L3: Spinal Cord and Brain Stem - L4: Brainstem

What does gray matter contain

neuronal cell bodies and synapses

Importance of gray matter

Folds and grooves increase the surface area, allowing for more neurons and synapses, shorter distance for signals to travel

Allows for more efficient processing information

Function of gray matter

Receives information from the WHITE MATTER

↓

Processing center for personality, intelligence, motor function, planning, organization, language processing, and processing sensory information in the brain

Processes information for motor and sensation from the spinal cord

Components of white matter

primarily axons coated with myelin

Contains ascending and descending fiber pathways

↓

Ascending: relays sensory info to the brain

Descending: Relays motor instructions DOWN from the brain

Located in the more central aspect of the brain and Peripheral aspect of the spinal cord → the ascending and descending pathways

Fxn of white matter - brain

Conducts, processes, and sends nerve signals up and down the spinal cord

first order neuron extends from ... and runs to

Extends from skin receptors and runs to dorsal root ganglion into the posterior horn of gray matter in the spinal cord

Second order neuron carries sensory impulses to ___

Carries sensory impulses to subcortical areas in the thalamus

Third order neuron carries ___ to ____

impulses to cerebral cortex

Components of descending pathways

Pyramidal Tracts

- Corticobulbar

- Corticospinal

Extrapyramidal Tract

What describes an upper motor neuron

Cerebral cortex and brain stem

Spinal cord to anterior gray horn

Corticospinal pathway synapses in the ____ of the spinal cord just prior to leaving the cord. Why is this important?

Synapse at the anterior horn.

This is important for motor neurons above the level of the synapse (connecting the cerebral cortex and anterior horn) are termed upper motor neurons and those beyond this level are Lower motor neurons

LMN is composed of

Spinal cord to skeletal muscles

UMN defect

spastic paralysis

no significant muscle atrophy

fasciculations and fibrillations NOT present

Hyperreflexia

Babinksi reflex may be present

LMN defect

Flaccid paralysis

Significant atrophy

Fasciculations and fibrillations present

Hyporeflexia

Babinski reflex NOT present

Where does the spinothalamic tract usually cross over?

Crosses over within 1-2 vertebral segments → at the area of injury (usually)

spinothalamic tract extends to

the thalamus and cerebral cortex

Injury to the spinothalamic tract causes loss of

Pain and temperature sensation contralaterally

Some loss of light touch

Pathway of spinothalamic tract

Dorsal Root Ganglion

Substantia gelatinosa: dorsal horn of the spinal cord

Contralateral spinal cord

Brain stem

Thalamus

Postcentral gyrus - contains the primary somatosensory cortex (function) so used interchangeably

Causes of injury to spinothalamic tract

Trauma

Syringomyelia

Anterior Spinal Artery Syndrome

Thalamic Pain syndrome

Posterior column crosses over at and extends to

brain stem

extends to the thalamus and to the cerebral cortex

Posterior column is involved with

fine touch:

- Meissner corpuscles

- Free nerve endings on hair follicles

Two point discrimination:

- Meissner Corpuscles

Conscious Proprioception:

- Muscle spindles

- Golgi tendon organs

Pressure and vibration: Pacinian Corpuscles

Pathway of the posterior column

Skin

↓

Fasicuculus Gracilis (lower extremities)/Fasciculus Cuneatus (Upper extremities)

↓

Medulla: cross over at medullary tegmentum

↓

Medial lemniscus

↓

Brain stem

↓

Thalamus

↓

Somatosensory cortex of postcentral gyrus

injury to the posterior column causes

ipsilateral symptoms

Causes of injury to the posterior column

Tabes Dorsalis → syphilis

Vit B12 deficiency

Brown Sequard Syndrome

Spinocerebellar tract controls

Controls UNCONSCIOUS proprioception

- Primarily lower limbs and trunk

- Walking

- There is no crossover of posterior portion but there IS crossover of the anterior portion

Causes of injury to the Spinocerebellar Tract

Tabes Dorsalis (tertiary syphilis)

B12 deficiency (pernicious anemia)

Vitamin E deficiency → similar sxs to B12 deficiency + hemolytic anemia

Friedreich’s ataxia

Brown Sequard Syndrome

Describe anterior cord syndrom

- Bilateral loss of motor, pain, and temp sensation below level of injury

- Intact vibration and proprioeption (dorsal column)

- Hyperflexion injury or disruption of anterior spinal artery

Describe central cord syndrome

- Sensory and motor deficit

- Upper ext affected more than lower ext

- Hyperextension injury (ex - often following a hyperextension injury in a patient with underlying spinal stenosis), the medial fibers (those for the upper extremities) are damaged disproportionately more than the lateral fibers (those for the lower extremities), leading to the characteristic greater weakness in the arms.)

- Classically in older patients who have underlying cervical dz (think cervical spinal stenosis)

Describe brown sequard syndrome

- Ipsilateral loss of motor, vibration, proprioception

- Contralateral loss of pain and temp

- Penetrating trauma or lateral compression

Syringomyelia causes injury to what tract

Spinothalamic Tract

Causes of Syringomyelia

Loss of normal flow of CSF:

- Trauma

- Birth defect (Chiari I malformation)

- Sxs can start as late as 25-40 y/o

Sxs of Syringomyelia are d/t

Cystic enlargement of the spinal cord

What is preserved in Syringomyelia and what is affected

Touch and proprioception are preserved because the posterior column is intact

Pain and temperature are affected bc the spinothalamic tract is affected

Upper extremity weakness > Lower extremity weakness

Syndromes seen with Syringomyelia

Horner’s Syndrome → Ptosis, anhidrosis, miosis

Scoliosis

Neuropathic arthropathy of the shoulder and elbow

Central Cord Syndrome → weakness/paralysis worse in the upper extremity compared to the lower extremities, fine motor skills diminished (writing, buttons, utensils), loss of pain/temp in the UE

Anterior Spinal Artery Syndrome affects which tract

Spinothalamic Tract

Anterior Spinal Artery Syndrome is a result of

Infarction of the anterior spinal artery or hyperflexion injury

Football, gymnastics

Beck’s Syndrome:

Causes include: aortic dissection, atherosclerosis, Lupus, AIDS, AV malformation

Anterior Spinal Artery Syndrome sxs

Sudden onset

Loss of pain and sensation B/L

Flaccid and areflexic paraplegia (infarct usually in the T spine)

Autonomic response → urinary incontinence

What is preserved in anterior spinal artery syndrome and why

Vibration and proception are preserved (bc they are apart of the posterior column)

Thalamic Pain Syndrome affects what tract

Spinothalamic Tract

Thalamic Pain Syndrome is a complication of

CVA/stroke

Thalamic Pain Syndrome sxs

Initial loss of ALL sensation to contralateral side

↓

Then pain to contralateral side

May seem to be psychosocial rather than physiologic

Pain worse with CHANGE in temperature

Sensation of pain as the body tries to reset → cannot shut down the signal; uncontrollable pain

Tabes Dorsalis → Syphilis affects which tract

posterior column

Tabes Dorsalis → Syphilis is a result of

Demyelination of the posterior column pathway

Sxs of tabes dorsalis

Delayed sensory input

Loss of reflexes

Decrease in vibration and position sense: Progressive ataxia

Charcot joints

Argyll Robertson Pupils (CN III, IV, VI) → Pupils unable to constrict but accommodation is preserved

Subacute Combined Degeneration of the Spinal Cord: Severe Vit B12 Deficiency affects which columns

Affects the posterior column and lateral column

Sxs of Subacute Combined Degeneration of the Spinal Cord: Severe Vit B12 Deficiency affects which columns

Compromised nerve transmission

Paresthesias

Loss of vibratory sense

Loss of proprioception

Spastic paresis and hyperreflexia (lateral column symptoms)

Might see macrocytic anemia on labs

What is NOT found in Subacute Combined Degeneration of the Spinal Cord: Severe Vit B12 Deficiency

NO CHARCOT JOINTS OR ARGYLL ROBERTSON PUPILS

Brown Sequard Syndrome affects which tract

posterior column

Brown Sequard Syndrome is a result of

C spine injury that involves only one side of the spinal cord:

- Trauma

- Stabbing

Abscess and tumor are rare causes

Sxs of brown sequard syndrome

Loss of spinothalamic tract, corticospinal (motor) tract, and posterior column

Classic Clinical Features:

- Loss of pain and temp → Contralateral

- Hemiparesis → Ipsilateral

- Loss of vibration and proprioception → Ipsilateral

Friedreich Ataxia affects which tract

Spinocerebellar Tract

Friedreich Ataxia is a result of degeneration of

Spinocerebellar tract

Dorsal root ganglia

Dorsal column

Lateral corticospinal tracts (think hyperreflexia → UMN sxs)

Friedreich Ataxia sxs

Ataxia

Loss of proprioception

Spastic paralysis

Loss of DTR

Ataxia and paresthesias are common sxs for ALL spinocerebellar tract injuries

Corticospinal tract controls

limb and trunk movement

Corticospinal tract pathway

Motor cortex to medulla

↓

- Cross over at this point

- Injury above the medulla will show contralateral sxs

- Injury below the medulla will show ipsilateral sxs

- Travels along the lateral funiculus in the spinal cord

- Ends at the Junction of the UMN and LMN

Voluntary motor control

the corticobulbar tract controls

head, neck, and face movement

corticobulbar tract: Motor cortex to LMN of CN:

V, VII, IX, X, XI, XII

Sxs of injury to corticobulbar tract tend to be ____ except in CN ____

Symptoms tend to be BILATERAL → EXCEPT in CN VII and XII with symptoms being contralateral

Causes of injry to corticobulbar tract

Upper motor neuron injury:

Stroke

ALS

MS

Tumors

Parkinson’s

Demyelinating diseases

NOT Bell’s Palsy

Extrapyramidal tract is located in ___ and is in charge of

Located in the brain stem

Involuntary Muscle Movements:

Muscle tone

Balance

Posture

Modulator of motor response

Injury of the extrapyramidal tract causes

Hypokinetic Symptoms

and

Hyperkinetic Symptoms

Difference between hyper and hypokinetic sxs for extrapyramidal tract injuries

Hypo:

Bradykinetic movement

Loss of pendulation with walking

Parkinson’s disease or Parkinsonism (medication induced) → Dopamine

Hyper:

Athetosis: Twisting, worm/snake like movement of the limbs

Chorea: Involuntary, brief and unpredictable movements (fidgety, can’t sit still) movement flow from one part of the body to the other (dance like)

Myoclonus: jerky movements

Emg differences for an UMN vs LMN

UMN:

Normal nerve conduction

Decreased interference pattern and firing rate

LMN:

Abnormal nerve conduction

Large motor units

Fasciculations and fibrillations

MCC of death for ALS

Pulmonary infx

Key for sxs for ALS

Mixed Upper and Lower Neuron symptoms

UMN sxs for injury to corticospinal tracts

LMN sxs for injury to anterior horns and grey matter

Progressive neurodegenerative symptoms

Sxs of ALS

Difficulty with the following d/t BULBAR involvement (CN IX, X, XI, XII):

- Swallowing

- Chewing

- Coughing

- Breathing

- Talking (dysarthia)

Vague sensory

complaints

Progressive weakness

Cognitive complaints

PE ALS and CNs involved

Drooping of the soft palate → IX, X

Depressed gag reflex → IX, X

Pooling of saliva in pharynx → IX, X

Weak cough

Tongue wasting with contraction and fasciculations

Sensory sensation typically preserved

Sphincter function usually intact

Spasticity (UMN finding)

Weakness, atrophy, and fasciculations (LMN findings)

EMG ALS

Acute and chronic partial denervation w/ reinnervation

- Changes in cervical, thoracic, and lumbar region

- Two spinal regions and bulbar musculature

Motor conduction velocity → normal to slightly reduced

Sensory conduction → normal

serum Cr Kinase and CSF in als?

Serum Cr Kinase:

Slightly elevated

CSF:

Normal

Tx for ALS

Riluzole

Benzothiazole: Glutamate Blocker

Edaravone→ Free radical scavenger (antioxidants)

Sodium phenylbutyrate

Noninvasive ventilation 4 hrs/d → start with maximal inspiratory pressure less than 60 cm H20

Drooling control:

- OTC decongestants

Anticholinergic: Trihexyphenidyl, Amitriptyline, Atropine

For pseudobulbar effect: Dextromorphan/quinidine

Tracheostomy

Gastrostomy tube

Advanced care directives

2 types of rxns for tertiary syph

Hyperproliferative gummatous rxn:

- Rapid onset

- Prompt response to therapy

Diffuse inflammation that involves the CNS, large arteries

- Fatal if not treated

Overall sxs for tertiary syph

skin

mucous membranes

skeletal

eyes

respiratory

gi

cv

general paresis - involvement of the cerebral cortex

Skin/mucous membrane sxs tertiary syph

Skin

Cutaneous lesions

Multinodular lesions

Solitary gummas (painless)

Mucous membranes:

Nodular gummas

Leukoplakia

Skeletal sxs tertiary syph

Destructive bone lesions

Periostitis

Osteitis

Arthritis: Myalgia/myositis w/o redness or swelling

Eye sxs tertiary syph

Gummatous iritis

Optic atrophy

Neurologic sxs for tertiary syph

Sxs can occur in any stage of disease

May be progressive, disabling, and life threatening

CN palsies

Resp sxs of tertiary syph

Gummatous infiltrates to larynx, trachea, and pulmonary parenchyma

Hoarseness

Respiratory distress

GI sxs of tertiary syph

Cirrhosis

Gastric lesions

Involvement of the cerebral cortex presents as ____ with tertiary syph (list the sxs)

Loss of concentration

Memory loss

Dysarthria

Tremors fingers/lips

Irritability

HA

Personality change → slovenly, irresponsible, confused, psychotic

asymptomatic diagnostic findings for tertiary syph

Abnormal CSF Findings:

- + spinal fluid serology

- Lymphocytic pleocytosis

- Inc protein

Symptomatic diagnostic findings for tertiary syph

Meningovascular Syphilis:

- HA

- Irritability

- CN palsies

- Unequal reflexes

- Irregular pupils (accomodation and poor light reflexes)

- CVA

- CSF similar to asymptomatic findings

What is tabes dorsalis

Chronic progressive degeneration to the:

Parenchyma of the posterior column to the posterior roots/ganglia

- Proprioception

- Vibration

Posterior sensory ganglia

Nerve roots

Sxs of tabes dorsalis

Paresthesias

Analgesia

Radicular type pain

Charcot joints: painless, destructive arthritis w/ progressive deformity

Argyll Robertson Pupil:

- Poor light rxn

- Accomodation intact

Hyporeflexia

Wide based gait/ inability to walk in the dark → lack of constriction of pupils

How to diagnose tabes dorsalis

LABS:

Lumbar puncture for CSF analysis:

- Normal to increased lymphocytic cell count

- Elevated protein

VDRL → screens for syphilis: should be +

RPR → screen for syphilis

Tx for tabes dorsalis

IV Penicillin G 18-24 million units per day dosed q 4 hours for 10-14 days

Ceftriaxone if PCN allergy:

Test for PCN allergy

2g IM or IV x 10-14 d

REPEAT serology tx q3-6 mo after tx

what does Guillain Barre Syndrome commonly follow

Illness

A/w campylobacter jejuni enteritis

- Undercooked or Raw poultry MCC

Inoculations

Surgery

Sxs of Guillain Barre Syndrome

Weakness:

Proximal emphasis

Starts in the legs → can extend to arms and face

Muscles of respiration/deglutition

Ascending weakness with eventual central weakness making it hard to breath

Sensory Deficits:

Distal paresthesias

Neuropathic and radicular pain

Autonomic sxs (may be life threatening)

Tachycardia

Hypo vs hypertension

Cardiac irregularities

Abn sweating

Pulmonary dysfunction

Dx of Guillain Barre Syndrome

LABS:

CSF:

Increased protein

Normal cell count

WBC greater than 50 cells/mcL

Tx Guillain Barre Syndrome

Hospitalization

Plasmapheresis

IVIG

Respiratory toileting

- Airway suctioning

- Chest PT

- Incentive spirometry

- Nasotracheal suctioning

Chest PT

DVT prophylaxis

ICU admission if decreasing forced vital capacity

what tx is INEFFECTIVE in Guilliane barre

Prednisone

- GBS has different immune mechanism that involves both cellular and humoral (antibody mediated) components

- Corticosteroids like Prednisone have little effect on this immune response

what is pernicious anemia

Impaired Vit B12 absorption d/t lack in intrinsic factor:

- Proprioceptive loss

- Weakness and spasticity (UMN sxs)

- Posterior column and corticospinal tract involvement

sxs of pernicious anemia

Glossitis

Anorexia

Diarrhea

Peripheral neuropathy

Balance/proprioception issues

Dementia sxs

Pale to icteric skin coloration

Loss of vibratory sense

Dx pernicious anemia

CBC:

Moderate to severe anemia

Megaloblastic changes

Decreased retic counts

Vit B12:

< 200 pg/mL

Elevated methylmalonic acid: build up can cause demyelination - not broken down d/t lack of B12

Elevated homocysteine levels: inc risk of thrombosis and vascular disease

Ddx:

Folic acid deficiency

Tabes Dorsali

Tx of pernicious anemia

Parenteral B12 - IM vs SubQ

Methylcobalamin: Oral vs SL 1 mg qday

Tx for pernicious anemia if the patient has neurologic sxs

Parenteral B12 preferred

- If neuro sxs <6 mo, may see improvement

- May see reticulocytosis at initiation of tx

- Hypokalemia

poliomyelitis: anterior or posterior horn involvement?

UMN or LMN involvement?

Contagious?

Anterior horn involvement

LMN involvement:

- Weakness

- Atrophy

- Fasciculation/fibrillations

- Hyporeflexia

HIGHLY contagious: Fecal oral

Sxs of poliomyelitis

Abortive:

- Fever

- HA

- Vomiting

- Diarrhea vs constipation

- Sore throat

Nonparalytic

- Abortive sx +

Meningeal irritation

- Muscle spasms

- Absence of paralysis

Paralytic:

- Flaccid asymmetric paralysis: proximal muscles of lower extremities

- Febrile period 2-3 d

- Sensory loss rare

- Spinal variant: Spinal nerve involvement

Bulbar:

- CN involvement IX and X

75% mortality rate

Dx poliomyelitis

LABS:

Throat washing

Stool studies

CSF:

- Inc opening pressure

- Normal glucose

- WBC < 500

tx of poliomyelitis

Hospitalization: skin precautions

ICU admission if respiratory sxs

Physical therapy

MOA Riluzole; who is this used for

ALL ALS patients

Inhibits presynaptic glutamate release

Blocks voltage gated Na channels

Dec rate of motor neuron death