Neurology Flashcards
(83 cards)
In what common situation is a lumbar puncture contraindicated?
In the setting of acute head trauma, signs of intracranial hypertension (e.g., papilledema), or suspicion for subarachnoid hemorrhage. Do a lumbar tap only after you have a negative computed tomography (CT) or magnetic resonance imaging (MRI) scan of the head in these settings. Otherwise, you may cause uncal herniation and death
What would you find in CSF analysis for a pt with bacterial meningitis? particularly cells, glucose, protein and pressure.
Cells >1000 (PMN) (normal 3), glucose <50 (normal is 50 - 100) Pressure >200mm Hg (normal 100 - 200mm Hg) Protein is >100 (normal 20 - 45) Note: Tuberculous and fungal meningitis have low cells(100), which are predominantly lymphocytes. In patients with fungal meningitis, a positive India ink preparation equals Cryptococcus neoformans.
For a pt with viral meningitis what would you expect to find in CSF analysis. Particularly cells, glucose, protein and pressure.
Cells >100 Lymphocytes (normal 0-3), Glucose - normal (normal is 50 - 100 mg/dL), protein normal or slightly increased (20 - 45 mg/dL), pressure is normal or slightly increased. Note: Tuberculous and fungal meningitis have low glucose (100), which are predominantly lymphocytes. In patients with fungal meningitis, a positive India ink preparation equals Cryptococcus neoformans.
For a patient with pseudotumor cerebi (idiopathic intracranial hypertension) what would you expect to find in analysis of their CSF cells, glucose, protein, pressure.
Cells normal (3mg/dL) glucose normal (50-100 mg/dL) protein normal (20-45 mg/dL) pressure >200 (100 - 200 mm Hg)
For a patient with Guillain-Barré syndrome what would you expect to find in analysis of their CSF cells, glucose, protein, pressure.
Cells 100 lymphocytes (normal 3), glucose normal (50 - 100mg/dL) protein >100 (normal 20 - 45 mg/dL) pressure is normal (100 - 200 mm Hg)
For a patient with cerebral haemorrhage what would you expect to find in analysis of their CSF cells, glucose, protein, pressure.
Cells - bloody (RBC) glucose normal (50 - 100 mg/dL) protein >45 mg/dL (normal 20 - 45 mg/dL) pressure >200 mm Hg.
Give a classic case description of multiple sclerosis
Multiple sclerosis classically presents with an insidious onset of neurologic symptoms in white women aged 20 to 40 years with exacerbations and remissions. Common presentations include paresthesias and numbness, weakness and clumsiness, visual disturbances (decreased vision and pain caused by optic neuritis, diplopia as a result of cranial nerve involvement), gait disturbances, incontinence and urgency, and vertigo. Also look for emotional lability or other mental status changes. Internuclear ophthalmoplegia (a disorder of conjugate gaze in which the affected eye shows impairment of adduction) and scanning speech (spoken words are broken up into separate syllables separated by a noticeable pause and sometimes with stress on the wrong syllable) are classic; the patient may have a positive Babinski sign.
What is the most sensitive test for diagnosis of multiple sclerosis? How is it treated?
MRI is the most sensitive diagnostic tool and shows demyelination plaques. Also look for increased IgG/oligoclonal bands and possibly myelin basic protein in the CSF. Treatment is not highly effective but includes interferon, glatiramer, mitoxantrone, natalizumab, cyclophosphamide, and methotrexate. Acute exacerbations are treated with glucocorticoids
Define Guillain-Barré syndrome.
Guillain-Barré syndrome is a postinfectious polyneuropathy. Look for a history of mild infection (especially upper respiratory infection) or immunization roughly 1 week before onset of symmetric, distal weakness or paralysis with mild paresthesias that start in the feet and legs with loss of deep tendon reflexes in affected areas. The hallmark of the disease is that motor function is often affected with intact or only minimally impaired sensation. As the ascending paralysis or weakness progresses, respiratory paralysis may occur. Watch carefully; usually spirometry is performed to follow inspiratory ability. Intubation may be required. Diagnosis is by clinical presentation. CSF is usually normal except for markedly increased protein. Nerve conduction velocities are slowed. The disease usually resolves spontaneously. Plasmapheresis (for adults) and intravenous immune globulin (for children) reduce the severity and length of disease. Do not use steroids; they no longer have a role in the treatment of Guillain-Barré syndrome
What causes nerve conduction velocity to be slowed?
Demyelination. Watch for Guillain-Barré syndrome and multiple sclerosis as causes
What causes an electromyography (EMG) study to show fasciculations or fibrillations at rest?
A lower motor neuron lesion (i.e., a peripheral nerve problem).
What causes an EMG study with no muscle activity at rest and decreased amplitude of muscle contraction upon stimulation
Intrinsic muscle disease such as the muscular dystrophies or inflammatory myopathies (e.g., polymyositis). You now know enough about EMG for the USMLE
What is the most common cause of syncope? What other conditions should you consider?
Vasovagal syncope is the most common cause and classically is seen after stress or fear. Arrhythmias and orthostatic hypotension are also common. Consider hypoglycemia as a cause. The other main categories include: n Cardiac problems (arrhythmias, hypertrophic cardiomyopathy, valvular disease, tamponade). Always check an electrocardiogram (ECG). Further testing with echocardiography or treadmill stress testing can be performed based on the ECG findings and degree of suspicion. n Neurologic disorders (e.g., seizures, migraine headache, brain tumor). Consider an electroencephalogram or CT/MRI scan if history suggests seizures or intracranial lesion. n Vascular disease (consider transient ischemic attacks (TIAs) or carotid stenosis, which can be ruled out with carotid artery ultrasound/duplex scanning, although this is not a common cause of syncope). n Medication effects (e.g., anticholinergic agents, beta blockers, narcotics, vasodilators, alphaagonists, antipsychotics). As many as half of patients have syncope of unknown cause after a standard diagnostic evaluation
For signs and symptoms of decreased or no reflexes, fasciculations, atrophy what area is most likely affected?
Lower motor neuron disease (or possibly muscle problem)
For signs and symptoms of Hyperreflexia, clonus, increased muscle tone what area/areas are most likely affected?
Upper motor neuron lesion (cord or brain)
For signs and symptoms of Apathy, inattention, disinhibition, labile affect what area is most likely to be affected?
Frontal lobes
For signs and symptoms of Broca (motor) aphasia what area is most likely to be affected?
Dominant frontal lobe*
For signs and symptoms of Wernicke (sensory) aphasia what area is most likely to be affected?
Dominant temporal lobe*
For signs and symptoms of Memory impairment, hyperaggression, hypersexuality what areas are most likely to be affected?
Temporal lobes
For Inability to read, write, name, or do math what area of the CNS is most likely affected?
Dominant parietal lobe*
For Ignoring one side of body, trouble with dressing what are of the CNS is most likely affected?
Nondominant parietal lobe*
For Visual hallucinations/illusions what area of the CNS is most likely affected?
Occipital lobes
Lesions of which part of the brain can cause dysfunction to Cranial nerves III and IV
Midbrain
Lesions of which part of the brain can cause dysfunction to Cranial nerves V, VI, VII, and VIII
Pons
