Neurology/ neurosurgery Flashcards
List 4 life-threatening causes of ataxia
- Brain tumors (post. fossa) —> raised ICP
- Intracranial hemorrhage
- Stroke
- Infection (encephalitis, ADEM, abscess)
What are four/five non-cancer causes of ataxia?
- Acute cerebellar ataxia post varicella infection
- Intracranial hemorrhage
- Stroke (vertebral or basilar artery)
- Cerebellar abscess
- ADEM
- Guillain Barre syndrome – Miller Fisher variant: triad ataxia, areflexia, ophthalmoplegia
- Labyrinthitis
- Migraines
- Toxin exposure – antiepileptics, lead, CO, alcohol
- Post-traumatic
Most common cause of postinfectious cerebellitis, and general illness course
post-varicella
age 1-3, 8d-3 weeks post infection, VZV usually case, other include EBV and mycoplasma; mild increase WBC/protein in CSF; recovery several weeks (residual deficits in 10-30%); imaging studies normal; may see dysarthria/nystagmus, n/v
Which toxins can cause ataxia? (list 4)
alcohol, phenytoin, carbamazepine, benzo, TCA, antihistamines, lead, ethylene glycol, risperidone, gabapentin
What is the Miller Fischer variant of GBS?
Ataxia, ophthalmoplegia, areflexia
Etiology of coma? (and an acronym to remember it)
TIPS
T: Trauma
I: Insulin/Hypoglycemia, Intussusception, Inborn errors of metabolism
P: Psychiatric
S: Seizures, Stroke, Shock, Shunt malfunction
AEIOU A: Alcohol abuse E: Electrolyte abnormalities, Encephalopathy, Endocrinopathy I: Infection O: Overdose/Ingestion U: Uremia
What is considered clinically important TBI (ciTBI)?
depressed skull fracture requiring surgery, neurosurgical intervention (ICP monitor, ventriculostomy, hematoma evacuation, craniectomy), hospital admission for > 48 hours, death
Most common causes of head trauma in peds?
falls (most common), MVC/ pedestrian (highest fatality), bicycle injuries, non-accidental injury
Causes of secondary brain injury?
further neuronal damage (due to hypoxia, hypoperfusion, cerebral edema)
How is CPP calculated?
How does cerebral blood flow autoregulation work?
CPP (cerebral perfusion pressure) = MAP – ICP
Cerebral blood flow is autoregulated to remain constant across wide range of CPP (autoregulation lost with severe injury – so cerebral blood flow becomes directly related to MAP – therefore very important to maintain normal MAP)
o Autoregulation lost when MAP < 60 or ICP > 40
Signs and symptoms of increased ICP?
- Symptoms of increased ICP: headache, vomiting, irritability, lethargy
- Signs of increased ICP: depressed LOC, Cushing triad (bradycardia, hypertension, irregular respirations), CN palsy
4 types of cerebral herniation syndromes and how they present?
- Subfalcine (unilateral motor deficits or lower limbs, bladder incontinence)
- Central (forced downward gaze, dil. unreactive pupils, quickly lethal)
- Uncal = transtentorial (CN 3 palsy - pupil dilated, down and out on side of herniation, contralateral - rarely unilateral hemiparesis)
- Tonsillar (dec LOC, resp failure, flaccif paralysis)
Characteristics of epidural hematoma?
Lens-shaped on CT
overlying fracture in 60-80% of cases, lucid interval btw initial LOC and subsequent deterioration very rare in children – fixed and dilated pupil on the side of the lesion and contralateral hemiparesis (compression of CN III & corticospinal tract)
CATCH study - name 4 findings that predict neurosurgical intervention and 3 that predict CT findings
WIGS SDH
High risk: Worsening headache Irritability GCS < 15 at 2 hours Suspected open or depressed skull #
Medium risk:
Signs of basal skull
Dangerous mechanism
Boggy hematoma
+ >/= vomiting 4 x (CATCH 2)
What is considered a dangerous mechanism for the CATCH study? for PECARN?
for CATCH:
MVC, fall from elevation ≥ 3 ft or 5 stairs, fall from bicycle with no helmet
for PECARN:
• MVC with rollover, patient ejection, or death of another passenger
• pedestrian or bicycle w/o helmet struck by motorized vehicle
• fall > 3 feet if age > 2 years, fall > 5 feet if age > 2 years
• head struck by high impact object
What are some signs and symptoms of basal skull fracture?
hemotympanum, “raccoon” eyes, otorrhea or rhinorrhea of the cerebrospinal fluid, Battle’s sign
What are 3 indications for skull x-ray
- skeletal survey
- evaluate for location of a radiopaque foreign body
- in rare instances to screen for # in selected asymptomatic children 3-12 months of age with concerning scalp hematoma or question of depression
What were the risk factors for identifying a skull # according to a 2015 CMAJ study?
CMAJ 2015 study: risk factors for findings skull fracture are age < 2 months, or parietal/ occipital hematoma (in 3-12 months)
For skull xrays: list 4 x-ray findings suggestive of more serious underlying injury
depressed, basilar, linear with >3 mm separation, growing skull #
List 4 differences in CSF between subarachnoid hemorrhage and traumatic tap.
- Elevated opening pressures
- Presence of blood in CSF that does not clear between tubes
- Xanthochromia (noted at least 2 hours post headache onset, ideally >6 hours)
- Elevated ratio of RBC to WBC, absence of WBCs
What are the different types of skull fractures?
linear (75-90%) diastatic (separation at suture sites or fracture that is widely split) depressed compound (communicate with laceration) comminuted (several fragments)
Complications of basal skull #?
intracranial injury, CSF leak (with dural tear), meningitis, CN impairment, hearing loss
Characteristics of subdural hematomas?
bleeding between dura and arachnoid membranes. Tearing of cortical bridging veins, crescent-shape on CT scan (crosses suture lines)
List some common symptoms of concussion
headache, confusion, dizziness, light-headedness, nausea/vomiting, memory impairment
Definition of concussion?
functional (not structural) brain injury from a force/ blow to the head. May or may not have LOC
Grading severity of head trauma by GCS score?
Minor head trauma: GCS 14-15
Moderate: GCS 9-13
Severe: GCS ≤ 8
GCS score (E4,V5, M6)
Post-traumatic seizures - and risk of recurrence
• Timing : immediate, early or late
o Immediate – within seconds, traumatic depolarization of the cortex, generalized, rarely recur
o Early – within 1 week, most within 24 hours. Increased risk with skull fractures, intracranial hemorrhage, and focal signs
o Late: > 1 week. More likely to recur, due to scarring, intracranial hemorrhage
Discharge instructions / anticipatory guidance for head trauma (list 5)
- Persistent or increasing headache
- Repeated vomiting
- Drowsiness or change in behavior
- Weakness or clumsiness of an arm or leg
- Stiffness of neck or complaints of pain with neck movement
- Vision changes
- Poor balance when walking
- Seizures
- Leakage of clear fluid from nose or ears
Steps in management of ICP in context of trauma
o Head of bed to 30 degrees, head midline
o Analgesia, sedation +/- paralysis
o PaCO2 35-45 (if herniating: 30-35 – moderate hyperventilation)
o Hypertonic 3% saline (6-10 ml/kg) +/- continuous infusion – aim Na 145-155
o Consider prophylactic anti-epileptics
o Barbiturate coma
Which meds to use to intubate in head trauma?
use atropine if < 1 year old, lidocaine and RSI (etomidate and midazolam listed as good options)
Ketamine NOT associated with increased ICP (may actually lower ICP – safe to use in RSI)
Definition of migraine without aura
- At least 5 attacks
- Headaches last 4-72 hours
- At least 2 of: unilateral (more common bilateral in kids), pulsating, mod-severe, worse with activity
- At least 1 of: photo/phonophobia, N/V
Types of primary headache? (3)
migraine, cluster, tension
Common migraine triggers (4)
stress, lighting changes, minor head trauma, hormonal (OCP, menstruation), nitrates, tyramine (cheeses)
List 4 migraine variants
basilar (mimic posterior fossa mass), ophthalmoplegic (CN 3,4,6), hemiplegic, retinal, confusional, Alice in Wonderland syndrome
List 3 migraine equivalents
abdominal migraine, cyclical vomiting, benign paroxysmal vertigo, benign paroxysmal torticollis
Headache red flags (6)
Nocturnal, worse in AM worsening severeity vomiting, early AM behavioral changes polyuria/polydipsia (craniopharyngioma) Neuro deficits
Migraine - prophylactic agents (3)
Prophylactic agents: propranolol, TCA, valproic acid, CCB, gabapentin, topiramate, lamotrigine
Risk factors for IIH
Obese, adolescent, female on OCP
- Medications: retinoid acid, tetracycline, nitrofurantoin, steroids, growth hormone, excessive vitamin A, OCP, lithium
- Endocrine: hypothyroidism, Cushing syndrome, hyperthyroidism, hypoparathyroidism, Addison disease, adrenal insufficiency
- Other: OSA, thrombosis of dural venous sinuses (head trauma, AOM, mastoiditis, obstruction jugular veins in SVC)
Treatment of IIH
LP to relieve CSF, Diamox to decreased CSF production, consider steroids in consultation with neurology
Acute treatment of migraine?
• NSAIDS (best evidence – level A) – ibuprofen or ketorolac
• Acetaminophen
• IV fluids
• Dopamine receptor antagonists: prochlorperazine, chlorperazine (risk of long QT), metoclopramide (risk of dystonic reaction – treat with Benadryl)
o Can also give ondansetron as antiemetic
• Triptans (sumatriptan nasal spray has level A evidence – serotonergic agent)
• Dihydroergotamine
Side effects and contraindications for Triptans?
- Contraindicated in hx of stroke, CV disease, uncontrolled HTN, hemiplegic migraine, pregnancy
- Side effects: flushing, tachycardia, disorientation, chest tightness
When to obtain CT before LP?
- Focal neurologic signs
- Decreased LOC
- Bradycardia, hypertension
- Papilledema
- Focal seizure
Dystonic reactions - common med triggers? Treatment?
Dystonic reactions – due to anti-dopamine drugs (neuroleptic, antiemetic, metoclopramide)
Treat with diphenhydramine (benadryl) or benztropine (cogentin) for 24-48 hours (long ½ life of offending meds)
Girl given Maxeran (metoclopramide) for migraine. Now torticollis and eye deviation. Diagnosis?
Drug-induced dystonic reaction
Symptoms of IIH?
Headache most common symptom, nausea, vomiting, dizziness, double or blurred vision, decrease VA can result, papilledema seen in all cases, may see CN VI palsy
A kid comes in with suspicion of pseudotumour cerebri
What are 4 parts of the diagnosis
Modified Dandy criteria:
- Signs and sx of raised ICP / papilledema
- High opening prressure (usually > 25 cm H20)
- normal MRI/ CT
- no alternate cause of inc ICP
Features that can make visual loss permanent in IIH?
o Rapid onset of symptoms/disease course
o Significant vision loss at presentation
o High grade papilledema
o Transient visual obscurations
o More severe obesity, male gender, anemia, younger age or onset in puberty, systemic HTN
o Higher LP opening pressure
Features of psychogenic non-epileptic seizures (pseudoseizures)
thrashing, eyes closed, not during sleep, always witnessed, vocalization, no post-ictal period, no incontinence, no tongue biting. More likely to occur in patients with underlying seizure disorder
Non-epileptic mimics of seizures
- breath holding spell
- syncope
- migraine
- tics
- benign myoclonus
- Sandifer sx - GERD
- narcolepsy
- pseudoseizures
When to consider LP in febrile seizure?
<12 mo, complex, pretreatment with abx, prolonged fever or those who do not return to baseline quickly
Features of simple febrile seizure
<15 min, GTC, 1/24 hr period (2 within <30 min considered single episode), normal development, normal neuro exam before and after
What are 6 signs of respiratory failure in a child who is seizing?
tachycardia, tachypnea, bradypnea, hypoxemia, cyanosis, SOB, apnea, grunting, stridor, decreased air entry, confusion
Inc risk of recurrence of febrile seizures
young age at first seizure, lower temp on first seizure, family hx of febrile seizures
Risk factors for developing epilepsy after febrile seizure
1–> 2% increased if abnormal development, family hx of epilepsy, complex febrile seizure
Work-up of afebrile seizure?
- Electrolytes – glucose, Ca, Na if young infant (formula dilution), or prolonged seizure, dehydration/ meds or conditions that affect electrolytes
- Anticonvulsant levels
- Head imaging – CT or MRI – focal seizures, signs of increased ICP, trauma, VP shunt
- Outpatient EEG – afebrile seizures
Tx of hyponatremic seizure
3ml/kg of 3%saline will raise serum sodium by 3mEq/L.
Administer 3ml/kg of 3%saline until seizures stop. (Max 100ml).
Focal seizures - predisposing factors
- Infectious: HSV encephalitis, Brain abscess
- Neoplastic - Brain tumor (primary vs mets), Leukemia with meningeal involvement
- Traumatic - Intracranial hemorrhage (epidural, subdural, intra-parenchymal)
- FmHx of focal epilepsy syndromes
- hx of focal cortical dysplasia
Stroke risk factors (list 6)
Sickle cell, homocystinuria, moya moya (structural arterial disease), hypercoagulable states (protein C, protein S deficiencies, factor V leiden), malignancy, pregnancy, severe dehydration, sepsis, substance use (cocaine, amphetamines, ethanol), embolic causes (rheumatic fever, CHD)
What is “bulbar palsy”, and list 5 causes
A bulbar palsy is a lower motor neuron lesion of cranial nerves 9, 10, 11
Causes:
• Genetic: Kennedy’s disease, acute intermittent porphyria
• Vascular causes: medullary infarction, such as lateral or medial medulary infarction.
• Degenerative diseases: amyotrophic lateral sclerosis, syringobulbia, Wolfram syndrome
• Inflammatory/infective: Guillain-Barre syndrome, poliomyelitis, Lyme disease
• Malignancy: brain-stem glioma, malignant meningitis
• Toxic: botulism, venom of bark scorpion (species Centruroides), some neurotoxic snake venoms
• Autoimmune: myasthenia gravis
Diagnostic criteria of transverse myelitis?
- Sensory, motor or autonomic dysfunction attributable to the spinal cord
- Bilateral signs and/or symptoms
- Clearly defined sensory level
- No evidence of compressive cord lesion
- Inflammation defined by cerebrospinal fluid pleocytosis or elevated IgG index or gadolinium enhancement
- Progression to nadir between four hours and 21 days
Causes of transverse myelitis?
- Autoimmune, demyelination
* Can be post-infectious: EBV, CMV, measles, mumps, C. jejuni; or first manifestation of MS
Symptoms of transverse myelitis?
Weakness (flaccid –> spastic), numbness, low back pain, urinary retention
Identify sensory tracts of the spinal cord
Spinothalamic = pain and temperature
Dorsal columns = vibration, proprioception (stand up straight)
Diagnostic features of Guillain-Barre:
Exam: ascending flaccid paralysis, weakness and areflexia/hyporeflexia, mild sensory loss, extremity pain/discomfort, initially no fever; can have autonomic instability, resp insufficiency
Testing: CSF (high protein, normal WBC), MRI showing enhancement of spinal nerve roots
Treatment of Guillain Barre
- supportive care
- regular bedside spirometry
- IVIG (if not ambulating)
- plasma exchange
- Steroids NOT effective
Pathophysiology of myasthenia gravis?
Antibodies against Ach receptor at post-synaptic part of NMJ –> fluctuating weakness of cranial and skeletal muscles *cranial nerves (ie. ptosis), fatiguable weakness
What 2 diagnoses to consider with severe acute weakness in myasthenia gravis?
myasthenic crisis vs. cholinergic crisis (from treatment)
- Secure airway, breathing, then give edrophonium (will improve weakness rapidly if due to myasthenic crisis).
- For myasthenic crisis: Steroids, plasmapheresis, cholinesterase inhibitors
- for cholinergic crisis - stop the meds
Stroke screening mnemonic?
Face (asymmetry, vision loss)
Arms and legs (weakness, numbness)
Speech (slurred, confused)
Time (abrupt onset)
3 types of strokes, and some causes of each
- Ischemic: arteriopathy (including Moya Moya, dissection), cardiac (R-L shunts, during surgery), prothrombotic states, systemic disorders (ie. Sickle cell, sepsis, MELAS)
- CSVT: focal neuro symptoms + signs of increased ICP
- Hemorrhagic: bleeding disorders, aneurysms (rare – associated with EDS, tuberous sclerosis and other syndromes), sickle cell
Findings on testing for HSV encephalitis
- MRI (diffusion-weighted) – focal parenchymal involvement or edema of temporal lobes
- EEG – focal slowing or epileptiform discharges in temporal lobes
Obstructive causes of hydrocephalus
stenosis of cerebral aqueduct – congenital, midbrain tumors, post-hemorrhage or infection, posterior fossa tumors
Non-obstructive causes of hydrocephalus?
- scarring of subarachnoid space and arachnoid villi (post-IVH, meningitis), brain tumors (CSF more viscous due to high protein)
- choroid plexus papilloma / carcicoma = increased production
What is the pathophysiology of hypotension in neurogenic shock? List 5 other signs of neurogenic shock.
- Spinal cord injury that eliminates sympathetic innervation to the blood vessels, causing profound vasodilation and bradycardia
- Clinical features: o Hypotension o Bradycardia o hypothermia o loss of rectal/bladder tone o Afebrile o Flaccid extremities o Sensation changes in extremities
What is the oculovestibular reflex?
oculovestibular reflex (CN 3, 6, 8); ensure eardrum ok, instill cold water, eye should move to cold water
Oculocephalic reflex?
Doll’s eye or oculocephalic (CN 3, 6, 8): only do if C-spine cleared; eyes moves opposite direction head turned
Facial palsy - how to differentiate UMN vs. LMN?
Upper motor neuron lesion:
o Central lesion
o Typically forehead sparing (b/c bilateral innervation for forehead mvmt)
Lower motor neuron lesion
o Peripheral lesion
o Consistent with Bell’s Palsy
o Involves full face, including forehead
Causes of LMN facial nerve palsy?
o Bell’s Palsy
o Guillain Barre syndrome
o Myasthenia Gravis
o Traumatic – Basal skull fracture, penetrating middle ear injury, barotrauma
o Infectious: otitis externa, acute otitis media, HSV, Lyme disease, mastoiditis, Mumps, mono, coxsackie
o Metabolic: Hyperthyroid, pregnancy, DM
o Oncologic: Leukemia, cholesteatoma
Treatment of Bell’s palsy?
- protection of cornea with ointment (lacri-lube); systemic - corticosteroids to improve likelihood to complete resolution (5 days and 5 day taper)
- consider antivirals if severe disease or vesicles in ear canal
complete recover in 60-80%
Features of different ischemic stroke territories?
- ACA – lower extremity weakness
- MCA – hemiplegia with upper limb predominance, hemianopsia and sometimes dysphasia
- PCA (least common) – vertigo, ataxia, nystagmus, hemiparesis and hemianopsia
Stroke treatment?
- Anticoagulation (after hemorrhagic ruled out) – ASA/LMWH/heparin, thrombolysis/thrombectomy
- Neuroprotective measures: oxygen, avoid hypotension, normovolemia, normothermia, normoglycemia, seizure control
- Sickle cell – exchange transfusion to achieve HgS < 30%
Symptoms of VP shunt failure?
nausea and vomiting
irritability
decreased level of consciousness
bulging fontanel
What is the most common pathogen for VP shunt infection in the first 6 months after surgery
S. aureus (and CONS) = early
gram negatives, E.coli/ pseudomonas = late (> 6 months)
Which imaging tests to perform in VP shunt failure?
Shunt series and CT/MRI brain
Abx for VP shunt infection?
CTX/vanco (ceftrazidine/vanco if worried about psuedomonas - late infection)
What is spinal shock?
Spinal shock is not a true form of shock. It refers to the flaccid areflexia (with dec reflexes, loss of sensation) that may occur after spinal cord injury, and may last hours to weeks. It may be thought of as ‘concussion’ of the spinal cord and resolves as soft tissue swelling improves. Priapism may be present.
Contraindications to LP
- suspected brain/spine mass
- symptoms and signs of impending cerebral herniation in a child with probable meningitis
- critical illness
- skin infection at the site of the lumbar puncture
- thrombocytopenia with a platelet count <20
