Neurology JC021: Where Is The Lesion? (1) Symptoms And Signs In Neurology Flashcards
Anatomical sites of neurology
- Cerebral cortex
- Extrapyramidal system (Subcortical area)
- Cerebellum
- Brainstem
- Spinal cord
- Peripheral nerves: Motor + Sensory
- NMJ
- Muscle
UMN vs LMN lesions DDx
UMN lesions:
1. Stroke
2. Multiple sclerosis
3. Traumatic brain injury
4. Tumour
5. Cerebral palsy
6. Atypical parkinsonisms
7. Multiple system atrophy
8. Amyotrophic lateral sclerosis
9. Spinal cord injury
LMN lesions:
1. Motor neuron disease
2. Peripheral neuropathy
3. Myopathy
4. NMJ disease
5. Cauda equina syndrome
General localisation from history
- Cerebral cortex
- **higher mental function deficit
- ↓ memory
- ↓ orientation
- **dysphasia (understanding + expression of speech)
- **apraxia (difficulty with motor planning, performing familiar, purposeful tasks despite normal power + sensation) (e.g. Jakob Creutzfeldt disease)
- ↓ consciousness
- hallucinations
- **seizures - Extrapyramidal system
- **coordination of movement
- **stiffness
- **tremor
- **abnormal movements
- falls
- dysphagia - Cerebellum
- **coordination + rhythm of movement
- **clumsiness, falls
- **gait problem
- cerebellar Vermis: **Truncal ataxia
- ***Ataxia: Dysmetria, Dysdiadochokinesia, Dysarthria, Dysphagia, Nystagmus, Hypotonia - Peripheral nerves
- **motor + **sensory function
- LMN signs
- numbness, pins / needles - NMJ
- muscle weakness (**diurnal variation (better in morning, worse at night), **fatiguability)
- diplopia, **drooping eyelid
- **dysphagia
- ***respiratory weakness - Muscle
- **proximal muscle weakness e.g. climbing stairs, standing up from low chair, combing hair
- **muscle tenderness
- may not have muscle wasting (esp. in early stage)
- ***no sensory disturbance
Revision: Pyramidal vs Extrapyramidal
Pyramidal:
1. Corticobulbar tract (to CN nuclei)
2. Corticospinal tract (to spinal motor neuron) (Lateral / Ventral)
Internal capsule —> Cerebral peduncle (Midbrain) —> Pons —> Pyramids of Medulla (decussation) —> Brain stem nuclei —> Corticospinal tract
Extrapyramidal:
1. Basal ganglia
- Caudate nucleus
- Putamen
- Globus pallidum
- Substantia nigra
- Brainstem motor nuclei
- Vestibular nuclei (medulla) —> Lateral vestibulospinal tract
- Red nucleus (midbrain) —> Rubrospinal tract
- Reticular nuclei (medulla, pons) —> Reticulospinal tract (Medial / Lateral)
- Tectospinal tract
Cerebral cortex
記: Aphasia (expressive / receptive), Apraxia, Agnoxia, Amnesia, Hemineglect
- Frontal lobe:
- disinhibition
- emotional lability
- reduced planning ability
- **expressive dysphasia (Broca’s area: Inferior **frontal gyrus, supplied by **MCA)
- **Snout reflex (嘟嘴) in diffuse encephalopathy (primitive reflex normally present in neonates, lose when age) (pursing of lips when light tapping on closed lips) - Temporal lobe:
- **amnesia (Hippocampus)
- **aggression (Amygdala)
- Temporal Lobe Epilepsy
- receptive dysphasia (Wernicke’s area: Superior **temporal gyrus, supplied by **MCA)
- ***upper quadrantic visual field defect - Parietal lobe:
- **agnosia (tactile, visual)
- **apraxia
- **acalculia
- **hemineglect (lesion in contralateral non-dominant lobe)
- ***lower quadrantic visual field defect - Occipital lobe
- contralateral **homonymous hemianopia with **macula sparing
- ***visual hallucinations - Lesion of dominant / non-dominant hemisphere
- right handed: left dominant hemisphere
- left handed: <50% still left dominant hemisphere
—> ***Prognostic purposes (worse if on dominant hemisphere (∵ more cortical function)) - Diffuse cortical lesion (e.g. Encephalopathy)
- coma, reduced consciousness - Thalamus (SpC Revision)
- input from sensory afferents, cerebellar, basal ganglia
- output to cerebral cortex
- ***contralateral sensory loss / impairment
***Clinical features of Stroke (from L25)
S/S:
- indicate Location + Extent of damage
- Negative features from loss of functions
- Sudden / Rapid in onset
Carotid territory (ACA, MCA, Ophthalmic artery —> Anterior + Lateral cerebral hemispheres, Retina):
- **Contralateral Hemiparesis +/- Hemifacial weakness (non-specific for localisation)
- **Contralateral Hemisensory loss
- **Aphasia (if **dominant hemisphere involved)
- **Visuospatial disorientation (if **non-dominant hemisphere involved)
- **Visual disturbance (retinal stroke / **Amaurosis fugax: ipsilateral monocular blindness, **Contralateral homonymous hemianopia (Temporal / Parietal optic pathway))
- **Deviation of head and eyes towards lesion side (Prevost sign: ∵ damage of frontal eye fields) (Pontine lesion: Gaze deviation to contralateral side)
- Dysarthria
- Dysphagia
Vertebrobasilar territory (Cerebellum, Medulla, Pons, Midbrain, Occipital cortex):
- **Cortical blindness
- **Homonymous visual field defects
- **Diplopia
- **Nystagmus
- **Vertigo
- **Horner’s syndrome
- Dysarthria
- **Dysphagia
- **Crossed hemiparesis (Ipsilateral facial weakness + Contralateral limb weakness)
- Tetraparesis
- **Crossed unilateral sensory loss
- Bilateral sensory loss
- **Ataxia
Common warning symptoms:
- Sudden weakness / numbness of face, arm, leg on one side of body
- **Sudden dimness of loss of vision (particular in 1 eye)
- Loss of speech / trouble talking / understanding speech
- Sudden, severe headaches with no apparent cause
- **Unexpected dizziness, unsteadiness, sudden falls (esp. along with any of previous symptoms)
Basal ganglia (Extrapyramidal system)
記: Parkinsonism
- Caudate nucleus
- Putamen
- Globus pallidum
- Substantia nigra
- ***Parkinsonism features
- ***Dystonia
- Various movement disorders
- ***Muscle spasms
Cerebellum
記: Ataxia
Ataxia 包含:
- Dysmetria (lack of coordination leading to overshoot / undershoot)
- Dysdiadochokinesia (impaired ability to perform rapid alternating movements)
- Dysarthria (poor articulation)
- Dysphagia
- Nystagmus
- Hypotonia
- Vermis
- **truncal ataxia
- **dysarthria (fragmented, unclear articulation of speech, loud speech, explosive, scanning) - Cerebellar hemisphere (Ipsilateral)
- **dysmetria (past-pointing, **intention tremor: finger-nose, heel-shin test)
- **dysdiadochokinesia (abnormal rapid repetitive movement)
- dysarthria
- “rebound phenomenon”
- **wide-based gait
- ***nystagmus
Brainstem
記: Lateral / Medial medullary syndromes
Consists of:
- Descending motor pathways
- Ascending sensory pathways
- Cranial Nerve nuclei
Specific syndromes:
- ***Lateral / Medial medullary syndromes
May develop (**乜都得):
1. Reticular formation
- **Reticular formation (ARAS + Reticulospinal tract) —> Coma
- Pin-point pupils
- Corticobulbar / Corticalspinal tract
- ***Corticobulbar / Corticospinal tract —> UMN signs in limbs (esp. contralateral) - CN
- **Cranial nerve nuclei —> Specific CN deficit
- **Bulbar nuclei —> Dysarthria, Dysphagia - Eye
- Medial Longitudinal Fasciculus —> **Internuclear ophthalmoplegia (impaired **adduction of contralateral eye)
- ***Vertical nystagmus
(5. Ascending sensory tracts (self notes)
- ***Sensory deficits)
Location of Cranial nerve nuclei
Motor
CN1: Olfactory bulb
CN2: Retina
CN3, 4: Midbrain (EOM)
CN5, 6, 7, 8: Pons
CN9, 10, 11, 12: Medulla (Bulbar function: dysarthria, dysphagia)
Sensory
CN5: whole brainstem to upper cervical cord (Sensation of face: pinprick, pain, temp)
Midbrain lesions: ***CN3
- Passes anteriorly + ***ipsilaterally from Oculomotor nucleus
- through Red nucleus + Cerebral peduncle (containing UMN)
- 記住: Midbrain
Cerebral peduncle lesion (**Weber’s syndrome (Motor)):
- Ipsilateral CN3 palsy (eyeball gazing downward + outward, diplopia, **ptosis, **mydriasis, loss of accommodation reflex)
- **Contralateral hemiplegia
Red nucleus lesion (**Benedikt’s syndrome (Sensory + Cerebellum)):
- **Ipsilateral CN3 palsy (eyeball gazing downward + outward, diplopia, **ptosis, **mydriasis, loss of accommodation reflex)
- **Contralateral loss of proprioception and vibration sensations (∵ Medial lemniscus affected)
- **Cerebellar ataxia
Dorsal midbrain / Superior colliculus lesion (**Parinaud’s syndrome):
- inability to move the eyes up / down (compression of **vertical gaze center at rostral interstitial nucleus of medial longitudinal fasciculus (riMLF))
Pons lesions
CN5, 6, 7, 8
Pontocerebellar angle syndrome (78Cerebellum):
- **Ipsilateral facial palsy (CN7)
- **Hearing problem (CN8)
- ***Cerebellar features (middle cerebellar peduncle)
Medial + Anterior pons lesion (6Motor):
- Alternating abducent hemiplegia
—> **Ipsilateral CN6 palsy
—> **Contralateral hemiplegia
Medulla lesions
Bulbar nuclei lesion: CN9, 10, 11, 12 —> Dysarthria (words formed with nasal tone but smooth rather than fragmented) + Dysphagia
記:
***Lateral medulla (10SSI)
1. CN10
2. Spinothalamic tract
3. Sympathetic supply
4. Inferior cerebellar peduncle
***Medial medulla (12DC)
1. CN12
2. DC column
3. Corticospinal tract
Lateral medullary syndrome (**Wallenburg’s syndrome):
- **CN10 —> Ipsilateral laryngeal, pharyngeal, palatal hemiparalysis —> Dysarthria + Dysphagia
- **Spinothalamic tract —> Contralateral pain + temp loss
- **Sympathetic supply —> Ipsilateral Horner syndrome
- ***Inferior cerebellar peduncle —> Ipsilateral cerebellar ataxia
Medial medullary syndrome:
- CN12 —> Ipsilateral tongue weakness
- Medial lemniscus (DC column) —> Contralateral loss of discriminative touch, conscious proprioception, and vibration sense
- ***Corticospinal tract —> Contralateral hemiplegia
Summary of Brainstem lesions
Midbrain:
1. Cerebral peduncle lesion (Weber’s syndrome (記: Motor)):
- Ipsilateral CN3 palsy (eyeball gazing downward + outward, diplopia, **ptosis, **mydriasis, loss of accommodation reflex)
- ***Contralateral hemiplegia
- Red nucleus lesion (Benedikt’s syndrome (記: Sensory + Cerebellum)):
- **Ipsilateral CN3 palsy (eyeball gazing downward + outward, diplopia, **ptosis, **mydriasis, loss of accommodation reflex)
- **Contralateral loss of proprioception and vibration sensations (∵ Medial lemniscus affected)
- ***Cerebellar ataxia - Dorsal midbrain / Superior colliculus lesion (**Parinaud’s syndrome):
- inability to move the eyes up / down (compression of **vertical gaze center at rostral interstitial nucleus of medial longitudinal fasciculus (riMLF))
Pons:
1. Pontocerebellar angle syndrome (**記: 78Cerebellum):
- **Ipsilateral facial palsy (CN7)
- **Hearing problem (CN8)
- **Cerebellar features (middle cerebellar peduncle)
- Medial + Anterior pons lesion (**記: 6Motor):
- Alternating abducent hemiplegia
—> **Ipsilateral CN6 palsy
—> ***Contralateral hemiplegia
Medulla:
1. Lateral medullary syndrome (Wallenburg’s syndrome) (記: 10SSI):
- **CN10 —> Ipsilateral laryngeal, pharyngeal, palatal hemiparalysis —> Dysarthria + Dysphagia
- **Spinothalamic tract —> Contralateral pain + temp loss
- **Sympathetic supply —> Ipsilateral Horner syndrome
- **Inferior cerebellar peduncle —> Ipsilateral cerebellar ataxia
- Medial medullary syndrome (記: 12DC):
- **CN12 —> Ipsilateral tongue weakness
- Medial lemniscus (DC column) —> Contralateral loss of discriminative touch, conscious proprioception, and vibration sense
- **Corticospinal tract —> Contralateral hemiplegia
Eye opening vs Eye closure
Eye opening:
Levator palpebrae superioris
- CN3
(- Parasympathetic on surface of CN3 (mentioned in lecture but not sure))
Superior tarsal muscle (a smooth muscle that originate from Levator palpebrae superioris)
- Sympathetic (Superior cervical ganglion —> travel along CN3)
Eye closure:
Orbicularis oculi
- CN7
