NP ch14: Cerebrovascular diseases Flashcards
(88 cards)
What does FAST mean in reference to strokes.
F: Face drooping
A: Arm weakness
S: Speech difficulty
T: Time to call ambulance
What are some other sudden onset symptoms of a stroke?
Headache
Loss of mental abilities
Loss of strength or paralysis
Sensory disorders
Confusion, disorientation, consciousness
What is the optimal clinical care for someone with a stroke arriving at hospital?
Optimal clinical care involves patients being admitted to a stroke unit. They are treated according evidence-based protocols that are implemented by a multidisciplinary team.
How do doctors distinguish the type of stroke? Why do they need to do this?
- A CT scan is required to make the distinction between haemorrhage and infarct
- Blood shows up white on a normal CT
- In the case of infarcts, the patient usually remains conscious, whereas decline in consciousness is more often seen after brain haemorrhage.
It is important to distinguish the type of stroke as one treatment for an infarct would be aspirin (blood thinner), but in a haemorrhage, thinning the blood would kill the patient faster.
What are the two main risk factors for stroke?
Age >65
Hypertension (High blood pressure)
(There are other risk factors, but we will get into those in specific stroke types)
How common are strokes?
- Worldwide: stroke every 2 seconds, 17 million times a year
- Strokes are second leading cause of death in people over 60 years of age
- Incidence varies widely between countries, and is related to age and standard quality of life.
- About 40,000 first strokes in the Netherlands every year
Is stroke incidence increasing?
- Yes,
- Total number of people living with the consequences of strokes is increasing
- Prevalence of strokes is increasing over the years due to ageing population
- However, young strokes (18-50 years) are also becoming more common
- Between 2005 and 2025, absolute number of people who have a stroke will increase by 40%
- However due to improved prevention and new treatments, the number of deaths via stroke between 1980 and 2005 has decreased by 40%
What are the two types of Cerebrovascular accidents? How common are they?
-
Ischaemic stroke / cerebral infarct (80%)
- Obstruction blocks blood flow to part of the brain
- Oxygen deprivation causes irreversible brain damage
-
Haemorrhagic stroke/cerebral haemorrhage (20%)
- Weakened vessel wall ruptures, causing bleeding in the brain
What is an infarct?
Infarcts are localized tissue death caused by lack of blood supply
What causes an infarct?
- Infarcts can be the result of an embolism (blood clot) causing a temporary obstruction of an artery.
- Embolism consists of coagulated blood platelets (thrombi) or fragments of calcifications in the vascular wall
- Infarct can be the result of local stenosis of a blood vessel.
- Stenosis (Narrowing of blood vessel) commonly occurs in the smaller and deep perforating arterioles.
- Infarcts can also be caused by inadequate blood flow (perfusion) to the brain
Where can infarcts occur? How common is an infarct in a location?
- Middle cerebral artery (MCA)
- Occurs 80% of the time
- Posterior cerebral artery (PCA)
- 5-10% of infarct cases occurs here
- Anterior cerebral artery (ACA)
- Prevalence of isolated infarcts is 0.6-3%
Show them figure 14.1 alex
What is a Transient Ischaemic attack (TIA)?
An ischaemic stroke in which the neurological symptoms disappear with 24 hours.
Most TIAs cause symptoms for a considerably shorter period of time, usually less than 30 minutes.
What are some side effects of TIAs?
- Despite loss of function being by definition temporary, persistent (subtle) cognitive disorders are described among TIA patients.
- Patients are also at increased risk of stroke
- At least 30% of TIA patients will suffer from a stroke within the next 5 years
What are the risk factors of an infarct?
- Age is the main risk factor
-
Atherosclerosis is a second important risk factor. It is the thickening/hardening of the arteries.
- It’s caused by smoking, hypertension, diabetes, obesity, or hypercholesterolaemia (High cholesterol levels)
What are the relative risks of risk factors for infarcts? (dont memorise this, but understand it)
The book provided a table of the main risk factors for stroke and the relative risk of an infarct, meaning someone with this factor is x times more likely to suffer an infarct than someone without
- Age >75 years vs 55-64 = 5
- High blood pressure = 4-6
- Atrial fibrillation (irregular heart beat) = 4
- Diabetes = 2-6
- Physical inactivity = 3
- Smoking = 2
- Obesity = 2
- Ischemic cardiac disease = 2
What are some acute treatments?
Treatments have to be within 4 hours of onset, and after the CT scan
-
Thrombolysis: injecting drug to dissolve the clot
- This increases the likelihood of a positive outcome, but the effects are possibly limited with regard to the cognitive effects.
- Thrombectomy: removal of the brain clot with a catheter
What are the consequences of an infarct in the MCA?
MCA → frontal, temporal, and parietal areas of the brain
- Memory issues are most common (When the medial temporal lobe is affected)
- Apraxia: Inability to carry out meaningful movements and gestures
- E.g. using a fork to eat soup
- Aphasia: Language dominant hemisphere (left)
- Neglect: Parietotemporal lobe (right) → not aware of the stimuli on the contralesional site
This is a summary she gave in the lecture, I’ll go over the consequences in more detail by effect later, but this list is a short goody
What are the consequences of an infarct in the PCA
PCA - Occipital and temporal lobes
Disturbances in perception
- Hemianopsia
- Visual agnosia
- Prosopagnosia
- (There are more, this a short list)
What are the consequences of an infarct in the ACA?
ACA → dorsal and medial parts of of the frontal and parietal lobes
- Executive functions and social cognitions
What is the most common cause of brain haemorrhages?
50% of BHs are caused by long-term exposure to hypertension
What is the most common type of brain haemorrhage (BH)?
An intracerebral haemorrhage (ICH).
Many haemorrhages occur in areas of the basal nuclei, usually as a result of the rupturing of deeper arterioles
What are other causes of ICHs?
- Arteriovenous malformation (Like what happened to the expert by experience)
- Inflammation of the vascular wall
- Coagulopathy
- Brain tumour
- Lobar bleeding is more superficial and may be caused by amyloid angiopathy (degenerative disorder found in the elderly)
- Haemorrhagic infarct, which is primarily a blockage but also bleeding because of damage to the vascular wall
- Trauma can cause a haematoma (TBI chapter)
What acute treatment is used for ICHs?
Acute treatment is often conservative, the objective is to prevent important brain areas from becoming compressed
Medication to reduce swelling
Surgery to relieve pressure on the brain is done in more severe cases
Treatment focus on prevention of re-bleeding
What is another type of BH that doesn’t occur in the brain?
Subarachnoid haemorrhage (SAH), in which the haemorrhage doesn’t occur in the brain but in the subarachnoid space.
SAH causes sudden and extremely severe headaches, followed by neck stiffness after a few hours