Neurology Flashcards
How does a CN1 lesion present?
- Anosia (uni or bilateral) aka loss of smell
What are the common causes of CN1 lesion? (4)
- Trauma
- Respiratory tract infection
- Meningitis
- Frontal lobe tumour
How does a CN2 lesion present?
- Low acuity/visual field defect
- optic disc problems
What can cause a CN2 lesion?
- MS
- giant cell arteritis
- diabetes
- optic chiasm compression
- glaucoma
How does a CN3 lesion present?
- Eyes go ‘down and out’ due to unopposed action of CN4 and 6
What can cause CN3 lesion?
- MS
- DM
- Giant cell arteritis
- Posterior communicating arterty aneurysm
How does a CN4 lesion present?
- Diplopia on looking down
What can cause CN4 lesion?
- usually due to trauma to orbit
- rare
How does a CN6 lesion present?
- Horizontal diplopia on looking out
What causes CN6 lesion?
- MS
- Pontine stroke
How does a CN5 lesion present?
- Motor = open jaw deviating to side of lesion
- Sensory = V1/2/3 pathology/ diminished corneal reflex
What can cause a CN5 lesion?
- Motor = rare but stroke
- Sensory = trigeminal neuralgia or herpes zoster
How would a CN7 lesion present?
- Droop and weakness
- Loss of taste in anterior 2/3 tongue
What can cause a CN7 lesion?
- Bell’s Palsy
- Otitis media
- Skull fracture
- stroke
What is Bell’s Palsy?
- Paralysis of facial nerve which causes muscular weakness on one side of the face
What can cause Bell’s Palsy?
- TB
- HIV
- Polio
- Sarcoid
What can happen to eyes and ears in Bell’s palsy?
- Eyes rotate up and out when try to close
- Ears hypersensitive
What is a dermatome?
An area of skin supplied by a single spinal nerve
What is a myotome?
A volume of muscle supplied by a single spinal nerve
Describe the common carotid artery.
- R = arises from brachiocephalic trunk
- L = arises from aortic arch
- No branches
- Bifurcate at approx. C3-4
What are the 4 lobes of the cortex?
- Frontal
- Parietal
- Occipital
- Temporal
What are the two “feeder” arteries into the Circle of Willis?
- Internal carotid
- Vertebral arteries
What is the role of the frontal lobe?
- Voluntary movement on opposite side of body
- Controls speech and writing
- Thought processes, reasoning and memory
What is the role of the parietal lobe?
- Receives and interprets sensations e.g. pain, pressure, size and body awareness
What is the role of the temporal lobe?
- Understanding spoken word
- Memory and emotion
What is the role of the occipital lobe?
- Understanding visual images and meaning of written words
What is the role of the cerebellum?
- Co-ordinates movement and balance
What would injury to the cerebellum lead to? (5)
- Movements that are slow and uncordinated
- Asynergia = loss of coordination
- Intention tremor = movement tremor
- Hypotonia = weak muscles
- Nystagmus = abnormal eye movement
What is the function of the brainstem?
- Special senses
- regulates consciousness
- autonomic regulation of body
What is schizophrenia?
- Described as type of psychosis
- Positive and negative symptoms
- Mental health disorder
What are some symptoms of schizophrenia?
- Positive include delusions, thought disorder, hallucinations
- Negative include withdrawn, unemotional, unable to carry on with everyday activities
What are the 6 muscles that move the eyeball?
- Lateral rectus
- Medial rectus
- Superior rectus
- Inferior rectus
- Superior oblique
- Inferior oblique
What is the role of the levator palpebrae superioris?
- Lifts the upper eyelid
- Loss of function gives ptosis
What is the function of the 4 rectus muscles?
- Lateral = pulls laterally (abduction)
- Medial = pulls medially (adduction)
- Superior = pulls up and medially and rotates
- Inferior = pulls down and medially and rotates
Describe the semi-circular canals.
- Accelerometers
- sit in the petrous part of temporal bone
- the fluid present in the canal stays where it is
What is defective outer or middle ear loss called?
- Conductive hearing loss
What is defective inner ear hearing loss called?
- Sensorineural hearing loss
What are the two types of stress?
- Eustress = good. Positive which is beneficial and motivating
- Distress = bad. Negative which is damaging and harmful
What is the difference in acute and chronic stress?
- Acute = response to novel situation experience as danger. Examples include illness, noise, short-term danger
- Chronic = repeated exposure. Examples include physical illness, unemployment, poverty
Describe the HPA axis.
- Perceived danger
- Hypothalamus
- Pituitary
- Adrenal cortex
- Stress response
What are physiological examples of stress responses
- Breathing rapidly, increasing oxygen
- Blood flow increase
- Increase HR and BP
- Sweating
What are the symptoms of PTSD?
- Flashbacks/nightmares
- Sweating
- Nausea
- Insomnia
- Impaired concentration
What is allostatic load?
- Refers to cumulative exposure to stressors, leads to ‘wearing out’
What is the difference between acute and chronic pain?
- Acute = pain less than 12 weeks
- Chronic = continuous pain over 12 weeks
What is nociceptive pain?
- Arises from actual or threatened damage and is due to activation of nociceptors
Describe the spinothalamic tract
- Sensory carries pain, temperature and crude touch from the body
Describe the trigemino-thalamic tract
- Sensory pathway carrying pain, temperature and touch from the face/neck/head
- Contributions from trigeminal, facial, vagus and CNVI
Describe the insular cortex. (2)
- Plays a role in perception, motor control and self-awareness
- Degree of pain is judged here
Describe the cingulate cortex. (2)
- Linked with limbic system, so associated with emotion formation and processing
- Maintains connections with pain processing areas
What are some examples of symptoms of depression?
- Low mood, anhedonia, low energy
- Cognitive symptoms include guilt, hopelessness and suicidal thoughts
What is the function of the amygdala? (3)
- Receives highly processed information
- Emotional memory
- Mediates fear response
What are the types of head injury?
- Non-missile (blunt)
- Missile, where penetration of skull or brain
What are examples of focal damage through a blunt head trauma?
- Scalp laceration
- ## Skull fracture
What would a skull fracture lead to?
- Increased risk of haematoma
- Infection
- Aerocele (air getting in)
What type of surfaces cause linear fractures?
- Flat surfaces
- One fracture line will not cross a pre-existing fracture line
What is an extradural haematoma? (4)
- Between inner surface of skull and dura
- Associated with skull fracture
- Occurs slowly over hours
- Classified with how deep into the brain meninges it is
Which artery is at danger in a skull fracture?
- Middle meningeal artery as it is slow bleeding
What is a subdural haematoma? (3)
- Between dura mater and arachnoid mater
- usually due to tears in bridging veins
- Slow constant bleed, which can be acute or chronic
What are causes of a subarachnoid haematoma? (3)
- Contusion/lacerations
- Base of skull fracture
- Vertebral artery rupture
What are superficial cerebral and cerebellar haemorrhages due to?
- Severe contusion
- leaves ‘bruising’
What are deep cerebral and cerebellar haemorrhages due to?
- Diffuse axonal injury or vascular injury
What are infections in the brain due to?
- Skull fracture
What is the damage mechanism for accelerated or decelerated damage?
- Force to head causes DIFFERENTIAL MOVEMENT
- contusion
- traction on bridging veins can cause subdural haemorrhage
What is the difference between “coup” and “contre coup”?
- Coup is at the site of impact
- Contre coup is away from the site of impact. If you bouncem the brain goes backwards
What is a contusion?
- Superficial “bruise” of the brain
What is a laceration?
- When contusion is severe enough that it tears the pia mater
What is a diffuse axonal injury?
- Syndrome of widespread axonal damage
- can be caused by a variety of processes
What is a traumatic axonal injury?
- involves acceleration and deceleration of the head
- If mild, will recover but with variable severity
- If severe, unconscious from impact and can be severely disabled
What is a diffuse vascular injury?
- Results in near immediate death
- generally the more important vessels and axons
What is brain swelling?
- Occurs in 75% patients
- Leads to increased intracranial pressure
What can herniation be due to?
- Bleeding
- Brain swelling
What is hypoxia-ischaemia?
- Insufficient blood flow
- Can cause infarction and ischaemic damage
- Heart finds it heart to keep BP up
- Can be widespread or confined