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33 Cards in this Set
- Front
- Back
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How does an epidural hemorrhage appear on CT?
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It's from an arterial bleed and has higher prssure that more readily "pushes in" the brain, and the blood forms the shape of a lens.
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How does a subdural hemorrhage appear on CT?
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It's from a venous bleed that forms the shape of a crescent.
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When do you give a head CT scan?
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The CT scan is always the best initial test for imaging the brain. This is especially true in trauma when looking for blood. The head CT is also the best initial test for a stroke, in which we are also looking for blood.
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What is the most accurate test for head trauma?
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Head Trauma and intracranial bleeding such as subdural and epidural hematomas, there is no test more accurate than the head CT scan.
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When is an MRI of the brain the right answer?
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The MRI is the most accurate test for strokes, multiple sclerosis, and most lesions of the brain stem and cerebellum.
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What is the most accurate test for a mass lesion?
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The only test more accurate than an MRI for a mass lesion is a brain biopsy. If briosy is not one fo the choices adn the question asks about the "most accurate test," then the answer is MRI.
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What are Anti-Acetylcholine Receptor (Anti-Ach-R) Antibodies?
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Myasthenia gravis is characterized by anti-acetylcholine receptor antibodies (anti-Ach-R) that are made when autoimmune disease causes antibodies that bind to postsynaptic acetylcholine receptors: You can't have neuromuscular transmission if there is no receptor on the muscle because it has been eaten by an antibody.
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What is more accurate than anti-Ach-R antibodies?
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Single-fiber electromyography (EMG) is the most sensitive diagnostic test for myasthenia gravis.
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When do you answer anti-acetylcholine receptor antiodies?
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Anti-Ach-R antibodies are the best initial test for the diagnosis of myasthenia gravis. They are more accurate than tensilon or edrophonium testing.
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What is carotid doppler?
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Carotid doppler is a sonographic evaluation of teh carotid arteries that allows a precise quantification of the degree of stenosis of these vessels. It is used to see whether teh patient needs a carotid endarterectomy or angioplasty.
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when is carotid doppler the answer?
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Answer carotid doppler when you are presented with a patient with signs or symptoms of ischemia in teh anterior circulation of the brain, such as amaurosis fugax or focal extremity weakness. It is the initial test to determine the etiology of embolic strokes or TIAs.
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What is the most accurate diagnostic test for carotid arteries?
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The most accurate test of the carotid arteries is the angiogram.
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When is a cervical spine X-ray the test answer?
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Look for a case of someone diving or falling and landing on his head, or having something really heavy land on his head. This gives increased axial loading.
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Wht is a CT Myelogram used for?
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The CT myelogram is to detect compression of the spinal cord form mass lesions, such as cancer, and occasionally from a hematoma or an infection, such as an epidural abscess.
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How is a CT Myelogram done?
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A spinal needle is introduced into the subarachnoid space. The patient is hung nearly upside-down in order to allow the contrast material iserted into the subarachnoid space to move and detect the lesion at the place it stops flowing. The MRI has essentially replaced the CT myelogram. The CT meylogram may have an advantage in detecting leptomeningeal cancer.
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When do you answer CT myelogram?
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A CT myelogram is virtually never done. It is most often a wrong answer on your test. The MRI is the answer if you strongly suspect cord compression. The only reason to answer CT myelogram is if the MRI is not possible to do because the patient cannot lie still or has a metal pacemaker and the magnet of the MRI would be dangerous to the patient.
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What is Edrophonium (Tensilon) Test?
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The edrophonium test is a very sensitive test for the diagnosis of myasthenia gravis. Edrophonium chloride is an acetylcholinesterase inhibitor with rapid onset and short duration of action. It prolongs the presence of acetylcholine is the neuromuscular junction and results in an immediate increase in muscle strength in affected muscles.
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When is Edrophonium the answer?
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Answer edrophonium testing when you see a case with muscular weakness that is worse with repetitive exercise. MG often starts with dysphagia, ocular weakness, or difficulty chewing because of masseter muscle weakness.
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What si the most accurate test for Myasthenia Gravis?
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Electromyography is the single most accurate test to confirm teh diagnosis of MG.
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What neoplasm is associated with MG?
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Thymomas are associated with the diagnosis of MG 10% of the time.
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What is an EEG?
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An electroencephalogram (EEG) is the measurement of brain wave patterns by putting electrodes into the scalp.
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When is EEG the best answer
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Answer EEG when the patient has the new onset of possible seizure activity. Also, EEG is useful in patients with recurrent sudden-onset syncope if there is no cardiac etiology identified. EEG may be contributory in diagnosing Creutzfeldt-Jakob disease, but it is not as good as a brain biopsy. EEG is not necessary to determine brain death if the brain stem reflexes are clearly absent.
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What is the most sensitive form of EEG?
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Sleep deprivation EEg has the greatest sensitivity. This is the answer if the patient has been seizure-free for 2 years and you want a test to see if it is safe to stop the anti-epileptic therapy.
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What is an EMG?
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Electromyography (EMG) is a test of muscular strength and electrical activity. EMGs are used to diagnose primary neuromuscular diseases. EMG is used to distinguish between neural and muscular disorders.
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How is an EMG performed?
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A needle is placed into the muscle. The electrical activity during rest and activity is compared. An abnormal pattern or amplitude of electrical activity tells that there is disease.
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When you see EMG in the case, what disease should you think of?
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An EMG is the case should make you think of myasthenia gravis, Guillain-Barre syndrome, and muscular dystrophy.
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When is EMG the most accurate diagnostic test?
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Single-fiber EMG is the single most accurate test for myasthenia gravis. Combined EMG and nerve conduction velocity testing is the single most accurate test for Gillain-Barre syndrome. EMG combined with muscle biopsy are the most accurate tests for polymyositis.
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What is an LP?
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Lumbar puncture is the insertion of a spinal needle into the subarachnoid space to aspirate CSF fluid.
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When do I answer LP?
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LP is the answer in the following scenarios:
1) Patients with suspected meningeal infection 2) Patient wiht the worst headache of her life, in whome the CT scan is negative to exclude subarachnoid hemorrhage. 3) New-onset seizures with fever 4) Any infant (less than 6 weeks old) with fever if the other studies are negative. |
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When is an LP contraidicated?
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LPs are contraindicated wiht any suspected mass lesion. Do a head CT scan before the LP when there are focal findings, pappilledema, or a new seizure, or when the patient is so confused as to make the neurological examination inaccurate.
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What is oligoclonal bands?
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Detection of elevated bands of IgG (oligoclonal bands) in the CSF is possible in a patient presenting wiht signs and symptoms of multiple sclerosis. The presence of these bands is not specific.
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When do you answer oligoclonal bands?
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Look for a young patient with weakness, numbness, unsteady gait, spastic paraparesis, diplopia, or sphincter disturbances (urinary urgency). Examining the CSF for oligoclonal bands is recommended only when the MRI is nonconfirmatory but your clinical suspicion for MS remains high.
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What condition is the most accurate test to diagnose MS?
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MRI of the brain is the most accurate test to diagnose MS, with a sensitivity of 90-95%.
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