid and remove excess CSF on. The arachnoid is associated with fine threads with the pia mater.

The pia mater is located directly on the brain surface and follows her in every furrow.

The subarachnoid space surrounding the brain and spinal cord and is home to the supplying blood vessels (arteries and veins ). There is a narrow gap, which is extended in some places (for example in the area of the base of the brain ) to cisterns. In the extensions of the subarachnoid space and in the interhemispheric fissure blood accumulates and is then often with imaging techniques ( computed tomography ) of typical patterns recognizable.

Cause, risks and history of bleeding

A bleeding in otherwise healthy brain usually arises at particular vulnerability of the vascular system. These are particularly aneurysms. It is to sac-like widening of arterial vessel walls, leading to a wall thinning in the affected area.

In most cases, aneurysms are congenital. They occur mainly in places then increased load through the blood stream to. In particular, bifurcations of arteries are at risk due to the formation of vortices and similar hemodynamic factors. They will relate mainly vascular segments that are altered by atherosclerosis or inflammatory arterial diseases. Significantly rare aneurysms can also be purchased in the course of life. A clustering of cases is found in fibromuscular dysplasia, polycystic kidney disease, as well as connective tissue diseases such as Marfan syndrome the.

In case of a subarachnoid hemorrhage, this thin wall portion of the burden of an otherwise well tolerated increase in blood pressure was no longer holds and the vessel bursts at this point.

Mainly vessels are affected, which form the circle of Willis ( Willis ). This vascular system at the base of the brain connects the largest arteries supplying the brain with each other.

Rupture ( tearing ) of aneurysms of the base of the brain are at 80 % of the disease cause of subarachnoid hemorrhage; also occur angiomas (benign vascular malformations ) and arteriovenous malformations. In 5-10 % of cases, no bleeding source found.

The bleeding usually occur after situations with short-term increase in blood pressure on, about defecation ( discontinuation of the chair ), physical exertion, heavy lifting or intercourse. However, ruptured aneurysms can also be done in complete peace and spontaneously. Subarachnoid hemorrhages occur more frequently in the elderly and in pregnancies. As proven risk factors for rupture of an elevated blood pressure and smoking are recognized.

In contrast to Erstblutung that is known only by their results, recurrent bleeding a causal therapy are available. Avoiding these recurrent bleeding is the goal of rapid diagnostics and surgical therapy.

In some cases, accidents lead ( craniocerebral trauma ) to a subarachnoid hemorrhage. It is, however, currently not say with certainty whether the cause of the bleeding is not in tearing abnormality ( eg aneurysm) is also here.

Complications

The feared consequences of subarachnoid hemorrhage are:

Rebleeding

The most severe subarachnoid hemorrhage based on multiple events. Profuse bleeding usually go smaller advance; any bleeding may follow. The cause of these recurrent bleeding is due to that the vascular malformation, which has led to the previous hemorrhage, continues to exist, provided that no such therapy was carried out in fact. About 35% of post-operative bleeding occur in the first three hours, up to 49 % within the first six hours. 60 % of patients who suffered a hemorrhage, died in the first three months. Most frequently, rebleeding within the first three days after the initial event. Their frequency is optimal medical care at around 7%.

Vasospasm

The subarachnoid hemorrhage leads to irritation of blood vessels. The result is an active constriction ( vasospasm or vessel ) of the affected vessels (particularly mediated by locally secreted vasoactive substances such as serotonin or prostaglandin ). So that there is a reduced supply of the brain tissue with oxygen. The sequence can be one part, an ischemic stroke, which performs a function of time and the size of the affected area to permanent damage to brain function. On the other hand lead later onset, generalized vasospasm to the insufficient supply of the entire brain.

The vasospasm is the determining factor influencing the outcome of treatment. He has a prevalence of 40 to 60 percent to at subarachnoid hemorrhage. 1/3 of the spasms will only have its consequences visible ( DIND = delayed ischemic neurological deficit ). The early detection of these conditions is transcranial Doppler ultrasonography ( see below). Vasospasm usually occur within 4 to 14 days - with a frequent peak between day 8 and 12 - after the initial event on.

The cause of vasospasm is not yet clear. Firstly, it is attributed to the action of substances which are released during the breakdown of red blood cells ( erythrocytes). These substances should vasoconstrictor ( pressor ) to healthy blood vessels act ( endothelins, prostaglandins). But it is also an effect on the meaning of the blockade of vasodilator ( vasodilating ) substances ( substance P ) is conceivable. An important role is played by the released hemoglobin, which binds NO necessary for the maintenance of normal vascular caliber. This property is referred to as the NO scavenging. The resulting NO deficiency contributes to the narrowing of the arteries. On the other hand also local inflammatory reactions be held responsible, for which the activation of the complement speaks.

Additional bleeding ( so-called parenchymatous hemorrhage ) If the blood penetrates the pia mater ( pia mater ) (such as a partial tear ), then originates in the brain tissue. The disease is further complicated by permanent damage more likely and larger.

Hydrocephalus

Due to the malfunction of the Pacchioni granulations ( arachnoid granulations ), the closure of the aqueduct and the exit points of the fourth ventricle, it can be used to build-up of cerebrospinal fluid (hydrocephalus, " water on the brain " ) can occur. Since the cerebrospinal fluid is modeled continuously, there is a hand to a mismatch between the space requirement of brain mass, normal blood volume and cerebral spinal fluid and on the other hand the space of the skull. This increases the pressure in the cranial cavity, which can cause (for example by jamming of parts of the brain at the folds [ falx ] the dura mater) to complex brain damage. Depending on the cause, a distinction is a aresorptiven ( Pacchioni granulations ) and occlusive ( aqueduct, exit points of the fourth ventricle ) hydrocephalus.

Hydrocephalus occurs immediately after subarachnoid hemorrhage sometimes, but sometimes days later. He is very well represented in the computer tomogram (CT). Since hydrocephalus is very dangerous, immediately a CT has to be made in this diagnosis. Hydrocephalus develops within the first 3 weeks after the initial event.

Hyponatremia

In 30% of patients experience an increased sodium excretion in a deficiency of sodium in the blood ( hyponatremia). The cause is probably the mechanical irritation of the hypothalamus, resulting in increased secretion of antidiuretic hormone ( SIADH ). With values ​​below 125 mmol / l serum occur reversible neurological symptoms. Antidiuretic hormone secretion leads to Na and H2O reabsorption in the kidney and thus Dilutional.

The problem is in the treatment of hyponatremia. A too rapid equalization of the levels of sodium can lead to central pontine myelinolysis with loss of nerve tissue in the area of the brain stem structures. Greatest risk for the development of hyponatremia between the 4th and 14th day after the initial event.

Clinical picture and classification of severity

The three cardinal symptoms of subarachnoid hemorrhage are:

The brain itself is not sensitive to pain, but the arteries and the meninges. The typical sudden, perceived as a devastating headache can be explained by the rupture of the vessel and the irritation of the neighboring vessels and the meninges.

The pain can also manifest itself in other places. So he shows up in rare cases in the thoracic, spine, or even the legs. Probably for the spread of blood in the subarachnoid space charge.

The disturbances of consciousness and unconsciousness, however, are rather non-specific reactions of the brain to the stimulus. Deficits of cranial nerves or focal ( related to a specific region of the brain) seizures are rare in the acute situation. However, such variations are triggers occasional misdiagnosis.

The neck stiffness, as a third symptom is an expression of irritation of the meninges. The dura mater of the neck region reacts painfully on strain, which can be determined by passive tilt of the head. In severe cases there is a spontaneous head hyperextension neck forward and back hollow formation ( opisthotonos ).

A visual impairment is observed when Terson syndrome, a vitreous hemorrhage that affects 10 to 20 percent of patients.

In a subarachnoid hemorrhage also occur frequently on cardiac symptoms. ECG changes and cardiac arrhythmias are often caused neurogenic, meaning that the damage to the brain causes defective regulation of heart action. Above average often bleeding into the heart muscle and heart attacks are found. This is believed to malfunction of the hypothalamus, a major regulatory center in the brain. These changes lead to an increased release of catecholamines, which causes a narrowing of blood vessels. In cardiac muscle, they will lead to a reduced supply of oxygen and the aforementioned consequences.

Warning bleeding

Approximately 25 percent of patients with severe subarachnoid hemorrhage and bleeding warning can be detected. The affected patients usually report of sudden, extremely severe headache ("like never before " ), which may also be anxiety- triggering often. After a short time they go into a lasting head or neck pain that will not be perceived threatening in general. The pain is accompanied by a relative lack of stiffness of the neck. This type of bleeding warning corresponds to the degree I according to Hunt and Hess ( see table below).

The problem with this warning bleeding consists primarily in the correct recognition. Are often the complaints of patients, but misinterpreted by doctors as migraine, extraordinary psychological stress or even as spine pain and also mishandled. Within 14 days usually followed by a much heavier recurrent subarachnoid hemorrhage.

Early and correctly identified, the patient could be helped timely and efficient in many cases.

Classification of severity

The classification of severity of subarachnoid hemorrhage takes place according to the classification of the WFNS ( World Federation of Neurological Surgeons ) or after HUNT and HESS (see table), which correlates well with the development of the disease.

The Glasgow Coma Scale is a classification of severity in traumatic brain injury. It is advantageous to face both severity classifications, as the Glasgow Coma Scale used very often in contrast to the WFNS in emergency and thus the correlation is obvious.

The decisive factor for the severity of subarachnoid hemorrhage is the duration of unconsciousness. In most cases, the patient awakening after a shorter time. However, 15 to 20 percent of the patients remain in a coma.

Diagnostics

Basis of the diagnostics is the assessment of the clinical picture, including the severity assessment, as with any other disease.

As technical tools have become the imaging method

• Computed tomography and
• Angiography

Proven.

In addition, the

• Ultrasonography ( transcranial Doppler as a method ) and the
• Lumbar puncture

Established. The two last-mentioned methods provide functional descriptions.

Computed tomography

Computed tomography (CT ) of the head ( cCT ) is currently the fastest method for the diagnosis of subarachnoid hemorrhage. It has the highest sensitivity (100 percent on the first day of bleeding ) and specificity of all imaging modalities and is under modern conditions - using a spiral CT with low loads - for the patient quickly and safely feasible. In 70 percent of cases can be already in a first recording, the source of bleeding suspect. CT examinations should be carried out immediately. In derartigem procedure rapid therapeutic action is made possible because a rebleeding might be fatal and must therefore be avoided. The classification according to Fisher allowed a classification of computed tomography morphology:

• Grade 1: No evidence of bleeding
• Grade 2: subarachnoid of less than 1 mm in width
• Grade 3: subarachnoid of more than 1 mm wide, but no Ventrikeleinbruch
• Grade 4: Subarachnoid hemorrhage of any width with Ventrikeleinbruch ( IVH ) or expansion into the brain parenchyma

Angiography

Cerebral angiography is performed as a standard method; it is a bound of contrast agent method of vascular imaging using X-rays. At high sensitivity, it must also be carried out in the first hours since then the aneurysm to be closed as a bleeding site in order to achieve a therapeutic benefit. This has long been proven method applies in its special form, the digital subtraction angiography, the virtual angiography method of computer tomography and magnetic resonance in the diagnostic accuracy still superior. However, the latter are usually available faster and less stressful for the patient.

Sonography

The aim of the assessment of vasospasm transcranial Doppler sonography serves. The method is an ultrasonic method as well as free from side effects. You should come in the first ten days after the acute bleeding daily used to recognize vasospasm, which initially symptom-free run ( DIND - see above).

In the Doppler method, the flow rate of the blood is determined based on the reflection from the moving blood cells. While flow velocities below 100 cm / s are considered normal, values ​​above 160 cm / s are considered to be critical.

Lumbar puncture

The classic lumbar puncture with cerebrospinal fluid samples is highly sensitive. After minutes is detectable at a subarachnoid hemorrhage in the brain, blood in the cerebrospinal fluid in the lumbar spine. This finding proves the subarachnoid purely qualitative, the localization of the bleeding is not so determined.

In this invasive method is the risk of passing through the manipulation ( leak in the lumbar dura mater ), and in an uncontrolled manner CSF lost their consequences. As a result, it may cause a negative pressure in the ventricles. This pressure loss syndrome is associated with other opportunities damage of the brain. A lumbar puncture should therefore only take place if the CT is no result, then the patient's symptoms but clear evidence of subarachnoid hemorrhage.

You should also remember that during the lumbar puncture itself may be small hemorrhages occur, but these are insignificant. However, you can color the bloody CSF and subarachnoid hemorrhage pretend. The red blood cells (erythrocytes) decay in the CSF and therefore give the other at her bound hemoglobin -free. This process is dependent on the time elapsed. Erythrocytes, which are released in case of subarachnoid hemorrhage in the skull are no longer detectable in the cerebrospinal fluid of Lumbalbereiches, but their dyes. To distinguish blood from a ruptured brain vessel of fresh blood (formed at the puncture ), the bloody CSF should be centrifuged in order to remove all cellular components can. Should the Liquor then still have discoloration (called xanthochromic supernatant), the diagnosis would be confirmed.

Therapy

First aid

In the following only treatment guidelines are described that meet in their scientific sophistication to the criteria of evidence-based medicine or have been included in the guidelines of the medical and scientific societies. So there are those methods that improve the survival and outcome of affected patients demonstrated and effective. Set the current state of medical action routine dar.

The subarachnoid hemorrhage usually requires observation and treatment methods of intensive care medicine.

Primary therapy follows the non-specific objectives of the stabilization of the general condition. On the part of the respiratory hypercapnia should be avoided ( CO2 increase in the blood due to inadequate breathing), as it can lead to brain pressure increase. Therefore, the decision for a ventilator is made generous.

Targeted methods pursue the objectives:

Prevention of rebleeding

It is the clipping and coiling have proven that. The choice of method depends not only on the availability especially on the specific circumstances of each aneurysm (availability, form, size of the aneurysm neck, the origin of vessels) from:

Both methods, clipping or coiling, usually done in the first 72 hours after hemorrhage or only 10 days later because the blood vessels in the meantime are particularly sensitive and the development of vasospasm is likely.

The coiling provides the advantage that you can advance to the patient gently to the affected vessel sites, without, must be opened depending on the location of the aneurysm, the skull and brain tissue injured or removed. It is also suitable for the prophylaxis of asymptomatic aneurysms.

Prevention and treatment of vasospasm

In addition to basic intensive care treatment guidelines, such as positive fluid balance, hypervolemia, avoidance of hypotensive blood pressure and low levels of sodium, the use of the calcium antagonist nimodipine has proven to be highly evident.

Precapillary sphincters relax calcium antagonists, ie muscle strong parts of arterial vessels. So you counteract vasospasm in subarachnoid hemorrhage. The calcium antagonist nimodipine is enriched by its particularly high lipid solubility strongly in the brain and is therefore suitable for the treatment of subarachnoid hemorrhage. Because vasospasm when the blood flow is disturbed at the site of action of the drug, nimodipine can but only in terms of prevention exert its effect in principle against vasoconstriction.

Should nimodipine both in mild cases ( HUNT and HESS I) and in the severe cases are given. The disadvantage is its antihypertensive effect, especially on intravenous administration. If this side effect not be controllable, it can be dispensed with in favor of an adequate blood pressure value to nimodipine.

Note: nimodipine is in recent times in the criticism. Reasons are:

• The widening effect of the drug in the area of the cerebral vessels can not be directly detected.
• In the area of ​​pulmonary vessels occurs Shuntbildungen. This short-circuiting of the functional circuit worsen pulmonary function.
• The reduction in blood pressure is highly pronounced. This contradicts the principles of 3H- therapy listed below, which will be given preference.

Nimodipine is currently attributed on the basis of survival analysis alone a neuroprotective effect, which is the reason for the assessment of the high evidence in the treatment of subarachnoid hemorrhage. The disadvantages of nimodipine are considered to be too severe, so it is no longer used in several centers.

In clinical trials are endothelin -1 receptor antagonists such as Clazosentan.

For the treatment of vasospasm 3H - therapy (hypertensive hypervolemic hemodilution, Triple -H therapy) is suitable with good evidence:

The 3H- therapy aims to improve the impaired blood flow to the damaged brain tissue by means of a high internal vessel throughput. For this purpose, the flow ( hypervolemia ) and the internal pressure of the vessels increases (hypertension) and the viscosity ( resistance) of the blood by reducing the volume of erythrocytes ( " blood thinners " ( hemodilution ) ) decreased. The process requires strict monitoring to overhydration of the organism with effects on gas exchange ( respiratory, pulmonary function ) and circulatory system is kept within reasonable limits.

In special cases, offers the transluminal balloon angioplasty. This is an invasive method, in which the vessel from the inside is spread via catheter technique. Since the containers must be easily accessible to the catheter, the method is suitable only in a few cases ( distal internal carotid artery, vertebral artery and basilar artery ). The transluminal balloon angioplasty, which is also used in coronary heart disease, is performed in the case of subarachnoid hemorrhage in only a few specialized centers.

Recent innovative approaches pursue a Vasospasmusprophylaxe by so-called ' Clot Removal '. This rinsing procedure be applied to early wash out the blood, as an essential triggering factor of vasospasm.

Treatment of Hydrocephalus

Besides outright admission to intensive care with assurance of gas exchange ( ventilation) is the construction of a ventricular catheter method of choice. With the catheter excess cerebrospinal fluid from the ventricular system (brain chambers ) is discharged to the outside.

30% of patients also suffer later with hydrocephalus. In these cases, the liquor can be discharged via a permanently implanted shunt system, for example the peritoneum.