Subarachnoid Hemorrhage (SAH) — Symptoms, Diagnosis and Treatment

Marfan´s syndrome

Table of Contents

Image: “Subarachnoid hemorrhage after aneurysm rupture” by openi. License: CC BY 2.0

Definition of Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a type of stroke caused by bleeding into the cranial and/or spinal subarachnoid space surrounding the brain. SAH may occur spontaneously or after trauma.

Image: “Layers Covering the Brain. This image was donated by Blausen Medical. Please visit our website to see more medical illustrations and animations.” by Bruce Blaus License: CC BY 3.0

Classification of Subarachnoid Hemorrhage

In non-traumatic SAH cases, we can distinguish:

Aneurysmal SAH
Perimesencephalic SAH
Non-perimesencephalic basal SAH
SAH of other non-traumatic causes (such as arteriovenous malformation, arteritis, intracranial arterial dissection, venous thrombosis, cerebral amyloid angiopathy, cerebral vasoconstriction syndrome and cocaine abuse)

Epidemiology of Subarachnoid Hemorrhage

Occurrence of a subarachnoid hemorrhage

The annual prevalence rate in Central Europe and the USA is 6 – 9 per 100,000 people. The peak age for patients with a spontaneous (non-traumatic) SAH is about 50 years. Women, on average, are affected more often than men. Subarachnoid Hemorrhage is the most common cause of death related to a stroke.

Etiology of Subarachnoid Hemorrhage

Causes of subarachnoid hemorrhage

The main cause of SAH is the rupture of a meningeal vessel. 85 % of SAH cases occur as a result of the circulation of an intracranial arterial aneurysm. In 25 % of reported cases, multiple aneurysms are responsible for SAH. They occur mainly during physical exertion, but can also happen during rest. The localizations of aneurysms are distributed to certain vessels in a descending order of frequency as follows:

40 %: posterior communicating artery
30 %: carotid siphon and MCA miscarriage
20 %: bifurcation of the middle cerebral artery
10 %: basilar artery, PICA miscarriage

Acquired aneurysms mainly occur within the framework of arteriosclerosis.

General risk factors	Risk factors in family history
Hypertension	Adult autosomal dominant polycystic kidney disease
Smoking	Coarctation of the aorta
Excessive alcohol consumption	Ehlers-Danlos IV
Sympathomimetic drugs	Marfan´s syndrome

Pathogenesis of Subarachnoid Hemorrhage

Origin and development of subarachnoid hemorrhage

Intracranial sequence after aneurysm rupture occurs, is as follows: rupture of an aneurysm ⇒ bleeding into the subarachnoid space ⇒ acute increase of intracranial pressure or reduction of the perfusion pressure ⇒ reduced cerebral blood flow ⇒ initial loss of consciousness ⇒ reactive hyperemia ⇒ possible recovery of consciousness

Consequences of blood leakage:

Adherence of basal cisterns with the disability of fluid passage (risk of hydrocephalus)
Vasospasm in the arteries of the pia mater (cerebral under-perfusion)

Symptoms and Clinic of Subarachnoid Hemorrhage

General symptoms

The main symptoms of a subarachnoid hemorrhage are the following:

Acute onset, violent, destructive headache (“thunderclap headache”)
Nausea
Vomiting
Meningism
Vigilance discrepancies (transient up to comatose)

Specific symptoms

Depending on the localization of the bleeding, specific cranial nerve palsies may occur:

Aneurysm of the posterior communicating artery: third nerve palsy
Aneurysm of the middle cerebral artery: hemiplegia
Aneurysm of the basilar artery: brain stem or cerebellar symptomatology

Image: “Circle of Willis” by Phil Schatz. Licence: CC BY 4.0

Warning bleeding

Approximately one quarter of patients with severe SAH demonstrate the so-called “warning bleeding”. Patients are affected by a sudden onset of a very severe headache, which later turns into a persistent head and neck pain after a short time (grade I Hunt and Hess). If this warning bleeding is detected early, a more efficient treatment for patients is possible.

SAH scale by Hunt and Hess

The classification according to Hunt and Hess divides the severity of SAH into 5 stages. In the following table, they are shown in relation to the Glasgow Coma Scale.

Degree	Symptoms	Glasgow Coma Scale (GCS)
I	Slight headache, neck stiffness	15
II	Moderate to severe headache, neck stiffness, cranial nerve palsies	13 – 14
III	Somnolence, lighter focal symptoms	13 – 14
IV	Stupor, severe neurological and autonomic disorders	7 – 12
V	Coma, stretch synergies	3 – 6

Complications of Subarachnoid Hemorrhage

Image: “Subhyaloid macular hemorrhage. Note the layered blood (black arrow) and breakthrough bleeding (white arrow)” by openi. License: CC BY 2.0

Frequently, it results to cardiac arrhythmias and the complex symptom, Terson syndrome. In the case of Terson syndrome, bleeding occurs in the vitreous body as well as in the retina due to a build-up of pressure in the retinal veins. A direct correlation between severity and expansion of cerebral hemorrhage is detected.

Diagnosis of Subarachnoid Hemorrhage

A case of SAH suspicion warrants a medical emergency. Immediate hospitalization is necessary in order to carry out further diagnostics. A groundbreaking symptom is a strong thunderclap headache (a patient always describes it as ” the worst ever ”).

Imaging techniques

Image: “Aneurysma der A. cerebri media: Computertomographie, 3D-Rekonstruktion (Volumen rendering)” by Hellerhoff. License: CC BY-SA 3.0

In the first 24 hours, CCT (cranial computed tomography) demonstrates a sensitivity of 95 %, which is far more common and available than the CMRI (cranial magnetic resonance imaging). If the results are positive, hyperdense material is visible in basal cisterns and outer CSF spaces.

CMRI with flair sequences, DSA (digital subtraction angiography) and CT/MR angiography are also useful to locate the source of bleeding.

CSF analysis

Image: “Xanthochromer Liquor” by Dschafar. License: CC0 1.0

If findings in the imaging are negative, the cerebrospinal fluid is examined by lumbar puncture. A visual inspection of the supernatant (CSF tubes against a white background) is sufficient for the exclusion or evidence of xanthochromia.

Bloody: fresh bleeding
Xanthochromic: yellowish color of fluid due to increased protein content

Monitoring

Patients with SAH should be supervised or subdued to intensive care procedures in a special monitoring unit, in order to detect complications at an early stage and treat them.

According to guidelines, it is recommended to supervise the following parameters in the monitoring procedure, in order to primarily detect vasospasms and hypervolemia:

Daily transcranial Doppler sonography
Fluid balance
Blood pressure monitoring
Measurements of central venous pressure

Under invasive neuromonitoring, we have measurements of: tissue oxygenation, blood flow, temperature or extracellular molecular concentrations.

Differential Diagnosis of Subarachnoid Hemorrhage

Diseases similar to subarachnoid hemorrhage

Symptoms	Important differential diagnoses
Headache, increased intracranial pressure	Decompensated occlusive hydrocephalus, insufficient fluid shunt, migraine, cluster headache
Altered consciousness, vomiting	Diabetes mellitus, liver disease, intoxication
Meningism	Meningitis, meningoencephalitis

Therapy for Subarachnoid Hemorrhage

Treatment of subarachnoid hemorrhage

Conservative measures

Stabilization of vital functions
Sedation
Monitoring of volume and electrolyte balance
Immobilization and avoidance of oppressive actions (poss. use of laxatives and antiemetics)
Neuroprotection: treatment of hyperglycemia, hypoglycemia, hyponatremia and fever
Hydrocephalus: In the case of an acute symptomatic hydrocephalus, fluid effluence is indicated; in the chronic course, the construction of a ventriculoperitoneal or ventriculoatrial shunt
Anticonvulsant therapy for epileptic symptoms
Subcutaneous thromboprophylaxis with low-molecular-weight heparins according to the supply of the aneurysm
No prophylactic administration of glucocorticoids and antifibrinolytics

Neurosurgical measures

If treatment of a ruptured aneurysm is justified and can be dealt with, this should be done within the first 72 hours (before the vasospasm onset). Two methods for aneurysm exclusion are mainly used:

Endovascular coiling: metal spirals (coils) are placed inside the aneurysm using a catheter, after which it is closed
Microneurosurgical clipping of the ruptured aneurysm: the aneurysm is closed off at its base from the outside

Image:Hirngefäßaneurysma, Zustand nach clipping” by Uwe Thormann. License: CC BY-SA 3.0

Next, the blood pressure must be set accordingly (adapted to the normal blood pressure range of the patient). In the case with normotensive patients, it should be in the target range of 120 – 140 mmHg; with hypertensive patients – at the level of 130 – 160 mmHg.

Very high blood pressure can encourage early re-occurrence of bleeding; very low pressure may put the patient in danger of cerebral perfusion pressure. The target value is a middle arterial pressure of 60 – 90 mmHg.

Prognosis of Subarachnoid Hemorrhage

Lethality and chances of recovery for patients with subarachnoid hemorrhage

If a patient has survived an aneurysm rupture, the risk of the closed aneurysm to re-rupture is 4 % on the first day and then 1 – 2 % per day within the first month. Mortality rate among such patients is relatively high; 35 % of them die within the first 30 days after the incident.

One third of those affected die during in-patient treatment or suffer for a long time from its consequences. The previous state of health before SAH or the state of mild discrepancies is reached only by one-third of all the patients after the incident.

Prevention of Subarachnoid Hemorrhage

Influential risk factors include smoking, hypertension and alcohol abuse. As far as an aneurysmal SAH is concerned, patients should be advised regarding their lifestyle.

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