Peripheral Neuropathies

Question 1

Polyneuropathy

Answer 1

Symmetrical distal sensory loss with burning or weakness.
Med rxn or systemic dz
Can be axonal or demyelinating

Question 2

Guillain-Barre Syndrome (GBS)

Answer 2

Acute immune-mediated group of polyneuropathies, usually provoked by preceding infection.

Question 3

GBS Patho

Answer 3

Acute inflammatory demyelinating polyneuropathy (AIDP)
Can be caused by preceding infxn, immunizations, surgery
Generation of antibodies against galgliosides that cause an immune response against axons

Question 4

Which bug usually causes GBS?

Answer 4

Campylobacter Jejuni

also CMV, EBV

Question 5

GBS clinical features

Answer 5

Symmetrical muscle weakness
Decreased DTR's
Respiratory involvement
Parasthesias in hands and feet
Severe back pain

Question 6

Where does weakness usually start in GBS?

Answer 6

Proximal legs, arm and facial muscles

Question 7

Dysautonia

Answer 7

Common in GBS

Tachycardia, urinary retention, HTN altering with Hypotension, bradycardia, ileus, loss of sweating.

Question 8

Therapy for GBS?

Answer 8

Plasmapheresis or IVIG

Question 9

GBS DIagnosis

Answer 9

LP: Elevated protein

Neurophysiology studies

Question 10

Bell’s Palsy

Answer 10

Acute peripheral facial palsy of unknown origin

Involves the facial nerve (CN VII)

Question 11

What does the facial nerve innervate?

Answer 11

Facial motor output
Parasympathetics to salivary glands (including lacrimal)
Taste for anterior 2/3 of tongue
Somatics for EAC and pinna.

Question 12

Bells palsy Epidemiology

Answer 12

Risk 3x greater in pregnancy
DM is risk factor
Recurrence is common

Question 13

Bells palsy patho

Answer 13

Herpes virus most likely cause
Can also be other viruses
Ischemia may play a role

Question 14

Bells palsy clinical presentation

Answer 14

Sudden onset over hours**
Eyebrow sagging, cant close eye
Mouth drawn to non-affected side
Decreased tearing**

Question 15

Bells palsy course

Answer 15

Onset over hours to 1-2 days
Maximal paralysis within 3 wks of onset
Some degree of recovery by 6 months
Usually recover fully

Question 16

Bells Palsy Mgmt

Answer 16

Eye care (drops)
Glucocorticoid therapy within 3 days of onset
For severe, valcyclovoir

Question 17

Myasthenia Gravis (MG)

Answer 17

Autoimmune disorder characterized by weakness and fatiguability of skeletal muscle.
Decrease in number of acth receptors

Question 18

What are the antibodies against in MG?

Answer 18

Acetylcholine receptors (AchR-Ab)

Question 19

MG Patho

Answer 19

Acetylcholine receptor antibodies mount immune response via complement against receptors.
T cells bind receptors and activate B cells.

Question 20

Which thymus abnormalities do MG patients usually have?

Answer 20

Thymoma or hyperplasia

Question 21

MG Bimodal distribution

Answer 21

Females peak in 2nd and 3rd decade

Males peak in 6th to 8th decade

Question 22

MG Clinical Manifestations

Answer 22

Fluctuating skeletal muscle fatigue worsened by contractile force.  
Ptosis, worse w/ upward gaze
Diploplia
Weakness with prolonged chewing
Dysphagia

Question 23

MG Neck and Limb Symptoms

Answer 23

Dropped head syndrome from weak neck

Limb proximal weakness Arms > Legs

Question 24

MG respiratory sx

Answer 24

Respiratory muscles weaken and leads to respiratory failure

Question 25

MG Course

Answer 25

Symptoms ok in morning, worse later in day | Maximal extent of dz seen in 3 yrs

Question 26

MG Dx

Answer 26

Detect circulating AChR-Ab | Electromyography

Question 27

MG Tx

Answer 27

Pyridostigmine Corticosteroids IVIG Thymus surgery

Question 28

Polyneuropathy Causes

Answer 28

Diabetic polyneuropathy most common | AIDS, B12 def, Toxins, Uremia

Question 29

Polyneuropathy Patho

Answer 29

Axonal injury is most common | Demyelinating seen in some autoimmune processes

Question 30

Polyneuropathy Presentation

Answer 30

Slowly progressive loss of sensation in feet 1st Dysesthesias, burning, pain Gait abnormalities Stocking and glove weakness

Question 31

Risk factors for diabetic polyneuropathy (DPN)

Answer 31

``` Duration and severity of hyperglycemia Increased triglycerides Increased BMI Smoking HTN ```

Question 32

Diabetic Polyneuropathy Patho

Answer 32

Accumulation of AGE's, collagen cross-linking, increased permeability, monocyte influx, vascular injury. Accumulation of sorbitol, interferes w/ cell metabolism. Axonopathy

Question 33

What is the most common neuropathy in the western world?

Answer 33

Diabetic neuropathy. | 50% of DM pts will develop

Question 34

DPN S/S

Answer 34

Loss of vibratory sensation and proprioception IMpaired pain, light touch and temp perception Decreased/absent DTRs Widespread losses are a late finding

Question 35

Best pain reliever for Polyneuropathy

Answer 35

Gabapentin (Neurontin)

Question 36

Best pain reliever for Diabetic PN

Answer 36

Pregabalin (lyrica)

Question 37

Other meds for Polyneuropathy

Answer 37

``` Gabapentin (Neurontin) TCA's (amitryptaline) Carbamazepine (Tegretol) - varying success Pregabalin (lyrica) - Diabetics Duloxetine (Cymbalta) ```

Question 38

Alcoholic Polyneuropathy Patho

Answer 38

Axonal neuropathy complicated by demyelination with coexisting nutritional deficiency Normal thiamine status Alcohol is direct neurotoxin

Question 39

Vitamin B12 Deficiency

Answer 39

Cobalmin | Must have adequate dietary intake and intrinsic factor

Question 40

B12 Patho

Answer 40

Defect in myelin formation leads to subacute degeneration of dorsal and lateral spinal columns.

Question 41

S/S of B12 Def.

Answer 41

Parasthesias, ataxia, loss of proprioception, weakness, spasticity, clonus, paraplegia

Question 42

B12 Tx

Answer 42

IM B12 injections 1000mg twice weekly

Question 43

VItamin E deficiency

Answer 43

Spinocerebellar syndrome | Seen in pancreatic deficiency, cholestasis

Question 44

Vitamin E deficiency tx

Answer 44

Large oral doses of IM Alpha-Tocopherol | then daily oral vitamin E

Question 45

Thiamine Deficiencies

Answer 45

Seen in malnutrition, alcoholism, bariatric surgery | Dri or wet Beriberi

Question 46

Dry beriberi

Answer 46

Neuropathy associated with calf cramps, muscle tenderness, burning feet, autonomic neuropathy may be present.

Question 47

Wet beriberi

Answer 47

High output CHF and neuropathy