Stroke and neuroanantomy Flashcards
UMN signs
Tone increased Power reduced Reflexes increased Plantar upgoing Clonus present
LMN signs
Tone decreased Power reduced Reflexes none Plantars down Clonus Nil
Frontal lobe functions
Primary motor cortex Personality Primitive reflexes Dysphasia expressive if dominant Anosmia Optic nerve compression Gait apraxia
Parietal lobe functions
Primary sensory cortex Gerstmann syndrome - dominant, acalculia, agraphia, L-R disorientation, finger agnosia (ALF) Sensory, visual and spatail inattention Construction and dressing apraxia Lower quandrantanopia
Temporal lobe functions
Primary auditory cortex
Receptive dysphasia (dominant)
Memory loss
Upper quandrantanopia
Occipital lobe functions
Homonymous hemanopia
Anton’s syndrome (individual denies their blindness)
Alexia
Blood supply to internal capsule?
Lenticulostriate arteries which are penetrating branches from the MCA M1
Course of the corticospinal tract?
Primary motor cortex through internal capsule Crus cerebri in midbrain Pons Medulla Crosses over at Lower medulla Spine
Function of the thalamus? Rules of 4
Anterior nuclei involved with language and memory function
Lateral nuclei involved mainly with motor and sensory function
Medial nuclei important for maintaining arousal and memory
Posterior nuclei involved mainly with visual function
Course of spinothalamic tract?
Sensory nerve -> dorsal root ganglion of the spine and crosses over immediately Medulla Pons Midbrain Thalamus Primary sensory cortex
Course of dorsal column tract (vibration, light touch, propioception)
Senosry nerve -> dorsal root ganglion -> dorsal column
Lower medulla -> crosse over at medial leminiscus
Medulla
Pons
Midbrsin
Thalamus
Brainstem. Rule of 4s?
4 cranial nerves in the medulla, 4 in the pons and 4 above the pons
There are 4 structures in the midline beginning with M
4 structures to the side beginning with S
4 motor nuclei that are midline are those that divide equally into 12 (except for 1 and 2) i.e. 3,4,6,12
The 4 medial structures are?
Motor pathway
Medial lemniscus
Medial longitudinal fasciculus and
Motor nucleus
4 side structures are?
Spinocerebellar pathways
Spinothalamic
Sensory nucleus of 5th CN
Sympathetic tract
Blood supply of the brainstem
Superior cerebellar artery
Anterior inferior cerebellar artery
Posterior inferior cerebellar artery
Occlusion of unilateral verterbrals can cause lateral brainstem syndromes
What are the lacunar syndromes (5 types)?
- Pure motor
- 33-50% of lacunar strokes
- posterior limb of internal capsule or anterior portion of pons - Ataxic hemiparesis
- posterior limb of internal capsule
- combination of cerebellar and motor symptoms
- usually affects the legs more than the arms hence it is known as homolateral ataxia - Dysarthria/Clumsy hand
- Basis pontis - Pure sensory
- Thalamic infarct - Mixed sensorimotor
- thalamus and posterior limb of internal capsule
Post stroke BP care. What are the limits?
tPA - BP 180/105 and then lower
No tPA - BP 220/120 and then lower
Increased systemic BP will improve blood flow tot he cerebral infarct via collateral blood vessels
Cause of anterior circulation stroke?
Intracranial stenosis
Severe carotid stenosis
Aortic arch
AF
Cause of posterior circulation stroke?
Atheroembolic disease
AF
What is the single most important modifiable RF for ischaemic and haemorhhagic stroke?
HT
Goal 120-140 mmHg
ACE/ARB and thiazide diuretic have better evidence
When do you give antiplatelets in stroke?
Post CTB and 24 hrs post t-PA
Aspirin, clopidogrel and asasantin are all appropriate 1st line therapy
what is the reversal agent for Dabigatran?
Idarucizumab (Praxbind)
Dabigatran and Rivaroxiban had higher rates of GI bleed compared with warfarin. T/F
True
Apixiban 5 mg BD demonstrated what benefits?
Superior to warfarin
Decreased rates of all cause bleeding
Decreased rates if ICH
Mortality benefit
Intracranial atherscerlosis. Tx? Risk of recurrence
Tx - aspirin and aggressive medical Mx
No difference between aspirin and warfarin with more complications on warfarin
No role for intracranial stenting due to increasing complications
Recurence is 12-14% in 2 years despite antiplatelets
Higher rates amongst Asians
ICH. Location of bleed and corresponding aetiology?
Intracerebral
- basal ganglia = HTN
- Lobar = amyloid angiopathy
- Pontine = HTN, vascular malformation
- Cerebellar = HTN, vascular malformation, tumour
Intraventricular
- Primary = tumours and malformations
- secondary = ICH, SAH
What is the Mx of an ICH stroke?
Aim BP 140/80 mmHg
AICA stroke. Areas affected.
CN V, VII and VIII
Inner ear, lateral pons, middle cerebellar peduncle and anterior inferior cerebellum
pseudo-labrynthitis
PICA stroke. Areas affected?
CN VI, VIII, IX, X
Lateral medullary syndrome
Acute vestibular syndrome without hearing loss or pseudo-neuritis
Head impulse test. Positive in which lesions?
Peripheral lesions
Asent in central lesions
How does a dissection present?
How do you differentiate between a vertebral and carotid artery dissection?
H/O trauma, headache, neck pain and Horner’s syndrome.
Both will present with Horner’s syndrome.
Dizziness is associated with vertebral artery dissection.
Cervical nerves exit above or below the vertebra?
Spinal nerves?
Exit above
Except for C8, exits above T1
Spinal nerves exit below the vertebra starting with T1
Grey matter:
Anterior horn
Posterior horn
Anterior horn:
lower motor neurons as well as interneurons that help to fine tune the motor output
Posterior horn:
Secondary sensory neurons and interneurons receiving input from the dorsal root ganglia (primary sensory neurons)
Outermost layer serves as superficial sensations including pain, temp and light touch.
Cerebral venous thrombosis. Epid Patho Presentation Mx
Epid:
Increased risk with hormonal Tx and post partum
12 in 100 000 pregnancies
Patho:
Thrombosis leads to increased capillary and venous pressure -> ischaemia, haemmorhage
Sinus obstruction leads to poor CSF absorption -> raised ICP
Presentation: Raised ICP 90% - subacute headache, visual changes, papilloedema Focal neurological abnormalities 44% Seizures 33% Encephalopathy - usually elderly pts
Mx:
Anticoagulation
- Heparin infusion or therapeutic clexane
- transition to warfarin
- 3-6 months in provoked and 6-12 months in unprovoked
Fibronolysis in severe cases
Raised ICP
- acetazolamide
- may need Sx intervention if severe
Hemicranectomy
OCP and stroke. What are the risk?
Slightly higher risk in older age groups.
No difference between 2nd and 3rd generation OCP.
No increased risk with low oestrodial.
