anterior horn, NMJ and muscle disease

Question 1

Clinical generalization of neuromuscular disorder symptoms

Answer 1

all motor neuron, neuromuscular junction and muscle diseases have no sensory changes accompanying the weakness. Coexisting sensory complaints suggest a nerve root, plexus or peripheral nerve disorder.

Question 2

Characteristics of neuromuscular junction disorders

Answer 2

Rapidly developing weakness (hours to days)- such as occurs in myasthenia gravis, botulism and organophosphate poisoning.

Question 3

proximal weakness indicates which type of disorder

Answer 3

muscle disorders-difficulty in climbing stairs, arising from low chairs and elevating arms over the head. Their gait is broad-based, the posture lordotic and movement has a waddling appearance of the buttocks.

Question 4

Distal weakness indicates which type of disorder

Answer 4

Distal weakness of hands and feet (often in association with distal sensory loss) is most characteristic of neuropathies. Patients have a slapping, foot-drop gait and a great deal of difficulty with fine hand movements

Question 5

Cranial weakness indicates which type of disorder

Answer 5

myasthenia gravis- affects extraocular, facial and oropharyngeal muscles. Typical features include droopy eyelids (ptosis), dopuble vision and speaking and swallowing abnormalities.

Question 6

Labs to test for neuromuscular disorders

Answer 6

1. Serum creatine kinase is elevated (due to muscle necrosis). 2. nerve conduction studies, needle electromyography, and repetitive nerve stimulation. 3. muscle/nerve biopsy. 4. genetic testing

Question 7

Uses of electrodiagnostic studies

Answer 7

1. nerve conduction studies broadly differentiate between primary demyelinating (very slow NCS) and axonal neuropathies. 2. Needle EMG useful in differentiating myopathic from neuropathic disorders

Question 8

Amyotrophic lateral sclerosis signs/symptoms

Answer 8

progressive weakness and wasting. Degenerating UMN causes spasticity and hyperreflexia. Initially, asymmetric limb weakness in the presence of fasciculations. A foot drop or marked hand deformity. Sensory exam normal

Question 9

ALS cause

Answer 9

degeneration of brainstem and spinal cord lower motor neurons

Question 10

ALS inheritance pattern

Answer 10

majority of cases are sporadic, although 5-10% are familial

Question 11

Muscles involved in ALS

Answer 11

Extraocular and facial muscles are often spared. Onset usually in legs before arms. May spread along neuraxis. Diaphragm weakness and impaired swallowing produce fatal aspiration pneumonia.

Question 12

Als treatment

Answer 12

medications for cramps, spasticity, excess saliva, and inappropriate laughing or crying. Riluzole extends life for 3 months. A feeding tube and positive pressure ventilation, either by mask or via tracheostomy, can extend life.

Question 13

RX used for cramps/spasticity

Answer 13

Helps with jaw quivering/clenching- hydration, benzodiazepams, phenytoin, quinine, lioresal, dantrolene, gabapentin

Question 14

Rx for pseudobulbar effects

Answer 14

tricyclic and SSRI antidepressants, dextromethorphan + quinidine.

Question 15

Rx of drooling, thick phlegm & laryngospasm in ALS

Answer 15

decrease saliva: glycopyrrolate, amitriptyline, diphenhydramine, oxybutinin, scopalamine, artane, salivary gland irradiation. thick saliva: metoprolol, propanolol nasal congestion: decongestants, antihistamines

Question 16

What is charcot marie tooth disease

Answer 16

Inherited neuropathies - type I(autosomal dominant) is demyelinating with slow nerve conduction velocities. Type 2 (autosomal dominant) has axonal degeneration with normal nerve conduction velocities. Type 4 is recessive. Each type has a letter for the gene causing the disorder

Question 17

Charcot Marie Tooth Disease (CMT1A) genetics

Answer 17

duplication of the DNA containing the peripheral myelin protein gene PMP22

Question 18

Charcot marie tooth phenotypes

Answer 18

1. onset of walking is normal but distal (hands and feet) weakness and sensory loss develops slowly in the first two decades of life. 2. already impaired as infants and experience delayed walking. Many are confined to wheelchairs later in life. 3. adult onset and may not appear until approximately 40 years of age

Question 19

test use in CMT

Answer 19

nerve conduction velocity- The cutoff between demyelinating and axonal forms of CMT was established as 38m/sec

Question 20

CMT therapy

Answer 20

No medications to reverse the dz. Focus on improving quality of life with physical therapy, occupational therapy and orthopedic surgery

Question 21

Diabetic sensory or sensorimotor distal polyneuropathy symptoms

Answer 21

A distal sensory or sensorimotor polyneuropathy is the most common type. numbness and burning dysesthesias in their feet which over time spreads up the legs and eventually into the hands. Weakness of foot dorsiflexor muscles results in a slapping foot drop gait. Grip strength and fine hand dexterity may be diminished

Question 22

Small fiber vs large fiber pattern in polyneuropathy

Answer 22

A loss of position, vibration and light touch, as well as decreased reflexes, is prominent in large fiber’ pattern. Relatively pronounced loss of pain and temperature sensation, in association with pain, indicates predominantly small fiber’ injury. NCVs are often near normal if only small fibers are involved.

Question 23

Diabetic Autonomic neuropathy symptoms

Answer 23

–Hypotension, diarrhea, impotence, urinary retention, sweating

Question 24

Diabetic Mononeuropathy nerve targets

Answer 24

–Cranial nerve (3, 6,7) or peripheral (median- carpal tunnel, ulnar, peroneal)

Question 25

Diabetic Lumbosacral plexopathy symptoms

Answer 25

–Pelvic girdle pain; asymmetric hip flexor weakness

Question 26

pathogenesis of diabetic neuropathies

Answer 26

Metabolic derangements and changes in endoneural vessels with associated ischemia may be the primary cause. Mononeuropathies are from occlusion of small, nutrient blood vessels supplying the nerves

Question 27

Treatment of diabetic polyneuropathy

Answer 27

Metabolic control, foot hygiene, pain management, Codeine/diphenoxylate for diarrhea, fluorocortisone/midodrine for hypotension, regular voiding for urinary retention

Question 28

Myasthenia gravis symptoms

Answer 28

Ptosis, ophthalmoparesis, jaw and neck weakness, facial muscle weakness, trouble swallowing leads to aspiration, respiratory muscle weakness, limb muscle weakness is variable and not major manifestation. Thymic enlargement common, and thymomas can occur

Question 29

Myasthenia gravis treatment

Answer 29

Symptomatic temporary benefit is obtained using oral cholinesterase inhibitors (pyridostimine). Corticosteroids reverse immune response (plus other immunosuppressive agents like azathioprine). Temporary (2-3 weeks) improvement with plasma exchange or IV IG infusion. Thymectomy recommended except in very young and old, to reduce adverse effects of meds (thymectomized patients need less immunosuppressive meds)

Question 30

Duchenne/Becker dystrophy genetics

Answer 30

X-linked recessive disorders caused by a variety of deletions, duplications and point mutations in the area of the X chromosome coding for the membrane protein dystrophin

Question 31

Duchenne vs Becker dystrophy

Answer 31

Becker dystrophy (BD) differs from Duchenne dystrophy (DUD) only in that the onset is usually later, the course is more benign, and survival is longer (into the 30s and 40s). Mental impairment is seen less often as well.

Question 32

Duchenne dystrophy symptoms

Answer 32

clumsy waddling gait from the time they first walk, lumbar lordosis, pseudohypertrophy of calves, toe walking, difficulty rising from floor (Gowers maneuver). Respiratory muscles become weak plus kyphoscoliosis reduces pulmonary reserve and they usually die from respiratory/heart failure in 20s

Question 33

Duchenne dystrophy diagnosis

Answer 33

Elevated serum CK, muscle biopsy and EMG show myopathic features (fibrosis, degeneration, opaque fibers), genetic test

Question 34

Duchenne dystrophy treatment

Answer 34

Vigorous stretching reduces contractures early in disease, surgical release of lower extremity contractures, long leg braces, spinal fusion for scoliosis >40 degrees, BiPAP, full ventilation

Question 35

Duchenne dystrophy genetic therapies

Answer 35

introducing the dystrophin gene into nuclei using viruses or stem cells; exon skipping using mRNA antisense oligoribonucleotides; administering medications (gentamycin) that read through stop codons; and upregulating utrophin, a related protein 7% shorter than dystrophin