Neuromuscular Disorders.

Question 1

Myasthenia Gravis

Answer 1

NMJ disorder where the body makes antibodies against the Ach receptor on the post synaptic cell.
- Initial symptoms: are fluctuating symptoms of skeletal muscle weakness involving: bulbar, neck and ocular muscles.
- ptosis, fatigable chewing and weak neck extensor muscles.
- Characterized by presentation later in the day , double vision
Dx: Tesilon test: endrophonium chloride ach inhibitor, Serum anti-AchR antibodies,MuSK antibodies may be present, Repetitive nerve stimulation EMG: shows decremental response. Single-fiber EMG: increased jitter.
Tx: pyrodostigmine, or immunosuppressants as steroids or azathioprine. Pt should be screened for thymoma and thymectomy has because standard of care for ages 18-55

Question 2

Feared complication of MG

Answer 2

Myasthenic crisis in which patient have respiratory insufficiency that is out proportion to the rest of their muscle weakness or increased weakness of bulbar muscles necessitation intubation. It is medical emergency, pt must have muscle strength monitored with serial FVC measurement.

Question 3

Guillain-Barre Syndrome

Answer 3

An autoimmune disorder often following GI or upper respiratory illness ( Campylobacter jejuni) where pts develop ascending weakness with minimal sensory symptoms. May develop over hrs to days and may have significant back pain. Loss of reflexes is a key to clinical diagnosis.

• Autonomic dysfunction ( BP changes and arrythmias( are source of morbidity
• CSF: shows albuminocytolic dissociation ( increased protein with normal WBC and RBC)
• Nerve conduction: shows signs of demyelination: decreased conduction velocities and temporal dispersion ( axonal variants exist would show decreased amplitude).
• Tx: IVIG or plasmapharesis NO STEROIDS.

Question 4

Miller-fisher syndrome

Answer 4

triad of opthalmoplegia, areflexia and ataxia and it present with descending symptoms and is associated with Anti-GQ1b antibodies

Question 5

Paresthesiae in the 4th and 5th digits with inability to make a fist ( claw hand). this is due to injury of which nerve

Answer 5

• Ulnar nerve: its course around the medial epicondyle makes it susceptible to traumatic injury when the medial epicondyle is hit with the elbow flexed.

Question 6

Inability to extend wrist and numbness on the back of the hand. This is due to an injury of which nerve?

Answer 6

• Radial Nerve: can occur when drunk pts fall asleep with arm slung over the back of chair, inappropriate use of crutched, break in humerus. ( wrist drop)

Question 7

Carpal Tunnel Syndrome

Answer 7

• Cause by compression of the median nerve in the wrist ( C6,7,8 and T1 roots). Patients complain of pain and paresthesias in the first three digits and lateral aspect of the fourth, and thenar eminence atrophy. Can awaken patient from sleep and feels better when shake hand.
• tinel’s test: elicits pain by gently banging on wrists
• phalen’s test: elicits pain by prolonged wrist flexion.
• Pt should be evaluated for pregnancy and endocrinopathies- DM, thyroid, and growth hormone.
• TX; use of splints at night but refractory pt may need release of transverse carpal ligament.

Question 8

Femoral Nerve Damage

Answer 8

Presents with weakness in knew extension and hip flexion and sensory loss over the medial and anterior thigh and medial shin. and arch of foot

Question 9

Meralgia Paresthetica

Answer 9

Lateral femoral cutaneous nerve syndrome occurs with compression of the nerve when it exits the inguinal ligament. P/w sensory symptoms on the lateral thigh and can be treated with weight loss and wearing looser clothes.

Question 10

Cheiralgia parethetica

Answer 10

Compression of superficial radial nerve mononeuropathy due to tight fitting handcuffs and p/w sensory loss on the back of the thumb.

Question 11

Foot drop

Answer 11

• Caused by damage to the deep branch of the peroneal nerve and leads to steppage gait in which pts will drag toes against the floor when walking and will bend leg at the knee.
• there is also numbness on the lateral calf and foot. can be seen in ppl who fall asleep with their legs crossed.

Question 12

Tibial Nerve

Answer 12

Plantar flexion of the foot

Question 13

Sciatic nerve

Answer 13

Hamstring muscles responsible for knee flexion.

Question 14

Wat nerve roots are responsible for the biceps, triceps, brachioradialis, knee jerk and ankle jerk reflexes?

Answer 14

Biceps: C6
Brachioradialis: C5, C6
Triceps : C6, C7( mostly C7)
Knee:L3/ L4 ( mostly L4) 
Ankle: S1

Question 15

Stocking glove peripheral neuropathy.

Answer 15

• Neuropathy in the distribution of the hands and feet ( distally). Mostly common reason are alcoholism and DM, but can be caused by Multiple myeloma

Question 16

What is the pattern of paralysis seen in Botulism?

Answer 16

-Descending paralysis. Guillain-barre, transverse myelitis and tick paralysis cause ascending paralysis

Question 17

Duchene MD

Answer 17

• X-linked recessive disorder caused by a mutation in the gene coding the cytoskeletal protein dystrophin. Presents with trouble walking in age 3-5, trouble getting up from sitting position.
• features include: calf hypertrophy ( due to infiltration of fatty tissue), dilated cardiomyopathy, and mild mental retardation. CK levels may be 100 X normal
• Tx: avoid exercise which injure muscules, Weekly steroid tx keep pts ambulatory for extra 2-3 yrs.
  ( death in 20s)

Question 18

Becker’s MD

Answer 18

Similar to Duchene’ s but milder and patients can often walk into early adulthood

Question 19

Elevated Ck in a patient with multiple comorbidities on multiple meds:

Answer 19

Check to make sure patient is no on statins can cause myopathies at high doses.
- chronic corticosteroid use also produced slowly progressive proximal myopathy.

Question 20

Inclusion body myositis

Answer 20

• Inflammatory myopathy
• Occurs after age 50
• Affects distal muscles of hands and feet
• May be asymmetrical such that appears there is a focal neuro deficit
• Ck is normal or moderately elevated
• Thought of as neurdegenerative

Question 21

Polymyositis

Answer 21

• Inflammatory myopathy
• Is a disease of ppl over 18
• subacute inflammatory myopathy that is progressive in a limb-girdle distribution
• Cardiac involvement is frequent
• Ck levels can be up to 50 times higher than normal
• Tx: oral steroids, followed by other immunosuppressants ( azathioprine, methotrexate or IVIG)

Question 22

Dermatomyositis

Answer 22

• inflammatory myopathy
• disease of adults and children
• Has skin manifestations including heliotrope rash, erythema on knuckles, knees elbows, neck and shoulders. Hands can be scaly
• up to 15 percent associated with cancer
• tx: steroids and immunosuppressants
• Increased levels of CK also points to dermatomyositis as well as raynauds and Anti-Jo-1 antibodies.
• Pts with this have higher likelihoods of having episodes of temporal arteritis: headache, fevers, alont with possibility of blurred or sudden loss of vision)
• Dx: measure ESR level within pt

Question 23

hyperkalemic periodic paralysis

Answer 23

autosomal dominant disease of Na channels. Serum and urinary K are high during attacks.

• present in children before age 10 with acute onset of proximal muscle weakness provoked by cold, resting after exercise, K rich foods.
• Tx: acetazolamide

Question 24

hypokalemic periodic paralysis

Answer 24

Autosomal dominant disease of Ca channels.

• Present early in childhood with acute episodes of soreness in back/thighs/limbs. They last several hours but start and end abruptly.
• can be tx with oral k supplementation

Question 25

Paramyotonia congenita

Answer 25

• caused by mutation in Na channels.

- severe stiffness caused by cold exposure, rest, or low K

Question 26

Myotonia congenita

Answer 26

Caused by mutation in cl channels

- p/w muscle stiffness that worse with rest, improved with exercise.

Question 27

Mitchondrial myopathy

Answer 27

• Proximal muscle weakness
• ragged red fibers on muscle biopsy
• systemic manifestations
• Serum or CSF lactate and pyruvate are often increased.

Question 28

A completely lacerated nerve will show what on EMG months later?

Answer 28

Fibrillations and sharp waves.