Week 1 Flashcards
Brain makes up __% of body weight but __% of cardiac output?
- 2%
- 15%
Can brain cells store nutrients & have alternatives to aerobic respiration?
NO
What happens when blood flow is restricted to the brain?
Unconsciousness follows within 15 seconds
When does nerve cell damage/death start after blood flow to the brain stops?
3 mins
At the core of the brain focal ischaemic lesions are ______, at the edge (penumbra) ______ can occur?
- Irreversible
- Recovery
What are the 4 arteries supplying the brain?
- x2 Internal carotid arteries (ant)
2. x2 Vertebral arteries (post)
Where does the vertebral artery branch from?
1st part of the subclavian artery
Whats the location of the vertebral artery?
- Ascends through foramina in transverse processes (upper 6 cervical)
- Enters skull via foramen magnum
- Pierces meninges to enter subarachnoid space
How/where is the Basilar artery formed?
Union of the 2 vertebral arteries at the lower border of the ventral pons
How does the basilar artery terminate?
Dividing into 2 posterior cerebral arteries
List all 7 vertebral arteries which join to form the basilar artery?
- Posterior cerebral
- Superior cerebellar
- Pontine
- Labyrinthine
- Anterior inferior cerebellar
- Posterior inferior cerebellar
- Anterior spinal artery
What are the 3 arteries which supply the cerebellum?
they also supply parts of the brainstem
- Superior cerebellar
- Anterior inferior cerebellar
- Posterior inferior cerebellar
Where does the internal carotid artery begin?
Bifurcation of the common carotid artery
How does the internal carotid artery ascend?
- In neck & passes into skull through carotid canal in temporal bone
- Passes through cavernous sinus
- Pierces the dura at anterior clinoid process & enters subarachnoid space
What does the internal carotid artery divide into?
Anterior & middle cerebral arteries
What is the Carotid Syphon?
Curve in the cavernous segment (C4)
What is the Circle of Willis?
Anastomosing system of arteries at the base of the brain
What are the 6 arteries anastomosing in the circle of Willis?
- Anterior cerebral
- Anterior communicating
- Posterior communicating
- Posterior cerebral
- Internal carotid
- Middle cerebral
What 4 structures is the circle of Willis closely related to?
- Cerebral peduncles
- Optic chiasma
- Pituitary stalk
- Oculomotor nerves
What does the anterior cerebral artery (ACA) supply?
Structures near the midline
Where does the middle cerebral artery (MCA) pass through?
Lateral fissure & emerges onto lateral surface of cerebral hemisphere
What are the Lenticulostriate (lateral striate) arteries?
Group of small arteries which arise at the commencement of the middle cerebral artery
What are the symptoms for Middle Cerebral artery (MCA) stroke?
- Contralateral hemiplegia (paralysis)
- Hemi-sensory loss
- Contralateral hemianopia (visual pathway)
- Dysphasia (dominant hemisphere)
- Anosognosia (neglect/impaired perception defects, non dominant hemisphere)
What are the symptoms for Anterior Cerebral artery (ACA) stroke?
- Weak contralateral leg & arm
- Sensory loss in contralateral foot & leg
- Gait apraxia (difficulty in walking movement)
- Akinetic mutism (paucity of movement and speech)
- Urinary incontinence
What are the symptoms for Posterior Cerebral artery stroke?
- Contralateral Homonymous hemianopia (same sided visual loss on opposite side of lesion)
- Macula sparing
What is the blood supply of basal ganglia & internal capsule?
- Medial striate branches of ACA
- Lateral striate branches of MCA
- Anterior choroidal
What is the blood supply of the thalamus?
Branches of PCA/ posterior communicating
What is the blood supply of the midbrain?
PCA/ posterior communicating
What is the blood supply of the Pons?
- Basilar
- Superior cerebellar (SCA)
- Anterior inferior cerebellar (AICA)
What is the blood supply of the medulla?
- Vertebral/anterior spinal
- Inferior cerebellar
- Basilar
- Posterior spinal
Where is the arterial lesion for signs of right sided tongue deviation & left sided weakness?
Right medial medulla
Where does the circle of willis lie?
Subarachnoid space
What can a berry aneurysm in the circle of willis cause?
Subarachnoid haemorrhage
Where is a frequent site for a berry aneurysm in the circle of willis?
Posterior communicating artery arises from the ICA
What forms the diffusion barrier in the BBB?
Endothelial cell + tight junction
Is depression just “feeling blue”?
- NO
- Its not a sign of weakness and people cannot merely “pull themselves together” and get better
What does the World Health Organisation say about depression?
“Common mental disorder. Globally, more than 300 million people of all ages suffer from depression”
What is Major depression?
- Unipolar depression (old term)
- Loss of interest & enjoyment
- Low mood
- Emotional, cognitive, physical & behavioural symptoms
What is Dysthymia?
Long-term chronic symptoms that do not disable but keep one from functioning well or feeling good
What is Bipolar disorder?
- Called manic-depressive illness
- Severe highs (mania) & lows (depression)
What are the 3 key symptoms for assessing depression via the criteria in DSM-IV (nice guidelines)
- Persistent sadness or low mood
- Marker loss of interest or pleasure
- At least 1 of these, most days, most of the time for at least 2weeks
What are the other associated symptoms you ask about when the patient has any one of the 3 key symptoms in DSM-IV?
- Disturbed sleep
- Appetite/weight
- Fatigue/loss of energy
- Agitation/slowing of movements
- Poor concentration/indecisiveness
- Worthlessness/excessive inappropriate guilt
- Suicidal thoughts/acts
What else do you ask about when assessing depression & its severity via DSM-IV?
- Duration
- Associated disability
- Past & Family history of mood disorders
- Availability of social support
What is CG90 (?
NICE clinical guidelines appendix C for assessing depression & its severity
What’s the definition of Anhedonia?
Loss of interest or pleasure in hobbies & activities that were once enjoyed
What are the cognitive symptoms of depression?
- Negative view of self
- Poor concentration & reduced attention, difficulty making decisions
- Mental slowing or rumination
- Suicidal ideation
What are the biological/behavioural symptoms of depression?
- Lowered appetite, weight loss/gain
- Insomnia, early-morning, feeling worse in morning
- Low energy, fatigue
- Loss of libido
- Social withdrawal
What 2 questions (according to CG90) should you ask people who may have depression?
- “During the last month, have you often been bothered by feeling down, depressed or hopeless?”
- “During the last month, have you often been bothered by having little interest or pleasure in doing things?”
What are risk factors for depression (combination of factors)?
- Genetic & family
- Early life experiences
- Stressful life events
- Gender
What evidence is there for genetic & family factors of depression?
- “~3 fold increase in 1st-degtree relatives of individuals with major depression”
- Twin & adoption studies show genetic component
What study shows there is a genetic & family factor for depression?
Fava & Kendler (2000)
What early life experiences can increase a person’s vulnerability to depression (Fava & Kendler, 2000)
- Poor parent-child relationship
- Marital discord & divorce
- Neglect
- Physical & sexual abuse
What did the interview that Brown & Harris (1978) did with Women in Camberwell show?
- 15-20% of women were mod-severely depressed with no treatment
- Rate 3x higher in those who lost their mother before 11 & also experienced severe recent loss
What 3 factors (according to Brown & Harris) contribute to low self-esteem, sense of mastery & hopelessness?
- Lack of intimate, supportive relationships
- Lack of employment
- Household >3 children
Most depressions are preceded by a __________?
Recent stressful event
According to Fava & Kendler, how does gene-by-environment interaction affect depression?
Genetic factors influence overall risk of illness BUT also influence sensitivity of individuals
Do genes on their own cause depression?
NO
What factors contribute to why major depression seems to be more common in women?
- They express/report symptoms more
- Hormones
- Early life stress (sexual abuse)
- Additional stresses (responsibilities home/work)
What does NICE guideline CG91 say about depression & chronic illness?
- 2x / 3x more common with chronic physical health problem
- Occurs in 20% with chronic physical health problem
- Can both cause & exacerbate depression
- Depression can be a risk factor in range of physical illnesses
What factors in medical patents cause depression to more regularly appear?
- Life threatening conditions
- Unpleasant treatments
- Pain & disability
- Low social support t& adverse social circumstances
- Personal/family history
- Alcohol/substance abuse
Why can assessment of depression in chronically ill patients be problematic?
- Signs of depression (fatigue, insomnia, weight loss) also expression of disease
- Drug treatments can cause depression (hypertensives, corticosteroids, chemo)
What is the relation of depression & coronary heart disease (CHD)?
- Major depression associated with 2- to 4 fold increase cardiac mortality in MI patients
- Depressed without cardiac disease have increased risk of cardiac mortality
- Higher prevalence of smoking, diabetes, reduced exercise
What can depression trigger which contributes to CHD?
Dysregulation of neurohormonal system (cortisol & catecholamine secretion)
What are the 4 treatment options for depression?
- Pharmacological
- Psychological
- Exercise (mild/mod depression)
- Electroconvulsive (severe & complex depression)
What is the model for treatment of depression?
Stepped care model (page 16 on CG90)
What are 3 different low-intensity psychosocial interventions for depression?
- Individual guided self-help based on the principles of cognitive behavioural therapy (CBT)
- Computerised cognitive behavioural therapy (CCBT)
- Structured group physical activity programme
What is Cognitive behavioural therapy (CBT)?
- Short-term psychological treatment
- Role of thinking in how we feel & what we do
- Identifying & challenging unhealthy modes of thinking
What 2 psychological interventions should people with depression & risk of relapse be offered?
- Individual CBT (relapsed despite antidepressants)
2. Mindfulness-based cognitive therapy (currently well with >3 previous episodes)
In high income countries _ x as many men die of suicide than women.
In low & middle income, ratio _ men to women.
- 3x
- 1.5
What are the 2 myths about suicide?
- People who talk of suicide do not do it
2. Talking openly about topic of suicide puts “the idea in their head”
What are 4 tips to talking to someone who is suicidal?
- Address motivation for suicide & develop alternatives
- Listen non-judgementally
- Don’t be critical
- Don’t say “cheer up”, “pull yourself together”
What are the 3 NICE guidelines 90, page 15 for taking a history from someone who there is a risk of self-harm or suicide?
- Assess whether the person has adequate social support & is aware of sources of help
- Arrange help appropriate to the level of risk (primary care staff/specialist)
- Advise the person to seek further help if the situation deteriorates.”
Describe the dura mater?
- Tough & fibrous
- Bridges crevices
- Attached to skull
- Includes branches of middle meningeal artery
Describe Arachnoid mater?
- Delicate
- Sealed bag for CSF
- Bridges crevices
Describe Arachnoid trabeculae?
“Ropes” across subarachnoid space
Where is the Cerebral artery branch embedded in?
Pia mater
Describe Pia mater?
- Delicate
- Dips into crevices
What are spaces filled with CSF called?
Cisterns
Name the 4 different cisterns in the brain?
- Superior cistern
- Cisterna magna (cerebellomedullaris)
- Cisterna pontis
- Interpeduncular cistern
What ligaments come off the pia mater?
Denticulate ligaments
Why are roots long at cord end?
Because spinal column grows faster & longer than spinal cord (S1 root exits well below its origin in cord)
Where can you safely perform a lumbar puncture to sample CSF?
Subarachnoid space well below L2, usually L4/5
Describe the veins which drain the brain?
- Thin walls, no valves
- Lie in subarachnoid space
- Drain into cranial venous sinuses
What are the 2 groups of veins which drain the brain?
- External cerebral veins
2. Internal cerebral veins
Name the 3 sinuses that the great cerebral vein drains into?
- Transverse sinus
- Straight sinus
- Superior sagital sinus
Whats another name for the great cerebral vein?
Vein of Galen
What are the 5 deep veins above the thalamus?
- Thalamostriate vein
- Choroidal vein
- Internal cerebral vein
- Basal vein
- Great cerebral vein
What are the 3 different dural folds called inside the skull?
- Falx cerbri
- Tentorium cerebelli
- Tentorial notch
What is the rate of cerebrospinal fluid production?
150ml produced at 0.5ml/min & turns over 4x a day
What are the different ventricles of the brain?
- Lateral x2
- Interventricular foramen
- 3rd ventricle
- 4th ventricle
- Aqueduct
Hows the CSF formed?
In choroid plexus and flows out of ventricle system into subarachnoid space via apertures in 4th ventricle
What are the 3 apertures in the 4th ventricle?
1 median
2 lateral
What are Arachnoid granulation’s?
Projections of the arachnoid membrane into the dural sinuses that allow CSF entrance from subarachnoid space into venous system (superior sagittal sinus)
What is a Subdural haemorrhage?
- Haematoma, usually associated with traumatic brain injury.
- Blood gathers between inner layer of dura mater & arachnoid mater
How does hydrocephalus occur?
Blocked transport, or overproduction/blocked absorption of CSF which dilate the ventricles and cause brain compression
What is a medical treatment for hydrocephalus?
Shunt from frontal horn of lateral ventricle into the peritoneum
What does CT stand for?
Computerised Tomography
How much more radiation is there in a CT head with contrast compared to a normal chest x-ray?
200x more than Chest X-ray
What are the technical points of viewing a CT image?
- Caudal view: looking from patients feet (left on image is the right on patient)
- More sulci, white bolbs and atrophy as you get older (age effect)
- Diagonal image plane to avoid too much exposure to the eyes
- Image is generated by absorption
What is greyer in CT scan- white/grey matter?
White matter
What colour does bone and air appear on CT scan?
- BONE: white
- AIR: black
Describe the ABC’S system for head CT & MRI interpretation?
A- adequacy, alignment, artifact
B- bones, blood, brain
C- cisterns, ventricles
S- subcutaneous, surfaces, soft tissue
What to look for at “A” in the ABC’S system for CT interpretation?
- Alignment: see if its symmetrical, midline shift
- Artifact: see if there is any metal ruining image or motion when taking the image
What to look for at “B” in the ABC’S system for CT interpretation?
- Bones: fractures
- Blood: extradural/subdural/subarachinoid haematoma
- Brain: look for any diffuse axonal injury, infarction, oedema, masses
What to look for at “C” in the ABC’S system for CT interpretation?
Cisterns & Ventricles: atrophy, hydrocephalus, oedema, intracranial hypertension, infection
What to look for at “S” in the ABC’S system for CT interpretation?
Subcutaneous, Surface & Soft tissue: subdural haematoma, cerebral oedema, compression, lesions, meningioma
What are the technical points of head/neck MRI?
- Caudal view: looking from patients feet (left on image is the right on patient)
- Age effect
- Any plane
- Image generated by emission
When (3) can you not perform a head/neck MRI?
- Pacemaker
- Cochlear implant
- Metal around eye/head
How do you know when the MRI image is taken at T1 or T2?
- T1: spinal fluid is black
- T2: spinal fluid is white
What are the 8 different MRI variants?
- Diffusion weighted
- Apparent diffusion coefficient (ADC)
- Fluid attenuated inversion recovery (FLAIR)
- Gradient echo imaging (GRE)
- Echo planar imaging (EPI)
- Perfusion
- Angiography
- Functional spectrography
What does SPECT stand for?
Single Photon emission tomography
What does PET stand for?
Positron emission tomography
What is the Anterolateral system composed of (3)?
- Spinothalamic pathways
- Spinomesencephalic pathway
- Spinoreticular pathway
What are the 2 pathways in the Spinothalamic pathways called?
- Neospinothalamic (discriminating)
2. Paliospinothalamic (undiscriminating)
What is the purpose of the thalamus in the brainstem?
- Connects reciprocally with every part of the cortex
- Receives “input” from all of cortex
- “Gatekeeper” for sensory info
- Control arousal & somnolence of cortex
What is the purpose of the Mesencephalon (midbrain)?
- Reflexes associated with hearing & vision
- Fine control of skeletal movement through red nucleus
- Habituation & motivation via dopaminergic centres
- Contains cerebral peduncles (ascending/descending info)
- Contains periaquaductal grey matter (pain modulator)
Where does the Neospinothalamic tract terminate in the anterolateral system?
Ventral posterior lateral nucleus (VPL) which is somatotropic so there is locational discrimination
Where does Paliospinothalamic tract terminate in the anterolateral system?
Dorsomedial (DM) & intra laminar areas which provide generalised location of pain
What is the Neospinothalamic tract mainly composed of?
Aδ fibres (sharp pain)
What is the Paliospinothalamic tract mainly composed of?
C fibres (dull pain)