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Flashcards in anterior horn, NMJ and muscle disease Deck (35):

Clinical generalization of neuromuscular disorder symptoms

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.


Characteristics of neuromuscular junction disorders

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


proximal weakness indicates which type of disorder

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.


Distal weakness indicates which type of disorder

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


Cranial weakness indicates which type of disorder

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


Labs to test for neuromuscular disorders

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


Uses of electrodiagnostic studies

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


Amyotrophic lateral sclerosis signs/symptoms

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


ALS cause

degeneration of brainstem and spinal cord lower motor neurons


ALS inheritance pattern

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


Muscles involved in ALS

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.


Als treatment

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.


RX used for cramps/spasticity

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


Rx for pseudobulbar effects

tricyclic and SSRI antidepressants, dextromethorphan + quinidine.


Rx of drooling, thick phlegm & laryngospasm in ALS

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


What is charcot marie tooth disease

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


Charcot Marie Tooth Disease (CMT1A) genetics

duplication of the DNA containing the peripheral myelin protein gene PMP22


Charcot marie tooth phenotypes

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


test use in CMT

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


CMT therapy

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


Diabetic sensory or sensorimotor distal polyneuropathy symptoms

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


Small fiber vs large fiber pattern in polyneuropathy

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.


Diabetic Autonomic neuropathy symptoms

–Hypotension, diarrhea, impotence, urinary retention, sweating


Diabetic Mononeuropathy nerve targets

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


Diabetic Lumbosacral plexopathy symptoms

–Pelvic girdle pain; asymmetric hip flexor weakness


pathogenesis of diabetic neuropathies

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


Treatment of diabetic polyneuropathy

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


Myasthenia gravis symptoms

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


Myasthenia gravis treatment

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)


Duchenne/Becker dystrophy genetics

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


Duchenne vs Becker dystrophy

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.


Duchenne dystrophy symptoms

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


Duchenne dystrophy diagnosis

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


Duchenne dystrophy treatment

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


Duchenne dystrophy genetic therapies

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