In The Name Of Allah The Beneficent The Merciful

‫بسم اللہ الرح ٰمن الرحیم‬

In the name of Allah the Beneficent the merciful

Where’s the Lesion?

Zafar Iqbal Dr Department of Neurosurgery Abbasi Shaheed Hospital

Aslam’s CC: ❚ “My balance is off.” ❙ Multiple ER visits for fall-related trauma

❚ “I’m losing the fine control of my fingers.” ❙ Loss of manual dexterity

❚ “I’ve had pneumonia three times.” ❙ Dysphagia to liquids>solids

All of Aslam’s Complaints Sounded Neurologic in Origin

His lesion should lie somewhere in the neuraxis.

Divisions of the Neuraxis ❚ Cortical Brain ❚ Subcortical Brain ❚ Brainstem ❚ Cerebellum ❚ Spinal Cord ❚ Root ❚ Peripheral Nerve

❚ Neuromuscula r Junction ❚ Muscle

Off the Top of my Head . . . ❙ Imbalance = Cerebellum ❙ Pneumonia = Brainstem (related dysphagia) ❙ Loss of Dexterity = Peripheral Nerve

Neurologic Examination ❚ ❚ ❚ ❚ ❚ ❚ ❚

Higher Cortical Function Cranial Nerves Cerebellar Function Motor Sensory Deep Tendon Reflexes Pathologic Reflexes

The Neuro Exam Should Evaluate the Entire Neuraxis Higher Cortical Function: cortex Cranial Nerves: subcortex, brainstem Cerebellar Function: cerebellum Motor: motor homonculous, subcortical pyramidal tracts, BS, cord, radicle, PN, muscle ❚ Sensory: ascending tracts, thalamus, subcortical tracts, sensory hononculous ❚ Deep Tendon Reflexes: afferent PN, radicle, cord, efferent PN, muscle ❚ Pathologic Reflexes: ❚ ❚ ❚ ❚

Aslam’s Exam Showed: ❚ Higher Cortical Function: normal ❚ Cranial Nerves: oropharyngeal dysarthria ❚ Cerebellar Function: hypotonia, assynergy, dysmetria, staccato dysarthria, intention tremor, appendicular ataxia ❚ Motor: hypotonia, normal strength ❚ Sensory: decreased vibration and temperature ❚ Deep Tendon Reflexes: areflexia ❚ Pathologic Reflexes: plantar flexing

So Where’s the Lesion?

Divisions of the Neuraxis ❚ Cortical Brain ❚ Subcortical Brain ❚ Brainstem ❚ Cerebellum ❚ Spinal Cord ❚ Root ❚ Peripheral Nerve

❚ Neuromuscula r Junction ❚ Muscle

Cortical Brain ❚ Depends upon hemispheric dominance ❚ Non-neurologists generalize: ❙ right: visual/spatial, perception and memory ❙ left: language and language dependent memory

❚ Look for aphasias, apraxias, and agnosias

Neurologic Examination when Cortical Brain is Lesioned ❚ Higher Cortical Function: aphasia, apraxia, agnosia ❚ Cranial Nerves: normal ❚ Cerebellar Function: normal ❚ Motor: weakness if you hit the motor homonculous ❚ Sensory: sensory abnormalities if you hit the sensory homonculous ❚ Deep Tendon Reflexes: hemi-hyper-reflexia ❚ Pathologic Reflexes: possibly Babinski’s reflex or frontal release signs

Divisions of the Neuraxis ❚ Cortical Brain ❚ Subcortical Brain ❚ Brainstem ❚ Cerebellum ❚ Spinal Cord ❚ Root ❚ Peripheral Nerve

❚ Neuromuscula r Junction ❚ Muscle

Subcortical Brain ❚ Deep white radiating fibers produce equal involvement of face/arm/leg ❙ weakness ❙ sensory abnormalities

❚ Visual radiating fibers are interrupted: ❙ deep parietal: pie on the floor ❙ deep temporal: pie in the sky

Neurologic Examination when Subcortical Brain is Lesioned ❚ ❚ ❚ ❚ ❚ ❚ ❚

Higher Cortical Function: normal Cranial Nerves: visual field cuts Cerebellar Function: usually normal Motor: weakness in face=arm=leg, UMN Sensory: sensory abnormalities in face=arm=leg Deep Tendon Reflexes: hemi-hyper-reflexia Pathologic Reflexes: Babinski’s reflex and possibly frontal release signs

Divisions of the Neuraxis ❚ Cortical Brain ❚ Subcortical Brain ❚ Brainstem ❚ Cerebellum ❚ Spinal Cord ❚ Root ❚ Peripheral Nerve

❚ Neuromuscula r Junction ❚ Muscle

Brainstem ❚ The Brainstem is basically spinal cord with embedded cranial nerves, producing the following abnormalities ❙ cranial nerve abnormalities ❙ classic spinal cord complaints ❘ bowel and bladder problems

❙ long tract signs: (bilateral and crossed) ❘ corticospinal (pyramidal): motor ❘ spinothalamic: pain/temp to the thalamus ❘ dorsal columns: prioprioception/vibration to thal.

Neurologic Examination when Brainstem is Lesioned ❚ Higher Cortical Function: normal ❚ Cranial Nerves: ❘ ❘ ❘ ❘ ❘ ❘

❚ ❚ ❚ ❚ ❚

III, IV, VI: diplopia V: decreased facial sensation VII: drooping VIII: deaf and dizzy IX, X, XII: dysarthria and dysphagia XI: decreased strength in neck and shoulders

Cerebellar Function: normal Motor: hemi-paresis, UMN Sensory: hemi-dysesthesias Deep Tendon Reflexes: hemi-hyper-reflexia Pathologic Reflexes: Babinski’s reflex

Divisions of the Neuraxis ❚ Cortical Brain ❚ Subcortical Brain ❚ Brainstem ❚ Cerebellum ❚ Spinal Cord ❚ Root ❚ Peripheral Nerve

❚ Neuromuscula r Junction ❚ Muscle

Cerebellar Function ❚ Some people believe that one can not test specifically for cerebellar abnormalities ❙ no one test on examination reliably evaluates the cerebellum

❚ ❚ ❚ ❚ ❚ ❚

H: A: N: D: S: T:

hypotonia assynergy of (ant)agonist muscles nystagmus dysmetria, dysarthria stance and gait tremor

Neurologic Examination when the Cerebellum is Lesioned ❚ Higher Cortical Function: normal ❚ Cranial Nerves: normal ❚ Cerebellar Function: ❙ nystagmus ❙ staccato dysarthria (abnormality of prosody)

❚ Motor: ❙ hemi-hypotonia ❙ intention > positional tremor ❙ axial instability with dysmetria

❚ Sensory: normal ❚ Deep Tendon Reflexes: normal ❚ Pathologic Reflexes: none

Divisions of the Neuraxis ❚ Cortical Brain ❚ Subcortical Brain ❚ Brainstem ❚ Cerebellum ❚ Spinal Cord ❚ Root ❚ Peripheral Nerve

❚ Neuromuscula r Junction ❚ Muscle

Spinal Cord ❚ ❚ ❚ ❚

Sensory level (horizontal) Weakness below the lesion (paraparesis) UMN signs below the lesion Bowel and bladder incontinence

Neurologic Examination when the Spinal Cord is Lesioned Higher Cortical Function: normal Cranial Nerves: normal Cerebellar Function: normal Motor: weakness below the lesion Sensory: horizontal level Deep Tendon Reflexes: hyper-reflexia below the lesion ❚ Pathologic Reflexes: Babinski’s reflex ❚ ❚ ❚ ❚ ❚ ❚

Divisions of the Neuraxis ❚ Cortical Brain ❚ Subcortical Brain ❚ Brainstem ❚ Cerebellum ❚ Spinal Cord ❚ Root ❚ Peripheral Nerve

❚ Neuromuscula r Junction ❚ Muscle

Root/Radiculopathy ❚ Pain is the hallmark of a radiculopathy ❚ Sensory abnormalities in a dermatome ❙ provocative maneuvres exacerbate the pain

❚ Weakness in a myotome (assymetric) ❚ LMN findings

Neurologic Examination when a Root is Lesioned Higher Cortical Function: normal Cranial Nerves: normal Cerebellar Function: normal Motor: assymetric weakness in a myotome ❚ Sensory: pain and dysesthesia confined to a dermatome ❚ Deep Tendon Reflexes: hypo- to a-reflexia if the root carries a reflex ❚ Pathologic Reflexes: none ❚ ❚ ❚ ❚

Divisions of the Neuraxis ❚ Cortical Brain ❚ Subcortical Brain ❚ Brainstem ❚ Cerebellum ❚ Spinal Cord ❚ Root ❚ Peripheral Nerve

❚ Neuromuscula r Junction ❚ Muscle

Peripheral Nerve (presuming nonfocality) ❚ Weakness: distal predominant ❚ Sensory Dysesthesias: distal predominant

Neurologic Examination with Diffuse PN Lesioning Higher Cortical Function: normal Cranial Nerves: normal Cerebellar Function: normal Motor: weakness is distal predominant Sensory: dysesthesias are distal predominant ❚ Deep Tendon Reflexes: loss of distal reflexes ❚ Pathologic Reflexes: mute responses to plantar stimulation ❚ ❚ ❚ ❚ ❚

Divisions of the Neuraxis ❚ Cortical Brain ❚ Subcortical Brain ❚ Brainstem ❚ Cerebellum ❚ Spinal Cord ❚ Root ❚ Peripheral Nerve

❚ Neuromuscula r Junction ❚ Muscle

Neuromuscular Junction ❚ Fatiguability is the hallmark ❚ Weakness: proximal and symmetric ❙ exacerbated with use, recovers with rest ❙ often affects facial muscles (ptosis, dysconjugate gaze, slack jaw)

❚ Sensation: preserved

Neurologic Examination in Disorders of the NMJ ❚ Higher Cortical Function: normal ❚ Cranial Nerves: fatiguabile ptosis, dysconjugate gaze, slack jaw ❚ Cerebellar Function: normal ❚ Motor: fatiguable proximal weakness in both UE’s and LE’s ❚ Sensory: normal ❚ Deep Tendon Reflexes: normal ❚ Pathologic Reflexes: none

Divisions of the Neuraxis ❚ Cortical Brain ❚ Subcortical Brain ❚ Brainstem ❚ Cerebellum ❚ Spinal Cord ❚ Root ❚ Peripheral Nerve

❚ Neuromuscula r Junction ❚ Muscle

Muscle ❚ Weakness of proximal arm and leg muscles ❙ symmetric

❚ Sensation is normal ❙ though patients complain of cramping and aching

Neurologic Examination in Disorders of Muscle ❚ Higher Cortical Function: normal ❚ Cranial Nerves: ptosis, dysconjugate gaze, dysphagia, dysphonia, (dysarthria) ❚ Cerebellar Function: normal ❚ Motor: proximal weakness in both UE’s and LE’s, atrophy and fasiculations, hypotonia ❚ Sensory: normal ❚ Deep Tendon Reflexes: preserved until late in the disease ❚ Pathologic Reflexes: none

Aslam’s Lesion Localizes to: Almost exclusively the Cerebellum, though to a minor degree the BS and PN are involved. Isolated heritable cerebellar dysfunction is rare, so we would expect to see other parts of the CNS involved.

Spino-Cerebellar Ataxia (SCA4) Prior to Aslam’s diagnosis, his cousin was the proband for this entity. ❙ Aslam has a 38-family member, 5 generation pedigree of this disorder

His family entered into a study, and his family led to the classification of SCA4: ataxia with axonal sensory neuropathy

Thank you