Neuropathies

Question 1

Most commonly targeted part of the neuron (in neuropathies)

Answer 1

Axon

ex, T2DM

Question 2

a generalized, relatively homogeneous process affecting many peripheral nerves, with the distal nerves usually affected most prominently

Answer 2

Polyneuropathy

Question 3

any disorder of the peripheral nervous system including radiculopathies and mononeuropathies

Answer 3

Peripheral neuropathy

Question 4

Classification of polyneuropathies

Answer 4

Rate of onset

Type of symptoms of deficits

Distribution

Question 5

Common example of mononeuropathies

Answer 5

Carpal tunnel

Sciatica

Bells palsy

Femoral (meralgia perasthetics)

Question 6

simultaneous or sequential involvement of individual noncontiguous nerve trunks

Answer 6

Mononeuropathy multiplex syndrome

Question 7

damage to motor or sensory nerve bodies

Answer 7

Neuronal degeneration

Question 8

damage to the axon below the cell body

Answer 8

Wallerian

Question 9

diffuse axonal damage

Answer 9

Axonal degeneration

Question 10

injury to the myelin sheath only

Answer 10

segmental demyelination

Question 11

Causes of polyneuropathy

Answer 11

COMMON: diabetes mellitus, alcohol abuse, and HIV infection

GENERAL CATEGORIES
Inherited (CMT - Shark tooth)

Infection / Autoimmune

Physical Injury

Systemic disease

Question 12

Idiopathic polyneuropathy often following minor infections, (particularly in LUNG and GI), immunizations, surgical procedures. Often idiopathic.

Answer 12

Guillan Barre

Question 13

Unilateral facial muscle weakness without noted neurologic disease, without apparent cause. Thought to primarily be caused by HSV - could also be Zoster, trauma, toxins.

Answer 13

Bell palsy

More than 60% of cases occur on right side

Question 14

Guillan Barre affects what part of neuron

Answer 14

Predominantly demyelinating

Damages myelin and/or Schwann cells

Question 15

Some causes of toxic / drug induced neuropathies

Answer 15

Predominantly axonal

Alcohol
Chemo
Organic compounds (pesticides, hexane glue)
Lead
Arsenic

Question 16

No specific cause identified in up to _____ of polyneuropathies

Answer 16

25%

Question 17

Clinical characteristics of poyneuropathies, in general

Answer 17

Symmetric distal sensory loss
Burning
“Pins and needles” sensations
Weakness

Can be asymptomatic and found incidentally on exam

Question 18

This particular sensory polyneuropathy is characterized by asymmetric weakness and wasting involving predominantly the proximal muscles of the legs, accompanied by local pain

Answer 18

Diabetic amyotrophy

Question 19

Example of “Chronic axonal polyneuropathy”

Answer 19

Diabetes

Question 20

Most commonly diagnosed neuropathy in western hemisphere

Answer 20

Diabetic peripheral neuropathy - 70% is mixed peripheral (sensory, motor, autonomic)

Question 21

the most common form of diabetic neuropathy and manifests as sensory loss beginning in the toes that gradually progresses over time up the legs and into the fingers and arms.

Answer 21

diabetic polyneuropathy

Question 22

PE findings of sensory polyneuropathy

Answer 22

“stocking glove”

Wasting muscles

depressed deep tendon reflexes

impaired vibratory sensation

Question 23

Caused by repeated micro fractures of foot bones, a long term consequence of diabetic polyneuropathy

Answer 23

Rocker-bottom charcot foot

Question 24

How is GBS demyelinating polyneuropathy distinct from axonal?

Answer 24

Primarily affects motor neurons

weakness (rather than sensory loss) is an early sign

Question 25

Chronic inflammatory polyneuropathies present

Answer 25

Weakness and generalized sensory loss often present together

Question 26

"stocking - glove" presentation

Answer 26

peripheral neuropathy (diabetic, usually)

Question 27

Diagnosis of polyneuropathy

Answer 27

Largely clinical (physical exam / history) ``` Labs to rule out other causes Lymes, B12, Thyroid, Alcohol abuse Amyloidosis ``` EMG to determine whether axonal or demyelinating

Question 28

What diagnostic studies might help you differentiate between axonal and demyelinating neuropathy? Or Myopathy?

Answer 28

EMG - spontaneous muscle fiber activity at rest = axonal loss Nerve Conduction Studies - axonal = lower amplitude - demyelinating = long latency and slower conduction

Question 29

Which nerve is preferred for biopsy?

Answer 29

Sural Nerve (ankle)

Question 30

Tx of polyneuropathy

Answer 30

Tight control of hyperglycemia Amitryptyline, Gabapentin help w neuro pain Duloxetine, an SSRI

Question 31

Most common microorganism indicated as precipitant of Guillan Barre

Answer 31

Campylobacter jejuni

Question 32

Common viral precipitant of GBS

Answer 32

Epstein Barr, CMV, HIV

Question 33

GBS - demyelinating or axonal neuropathy?

Answer 33

Demyelinating (mostly)

Question 34

Clinical presentation, Guillan Barre

Answer 34

Symmetrical extremity weakness, begins DISTALLY and ASCENDS Mostly affects motor - weakness Cranial nerves can be affected - sensory abnormalities Autonomic disfunction - 30% need ventilation

Question 35

Tx Guillan Barre

Answer 35

*patients should be hospitalized, risk of ventilation need* Plasmapheresis is very effective IV IgG - effective and better for children / CV risk 60% have full recovery within 1 yr

Question 36

Characterized by insidious onset of muscle weakness and fatigue. Can be exacerbated by infection. Antibodies against acetylcholine receptors present. More common in young women.

Answer 36

Myasthenia Gravis

Question 37

Antibodies in MG directed against -

Answer 37

Acetylcholine receptors, esp in muscle

Question 38

Clinical features of MG

Answer 38

Ptosis Diplopia Chewing / Swallowing difficulty Respiratory difficulties Limb weakness Or combo of all Relapse / remissions over a long period

Question 39

Tx for MG

Answer 39

Anticholinesterase (Pyridostigmine, Edrophonium) Steroids, IvIG, plasmapheresis for refractory Thymectomy?

Question 40

Diagnosis MG

Answer 40

CT or MRI of Chest to rule out Thymoma Electrophysiologic studies show decrementing muscle response Labs for acetylcholine receptor antibodies and/or MuSK (muscle-specific tyrosine kinase) antibodies

Question 41

"Unilateral shock-like pain" idiopathic or caused by neuromuscular compression

Answer 41

Classic Trigeminal Neuralgia

Question 42

"Unilateral shock-like pain" concomitant to trauma, herpes, MS, or CNS lesion

Answer 42

"Painful" or Secondary Trigeminal Neuralgia

Question 43

Risk factors for classic Trigeminal Neuralgia

Answer 43

HTN, migraines, risk factors (compression) Berry aneurysm

Question 44

Autonomic symptoms of trigeminal neuralgia

Answer 44

Lacrimation Rhinorrhea

Question 45

Tx Trigeminal Neuralgia

Answer 45

Carbamazapine preferred Gabapentin, Lamotrigine, ValPro Surgery, ablation / decompression

Question 46

Regional pain in limb after surgery, injury, or vascular event with edema, color changes in skin, bone thinning, restricted mobility.

Answer 46

Complex Regional Pain Syndrome

Question 47

Hallmark feature of CRPS

Answer 47

Severe burning or throbbing pain, with allodynia Cyanosis, sensitivity to temp, atrophy may be present

Question 48

Diagnosis of CRPS

Answer 48

Mainly clinical Regional nerve block - complete relief = CRPS MRI, X Ray can help

Question 49

Tx CRPS

Answer 49

Early mobilization after injury / surgery Neuro drugs: Amitryptiline, Gabapentin, Lamotrigine NSAIDs Calcitonin helps the bone resorption

Question 50

End result of bells palsy, regardless of specific cause

Answer 50

Damage to myelin in facial nerve (CN VII)

Question 51

Bells palsy seen more frequently in which patient population

Answer 51

Pregnant women Diabetics

Question 52

Clinical features Bells Palsy

Answer 52

Facial Paralysis - progressed from weakness - forehead, lower face Pain in ipsilateral ear May have impairment of taste, lacrimation, or hearing

Question 53

Timeline for bells palsy

Answer 53

Peaks in about 21 days or less about 6 months to recover

Question 54

DDX for Bells Palsy

Answer 54

Lymes! stroke, tumor, AIDs, sarcoidosis

Question 55

Tx Bells Palsy

Answer 55

60% require no treatment Eye drops, supportive Oral prednisone