Intracranial bleeding Flashcards
(40 cards)
What is the pressure in the skull? What is considered pathological?
- Normally ≤15 mmHg in adults
- Pathologic intracranial hypertension (ICH) is present at pressures ≥20 mmHg
What are symptoms of increased intracranial pressure?
- Headache, vomiting, pupillary changes, impaired eye movement, depressed global consciousness, decrease of sensory/motor function, changes in vital signs
- Symptoms in children are different: We will find bulging fontanels, cranial suture separation, increase of head circumference, high pitched crying
What can the neurosurgeon can do in case of an increase of intracranial pressure due to trauma or hematoma?
We can measure the ICP and perform a ventriculostomy, to reach the ventricular system with a catheter with 2 aims: to subtract more CSF and decrease the ICP, and the 2nd is to measure the ICP directly from the skull.
Ventriculostomy
Artificially created opening between the cerebral ventricles and either a sterile extracranial space (drainage bag) or the intracranial subarachnoid space (ventriculocisternostomy)
When there is no more CSF to subtract, the swelling is out of control, what can the neurosurgeon do?
Decompressive craniotomy
What is a decompressive craniotomy
Neurosurgical procedure in which part of the skull is removed to allow a swelling or herniating brain room to expand without being squeezed
What can cause SAH?
Berry aneurysm (at bifurcation of vessels in circle of Willis)
Trauma (dissecting
aneurysm)
Atherosclerosis (fusiform
aneurysm)
Infection (mycotic
aneurysm)
Arteriovenous malformation
(AVM)
What differentiates a normal arterial wall from one that has developed an anurism?
- The normal arterial wall is composed of endothelium, internal elastic membrane (part of tunica intima), a muscular tunica media and adventitia
- In the wall of aneurysm there is disrupted anatomy (disrupted resistance of the wall) – we have endothelium, no internal elastic lamina and media muscularis layer, just a fibro-hyaline tissue followed by the adventitia
Where do aneurysms form within the brain?
- Aneurysms grow in the middle of a bifurcation of intracranial vessels
- Most intracranial aneurysms (approximately 85 percent) are located in the anterior circulation, predominantly on the circle of Willis
- ACA (30%), Posterior communicating artery (25%), Middle cerebral artery (20%)
- Common sites include the junction of the anterior communicating artery with the anterior cerebral artery, the junction of the posterior communicating artery with the internal carotid artery, and the bifurcation of the middle cerebral artery
What are the different types of aneurysms?
They include:
- Saccular aneurysms
- Fusiform aneurysm
- Giant aneurysm (the diameter is >2.5 cm, can involve more than one artery)
- Mycotic aneurysms usually result from infected emboli due to infective endocarditis (caused by infected artery wall, these are not located in Circle of Willis, but in the distal part of the cranial vessels)
What can an aneurysm be divided into morphologically?
Neck, sack, and dome in saccular aneurysm
What are risk factors for intracranial aneurysm formation?
Include:
1) Smoking – one of the main risk factors
2) High blood pressure/hypertension
3) Alcohol consumption
3) Congenital resulting from inborn abnormality in arterial wall
4) Family history of brain aneurysms – SAH history in the same family seems to increase the risk of new SAH in the same family. Subjects with “Familial Intracranial Aneurysms (FIA)” run a risk >4.2x higher compared to general population to have an unruptured intracranial aneurysm
5) Age > 40y/o
6) Gender – women have an increased incidence compared to men (ratio 3:2)
7) Other disorders (ex: Ehlers-Danlos Syndrome, Polycystic Kidney Disease, Marfan Syndrome, Fibromuscular Dysplasia (FMD))
8) Presence of Arteriovenous Malformations (AVM)
9) Drug use (particularly cocaine)
10) Infection
What are risk factors for intracranial aneurysm rupture?
1) Smoking
2) High blood pressure/hypertension
3) Physical exertion (due to increased blood pressure)
What can risk factors for intracranial aneurysm be divided into?
Modifiable and non modifiable
What are modifiable risk factors for intracranial aneurysms?
1) High cholesterol level
2) Alcohol abuse
3) Arterial hypertension
4) Atherosclerosis
5) Cigarette smoke
6) Oral contraceptive
What are non modifiable risk factors for intracranial aneurysms?
1) Female sex
2) Genetic link for subarachnoid hemorrhage (SAH)
a. Autosomal dominant polycystic kidney disease (ADPCKD)
What are causes of subarachnoid hemorrhage?
- Most subarachnoid hemorrhages (SAHs) are caused by ruptured intracranial saccular (berry) aneurysms
- Around 20 percent of SAH cases are nonaneurysmal
What is the cause of hemorrhagic stroke?
50/50 split between intracerebral and subarachnoid hemorrhage
What are saccular aneurysms?
Thin-walled protrusions from the intracranial arteries that are composed of a very thin or absent tunica media, and an absent or severely fragmented internal elastic lamina (typical aneurysm formed by neck + sac + dome)
What are fusiform aneurysms?
- Fusiform aneurysms consist of enlargement or dilatation of the entire circumference of the involved vessel that may in part be formed due to atherosclerosis
- The entire vessel is altered, so there is no neck or dome, but just a dilation of the entire vessel with a fusiform shape
How are intracranial aneurysms formed?
- It is believed that most intracranial aneurysms develop over a short period of hours, days, or weeks, attaining a size allowed by the elasticity limits of the aneurysmal wall; at this point, the aneurysm either ruptures or undergoes stabilization and hardening
- Those aneurysms that do not rupture gain significant tensile strength due to compensatory hardening with formation of excessive collagen. Therefore, the likelihood of rupture decreases unless the size of the aneurysm is fairly large at the time of initial stabilization
Clinical manifestations of SAH
- Sudden-onset, severe headache typically described as the “worst headache of my life” (thunderclap headache)
- Decreased global consciousness
- Vomiting
- Neck pain or stiffness
SAH diagnosis
- First step in the diagnosis of SAH is noncontrast head CT
- A lumbar puncture should be done if the head CT is negative (mandatory if there is a strong suspicion of SAH despite a normal head CT)
- If both tests are negative, they effectively eliminate the diagnosis of SAH as long as both tests are performed within two weeks of the event
- CTA (site, morphology, may allow planning of treatment without DSA)
- Digital subtraction angiography (type of malformation, the location, morphology, and vasospasm)
CSF findings in SAH
Elevated opening pressure, an elevated RBC count that does not diminish from CSF tube 1 to tube 4, and xanthochromia (presence of bilirubin in CSF)
