Neurology Flashcards

Question

MAO-Inhibitors. Types and their uses. Indications. UE.

Answer 1

MAOI - Non-selective inhibitors of monoamine oxidase --> decrease breakdown of adrenaline, NA, serotonin and dopamine. Used for depression. - Selective MAO-B inhibitor - selegiline. Mainly inhibits breakdown of dopamine --> increased dopamine level. Used for Parkinson's disease. The major UE is a hypertensive crisis. Ingestion of foods containing TYRAMINE (cheese, cured meats, beer) when MAO is inhibited --> tyramine entry into systemic circulation --> stimulation of SNS --> hypertensive crisis. Risk of serotonin syndrome if used with other serotonergic drugs - e.g. SSRI, SNRI, TCAs, St John's Wort. Serotonin Syndrome: Classic triad is: 1. Neuromuscular excitability --> hyper-reflexia, hypertonia, myoclonus, tremor 2. Autonomic dysfunction --> tachycardia, tachypnoea, hyperthermia, HTN, sweating, diarrhoea 3. Altered mental status --> agitation, coma

Answer 2

L-DOPA: MOA: converted to dopamine by DOPA decarboxylase at the presynaptic neuron --> increased dopamine acting on receptors. Usually first-line, especially in older patients > 65 years CARBIDOPA: DOPA decarboxylase inhibitor MOA: prevents peripheral conversion of L-DOPA to dopamine --> increased L-DOPA reaching brain and decreased peripheral dopamine = decreased UE. DOPAMINE AGONISTS: pramipexole, cabergoline, pergolide, ropinirole, bromocriptine MOA: act on dopamine receptors in the striatum --> increased dopaminergic effect Often used in younger patients COMT INHIBITORS: entacapone, tolcapone MOA: inhibition of COMT enzyme (breaks down L-DOPA into 3-MT) in the periphery (and tolcapone also acts in CNS) --> increased L-DOPA --> increased dopaminergic effect. Uses: in combination with L-DOPA and carbidopa for refractory PD and if on-off effect problematic. MAO-B INHIBITORS: selegiline MOA: inhibition of MAO-B enzyme (breaks down L-DOPA to DOPAC) in the CNS --> increased L-DOPA ACH MUSCARINIC ANTAGONISTS: block overactivity of muscarinic acetylcholine receptors AMANTADINE: NMDA receptor antagonists - block neurotoxic effect of excess glutamate UE and RISKS with Anti-Parkinson's medication: - On-off effect (periods of good function alternating with poor function as L-DOPA wears off) - Dystonia/ dyskinesia (abnormal tone and movements) - Impulse-control disorders: especially with dopamine agonists - e.g. pathological gambling, hypersexuality - Drug-induced psychosis

Answer 3

TRIAD: 1. Bradykinesia 2. Tremor - asymmetrical, resting, pill-rolling 3. Rigidity - lead pipe or cogwheeling ``` PRODROMAL: Constipation Anosmia REM sleep disorder Psychiatric - e.g. mood changes ``` ``` OTHER FEATURES: Gait - shuffling, small steps, festination, slow turns, freezing, reduced arm swing Postural instability --> falls Autonomic dysfunction --> bladder and bowel dysfunction (constipation, urinary retention, incontinence), orthostatic hypotension Mask-like facies Primitive reflexes - glabellar tap Stooped posture Micrographia ```

Answer 4

Signs of increased ICP - e.g. focal neurologic signs, papilloedema, markedly reduced LOC (<8) Space occupying intracranial mass Uncontrolled bleeding diathesis Local overlying skin infection Unstable patient

Answer 5

Local discomfort Headache Failure to obtain CSF (dry tap) Bleeding - traumatic tap, spinal haematoma Neurological - nerve damage (should not occur if performed correctly), brainstem herniation Infection

Answer 6

- Informed consent - Positioning - lying on side or sitting up; back curved - Measure from top of iliac crests, which are at level of L3/4 interspace --> go into this level or 1 below (spinal cord stops at L1/2 level) - Prepare: sterile field, skin - Local anaesthetic - Insert needle and advance until resistance gives - Remove stylet and collect CSF into 3 tubes (5-10 drops/tube) - Remove needle - Apply dressing - Document - Monitor

Answer 7

``` Signs of raised ICP Known CNS disease Suspected SAH Seizure in past 1 week Age > 60 years Immunocompromise ```

Answer 8

``` Test for: WBC RBC Protein Glucose CSF pressure MCS ``` ``` VIRAL: WBC 5-1,000; lymphocytes Protein increased + Normal glucose Normal CSF pressure Negative gram stain and culture ``` ``` BACTERIAL: WBC 1,000+; PMNs Protein increased +++ Decreased glucose Increased CSF pressure Positive gram stain and culture ```

Answer 9

Strep pneumoniae N meningitidis Haemophilus influenzae type b + possibly consider Neonates -- GBS and E coli Neurosurgery or penetrating injury -- S aureus

Answer 10

Rapid assessment with concurrent hx, examination and investigation and treatment. NO IX should delay the administration of IV ABX if bacterial meningitis is suspected. Bedside: LP Labs: FBC, EUC, LFTs, CRP, BGL (blood glucose used to interpret CSF glucose), blood culture (at least 2 sets from different sites), VBG (lactate), coags (may contraindicate LP, but do not wait for results before LP unless coagulopathy likely) Imaging: in some patients, CT brain is required before LP Treatment: - Admit - Consult: ID + neurology - Immediate empiric IV ABX plus dexamethasone (must be given before or concurrent with ABX for best effect) - Swap to targeted ABX when results of MCS known - Supportive care: - -- IV cannula + IV fluids - -- Raise head if raised ICP - -- Monitor: for sepsis - Infection control measures - droplet precautions - Chemoprophylaxis for close contacts of patients with N meningitidis and HIB - Report to public health - Audiometry

Answer 11

ACUTE: - Seizure - Septic shock - ARDS and respiratory failure - DIC - SIADH - Brain abscess CHRONIC: - Sensorineural deafness - Blindness - Weakness - Ataxia - Cognitive impairment

Answer 12

- Age: very young (< 5 years) or very old (>65 years) - Immunocompromise: HIV, steroids, asplenic - Not immunized - Recent infection: URTI, sinusitis, otitis, mastoiditis - Head trauma - Neurosurgery - Crowded living conditions - Close contact with infected person

Answer 13

Enteroviruses (most common!!) HSV, CMV, EBV, VZV Measles Mumps

Answer 14

TRIAD is: (1) fever, (2) headache, (3) neck stiffness VITAL SIGNS: fever, tachycardia, possibly hypotension (septic shock) SYSTEMIC: - malaise - rash: non-blanching purpura in N meningitidis - N&V NEUROLOGICAL: - Headache - Neck stiffness - Kernig sign (lying supine with hip flexed to 90 --> passive knee extension is resisted) - Brudzinski sign (lying supine and passively flex neck --> hip/ knee flexion) - Photophobia - Papilloedema FX that suggest encephalitis: - Altered LOC - Seizures - Focal neurological signs

Answer 15

Same as for bacterial meningitis, but acyclovir instead of ABX. Rapid assessment with concurrent hx, examination and investigation and treatment. NO IX should delay the administration of IV ABX if bacterial meningitis is suspected. Bedside: LP Labs: FBC, EUC, LFTs, CRP, BGL (blood glucose used to interpret CSF glucose), blood culture (at least 2 sets from different sites), VBG (lactate), coags (may contraindicate LP, but do not wait for results before LP unless coagulopathy likely) Imaging: in some patients, CT brain is required before LP Treatment: - Admit - Consult: ID + neurology - Acyclovir - Supportive care: - -- IV cannula + IV fluids - -- Raise head if raised ICP - -- Monitor: for sepsis - Infection control measures - droplet precautions - Audiometry

Answer 16

``` BOTH UMN and LMN signs. Bulbar and pseudobulbar signs - - Dysarthria - Dysphagia - Involuntary inappropriate laughing/ crying ```

Answer 17

EMG - stimulate a peripheral nerve and measure the action potentials in associated muscle. Nerve conduction studies - stimulate a nerve (motor or sensory) at 2 points and measure the conduction velocity and amplitude of the action potential