Week 3 Flashcards
what are the names of 3 common cognitive screens?
- mini mental state examination (MMSE)
- montreal cognitive assessment (MOCA)
- addenbrooke’s cognitive examination (ACE-III)
what are the ‘special’ senses and which cranial nerves allow these?
- olfaction (I)
- vision (II)
- taste (VII, IX and X)
- hearing and balance (VIII)
which cranial nerves are involved with ‘ordinary’ sensation?
- mainly the Vth (trigeminal nerve).
- the ear from the facial (VII) and (glossopharyngeal (IX) nerves.
the eye muscles are controlled by which cranial nerves?
- oculomotor III
- trochlear IV
- abducens VI
the muscles of mastication are controlled by which cranial nerve?
V (trigeminal)
the muscles of facial expression are controlled by which cranial nerve?
facial VII
the muscles of the larynx and pharynx are controlled by which cranial nerves?
mainly vagus (X) but also glossopharyngeal
which cranial nerve controls movement of the SCM and trapezius muscles?
accessory (XI)
which cranial nerves have autonomic functions (all parasympathetic) and what are the functions?
- oculomotor III > pupillary constriction.
- facial VII > lacrimation.
- facial VII > salivation from submandibular and sublingual glands.
- glossopharyngeal IX > salivation from parotid gland.
- vagal X input to organs in thorax and abdomen.
how do we test the function of the optic nerve II?
- visual acuity
- visual fields
- pupillary reactions
- fundoscopy
- colour vision
how do we test the function of the oculomotor, trochlear and abducens cranial nerves?
- any evidence of ptosis?
- pupil of equal size?
- pupillar reactions.
- eye movements > vertical and horizontal.
how do we test the function of the trigeminal nerve?
- sensation in the opthalamic, maxillary and mandibular regions with e.g. cotton wool.
- power in muscles of mastication.
- corneal reflex.
- jaw jerk.
how do we test the function of the facial nerve?
- test muscles of facial expression.
- corneal reflex.
- taste.
how do we test the vestibulocochlear nerve function?
- hearing using Rinne’s and Weber’s tests.
- vestibular function using Dix-Hallpike maneouvre and Utenberger’s test.
how do we test the function of the glossopharyngeal and vagal nerves?
- movement of the palate
- gag reflex
- quality of speech
- quality of cough
how do we test the function of the accessory nerve XI?
- head turning and shoulder shrugging.
how do we test th function of the hypoglossal nerve?
appearance, movement and power of tongue
what is the location of the oculomotor and trochlear cranial nerve nuclei?
mid brain
what is the location of the trigeminal, abducens and facial cranial nerve nuclei?
pons
what is the location of the vestibulocochlear cranial nerve nuclei?
pontomedullary junction
what is the location of the glossopharyngeal, vagus, accessory and hypoglossal nerve nuclei?
medulla
what causes optic neuritis?
- demyelination within the optic nerve.
- often associated with multiple sclerosis.
what are the consequences of optic neuritis?
- monocular visual loss
- pain on eye movement
- reduced visual acuity
- reduced colour vision
- optic disc may be swollen
what are some causes of an isolated third nerve palsy?
microvascular causes (painless, pupil spared):
- diabetes
- hypertension
compressive causes (painfule, pupil affected):
- posterior communicating artery aneurysm
- raised ICP
what are some causes of an isolated sixth nerve palsy?
- idiopathic
- diabetes
- meningitis
- raised ICP
what causes trigeminal neuralgia?
- caused by compression of trigeminal nerve in the posterior fossa.
what is the first-line treatment for trigeminal neuralgia?
carbamazepine
what is dysarthria?
disordered articulation
slurring of speech
what causes pseudobulbular palsy?
- bilateral UMN lesions of CN IX-XII
- site > internal capsule
- MND, MS
what causes a bulbar palsy?
- bilateral LMN lesions affecting IX-XII
- site > medulla
- MND, polio, tumours, vascular lesions of the medulla, syphilis.
what are symptoms and signs of bulbar palsy?
- absent/reduced gag reflex
- wasted, fasciculating tongue
- jaw jerk absent/normal
- dysarthria (nasal)
- dysphagia
what are symptoms and signs of pseudobulbar palsy?
- exaggerated gag reflex
- spastic tongue
- jaw jerk increased
- spastic dysarthria
- emotional lability
how would you describe a functional neurological disorder?
change in function rather than structure of a system (blackouts, paralysis, abnormal movements).
what is Hoover’s sign when assessing functional symptoms and signs in neurology?
meningitis definition
- inflammation/infection of meninges.
encephalitis definition
inflammation/infection of brain substance
myelitis definition
inflammation/infection of spinal cord
signs and symptoms of meningitis
- headache
- fever
- neck stiffness
- photophobia
- nausea and vomiting
- focal neurology
- seizures
- reduces conscious level
- non-blanching petechial rash indicative of sepsis
what test is used to look for a petechial skin rash in meningitis?
Tumbler test
what are the organisms responsible for bacterial meningitis?
- Neisseria meningitidis (meningococcus).
- Streptococcus pneumoniae (pneumococcus).
what type of virus can cause meningitis?
enteroviruses
what are the signs and symptoms of encephalitis?
- fever
- flu-like prodromal illness (4-10 days)
- seizures
- focal neurological deficits
- headaches
- cerebral dysfunction: confusion, abnormal behaviour, memory disturbance, depressed concious level)
how could you perhaps differentiate between viral encephalitis and bacterial meningitis?
- onset of viral encephalitis is generally slower than for bacterial meningitis and cerebral dysfunction is a more prominent feature.
aetiology of encephalitis
- mainly viral with the most common pathogen being herpes simplex virus type 1 (HSV-1).
- other viral causes > varicella-zoster virus, epstein-barr virus, cytomegalovirus.
- meningitis > meningoencephalitis.
- autoimmune encephalitis.
what are features of auto-immune encephalitis caused by anti-VGKC (voltage gated potassium channel) antibodies?
- frequenct seizures
- amnesia (not able to retain new memories)
- altered mental state
anti-NMDA receptor antibodies are a feature of which autoimmune condition?
autoimmune encephalitis
what are the investigations of meningitis?
- blood cultures (bacteraemia)
- lumbar puncture (CSF culture/microscopy)
- no need for imaging if no contraindications to lumbar puncture (CT head if contraindicated).
what are the investigations of encephalitis?
- blood cultures and viral PCR
- imaging (CT scan +/- MRI)
- lumbar puncture (CSF analysis with viral PCR)
- EEG
what would CSF findings show in bacterial meningitis?
Opening pressure, cell count (and type of WBC raised), glucose, protein
- opening pressure > increased.
- cell count > high, mainly neutrophils.
- glucose > reduced.
- protein > high.
what would CSF findings show in viral meningitis and encephalitis?
opening pressure, cell count (and type of WBC), glucose, protein
- opening pressure > normal/increased.
- cell count > high, mainly lymphocytes.
- glucose > normal (60% of blood glucose).
- protein > slightly increased.
aetiology of Arbovirus encephalitides
- transmitted to man by vector (mosquito or tick) from non human host e.g.: West Nile virus.
describe a brain abscess
localised area of pus within the brain
what is a subdural empyema?
thin layer of pus between the dura and arachnoid membranes over the surface of the brain
what are the clinical features of brain abscess and empyema?
- fever
- headaches
- focal symptoms/signs: seizures, dysphasia, hemiparesis etc.
- signs of raised intracranial pressure: papilloedema, depressed conscious level.
- meningism may be present, particulary with empyema.
- features of underlying source e.g. dental, sinus or ear infection.
what are some causes of brain abscess and empyema?
- penetrating head injury
- spread from adjacent infection: dental, sinusitis, otitis media
- blood-borne infection e.g. bacterial endocarditis
- neurosurgical procedure
how do we diagnose brain abscess and empyema?
- CT or MRI.
- investigate source.
- blood cultures.
- biopsy (drainage of pus).
what are the most common organisms responsible for a brain abscess?
- streptococci in 70% of cases, especially the penicillin-sensitive kind: strep anginosus, strep intermedius, strep constellatus.
- anaerobes in 40-100% of cases: bacteroides, prevotella.
what is the management for a brain abscess?
- surgical drainage if possible
- penicillin or ceftriaxone to cover streptococcus (high dosage).
- metronidazole for anaerobes (high dosage).
- culture and sensitivity tests on aspirate provide useful guide
what are some HIV indicator illnesses affecting the brain?
- cerebral toxoplasmosis
- aseptic meningitis/encephalitis
- primary cerebral lymphoma
- cerebral abscess
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which spirochaetes can infect the CNS?
- lyme disease (Borrelia burgdorferi)
- syphilis (trepomena pallidum)
- leptospirosis (leptospira interrogans)
describe stage 1 of lyme disease
early localised infection (1-30 days)
- early localised infection (1-30 days)
- characteristic expanding rash at the site of the tick bite: erythema chronicum migrans (circular, target-shaped lesion)
- 50% flu like symptoms (days-1week): fatigue, myalgia, arthralgia, headache, fever, chills, neck stiffness)
describe stage 2 of lyme disease
early disseminated disease, lasting from days to months
- early disseminated disease, lasting from days to months
- continued flu-like symptoms
- neuroborreliosis: facial nerve and other cranial nerve palsies, aseptic meningitis, encephalitis, peripheral mononeuritis etc.
- cardiovascular involvement: myocarditis, heart block and other arrhythmias, pericarditis
- early painful arthritis
describe stage 3 of lyme disease
late disseminated disease, lasting from months to years
- late disseminated disease, lasting from months to years.
- arthritis
- late neurological disorders: polyneuropathy, chronic encephalomyelitis, dementia, psychosis
- acrdermatitis chronica atrophicans: blue-red discolouration and swelling at extensor surfaces
investigations for lyme disease
- complex range of serological tests
- CSF lymphocytosis
- MRI brain/spine (if CNS involvement)
- nerve conduction studies/EMG (if PNS involvement)
what is the treatment for Lyme disease?
- prolonged antibiotic treatment: IV ceftriaxone, oral doxycycline.