Coma, MN Disease, Radiculopathy

Question 1

Familial Muscular Atrophy

Answer 1

anterior horn cell disease

Question 2

Poliomyelitis

Answer 2

anterior horn cell disease - infection by polio virus

Question 3

Amyotrophic Lateral Sclerosis

Answer 3

• Upper +/- Lower motor neuron degeneration
• progressive and lethal within about 5yr (usually)
• weakness, atrophic fasciculations, hyperreflexia, positive Babinski, spasticity
• atrophy progresses distal to proximal
• normal sensation

Question 4

Werdnig-Hoffmann

Answer 4

“Infantile SMA”

• AR; SMN1/2 on CHR 5q - SMN1 absent, SMN2 short determines infantile type (instead of longer which would be juvenile)
• progressive LMN disease
• fatal (usually 2/2 respiratory failure)
• floppy baby, frog leg posture

Question 5

Wolfart-Kugelberg-Welander

Answer 5

“Juvenile [Proximal Chronic] SMA”

• AR; SMN1/2 on CHR 5q - SMN1 absent, SMN2 longer determines juvenile (instead of infantile, shorter) type
• progressive LMN disease

Question 6

[Progressive] Spinal Muscular Atrophy (SMA)

Answer 6

• progressive LMN disease
• Infantile (AR): Werdnig-Hoffman
• Juvenile (AR): Wolfart-Kugelberg-Welander
• Adult-Onset: sporadic, some are familial

Question 7

Progressive Bulbar Palsy

Answer 7

• like ALS but primarily affects the muscles innervated by the medulla (“bulbar atrophy”)
• also tongue atrophy

Question 8

Progressive Lateral Sclerosis

Answer 8

• only affects UMNs (so like ALS but specific to UMNs)

- sporadic, more benign course (slower progression than ALS)

Question 9

Differential for ALS

Answer 9

• Multisystem atrophy: late onset degenerative nerve disease that is progressive but slower than ALS
• Craniocervical junction disorders: get MRI to rule out
• Cervical spondylosis: would see mostly arm/hand weakness and maybe sensory loss (maybe not); also see on MRI as protruding discs
• Post-polio syndrome: must have had polio in childhood (cause of this is unknown - age-related degeneration of previously infected LMNs?)

Question 10

Kennedy Disease

Answer 10

“Spinal Bulbar muscular atrophy”

• caused by androgen receptor mutations (X chr)–DNA test to diagnose
• classic phenotype = LMN syndrome, gynecomastia, testicular atrophy
• more benign, may present w/o family history

Question 11

Non-progressive unilateral limb weakness and atrophy

Answer 11

• a more benign motor neuron syndrome

- etiology unclear but may be caused by dural compression of the spinal cord

Question 12

How to differentiate ALS from a muscle weakness type presentation of myasthenia gravis or Eaton-Lambert syndrome?

Answer 12

Do an EMG.

Also, rule out myopathies with muscle biopsy and serum CPK.

Question 13

Bunina body

Answer 13

• dense granule inclusions of ubiquitin in cell body cytoplasm of anterior horn cell neurons
• seen in ALS

Question 14

Etiology of ALS

Answer 14

unknown; some genetic associations include:

• superoxide dismutase (SOD) mutation (AD, Chr 21)
• Chr 17-linked FTD
• others; but all (except SOD mutation) are rare

Question 15

Treatment of ALS

Answer 15

• there is no cure
• Glutamate antagonists help
• symptomatic treatments (anticholinergics, antidepressants, respiratory assistance)
• PT
• experimental treatments are out there

Question 16

2 MCC’s of radiculopathies

Answer 16

1. disc herniation/degeneration (50yo)

Question 17

Clinical Features of Radiculopathies

Answer 17

PAIN

• radiates
• sharp, hot, stabbing, electric
• worse when root is stretched (neck extension or straight leg raise maneuvers)
• pain relieved by walking uphill or riding bike
• negative sx: weakness, atrophy, paresthesias, diminished or absent sensory loss, muscle stretch reflexes

Question 18

New onset back pain - what could it be?

Answer 18

1. Emergency? - spinal cord compression; cauda equina syndrome; spinal column fracture/dislocation
2. Bone disease? - OP, OM, Paget, steroids, congenital
3. Infection? - of the spinal cord is called myelitis; will have fever, pain
4. Neoplasm? - will often have pain at rest, hx of cancer (if current known cancer consider mets), constitutional sx, neuro deficit (local lesion)
5. Spinal stenosis? - inc. pain with extension, dec. pain with flexion

Question 19

EDX (electro-diagnostic) testing is used for…

Answer 19

assessing nerve fiber function; helps characterize the lesion better than clinical exam

Question 20

Treatment for radiculopathy

Answer 20

• most improve within 6wk
• keep moving, do PT
• may use NSAIDs, benzo’s, nerve blocks if severe
• surgery for structural lesion (don’t do surgery unless there’s a specific known lesion to address)

Question 21

Etiology of most slowly generalized, symmetric, progressive stocking-glove neuropathy

Answer 21

Toxic-metabolic:

1. diabetes
2. alcohol abuse

Question 22

C6 - innervates which finger?
C7 - innervates which finger?
C8 - innervates which finger?

Answer 22

C6 - thumb
C7 - middle finger
C8 - pinky
In between fingers are mixed

Question 23

Etiology of most subacute-onset, generalized, symmetric, weakness with distal sensory abnormalities

Answer 23

acquired demyelinating neuropathy

Question 24

Etiology of most chronic generalized, symmetric, stocking-glove distribution weakness, out of proportion to degree of sensory loss

Answer 24

hereditary dysmyelination

Question 25

Multiple mononeuropathy - characteristics and etiologies

Answer 25

- asymmetric | - etiologies may be ischemic, inflammatory/immune-mediated; infectious, genetic, mechanical entrapments, neoplastic

Question 26

2nd most common entrapment neuropathy

Answer 26

ulnar - numb pinky | or really any nerve that comes from C8

Question 27

Froment's sign

Answer 27

- in order to grasp something between the thumb and index finger (first dorsal interosseous) the patient must flex the last phalanx of the thumb - cheating to hold the paper when you try to pull it away - flexing palmaris longus

Question 28

Brain structures that mediate consciousness | Lesions of what areas will cause coma?

Answer 28

- extensive acute bilateral hemispheres - lesions of thalamus and hypothalamus - periaqueductal gray - upper 1/3 of pontine tegmentum

Question 29

How to distinguish structural vs. metabolic coma?

Answer 29

- structural will have focal neuro deficit, abnormality on CT, and may produce herniation; likely requires surgical intervention; pupils are first to go - metabolic will have a non-focal exam, normal brain imaging or diffuse changes; medical management; pupils are last to go (will still be sluggish)

Question 30

What treatment is needed immediately for a patient in coma?

Answer 30

1. stabilize vitals - ABCs, cardiac monitoring, IV access * it's unusual to have normal vitals in a true coma 2. stabilize neck, determine circumstances of onset 3. rapidly examine the patient 4. empirical D50, thiamine, naloxone 5. give O2, control ICP*, stop seizures, tx infxn, restore electrolytes, control agitation * hyperventilation will rapidly reduce ICP for ~30min

Question 31

How to prognosticate outcome after coma?

Answer 31

- at presentation: higher the GCS, better the outcome - non-traumatic coma at day 3: poor prognosis if no pupillary light/corneal reflex or no/flexor/extensor motor response - hypoxic coma: absence of purposeful motor movements at day 3 carries poor prognosis

Question 32

``` Lethargic vs. Hypersomnic vs. Obtunded vs. Stuporous vs. Coma ```

Answer 32

Lethargic - sleepy but easily aroused Hypersomnic - excessively sleepy, but normal when awakened Obtunded - mental blunting, decreased alertness Stuporous - eyes open briefly after vigorous stimulation, then return to deep sleep; impaired cognition Coma - eyes remain closed after vigorous stimulation (2-4wk in coma they'll have eye opening and sleep-wake cycles)

Question 33

Abulia vs. Akinetic mutism vs. Minimally conscious state vs. Vegetative state

Answer 33

Abulia - awake but apathetic, no spontaneity Akinetic mutism - silent, alert-appearing immobility Minimally conscious state - fragments of awareness Vegetative state - awake but no awareness or meaningful interaction with the environment

Question 34

Two components of consciousness

Answer 34

1. Arousal: sleep-wake cycles, seated in AAS; disease causes stupor/coma 2. Content/Awareness: puposeful interaction with the world, these behaviors are premeditated and not reflexive; disease of these cognitive circuits causes dementia

Question 35

How to recognize central herniation at the bedside?

Answer 35

Progressive failure of brainstem in rostral direction: - increasing lethargy 2/2 pressure first on reticular gray in both thalami - then SNS tracts from hypothalamus --> small pupils - EW failure --> fixed pupils - Cheyne-stokes respirations Late signs: - decorticate/flexor posturing - decerebrate/extensor posturing

Question 36

Distinct clinical syndrome of pontine hemorrhage

Answer 36

- abrupt coma - pinpoint pupils - decerebrate rigidity or flaccid quadriplegia - horizontal gaze paresis with vertical ocular bobbing - at risk for locked-in syndrome

Question 37

Metabolic encephalopathy

Answer 37

- metabolic insult to the brain causing a non-focal exam with negative CT - clues: pupils stay reactive till the end; asterixis*, multifocal myoclonus, and tremor are present - MCC in elderly are dehydration, drug intoxication, and infection * aka negative myoclonus, a lapse in muscle tone

Question 38

Transition from decorticate to decerebrate posturing

Answer 38

- you are decorticate when you have flexor posturing, because the conscious control of the descending motor tracts (which are flexor-facilitatory) is compromised - you progress to decerebrate when the extensor facilitatory tracts that originate in the pons are the only ones left working; that is you lost midbrain and the higher (flexor facilitatory) tracts