03-10-23 - Neurological Case Studies - Interactive Lecture Flashcards
Often where is the clue for the location for a neurological lesion?
When are neurological examinations conducted?
What are 3 questions that should be asked with neurological lesions?
- The clue is often in the history for neurological lesions
- A neurological examination is done to confirm or rule out these impressions and clarify uncertainties
- 3 questions that should be asked with neurological lesions:
1) Where is the lesion located?
* Localising symptoms or signs present?
* Functional anatomy, including blood supply.
2) What type of lesion?
* Speed of onset of symptoms.
* The natural history of the lesion (disease process); Progressive, regressive, remitting-relapsing
* A lesion restricted to the nervous system/ part of a systemic illness (more than one system involved).
3) What is the treatment?
* Will be taught in lectures throughout the semester and in later parts of your clinical training
What are 5 different types of conditions, starting with fastest to slowest speed of onset?
- 5 different types of conditions, starting with fastest to slowest speed of onset:
1) Vascular
* Older, male. Sudden onset (minutes).
* Vascular risk factors present.
* E.g OCP (progesterone only), pregnancy, smoking, hypertension, atrial fibrillation, Atherosclerosis, diabetes, hypercholesterolaemia
2) Infectious
* Onset of symptoms could be acute (hours) or subacute (days).
* Systemic inflammatory features present e.g. fever
* Calor, dolor, rubor, and tumor: Heat, pain, redness, and swelling. The four classical signs of inflammation
* Infections that affect the CNS could be arterial, bacterial, viral, fungal, and more commonly, microbacterial
3) Autoimmune
* Young, female.
* Possibly relapsing – remitting course (e.g. multiple sclerosis).
* Maybe part of a systemic illness (vasculitis).
* Usually characterized by relapses and remissions
4) Tumour
* Slow growing, gradual, weeks-years.
* Primary or metastasis
* Common types of cancer that metastasise to the brain are lung, skin (melanoma), breast, renal cancers
5) Degenerative
* Slow, months to years, e.g. Parkinson’s disease, motor neurone disease
1 - Where is the lesion located?
What are clues that point to a brainstem lesion?
What are 3 questions that can be used to determine the location of a brainstem lesion?
What can be indicated if there are motor and sensory symptoms present?
- 1 - Where is the lesion located?
- Brainstem lesions often present with signs and symptoms on both sides of the body (above and below the neck) but distribution is asymmetrical.
- 3 questions that can be used to determine the location of a brainstem lesion:
1) Which cranial nuclei are involved? This gives the level in the brainstem.
2) Which tracts are involved? This indicates if the lesion is medial, lateral or bilateral
3) Which side is affected and what is the symptom?
- If motor tract involved - contralateral hemiparesis (UMN signs).
- If ascending tracts (sensory) involved - contralateral loss of fine touch and JPS or loss of pain and temperature
- Ipsilateral cranial nerve signs (LMN) in the head and neck.
- Ipsilateral Horner’s syndrome.
Clues to the area of the lesion.
What are the rules of 4 with cranial nerves?
What are clues for lesions affecting different levels of the brainstem?
- Clues to the area of the lesion
- The rules of 4s with cranial nerves: There are 4 cranial nerve nuclei in the pons, 4 above pons and 4 below pons. Help locate level of lesion in BS.
- (More specifically 2 above midbrain, 2 in midbrain, 3 in pons, 4 in medulla, CN-VIII both in pons and medulla)
- Clues for lesions affecting different levels of the brainstem:
1) Midbrain – defect is eye movement
2) Pons – defect is mastication
3) Medulla – defect is swallowing, phonation, speech
What cranial nerves are located at each level of the brainstem?
What side do lesions in cranial nerve/nucleus affect?
What side do lesions in the corticobulbar fibres affect?
- Cranial nerves are located at each level of the brainstem:
1) Midbrain - III, IV
2) Pons - V-VIII
3) Medulla - IX-XII - Lesions in the cranial nerve/nucleus affect the side (psilateral)
- If the lesion is present in the corticonuclear (corticobulbar) fibres (from the cortex to the cranial nerve nuclei) then then affected side will be contralateral to the lesion
What are the 4 Ms of the cranial nerve nuclei?
What type of nuclei are they?
What do they control?
What level are they each?
What are signs of dysfunction of each of these nuclei?
What will occur if theres a thrombose in the artery supplying the midline/medial part of the brainstem?
- The 4Ms of the cranial nerve nuclei are the 4 medial nuclei
- They are 4 somatic motor nuclei that control the eyes and tongue
- Levels - MB (III+IV), pons (VI) and medulla (XII)
- Signs of dysfunction of each of these nuclei:
1) Oculomotor nucleus (CN3)
* Dysfunction - Eye turned out and down.
2) Trochlear nucleus (CN4)
* Dysfunction - unable to look down when eye looking inwards.
3) Abducens nucleus (CN6)
* Dysfunction - problem abducting eye.
4) Hypoglossal nucleus (CN12)
* Dysfunction - tongue deviates towards side of lesion
* Problems with speech and swallowing, but since this is one-sided, patients may omit this
- If there is a thrombosis that affects the artery that supplies the midline/medial brainstem, this will affect these structures
What are the 3 medial tracts of the brainstem?
What do they each control?
- 3 medial tracts of the brainstem:
1) Corticospinal tract (pyramidal tract)
* Supplies motor fibres to the opposite side body
* The pyramidal tract originates from the cerebral cortex, and it divides into two main tracts: the corticospinal tract and the corticobulbar tract.
* At the base of the pyramids, approximately 90% of the fibres in the corticospinal tract decussate, or cross over to the other side of the brainstem
2) Medial lemniscus (ML) of dorsal column pathway
* Receives senses from the opposite side body
3) Medial longitudinal fasciculus
* connects eye nuclei III + VI (oculomotor and abducens)
What are the 4 structures in the ‘midline’ beginning with M (Rule of 4M) from dorsal to ventral?
What clinical features can we see from lesions in each of these areas?
- 4 structures in the ‘midline’ beginning with M (Rule of 4M) from dorsal to ventral:
1) Motor nuclei of the cranial nerve(s)
* Clinical features of lesion - Ipsilateral features of CN lesion in the head and neck
2) Medial longitudinal fasciculus
* Clinical features of lesion - ipsilateral inter-nuclear ophthalmoplegia (paralysis or weakness of the eye muscles)
3) Medial lemniscus
* Clinical features of lesion - Contralateral loss of joint position sense
4) Motor pathway (corticospinal and corticonuclear)
* Clinical features of lesion - Contralateral UMN signs in the limbs and trunk
What are 5 clinical signs of UMN lesion?
5 clinical signs of UMN lesion:
1) Spastic paresis/paralysis
2) Spasticity (tone)
3) Hyper-reflexia
4) Clonus (sustained, rhythmic contractions)
5) Positive Babinski’s (upgoing plantar reflex)
What types of Nuclei are found on the lateral brainstem?
What structures do they supply?
What are the 5 nuclei located on the lateral brainstem?
What do they control/What do lesions in each of these nuclei cause?
Where are CN11 cell bodies located?
What deficits does a lesion in this area cause?
- On the lateral brainstem, there are sensory (Special somatic afferent – SSA and General somatic afferent GSA) and special visceral efferent (SVE)
- They are responsible for jaw, face, pharynx/larynx - ear/balance/head sensation
- 5 nuclei located on the lateral brainstem:
- Sensory (SSA and GSA):
1) Vestibulocochlear nuclei complex (CN8)
* Lesions in this nucleus cause Ipsilateral deafness, balance problems
2) Trigeminal (spinal) Nucleus (CN5)
* Receives signals on pain and temperature
- SVE – supply muscles derived from the pharyngeal arches, making them special visceral efferent:
3) Trigeminal nucleus (CN5)
* Supplies muscles of mastication
4) Facial nucleus (CN7)
* Lesions in this nucleus cause Ipsilateral facial weakness (superior and inferior facial muscles
5) Nucleus ambiguous
* Supplies motor to pharynx and larynx (CN IX and CN X)
* Lesions in this nucleus cause swallowing and phonation difficulties
- CN XI cell bodies are in the spinal accessory nucleus in spinal cord (C1-C6)
- Lesions in this area cause unilateral weakness of SCM and trapezius.
What are the 3 lateral tracts of the brainstem?
What do they each supply?
What can lesions in these tracts cause?
What side are conditions related to the cerebellum?
Why is this?
- 3 lateral tracts of the brainstem:
1) Spinothalamic/anterolateral
* Supplies contralateral body (crosses at spinal cord level)
* Lesions in this area cause pain/temp defect
2) Spinocerebellar
* Supplies Ipsilateral body
* From spinal cord to cerebellum
* Involved in balance
* Lesions in this area cause ataxia ( a term for a group of disorders that affect co-ordination, balance and speech)
3) Sympathetic
* Ipsilateral from hypothalamus to spinal cord to eye
* Lesions in this area cause Horner’s
- Anything related to the cerebellum is ipsilateral
- The cerebellum controls the same side of the body and receives input from the same side of the body
- These pathways either don’t cross, or cross twice, resulting in them coming to the same hemisphere
What are the 4 structures in the lateral brainstem that begin with S (Side) from dorsal to ventral?
What are the clinical features for lesions in these areas?
- 4 structures in the lateral brainstem that begin with S (Side) from dorsal to ventral:
1) Spinocerebellar pathways
* Lesions in this areas cause Ipsilateral ataxia in the limbs
2) Spinothalamic pathway
* Lesions in this area Contralateral loss of pain and temperature in the limbs
3) Sensory nucleus of CN V
* Lesions in this area cause Ipsilateral loss of fine touch, pain and temperature in face and anterior 2/3 of scalp
4) Sympathetic pathway
* Lesions in this area results in Horner’s syndrome: partial ptosis, meiosis
Describe the roles of the non-cranial nerve nuclei (in picture) in the:
* Brainstem (6)
* Pons (2)
* Medulla (4)
What provides the blood supply to the median structures of the brainstem?
Describe the arterial supply the 4M (medial) structures of the brainstem.
What are Structures in the medial aspect of the brainstem including CN and their nuclei likely to be affected by?
- The blood supply to the medial aspect of thebrainstem comes from the paramedian arteries
- Arterial supply the 4M (medial) structures of the brainstem:
1) Midbrain (CN3 and CN4)
* Posterior cerebral artery
2) Pons (CN6)
* Basilar artery
3) Medulla (CN12)
* Anterior spinal artery
- Structures in the medial aspect of the brainstem including CN and their nuclei likely to be effected by a vascular lesion at the different levels within the brainstem.
Describe the arterial supply the 4S (lateral(side)) structures of the brainstem.
What are Structures in the medial aspect of the brainstem including CN and their nuclei likely to be affected by?
- The blood supply to the 4S (*lateral(side)) structures of the brainstem is from the circumferential arteries:
1) Midbrain (CN5)
* Posterior cerebral artery and superior cerebellar artery
2) Pons (CN5, CN7, CN8)
* Pontine arteries of the basilar artery
3) Medulla (CN5, CN9, CN10)
* PICA (posterior interior cerebellar artery) and vertebral artery
- Structures on the sides of the brainstem including CN and their nuclei likely to be effected by a vascular lesion at the different levels within the brainstem.
Case 1:
A 45 year old male presents with a sudden onset of dysarthria. On examination he is found to have deviation of his tongue to the right, a left hemiplegia and loss of JPS to the upper and lower left limbs.
1) At what level is the lesion?
2) What is/are the clue(s)?
3) Which nerve/nucleus?
4) Which side?
5) Which side of the brainstem is affected?
6) What do we have on the Medial aspect?
7) Left hemiplegia + UMN signs (in left upper and lower limbs)
8) Loss of JPS, fine touch, vibration sense from left side of body
9) What does “sudden onset” indicate?
10) Which artery supplies this region?
11) What condition is this?
1) At what level is the lesion? - In the upper/mid medulla
2) What is/are the clue(s)? - Disarthria (caused by tongue weakness)
3) Which nerve/nucleus? - Hypoglossal nucleus/nerve
4) Which side? - Right. May observe atrophy and fasciculation of the tongue (LMN signs)
* Because the tongue is deviated to the right and cranial nerves control ipsilateral structures, it’s the right side – need patient to stick their tongue out
5) Which side of the brainstem is affected? - The lesion is medial
* M or S, the lesion is medial
6) What do we have on the Medial aspect? - 4 Ms
7) Left hemiplegia + UMN signs (in left upper and lower limbs) - What is affected? - R Corticospinal tract
* Left hemiplegia – on the right side, the corticospinal tract goes down, it hasn’t crossed yet, so if there is damage in here, it will affect the contralateral muscles
8) Loss of JPS, fine touch, vibration sense from left side of body - What is affected? - Right medial lemniscus
* Loss of JPS on the left side, because the fibres have already crossed
* They have come from the upper/lower limbs, into the spinal cord, ascended, crossed the midline and gone into the upper parts of the medulla
* They have already crossed, so their wont be any JPS on the contralateral side, meaning there is right medial lemniscus damage
9) What does “sudden onset” indicate? - Vascular
10) Which artery supplies this region – Anterior spinal artery -
11) What condition is this? - Medial medullary syndrome
Medial medullary syndrome diagram (in picture)
Question 2:
* A 35-year-old female presents with tinnitus and gradual loss of hearing in the right ear. The patient mentions she has also been having symptoms of vertigo over the past few weeks with occasional vomiting, in addition to slight weakness on the right side of her face. On examination she is found to have mild nystagmus, a right-sided facial paraesthesia and loss of corneal reflex.
1) At what level is the lesion?
2) What is/are the main clue(s)?
3) Which nerve(s) may be affected?
4) What are the clues?
5) On which side is the lesion?
6) Which side of the brainstem is affected?
7) What do we have on the lateral aspect?
8) What else are there on the SIDE?
9) How do you explain facial muscle weakness?
10) How do you explain facial paraesthesia?
11) Afferent/efferents of corneal reflex?
12) What does “gradual loss”
13) What condition is this?
1) At what level is the lesion? – Pons
2) What is/are the main clue(s)? -Gradual loss of hearing with tinnitus (along with vertigo) – related to vestibulo-cochlear nerve (CN8)
3) Which nerve(s) may be affected? - Vestibulo-cochlear, facial, trigeminal
4) What are the clues? - weakness on the right side of her face, facial paraesthesia on the right, loss of corneal reflex
5) On which side is the lesion? – Right (due to tinnitus in the right ear)
6) Which side of the brainstem is affected? – lateral side)
7) What do we have on the lateral aspect? 4S
8) What else are there on the SIDE? - Motor nucleus of facial nerve (SVE) and Spinal and principal nuclei of trigeminus
9) How do you explain facial muscle weakness? - Involvement of CN-VII (facial)
10) How do you explain facial paraesthesia? - Involvement of CN-V (trigeminal)
11) Afferent/efferents of corneal reflex? - Trigeminal and facial nerves
12) What does “gradual loss” - Neoplasm
13) What condition is this?
* Cerebello-pontine angle tumour (acoustic neuroma/vestibular schwannoma) (benign tumour) growing in the cerebellar-pontine angle cistern
- CSF filled subarachnoid space within posterior cranial fossa in between anterior surface of cerebellum, lateral surface of pons and petrous part of temporal bone.
- CN V, VI, VII and IX are in close proximity and maybe compressed as the tumour grows.
- Right cerebellum maybe involved so nystagmus (ataxia, intention tremor (arm) are also possible).
- The tracts on the side and vital nuclei are often not involved as they lie deep to the superficial surface of pons.
- The cerebello-pontine angle contains the internal acoustic meatus, through which the facial and vestibulocochlear nerves (CN7 and CN8) enter, with the trigeminal ganglion being close
- A tumour can affect all of these structures
Cerebello-pontine angle tumour diagram (in picture)
Question 3.
* A 40 year old female is undergoing a yearly physical exam at her GP. Upon examination of her visual system, she is found to have
* Impaired adduction in the left eye when asked to look to the right.
* An apparent nystagmus in the right abducting eye
* Impaired adduction of the right eye when asked to look left
* An apparent nystagmus in the left abducting eye
- On further questioning she tells her GP she had an episode of pain behind the right eye with partial loss of colour vision, which lasted 1 month in her 30s.
What is this case to do with?
What occurs when we look to the right?
What nerves are responsible for this action?
What can result if there is not a connection between these 2 nerves?
What can happen to the MLF in demyelinating conditions? What structures are affected?
- This case is about the medial longitudinal fasciculus (MLF) and inter-nuclear ophthalmoplegia
- When you ask a patient to look to the right side, the right side abducts, while the left eye adducts
- These 2 motions are supplied by different nerves – the abducent and oculomotor (CN6 and CN3)
- There should be a connection between these 2, so when we look right and left, we don’t have double visions – this is called horizontal/lateral gaze
- Medial Longitudinal Fasciculus is one of the first central NS tracts to be myelinated during development (oligodendroglia).
- Demyelinating conditions e.g. multiple sclerosis can slow conduction through MLF causing inter-nuclear ophthalmoplegia (commonly bilateral lesions)
- It is also one of the first tracts to degenerate
- Structures involved include the motor nucleus of abducens and the oculomotor, the medial longitudinal fasciculus (MLF), and laterally, the nerves.
What is the medial longitudinal fasciculus (MLF)?
What does it link?
What structures are responsible for horizontal gaze?
What does MLF integrate? What does the MLF also have connections with?
What can vestibular pathologies in this area cause?
- Medial longitudinal fasciculus (MLF) is a myelinated fibre tract found in the brainstem
- It links the three main nerves which control eye movements:
1) Oculomotor Nerve (CN3)
2) Abducens (CN6)
3) Trochlear (CN4) - Oculomotor Nerve (CN3) Abducens nerve (CN6) are responsible for horizontal gaze
- The MLF integrates movements directed by the frontal eye field (gaze centers) and information about head position and movement (from the vestibulocochlear nerve – CN8)
- The MLF also has connections to the cerebellum and inner-ear
- This means cerebellar or vestibular pathologies can cause inter-nuclear ophthalmoplegia and can disrupt horizontal gaze
Describe the normal horizontal gaze diagram (in picture)
Describe looking to the right with a lesion in the left MLF (in picture)
Describe looking to the left with a lesion in the left MLF (in picture)
Question 4 -
A 60 year old male presents with sudden onset dysphagia and difficulty walking. He noticed his right eyelid had suddenly dropped. When he entered the room his gait seemed ataxic. On examination he has partial ptosis and meiosis of right eye, with loss of pain and temperature sensation on the same side of the face. In his left lower limbs he has lost sense of pain and temperature, however joint position sense remains intact. His palate has deviated to the left.
1) At what level is the lesion?
2) What is/are the clue(s)?
3) Which nerve(s) may be affected?
4) Which nucleus?
5) Which side of the brainstem is affected?
6) On which side is the lesion?
7) What does “sudden onset” indicate?
8) Which artery supplies this region?
9) What condition is this?
1) At what level is the lesion? - Most likely in medulla
2) What is/are the clue(s)? - Dysphagia (difficulty swallowing)
3) Which nerve(s) may be affected? - Vagus (and glossopharyngeus)
4) Which nucleus? - Nucleus ambiguus – On examination ipsilateral loss of gag reflex and palate will pull up to left side
5) Which side of the brainstem is affected? - Right
6) On which side is the lesion? - Lateral (side)
7) What does “sudden onset” indicate? - Vascular
8) Which artery supplies this region? - PICA or vertebral artery
9) What condition is this? – This is lateral medullary syndrome as a result of a stroke
* Occasionally there is ipsilateral SCM and/or trapezius weakness.
- Structures are affected in the following problems:
1) Loss of pain and temperature, crude touch from left upper and lower limbs and face - Spinothalamic tract
2) Difficulty in walking; limb ataxia on right side - Spinocerebellar tract
3) Right Horner’s syndrome (partial ptosis, meiosis, anhydrosis) - Sympathetic pathway
4) Loss of pain and temperature from right side of face - Trigeminal nucleus
Lateral medullary syndrome diagram (in picture)
