Neurology/NeuroSx Flashcards
What are 7 signs of early ischemia secondary to stroke on CT?
- Hypodensity
- Hyperdense MCA sign (acute thrombus in vessel)
- Sulcus effacement (loss of definition of sulci due to edema)
- Disappearing basal ganglia (loss of definition between the basal ganglia)
- Loss of Insular ribbon sign (loss of definition in the insular cortex)
- Loss of grey-white differentiation
- Mass effect/ Ventricular compression
Define wernicke’s aphasia
Receptive aphasia
- person not able to comprehend but can talk fluently
Define Broca’s aphasia
Expressive aphasia
- Person is able to comprehend but cannot fluently express it
What is a normal opening pressure for LP?
5-20 cm H2O
Obese: 25 cm H20
What would the expected CSF results be in bacterial meningitis?
- WBC - elevated, mostly neutrophils also lymphocytes (more with early bacterial and viral) >1000
- Gram stain - 80% will see organism
- Glucose: decreased (normal 0.6:1 CSF to serum glucose). also low in fungal.
- Protein: elevated
- Lactate: elevated (more in bacterial, non-specific)
What is the ddx for elevated protein in CSF? (6)
- Bacterial meningitis
- Fungal meningitis (cryptococcus)
- Vasculitis
- Demyelinating dz (MS)
- Syphilis
- Neoplasms
- TB meningitis
- Guillain barre syndrome (icr protein no wbc)
What results in Xanthrochromia? breakdown of what substances?
Is breakdown of oxyhemoglobin, bilirubin and methemoglobin in the CSF
What are 2 other causes of xanthochromia and RBC in LP other than SAH?
- Nonaneurysmal perimesencephalic subarachnoid hemorrhage (PMSAH) 5% of SAH
- Other non-aneurysmal bleeds
Generally good prognosis, observation is all thats needed.
What is the ddx Ring enhancing lesion on CT?
'DRMAGICL' Demyelinating disease Resolving hematoma, Radiation necrosis. Mets Abscess GBM Infarct (subacute) Contusion Lymphoma
DDX blown pupil
Herniation
PComm aneurysm
CN III palsy
AntiCholinergics
What is the management of malignant spinal cord compression?
- Steroids indicated → loading dose of dex in ED 10-16mg
AHS guidelines: 4 mg q4-6h after initial bolus. - Immediate radiation therapy should be considered
Stroke syndromes: Describe clinical findings for Anterior cerebral a. stroke territory
- Apraxia, Altered mentation + insight
- Bowel, bladder incontinence
- Contralateral paralysis + hypoesthesia → Leg»_space;arm
- Primitive reflexes (grasp, suck) - ‘frontal release signs’
Stroke syndromes: Describe clinical findings for stroke in the Middle Cerebral Artery (MCA) territory.
- Agnosia
- Aphasia (if dominant hemisphere)
- Marked contralateral motor +sensory findings
- Face + Arm»_space; Leg
- Numbness in same distribution as weakness
- Ipsilateral hemianopsia
- Gaze towards lesion → disruption of cortical lateral gaze centres
Stroke syndromes: Describe clinical findings for stroke in PCA territory
- PCA: Portions of parietal + occipital lobes → vision, thought processing are impaired
- Visual agnosia (inability to recognize seen objects)
- Alexia (inability to understand writing)
- CN III palsy
- Homonymous hemianopsia +/- visual neglect
- VF defecits
- Nystagmus
- Diplopia
- Vertigo, syncope, weakness, paralysis, spasticity, ataxia,
- dysarthria, dysphagia
- Crossed deficits: motor and sensory deficits on opposite sides
- Nausea, vomiting
- Can present with coma!!
List 2 strokes that can cause depression of consciousness:
- Stroke in unaffected hemisphere of a patient who has had a previous contralateral stroke. so will have bilateral cerebral hemisphere involvement.
- Posterior circulation stroke affecting brainstem → RAS
What is the gaze preference in seizure and stroke?
- Seizure → look away form irritative focus
- Stroke → look towards catastrophe
List 10 stroke mimics
Other intracranial pathology:
- SDH / EDH → in elderly, those at most risk for a fall and stroke!
- Intracranial lesions → tumor, abscess
- CVT (although really is a stroke syndrome itself)
- Atherosclerotic dz - steal like syndrome
Other acute neurologic syndromes:
- Seizure (distinguishing feature = amnesia)
- Todd’s paralysis (post ictal paralysis)
- Migraine with aura (evolves over 10-45min)
Metabolic abnormalities:
- Hypoglycemia
- Wernicke’s encephalopathy (ataxia, confusion, opthalmoplegia)
Peripheral nerve pathology:
- Bell’s palsy
- Peripheral nerve palsy
- Demyelinating disease
Vestibular apparatus pathology:
- Labrynthitis
- Vestibular neuritis
- Meniere’s (vertigo, hearing loss, tinnitus)
- Peripheral vertigo → BPPV
Vasculitis / inflammatory:
- Giant cell arteritis (Claudication, myalgias, H/A, visual disturbance)
- Polyarteritis nodosa
- SLE
Drug toxicity:
- Lithium
- Dilantin
- Carbamazepine
Other:
- Air embolism in right context (diving, medical procedures)
- HTN encephalopathy (esp in DDx for ICH)
What is the SN and SP of CTA to detect intracranial occlusions?
SN: 92-100%
SP 82-100%
Should be obtained, if available, in ischemic and hemorrhagic strokes
Pathophysiologically, what 3 mechanisms can result in NMJ dysfunction?
- Blockade of nicotinic receptors → myasthenia gravis
- Reduced ACh released → botulism
- Inactivation of acetylcholinesterase by irreversible binding, resulting initially in hyperstimulation followed by paralysis → organophosphate toxicity
Name 3 conditions that are myopathies (proximal > distal muscle weakness)
- Polymyositis
- Dermatomyositis
- Rhabdomyolysis
- PMR
- Metabolic (hypokalemia)
- Periodic paralysis (familial/thyrotoxic)
Name 3 conditions that effect the NMJ?
- Myesthenia Gravis: block nicotinic ACh receptors
- Botulism: inhibit pre-synaptic Ach release
- Eaton-Lambert (rare - paraneoplastic syndrome)
- Tick paralysis
What is myasthenia Gravis (MG)?
- Blockade of nicotinic ACh receptors at the NMJ
- From autoantibodies against receptor or muscle specific tyrosine kinase
- Result: destruction of nicotinic ACh receptors → reduced total # available
Involves: ocular, bulbar, cervical, proximal limb, and respiratory muscles.
How do MG patients present ?
- Progressive weakness and
- Easy fatiguability with repeated activity
- Occular muscle weakness first sign in ~40% → ptosis, diplopia, blurred vision worse at the end of the day
- Bulbar muscles involved → dysphagia, dysarthria
- 17% have involvement of muscles of respiration
What does an ice bag placed on the face do to the ptosis in MG?
Improves it!!
- Cold temporarily blocks acetylcholinesterase → increases ACh at synaptic cleft → improved ocular muscle strength
o Apply ice bag to more severely affected eye for 2 min.
o Improvement in ptosis of 2mm is diagnostic
o Sn: ~80%; Sp: ~100%
- Same response as with edroponium administration → short acting ACh-esterase blocker (will soon no longer be available)
o 1mg test dose, them 3 → 3 → 5mg doses (max 10mg) with atropine at bedside
What is Lambert-Eaton myasthenic syndrome?
- Rare. Paraneoplastic syndrome, 50% associated with lung SCC
- Compared to MG: weakness improves with repeated stimulation → more ACh in synapse to bind receptors
- Sx: improving weakness with use, hyporeflexia, autonomic dysfunction (dry mouth)
- Rx: Treat cancer +/- IVIG
What is a myasthenic crisis?
Respiratory crisis with respiratory failure
List 5 conditions that can precipitate a myasthenic crisis?
- Pregnancy
- Infection
- Surgery
- Aspiration
- Cessation of anticholinesterases
List 10 drugs that can precipitate a myasthenic crisis?
Sedative / Anasthetics
- Diazepam*
- Ketamine*
- Lidocaine*
- NM blocking agents*
Cardiovascular:
- BBs*
- CCBs*
- Quinidine
- Lidocaine*
- Procainamide
Antibiotics:
- Aminoglycosides*
- Tetracyclines
- Clindamycin*
- Polymxin B*
- Colistin
- Fluoroquinolones*
Other:
- Phenytoin*
- NM blockers*
- Corticosteroids** this is a part of their treatment.
- Thyroid replacement
- Anticholinergics
- Diuretics*
- Statins*
Outline your approach to the patient in myasthenic crisis:
- Determine need for intubation:
Negative inspiratory force (NIF)