Hertz peripheral nerves etc.

Question 1

actin and myosin are the gears. What’s the energy?

Answer 1

ATP

Question 2

workup of nerve stuff

Answer 2

serum chemistries
nerve conduction studies
muscle biopsy
nerve biopsy (sural nerve, innervates sensory portion of the skin by knee) 
EMG
CSF- look at white cells and protein

Question 3

Charcot Marie-Tooth syndrome

Answer 3

Mutant forms of Myelin Protein Zero (MPZ)

–> demyelinating neruopathy

Question 4

severe atrophy on one leg, what disease?

Answer 4

poliomyelitis
affects anterior horn (nerve itself)
–> denervation atrophy

Question 5

what do we see in electron microscopy of demyellinated nerves?

Answer 5

vacuoles

Question 6

Guillain-Barre

Answer 6

mostly acute-onset immune-mediated demyelinating neuropathy

2/3 of cases are preceded by an acut, influenza-like illness from which the affected individual has recovered by the time the neuropathy becomes symptomatic. Infections with campylobacter jejuni, CMV, Epstein-Barr virus, and mycoplasma pneumoniae, or prior vaccination, have significant epidemiologic associations with Guillain-Barre.

ASCENDING PARALYSIS, won’t see reflexes on achilles tendon, e.g.

Question 7

blue/ black dots on nerve biopsy?

Answer 7

lymphocytes; immune response causing demyelination

Question 8

clinical features of guillain barre

Answer 8

ascending paralysis and areflexia

deep tendon reflexes disappear early (can have sensory involvement)

nerve conduction velocities are slowed (multifocal destruction of myelin segments in many axons within a nerve)

CSF protein levels elevated (due to inflammation and altered premeability of the microcirculation within the spinal roots as they traverse the subarachnoid space)

Question 9

difference between acute and chronic guillain barre

Answer 9

2 months

chronic–> symmetrical mixed sensorimotor polyneuropathy

Question 10

onion bulb neuropathy

Answer 10

an onion bulb - thinly myelinated axon surrounded by multiple concentrically arranged schwann cells (electron microscopy)

Question 11

ulnar deviation with big nodes (fingers)

Answer 11

rheumatoid arthritis

Question 12

neuropathy associated with systemic autoimmune diseases

Answer 12

rheumatoid arthritis
Sjogren syndrome
SLE

can be associated with peripheral neuropathies that often take the form of distal sensory or sensorimotor polyneuropathies

Question 13

vasculitis

Answer 13

noninfectious inflammation of blood vessels that can involve and damage peripheral nerves

Question 14

Segmental vasculitidies with “beading”

Answer 14

Polyarteritis nodosum

Question 15

black dot on skin

Answer 15

kaposi sarcoma (can be nodular too)

Question 16

papules

Answer 16

= tuberculoid leprosy

Question 17

bulls eye rash

Answer 17

lyme disease

Question 18

pseudomembrane back of throat

Answer 18

diptheria

Question 19

vesicles along a nerve

Answer 19

herpes zoster

Question 20

most common cause of peripheral neuropathy

Answer 20

diabetes

–> marked loss of myelinated fibers, thickening of endoneurial vessel wall

Question 21

clinical features of diabetic neuropathy

Answer 21

distal symmetric diabetic polyneuropath- sensory symptoms, numbness, loss of pain sensation, difficulty with balance, paresthesias or dysesthesias

–> increased susceptiibility to foot and ankle fractures and chronic skin ulcers –> amputations

dysfunction of the ANS - protean manifestations, including postural hypotension, incomplete emptying of the bladder (–> recurrent infections), sexual dysfunction

Question 22

Uremic neuropathy

Answer 22

renal failure –> peripheral neuropathy. Typically this is a distal, symmetric neuropathy that may be asymptomatic or may be associated with muscle cramps, distal dysesthesias, and diminished deep tendon reflexes. In these patients axonal degeneration is the primary event; occasionally there is secondary demyelination. Regeneration and recovery are common after dialysis

Question 23

Thyroid dysfunction

Answer 23

Hypothyroidism can lead to compression mononeuropathies such as carpal tunnel syndrome or cause a distal symmetric predominantly sensory polyneuropathy. In rare cases, hyperthyroidism is associated with a neuropathy resembling Guillain-Barré syndrome.

Question 24

Vitamin B12 (cyanocobalamin) deficiency

Answer 24

classically results in subacute combined degeneration with damage to long tracts in the spinal cord, and also peripheral nerves.

Question 25

Other vitamin deficiencies and peripheral neuropathies

Answer 25

Deficiencies of vitamin B1 (thiamine), vitamin B6 (pyridoxine), folate, vitamin E, copper, and zinc

Question 26

salty white stuff around mouth is what?

Answer 26

uremic frost

guy in renal failure

Question 27

bilateral mammillary body hemorrhages is what until proven otherwise?

Answer 27

Wernickes

Question 28

Toxic Neuropathies

Answer 28

Peripheral neuropathies may appear after exposure to industrial or environmental chemicals, biologic toxins, or therapeutic drugs.

Alcohol (independent of associated nutritional deficiencies), heavy metals (lead, mercury, arsenic, and thallium), and organic solvents. Various medications can cause toxic nerve damage, but the most notorious are chemotherapeutic agents. These include vinca alkaloids and taxanes, microtubule inhibitors that interfere with axonal transport, and cisplatin, which may cause a neuronopathy.

Question 29

basophilic stippling on blood smear

Answer 29

lead poisoning

Question 30

spots on hand from

Answer 30

arsenic

Question 31

Neuropathies Associated with Malignancy

Answer 31

Direct infiltration or compression of peripheral nerves by tumor is a common cause of mononeuropathy and may be a presenting symptom of cancer.

Paraneoplastic neuropathies. These can occur at any time during the patient’s course, but often precede the diagnosis of the underlying tumor. Sensorimotor neuronopathy is the most common paraneoplastic form, but a chronic inflammatory demyelinating polyradiculoneuropathy-like picture, plexopathy, and autonomic neuropathy may also be seen. Paraneoplastic sensorimotor neuronopathy is * most commonly associated with small cell lung cancer.

Neuropathies associated with monoclonal gammopathies. Neoplastic B cells may secrete monoclonal immunoglobulins or immunoglobulin fragments (so-called paraproteins) that damage nerves. For example, tumors that secrete IgM immunoglobulin may be associated with a demyelinating peripheral neuropathy.

Question 32

example of tumor that grows and –> arm trouble

Answer 32

pancoast tumor - direct extension into brachial plexus

Question 33

large cells with little cytoplasm

Answer 33

oat cell

Question 34

clock face nuclei with paranuclear hoff body

Answer 34

multiple myeloma

Question 35

traumatic neuroma from hitting floor between 2nd and 3rd metatarsal head of foot

Answer 35

morton neuroma

Question 36

Hereditary motor and sensory neuropathies,

Answer 36

also known as Charcot-Marie-Tooth (CMT) disease

simple—an inherited disease associated with distal muscle atrophy, sensory loss, and foot deformities

Question 37

congo red stain and peripheral neuropathy

Answer 37

familial amyloid polyneuropathy

Question 38

Robbins Key concepts peripheral neuropathies

Answer 38

• patterns: mononeuropathy, mononeuritis, pultiplex, polyneuropathy, and polyradiculoneuropathy
• damage may occur in Schwann cells (demyelinating neuropathy), axons, or central neurons, or mixed.
• inflammatory disease, infections, metabolic changes, toxic injury, trauma, paraneoplastic disorders, and inherited gene defects can all –> peripheral neuropathy
• DM most common cause- usually distal symmetric neuropathy
• Guillain Barre and chronic inflammatory demyelinating pollyradiculoneuropathy - major acute and chronic acquired demyelinating peripheral neuropathies
• inherited peripheral neuropathies are genetically and phenotypically diverse disorders, often present in adulthood and may be marked by sensory, motor or autonomic dysfunction, alone or in combo

Question 39

Diseases of the Neuromuscular Junction

Answer 39

Regardless of cause, disorders that impair the function of neuromuscular junctions tend to present with * painless weakness.

Autoantibodies that inhibit key neuromuscular junction proteins are the most common cause of disrupted neuromuscular transmission, as found in myasthenia gravis (literally, * grave weakness)

Question 40

Myasthenia Gravis

Answer 40

Myasthenia gravis is an autoimmune disease that is usually associated with autoantibodies directed against acetylcholine receptors.

There is a strong association between pathogenic anti-acetylcholine receptor autoantibodies and * thymic abnormalities.

Question 41

diplopia and ptosis

Answer 41

myasthenia gravis until proven otherwise

Question 42

droopy lids plus giant thymus

Answer 42

myasthenia gravis

about 10% of MG patients have thymoma (thymectomy can help); some have thymic hyperplasia

Question 43

Diagnosis of Myasthenia Gravis

Answer 43

is based on clinical history, physical findings, the * identification of autoantibodies, and electrophysiologic studies. The latter reveal a * decrement in muscle response with repeated stimulation, a characteristic of this disorder.

Question 44

Lambert-Eaton Myasthenic Syndrome

Answer 44

antibodies that block acetylcholine release by inhibiting a presynaptic calcium channel

• In contrast to myasthenia gravis, rapid repetitive stimulation increases muscle response. Muscle strength is augmented after a few seconds of muscle activity. Patients typically present with weakness of their extremities.

In about half of cases there is an underlying malignancy, most often * neuroendocrine carcinoma of the lung. (CENTRAL tumor) Symptoms may precede the diagnosis of cancer, sometimes by years.

Question 45

lambert eaton symptoms precede

Answer 45

findings of small cell carcinoma

Question 46

Botulism

Answer 46

caused by exposure to a neurotoxin (popularly known as Botox) that is produced by the anaerobic Gram-positive organism Clostridium botulinum. Botox acts by blocking the release of acetylcholine from presynaptic neurons.

symptoms: double vission, difficulty swallowing, blurred vision, dry mouth, droopy eyelids, muscle weakness, slurred speech

Question 47

Curare

Answer 47

common name for botulism related muscle relaxants that block acetylcholine receptors, resulting in flaccid paralysis.

Question 48

Robbins Key Concepts- NMJ

Answer 48

diseases of NMJ –> painless weakness
Myasthenia gravis and Lambert-eaton myasthenic syndrome (most common forms)- both immune mediated, cuased by antibodies to postsynaptic Ach receptors and presynaptic calcium channels
Myasthenia gravis- often associated with thymic hyperplasia or thymoma, frequently involves ocular muscles, marked by fluctuatin weakness that worsens with exertion
Lambert Eaton- weakness in extremities that improves with repetitive stiulation and often a paraneoplastic disorder associated with lung cancer.
Genetic defects in NMJ proteins–> congenital myasthenic syndrome
Bacterial toxins such as botox can block NMJ by blocking release of Ach from presynaptic neurons