Nervous System Disorders Flashcards
Pathophysiology of isoniazid toxicity
Overdose causes pyridoxine (vit B6) and GABA deficiency
Clinical scenario of isoniazid toxicity
Seizures usually start 30-120 minutes after severe isoniazid ingestion
Less severe ingestions present as AMS
Tx for isoniazid toxicity
Pyridoxine and benzos (seizures), though pyridoxine only thing that will stop seizures
What are the adverse effects of isoniazid ingestion?
Hepatotoxicity and peripheral neuropathy
Altered mental status, status epilepticus
What are Brudzinski’s and Kernig’s signs?
Brudzinski - Flexing neck causes hips and knees to flex
Kernig - Resistance and pain with knee extension while hip is flexed at 90 degrees
Brudzinski’s - bend the brain; Kernig’s - extend the knees
Cause of normal-pressure hydrocephalus
Most often a build up of CSF due to decreased absorption
Don’t forget to perform this type of exam when working up Bell’s Palsy
Ear exam - otitis media, malignant otitis, mastoiditis can all affect CN VII and look for vesicles that could represent Ramsay Hunt syndrome (Zoster)
Isoniazid is a known cause of what systemic autoimmune disorder?
Systemic lupus erythematosus
Tx for dystonic reaction
Diphenhydramine or benztropine
Cause of extrapyramidal symptoms
Blockade of dopamine receptor leads to a relative acetylcholine excess - hence anticholinergics as tx
Types of extrapyramidal symptoms and time of onset
- Acute dystonia (spasm of tongue, neck, face, and back); hours to days
- Akathisia (compulsive, repetitive motions, agitation); hours to days
- Parkinsonism (tremor, shuffling gait, drooling, stooped posture, instability); 5-30 days
- Tardive dyskinesia (lip smacking, worm-like tongue movements, “fly-catching”); months to years
What is dyschromatopsia?
Change in color perception. Can be a symptom of MS
What will LP show in MS?
50% of cases will show pleocytosis with increased number of lymphocytes.
85-95% of cases will show oligoclonal bands of IgG
Treatment for MS
- Acute attacks: glucocorticoids
- Plasma exchange
- Disease-modifying therapy
- Possibly hematopoietic stem cell transplantation
Hallmark of encephalitis
Abnormal brain function
- AMS
- Psychiatric symptoms
- Emotional lability
- Ataxia
- Seizures
- Lethargy/Coma
- Sometimes focal neuro changes
Most common viral cause of encephalitis
Enterovirus
Anti-N-methyl-D-aspirate receptor autoimmune encephalitis can be the presenting symptom of what tumor?
Ovarian teratoma
Clinical manifestations of optic neuritis
- Sudden loss of monocular partial or complete vision
- Pain with movement of affected eye
- Optic disk pallor may be seen
- Afferent pupillary defect
- Uhthoff phenomenon - transient worsening of vision with increased body temp
Etiologies of optic neuritis
- MS (most common)
- Infection (lyme, herpes, syphilis)
- Autoimmune (lupus, neurosarcoidosis)
- Methanol poisoning
- B12 deficiency
- Diabetes
Tx for optic neuritis
Corticosteroids (IV)
Most common complication with VP shunts
Obstruction - proximal are more common in the first year after placement and 2/2 catheter migration, clot or choroid plexus within the tubing, or tissue debris.
Distal more common 2+ years after placement and include pseudocyst formation in abdomen and disconnection or kinking of the tubing
Infection is second most common
Describe slit ventricle syndrome
Q165329
Where is the most common location for a shunt fracture to occur?
Just above the clavicle
Peripheral vs. Central vertigo
Q312352 table
Clinical presentation of botulism
Descending, symmetric, flaccid paralysis (upper>lower)
- first cranial nerve dysfunction with diplopia, dysphonia, dysphagia, and dysarthria; vertigo also common; decreased salivation -> painful tongue and sore throat
- weakness in upper and lower extremities and muscles of respiration -> tachypnea and respiratory failure
- DTRs may be decreased
- Normal sensory exam
Nonspecific flu-like illness Postural hypotension Parasympathetic blockade - decreased salivation - GI ileus - Urinary retention
Clinical presentation of botulism (infants)
- Constipation
- Weak suck, feeble cry, poor gag reflex, pooled secretions
- Generalized weakness, hypotonia, loss of head control
- “Floppy baby”
Causes of botulism
- Infant: ingestion of honey or corn syrup contaminated with spores
- Food-borne - inadequately preserved or undercooked foods; home canning; ingestion of preformed toxin
- Wound: iatrogenic or inadvertent from cosmetic or therapeutic injection
Management of botulism
- Contact CDC
- Supportive care
- Respiratory monitoring
- Equine serum heptavalent botulism antitoxin (>1 year old)
- Human-derived botulism immune globulin (<1 year old)
- Abx (for wounds)
What is the role of dexamethasone in a child presenting with a high-risk for H. Flu meningitis?
Has been shown to decrease hearing loss associated with H. Flu meningitis in children
Exclusion criteria for tPA
- Significant head trauma or prior stroke in previous 3 months
- Sx suggest SAH
- Arterial puncture at noncompressible site in previous 7 days
- History of prior ICH
- Intracranial neoplasm, AVM, or aneurysm
- Recent intracranial or intraspinal surgery
- SBP >185 or DBP >110
- Active internal bleeding
- Acute bleeding diathesis
- Plt <100,000
- Heparin received within 48 hrs resulting in abnormally elevated aPTT
- Current use of anticoagulant with INR >1.7 or PT > 15 sec
- Current use of direct thrombin inhibitors or direct factor Xa inhibitors with elevated aPTT, INR, or factor Xa assay
- Glucose <50
- CT shows multilobar infarction
- Suspected/confirmed endocarditis
Relative exclusion criteria
- pregnancy
- Sz at onset with postictal residual neuro impairments
- Major surgery or serious trauma within previous 14 days
- Recent GI or urinary tract hemorrhage (within previous 21 days)
- Recent MI (within previous 3 months)
What is the rate of intracranial hemorrhage in patients given tPA for acute myocardial infarction?
Less than 1%
Presentation of carotid artery dissection
- Severe neck, facial, or retroorbital pain
- Unilateral headache
- Pulsatile tinnitus
- Partial Horner (ptosis, miosis)
- Contralateral hemiparesis
Tx for carotid artery dissection
If signs of acute ischemic stroke -> thrombolytic therapy
If no evidence of acute ischemic stroke -> anticoagulation or antiplatelet medication
Remember to start what oral therapy if diagnose SAH
Nimodipine 60mg q4 hrs, ideally given within 4 days of aneurysmal rupture
When is TXA indicated to prevent earlier re-bleeding in patients with aneurysmal SAH?
For short period of time when surgical clipping or endovascular coiling of the aneurysm will be delayed and there are no contraindications to its use
What clinical feature can differentiate a patient with cluster headache from another primary headache syndrome?
Restlessness or pacing behavior
Which medication is recommended as initial preventive therapy for patients with chronic cluster headaches?
Verapamil
INR Reversal rules
- INR above therapeutic range but <5; no significant bleeding
- Lower dose or omit dose, monitor more frequently, and resume at lower dose when INR is therapeutic
- If only minimally above therapeutic range, no dose reduction may be required - INR >5, but <10; no significant bleeding
- Omit next 1-2 doses, monitor more frequently and resume at lower dose when INR is therapeutic
- Alternatively, omit dose and give vitamin K (=5 mg PO), particularly if at increased risk of bleeding
- If more rapid reversal required due to surgery requirement, vitamin K (2-4 mg PO) can be given with exception that a reduction of INR occur in 24 hours
- If INR still high, additional vitamin K (1-2mg PO) - INR >/=10; no significant bleeding
- Hold warfarin and give vitamin K (2.5-5 mg PO) with expectation INR will be reduced substantially in 24-48 hours
- Resume therapy at lower dose when INR is therapeutic - Serious bleeding at any elevation of INR
- Hold warfarin; give vitamin K (10mg by slow IV infusion), supplemented with four-factor PCC
- Vitamin K can be repeated every 12 hours if necessary - Life threatening bleeding
- Hold warfarin; give FFP, PCC, or recombinant factor VIIa, supplemented with vitamin K (10mg by slow IV infusion)
- Repeat if necessary, depending on INR
What factors are replaced with 3-factor PCC?
II, IX, and X
Hunt and Hess classification of SAH
Grade I - mild headache, normal mental status, no nerve deficits (70% survival)
Grade II - severe headache, normal mental status, may have CN deficit (60%)
Grade III - somnolent, confused, may have CN or mild motor nerve deficit (50%)
Grade IV - stupor, mod-severe motor deficit, may have intermittent reflex posturing (20%)
Grade V - coma, reflex posturing or flaccid (10%)
When is vasospasm most common after a SAH?
2-21 days
Most common cause of SAH
Ruptured aneurysm
Cushing’s triad
HTN
Bradycardia
Irregular and shallow respirations
What time after onset of symptoms does xanthrochromia generally start following a SAH?
12 hours
Tx for cryptococcal meningitis
Amphotericin B and flucytosine followed by fluconazole suppression until adequate immune reconstitution (if this does not occur, then indefinitely)
Tx for neonatal seizures
Phenobarbital
What worrisome maternal hx should you consider in a neonate with seizures?
Maternal drug use -> withdrawal seizures
What should raise concern for encephalitis from just meningitis?
Behavioral/Personality changes and neurologic deficits
Which mosquito-transmitted viruses commonly cause encephalitis in the US?
Eastern and Western Equine
West Nile
St. Louis
Lacrosse
The radial nerve arises from what nerve roots?
C5-T1
Tx for radial nerve palsy
Wrist splint with 60 degrees of dorsiflexion to prevent atrophy and contractures
About 90% of radial nerve mononeuropathies that occur because of sleep, coma, or anesthesia will recover within 6-8 weeks
Ulnar nerve neuropathy symptoms
Decreased finger adduction/thumb grasp, 4th/5th digit paresthesias
Sciatic neuropathy symptoms
Decreased knee flexion
Foot drop
Common peroneal neuropathy symptoms
Foot drop
Lateral femoral cutaneous neuropathy symptoms
Upper thigh dysesthesia/numbness
Clinical presentation of transverse myelitis
- Transverse level of sensory impairment
- Paraplegia
- Sphincter disturbance
Etiologies of Transverse Myelitis
- Acquired CNS autoimmune disorders - MS, neuromyelitis optica, acute disseminated encephalomyelitis
- Infectious: West Nile, Herpes, HIV, HTLV-1, Zika, Lyme, Mycoplasma, Syphilis
- Systemic Inflammatory Autoimmune Disorders: Ankylosing spondylitis, Behcet disease, scleroderma, Sjogren, Lupus
- Other: neurosarcoidosis, paraneoplastic syndromes
Dx of transverse myelitis
MRI will show swelling of cord and is generally performed to exclude compressive lesion
LP shows lymphocytosis and elevated protein
Tx of transverse myelitis
IV glucocorticoids
Plasma exchange
Which segment of the spine is most commonly involved in transverse myelitis?
Thoracic - cervical spine rarely affected
Anterior cord syndrome is most commonly caused by what type of injury?
Flexion injury
Blockade of which receptor helps reduce the incidence of extrapyramidal effects?
Muscarinic acetylcholine receptors
Ulnar nerve functions
- Innervation of forearm muscles
- Intrinsic muscles of hand
- Sensation to little finger and ulnar half of ring finger
Median nerve function
- Muscles of wrist flexion and finger flexion
- Sensation over volar surface of hand from thumb to radial half of ring finger
Radial nerve function
- Muscles of wrist extension
- Muscles of finger and thumb extension
- Sensation of dorsal aspect of hand from thumb to radial half of ring finger (except tips of index, middle and radial half of ring finger)
What is the innervation of the biceps muscle?
Musculocutaneous nerve (C5 and C6)
Motor hand function testing
Median: OK sign
Ulnar: Scissors motion or spreading fingers
Radial: thumbs up; wrist/finger extension
What nerve root plays the most significant role in motor function of diaphragm?
C4
What is the significance of sacral sparing in a spinal injury?
It shows potential for recovery and is more common with incomplete cord syndromes
Key differences between conus medullaris syndrome and cauda equina syndrome
Conus medullaris - sudden and bilateral, radicular pain less severe, less marked hyperreflexic distal paresis of lower limbs, fasciculation, early urinary and fecal incontinence, localized numbness to perianal area
Cauda equina - more marked asymmetric areflexic paraplegia, atrophy more common, gradual and unilateral, localized numbness at saddle area, sphincter dysfunction tends to present late
What vertebral level is responsible for the sensation of the big toe?
L5
Clinical distinction between encephalitis and meningitis
Presence of neurologic abnormality in encephalitis - new psych sx, cognitive deficits (aphasia, amnesia, acute confusional state), seizures, movement disorders
Which anatomical regions of the brain does infectious encephalitis have a predilection for?
Gray matter of temporal lobes and inferior frontal lobe
Describe caloric testing
Requires an intact TM not fully obscured by blood or cerumen
Intact brain stem function, caloric testing elicits nystagmus with both a fast and slow component
Fast beating portion of nystagmus moves toward opposite or same ear depending on temperature of water
COWS - cold opposite; warm same
In comatose patient, cold water will produce tonic deviation of eye toward ear instilled with cold water
What is the most common cause of pupil-sparing third cranial nerve palsies?
Vascular complications of diabetes with infarction of the nerve
Risk factors for spinal epidural abscess
- IVDU/endocarditis
- Chronic renal failure
- Diabetes
- Immunosuppression
- Recent back surgery, epidural puncture
What lab test is most likely to be abnormal in patients with spinal epidural abscess?
ESR is often elevated despite a frequently normal WBC count
Most common cause of death in Parkinson disease
Respiratory failure
Four characteristic complaints of Posterior Reversible Encephalopathy Syndrome
- Headache
- AMS
- Visual Disturbance
- Seizures
Symptoms evolve fairly rapidly over hours to days
What will neuroimaging show for PRES?
Bilateral vasogenic edema
White matter edema in bilateral posterior cerebral hemispheres
Which antihypertensive agents are recommended in the tx of PRES?
Labetalol or Nicardipine
Most appropriate order of medications in suspected meningitis
- Dexamethasone
- Empiric antibiotics
- Head CT
- LP
What is the most reliable physical exam finding in patients with meningitis?
Jolt accentuation - baseline headache increases when the patient turns the head horizontally two or three rotations per second
Tx for Temporal (Giant Cell) Arteritis
Prednisone (if no vision loss) Methylprednisolone IV (if vision loss is present)
What systemic disease is frequently associated with temporal arteritis?
Polymyalgia rheumatica (30-40% of patients)
What causes NPH?
Most commonly due to impaired absorption of CSF
What symptom of NPH is most responsive to shunting
Gait impairment
What type of posturing most commonly associated with uncal or cerebellar tonsillar herniation?
Decerebrate or extensor posturing
What common extrapyramidal sx is irreversible?
Tardive dyskinesia develops over months to years of antipsychotic exposure and is usually irreversible
What nerve injury may be associated with fibular head fracture? What physical exam findings would be found?
Common peroneal nerve
- splits into deep peroneal nerve -> sensation between first and second toe and motor function to tibialis anterior (dorsiflexion and inversion of ankle) and extensor hallucis longus (extension of great toe)
- and superficial peroneal nerve -> peroneus longus (aids in ankle eversion but tibialis does most) and sensation to dorsum of foot
Most frequent cause of stroke in patients <45 y/o
Carotid artery dissection
Carotid artery dissection presentation
- Unilateral neck pain
- Headache around eye or frontal area
- Abrupt onset
- Partial ipsilateral Horner syndrome
Tx of choice for carotid artery dissection?
Anticoagulation (heparin followed by warfarin) if no evidence of acute ischemic stroke
Thrombolytic therapy if evidence of acute ischemic stroke
