Flashcards in Myopathy Deck (93)
What is the most common distal symmetric polyneuropathy?
What is the difference between positive and negative symptoms with polyneuropathy?
Positive = gain of pain etc
Negative = loss of sensation, motor etc
What are the s/sx of large fiber neuropathy? Small fiber?
Large fiber = loss of myelinated fibers (proprioception)
Small = Loss of unmyelinated fibers (loss of pain, light touch)
True or false: symmetric proximal neuropathy excludes DM as the cause
Focal and multifocal neuropathies are usually caused by what insult?
What is peroneal neuropathy?
Entrapment of nerve at fibular head
What is the prevalence of peripheral neuropathy in DM pts?
near 100%, but variable expressivity
Which is more common with DM neuropathy: pain and paresthesias, or sensory/motor loss?
Pain and paresthesias
What are the risk factors for developing DM neuropathy? (4)
-duration of disease
What is the polyol pathway of DM neuropathy pathogenesis?
Elevated BG levels lead to a high nerve glucose concentration, which is converted for sorbitol by aldose reductase
Resulting decrease in myoinositol interferes with Na pump
What is the microvascular theory of DM neuropathy?
Pathologic changes in diabetic nerves include capillary basement membrane thickening and resulting neuronal ischemia
What is the glycosylation end-product theory of DM neuropathy?
Chronic intracellular hyperglycemia leads to glycosylation end products which deposit around peripheral nerves
What is the usual presentation of DM neuropathy?
Insidious onset of stocking glove pattern of neuropathy
What are the labs that should be obtained with peripheral neuropathy?
What is the vitamin that should always be checked for with neuropathies?
B12 and folate
What is the role of EMGs with evaluating neuropathies?
-May confirm symptoms are related to neuropathy
-Distinguish between axonal and demyelinating neuropathies
What is the treatment for Peripheral neuropathies 2/2 immune mediated diseases?
IVIG or plasma exchange
Is lowering BG levels to treat peripheral neuropathies more effective in DM I or DM II?
More effective in DM I
What are the two major antidepressants used to treat symptoms with peripheral neuropathies?
What are the antiepileptic drugs that are used to treat neuropathic pain?n (3)
What is the treatment for absence seizures?
What is the treatment for trigeminal neuralgia, and for partial and complex seizures?
What are the two major analgesics for neuropathy?
What are the two topical agents used to treat neuropathies?
What is the bimodal age onset for MG?
15-30 y/o women
60+ yo men
What is the most common presentation of MG?
Lid ptosis or diplopia with fatigue
What are the usual bulbar s/sx with MG? (2)
-Neck flexor weakness
How do you assess for ocular motor weakness with MG?
-Upgaze for 30-60 seconds leads to asymmetric ptosis
-facial muscle weakness
What are the oropharyngeal s/sx of MG? (2)
-Flaccid dysarthria with nasal regurgitation
Which is usually affected more often with MG: upper or lower extremities?
Upper extremities--particularly the deltoid and wrist extensors
What is myasthenia crisis?
Respiratory failure 2/2 intercostal and diaphragmatic weakness
How do you monitor myasthenia crisis?
Follow VC and NIF (negative inspiratory forces)
What are the antibodies that mediate MG?
What is the diagnostic drug and treatment drug for MG?
-Edrophonium is test
-Pyridostigmine is treatment
How do you diagnose MG? (3)
-Electrodiagnostic repetitive stimulation
-Anti-ACh antibodies test
True or false: there is a good correlation between the titer levels of Anti-ACh antibodies and the severity of MG
What are the CT chest findings of MG?
What is the treatment for MG?
What are the side effects of Pyridostigmine?
Wet picture--GI hyperactivity
What is the immunotherapy/surgical treatment for MG?
Thymectomy can reduce the immune response
What is the role of immunosuppressants in the treatment of MG?
All can improve weakness, but carry their own side effects.
What is the treatment for a MG crisis? (2)
Are myopathies usually bilateral or unilateral? Proximal or distal?
What is the characteristics gait with myopathy?
Waddling gait since it involves the stronger truncal muscles
Is there preserved sensation/reflexes with myopathies?
Are CKs useful for diagnosing myopathies
Yes--elevated in majority of myopathies, but also elevated in rhabdo and seizures
What are the primary inflammatory myopathies?
Inclusion body myositis
What is polymyositis? Progression? S/sx?
Polymyositis is an inflammatory myopathy mediated by cytotoxic T cells with an as yet unknown autoantigen
Subacute proximal weakness--painless
Spares eye, face
True or false: there is a high incidence of malignancy causing polymyositis
How do you diagnose polymyositis? (3)
-EMG with myopathic and inflammatory changes
-Muscle bx (definitive)
What is the treatment for polymyositis?
When does dermatomyositis usually present? Cause?
-Childhood or adult onset
-Unknown, but may be related to viral or bacterial infx causing autoimmune response
What are the s/sx of dermatomyositis?
skin rash and proximal muscle weakness
What is the treatment for dermatomyositis?
When does inclusion body myositis usually present?
What are the s/sx of inclusion body myositis?
Finger/wrist flexor and quad weakness
How does inclusion body myopathy respond to steroids?
How does the progression of disease differ between polymyositis, dermatomyositis, and inclusion body myositis?
Polymyositis and dermatomyositis are subacute in onset, while inclusion body is a slow, chronic condition
What are the muscles that are usually affected with inclusion body myositis?
Finger/wrist flexor weakness
What is the major risk factor for steroid myopathy?
More than 30 mg of prednisone QD for more than 2 months
What is the usual onset of steroid induced myopathy
Subacute to chronic presentation of proximal weakness
What are the EMG findings of steroid myopathies?
What are the CK findings of steroid myopathy?
True or false: all cholesterol lowering agents have the potential to cause myopathic effects
What is statin myopathy?
Any muscle complaint related to statin use
What is the difference between myalgias and myositis?
Myositis has CK elevation
What are the CK level with rhabdo?
more than 10x normal with elevated Cr
What is the treatment for statin myositis?
If rhabdo, d/c drug and change
Unless CK elevates (__)x with statin use, there is no need to stop statin therapy
What are the motor symptoms of motor neuron disease?
What are the motor symptoms of neuropathies (symmetric/asymmetric? Distal or proximal?)
Distal more than proximal
What are the motor symptoms of myopathies (symmetric/asymmetric? Distal or proximal?)
Proximal greater than distal
What are the sensory symptoms of motor neuron diseases?
What are the sensory symptoms of neuropathies?
What are the sensory symptoms of NMJ diseases?
What are the sensory symptoms of myopathies?
What are the reflex findings with Motor neuron disease?
What are the reflex findings with neuropathies?
What are the reflex findings with NMJ/myopathies
What is asymmetric proximal motor neuropathy (diabetic amyotrophy)?
Prominent anterior thigh pain with weakness of quadriceps/iliopsoas, with loss of patellar reflex
True or false: the loss of the calcaneal reflex is always pathologic
false--very commonly lost with normal aging process
How can you tell if MG patients will progress to a systemic form of the disease?
83% of patients will progress to generalized disease in less than 36 months
What is the manifestation of MCAD deficiency?
What is the classic presentation of Carnitine deficiency?
What is type I - V GSD?
I = glucose-6-dehydro deficiency
II = Acid maltase (alpha glucosidase deficiency)
III = Cori disease (debranching)
V = McArdle's disease (glycogen phosphorylase)
What is the cause and presentation of LHON?
Sudden onset of blindness in young adults 2/2 mutations in subunits of complex I of the ETC
What is the cause and presentation of MERRF?
-myoclonic epilepsy and ragged red fibers
0point mutation for lysine tRNA leads to mitochondria containing paracrystalline arrays, and diminished cytochrome oxidase deficiency
What is the cause and presentation of MELAS?
-Mitochondrial encephalopathy, lactic acidosis, stroke-like activity
-point mutation in leucine tRNA
Both MELAS and MERRF have ragged red fibers. How can you differentiate the two?
Cytochrome oxidase activity is normal in MELAS, but diminished in MERRF
True or false: there are usually no malignancies associated with inclusion body myositis
What causes inclusion body myositis?
T cells mediated attacked against muscles, causing vacuoles to develop in muscles with abnormal protein deposits
What are the major muscles that are affected with NMJ disorders?
Cranial, limb girdle, and proximal muscles