Flashcards in Multiple Sclerosis Deck (42):
What is multiple sclerosis?
immune-mediated disease of the CNS in which myelin sheaths of axons in the brain and spinal cord are damaged (which slows, but does not eliminate conduction of nerve impulses) - over time may lead to severing of axons and permanent loss of nerve function
What are the initial (presenting) symptoms of MS?
fatigue (most common), change in sensation in the arms/legs/face, optic neuritis, weakness, double vision (diplopia), unsteady gait, problems with balance, unilateral vision loss, bladder problems, vertigo
What is Lhermitte's sign?
electrical sensation that runs down the back and into the limbs that is produced by neck flexion - suggests lesion of the dorsal columns of the cervical cord or caudal medulla
What is Uhthoff's phenomenon?
worsening of neurologic symptoms when the body is overheated from hot weather, exercise, fever, or saunas/hot tubs
What features are suggestive of MS?
relapses and remissions, onset between 15 and 50, optic neuritis (inflammation of optic nerve), Lhermitte sign, internuclear ophthalmoplegia, fatigue, Uhthoff's phenomenon (heat sensitivity)
What are shadow plaques?
plaques that have been partially remyelinated by a remyelinating oligodendrocyte
What are the core requirements for diagnosis of MS?
dissemination in time and place - evidence that damage has occurred in at least two separate areas of the CNS at different points of time, with no other explanation
What are the McDonald MS Diagnostic Criteria?
objective clinical evidence of CNS lesions in both time and space: (1) disseminated in space - 1 or more lesions in at least 2 of 4 MS-typical regions or development of further clinical attach implicating different CNS site and (2) disseminated in time - presence of lesions in two separate MRI images or evidence of two separate clinical attacks
What are the four MS-typical regions of the CNS?
periventricular (area around the ventricle of the brain), juxtacortical (next to the cerebral cortex), infratentorial (area located below the tentorium cerebelli), and spinal cord
What types of cells are seen in the CSF of patients with MS?
oligoclonal IgG bands
What are black holes in MS?
areas in the brain where myelin has been completely lost and nerve cells have been damaged beyond repair
What is the imaging test of choice for MS?
MRI - demonstrates plaques and black holes
What are evoked potentials?
electrical events generated in the CNS by peripheral stimulation of a sensory organ - used to detect subclinical/abnormal CNS function that may not be visible via routine imaging
What are oligoclonal bands?
a protein (immunoglobulin - IgG) - presence suggests inflammation of the CNS due to infection or another disease - if similar bands aren't present in your blood, may indicate multiple sclerosis
What is clinically isolated syndrome in MS?
first neurological event suggestive of demyelination - high risk for developing clinically definite MS
What is the characteristic of progressive relapsing MS?
steady decline since onset of symptoms with super-imposed attacks
What is the characteristic of secondary progressive MS?
initial relapsing/remitting MS that suddenly begins to decline without periods of remission and relapse - diagnosis made retrospectively 10-20 years after disease onset
What is the characteristic of primary progressive MS?
gradual progression from onset without relapse or remission
What is the characteristic of relapsing/remitting MS?
unpredictable attacks that may or may not leave permanent deficits followed by periods of remission (85-90% of cases at onset)
What is the Expanded Disability Status Scale (EDSS)
method of quantifying disability in MS based on 8 functional systems: (1) pyramidal (ability to walk), (2) cerebellar (coordination), (3) brain stem (speech and swallowing), (4) sensory (touch and pain), (5) bowel and bladder, (6) visual, (7) mental, and (8) other (any other neurological finding)
What is the primary class of medication treatment of MS?
What are some indicators of poor prognosis in MS?
frequent/multifocal attacks early on, pyramidal involvement, ataxia, cognitive difficulties, spinal progression
How are relapses managed in MS?
relapse = new symptoms or sudden worsening of symptoms lasting 24 hours with objective change in neurologic findings - Tx with corticosteroids (3-5 days of high dose intravenous methylprednisolone)
How is spasticity treated in MS?
eliminate sources of pain, exercise (ROM, weight bearing), cryotherapy (cooling and stretching), casting, EMG biofeedback, electrical stimulation, baclofen (Lioresal), Botox
What is a pseudoexacerbation in MS?
temporary worsening of MS symptoms (e.g., in response to elevation in core body temperature) - use cooling strategies
Where is cerebrospinal fluid produced?
choroid plexus in the lateral, third, and fourth ventricles - circulates through the subarachnoid space between arachnoid and pia mater
What is the normal CSF volume in adults?
125-150 mL - 20% contained in the ventricles
What is the normal rate of CSF production?
How is CSF absorbed?
in the arachnoid villi - one-way valves permitting unidirectional flow of CSF into the blood
What types of molecules can cross the blood-brain barrier?
lipid-soluble molecules or drugs - ionically charged molecules require active transport
What is the normal CSF pressure?
less than 150 mm H2O - may range between 60 and 250 mm H2O
What are the two components of the blood-brain barrier?
blood-brain and blood-CSF - both separate the CNS from the systemic immune system
What is the blood-brain barrier?
systems that separate the brain and CSF from the blood and prevent entry by simple diffusion of fluids, electrolytes, and other substances from the blood into the CSF/brain
What is xanthochromia?
discoloration of the CSF due to lysing of RBCs - pink (when hemoglobin is broken down to oxyhemoglobin) and later yellow (due to bilirubin) - can be detected as soon as 2-4 hours after RBCs have entered the subarachnoid space (used to diagnose subarachnoid hemorrhage)
What is the normal appearance of CSF?
clear and colorless - as few as 200 WBCs/microL or 400 RBCs/microL will cause CSF to appear turbid (will appear grossly bloody if > 6000 RBCs/microL are present)
What is a normal cell count in CSF?
normally acellular but 5 WBCs/mirocL and 5 RBCs/microL is considered normal - > 3 polymorphonuclear leukocytes (PMNs)/microL is abnormal
What is normal immunoglobulin concentration in CSF?
immunoglobulins almost totally excluded from CSF - normal blood to CSF ratio of IgG is 500:1 or more - elevations in oligoclonally expanded immunoglobulin concentrations in the CSF (oligoclonal bands) can occur in any disorder that disrupts blood-brain barrier (e.g., MS)
What is benign MS?
occurrence of a single demylenating event without a relapse 15 years after disease onset - retrospective diagnosis
What is the diagnostic test of choice for MS?
MRI to support the clinical diagnosis
How is an MS attack defined?
patient reported or objectively observed event typical of acute inflammatory demyelinating event in the CNS - current or historical, at least 24 hours duration, absence of fever/infection - commonly sensory disturbance, motor weakness, visual complaints
What are Dawson fingers?
plaques seen in MS that have an ovoid appearance - arranged in right angles to the corpus callosum