neurology Flashcards
spastic gait
Pace shortens and narrow base is maintained
more pronounced in extensor muscles causing stiff and slow walking.
parkinsonian gait
posture is stooped and arm swing reduced
gait becomes hesitant with shorter rapid steps which slows down to a shuffle in advanced disease
Describe the presentation of cerebellar ataxia
In lateral cerebellar disease - stance becomes broad-based and uncoordinated
In midline (vermis) cerebellar disease - truncal ataxia leads to a tendency to fall backwards or sideways
Outline the effect of gait occurring in sensory ataxia?
Loss of proprioception - leading to a broad-based, high-stepping gait
syncope
a short duration (usually 20-30s) of loss of consciousness caused by a global reduction in cerebral blood flow
components of motor axis
motor cortex
corticospinal tracts
anterior horn cells
spinal nerve roots
peripheral nerves
neuromuscular junctions
muscle fibres
components of pyramidal system
corticospinal tract
corticobulbar tract
upper motor neurone lesion features
signs on opposite side to lesion
no muscle wasting
spasticity (+/- clonus)
hyperreflexia
extensor plantar response (Babinski signs)
lower motor neurone lesion features
signs on same side as the lesion
fasciculations
wasting
hypotonia
hyporeflexia
two patterns of clinical features which occur in an upper motor neurone lesion?
hemiparesis and paraparesis
hemiparesis
weakness of limbs on one side (usually caused by a lesion within the brain or brainstem e.g. a stroke)
paraparesis
weak legs.
indicative of bilateral damage to the corticospinal tracts (most commonly due to lesions below the T1 spinal level
lower motor neurone
motor pathway from anterior horn cell or cranial nerve via a peripheral nerve to the motor endplate
most common causes of a lower motor neurone lesion
anterior horn cells lesions e.g. motor neurone disease
spinal root lesion e.g. cervical and lumbar disc lesions
peripheral nerve lesions e.g. trauma, compression etc.
most common disease of the neuromuscular junction?
Myaesthenia Gravis
elevation of what plasma muscle enzyme indicates muscle disease?
creatine kinase
sensory peripheral nerves carry information from the dorsal root ganglion to the brain via three main pathways, what are they?
posterior columns
spinothalamic tracts
spinocerebellar tract
sensory modalities transmitted via the posterior columns
vibration
two-point discrimination
light touch
sensory modalities transmitted via the spinothalamic tract
pain
temperature
route of the posterior column
fibres ascend uncrossed to the gracile and cuneate nuclei in the medulla.
axons from the second-order neurones cross the midline to form the medial lemniscus and pass to the thalamus
route of the spinothalamic tract
fibres synapse in dorsal horn of the cord, cross the cord at that spinal level and ascend to the thalamus
sensory modalities are transmitted via the spinocerebellar tract?
proprioception
route of the spinocerebellar tract
does not decussate i.e. innervates the ipsilateral side of the body
The quality and distribution of the symptoms depend on the site of the lesion. Outline the potential sites of nerve lesions and their corresponding characteristics?
Peripheral nerve lesions - symptoms in the distribution of the affected nerve
Spinal root lesions - symptoms referred to affected dermatome
Spinal cord lesions - Symptoms are evident below the level of the lesion
Pontine lesions - Loss of all possible sensation on the opposite side of the lesion
Thalamic lesions - A rare cause of complete contralateral sensory loss
Cortical lesions - sensory loss, neglect of one side of the body and subtle disorders of sensation
What root value does the ankle jerk reflex correspond to?
S1
What root value does the knee jerk reflex correspond to?
L2, 3, 4
What root value does the biceps jerk reflex correspond to?
C5
What root value does the supinator jerk reflex correspond to?
C6
What root value does the triceps jerk reflex correspond to?
C7
What root value does the abdominals reflex correspond to?
T8-11
corticobulbar tract
component of the pyramidal system.
responsible for transmitting neurones from cerebrum to the cranial nerves.
- control muscles of the face and neck - facial expression
- mastication, swallowing
extrapyramidal system
component of the motor system which do not travel through the pyramids.
- complex movements
- postural control
components of extrapyramidal system
Hint = RPMLT
rubrospinal tract
pontine reticulospinal tract
medullary reticulospinal tract
lateral vestibulospinal tract
tectospinal tract
cranial nerve nuclei that are located in midbrain
CN 1, 2, 3, 4
cranial nerve nuclei that are located in pons
CN 5, 6, 7, 8
cranial nerve nuclei that are located in medulla
CN 5, 7, 8, 9, 10, 11, 12
causes of anosmia (first cranial nerve pathology)
nasal congestion (most common)
anterior fossa tumours
head injury
what structure do the optic nerves enter the cranial cavity through?
optic foramina
Outline the course of the optic nerve
Optic nerve transmitted into the cranial cavity
Forms optic chiasm
Continued as the optic tracts
Fibres of the optic tract project to the visual cortex of the occipital lobe through the lateral geniculate body and third cranial nerve nucleus for pupillary light reflex.
Specific visual field losses can indicate a specific pathology. What does the presence of paracentral scotoma indicate?
Retinal lesion
Specific visual field losses can indicate a specific pathology. What does the presence of monocular field loss indicate?
Optic nerve lesion
Specific visual field losses can indicate a specific pathology. What does the presence of bitemporal hemianopia indicate?
Chiasmal lesion
Specific visual field losses can indicate a specific pathology. What does the presence of homonymous hemianopia indicate?
Optic tract/radiation/cortex/pole lesion (usually due to posterior cerebral artery infraction)
Specific visual field losses can indicate a specific pathology. A lesion in what lobe(s) of the brain may present as a homonymous quadrantanopia indicate?
Temporal/parietal lesion
Name some causes for persistent pupillary dilatation
A third cranial nerve palsy
Antimuscarinic eye drops
Myotonic pupil (no pathological indication - no constriction on light or convergence)
Name some causes of persistent pupillary constriction
- Parasympathomimetic eye drops (used in treatment of glaucoma)
- Horner’s Syndrome
- Argyll Robinson pupil (abnormality seen in neurosyphilis - absent reaction to light but convergence causes constriction)
- Opiate addiction
A palsy of the seventh cranial nerve, cerebellar signs and involvement of the fifth, sixth and eighth cranial nerves indicates a lesion at what anatomical position?
Cerebellopontine angle (most commonly meningioma or acoustic neuroma)
What is the motor function of the trochlear nerve (CN IV)?
Superior oblique muscle
What is the motor function of the abducens nerve (CN VI)?
Lateral rectus muscle
What is the motor function of the oculomotor nerve (CN III)?
Superior, inferior and medial rectus muscles
Sphincter pupilae
Levator palpebrae superioris
The brainstem, cortex and cerebellum coordinate the third, fourth and sixth cranial nerve to ‘conjugate’ eye movements. What is the clinical presentation of a defect in this coordination (called supranuclear palsy)?
Lead to paralysis of conjugate movements of the individual muscles innervated by the third, fourth and sixth cranial nerves
Describe the clinical picture of an infranuclear palsy of the third cranial nerve
Unilateral complete ptosis with ‘down and out’ appearance
Total paralysis leads to a dilated, fixed pupil
Partial paralysis paralysed pupil but still reacted to reactive to light
Describe the clinical picture of an infranuclear palsy of the fourth cranial nerve
Torsional diplopia (two objects at an angle) when attempting to look down
Head is tilted away from the side of the lesion
Describe the clinical picture of an infranuclear palsy of the sixth cranial nerve
The eye cannot be abducted beyond the midline
Eye turns in medially with concurrent diplopia
What is the most common cause of a total and partial third cranial nerve palsy respectively?
Total palsy - berry aneurysm of the posterior communicating artery
Partial palsy - diabetes mellitus
What is often the earliest sign of a fifth cranial nerve lesion?
Diminution of the corneal reflex
What is the clinical presentation of a total fifth cranial nerve palsy?
Unilateral sensory loss on the face, tongue and buccal mucosa with jaw deviation to the side of the lesion
What is the cardinal feature of a supranuclear palsy of the fifth cranial nerve?
Brisk jaw jerk reflex
What is trigeminal neuralgia?
Severe paroxysms of knife-like pain occur in one or more sensory divisions of the trigeminal nerve brought on by a specific trigger
No objective clinical signs
How is trigeminal neuralgia treated?
Anticonvulsant carbamazepine suppresses attacks
Thermocoagulation of the tigeminal ganglion may be necessary
What are the two major branches of the seventh cranial nerve unrelated to facial muscle innervation?
Chorda tympani - providing taste to the anterior two third of the tongue
Nerve to the stapedius - dampening effect on sound
What are the potential features of a facial nerve palsy in addition to the paralysis of facial muscles?
Hyperacusis (undue sensitivity to sounds)
Loss of taste to the anterior two thirds of the tongue
Outline the features of a lower motor neurone lesion of the facial nerve
Ipselateral weakness of the facial muscles
Hyperacusis
Loss of taste of the anterior two thirds of the tongue
What is Bell’s Palsy?
Common, acute isolated unilateral facial nerve palsy probably due to a viral herpes simplex infection causing swelling within the petrous part of the temporal bone
How is a lower motor neurone facial palsy managed?
Protect cornea from ulceration Oral prednisolone (60mg/day for 10 days)
Antivirals used in severe cases
What is the differential diagnosis of paralysed facial muscles?
Bell’s Palsy
Ramsey-Hunt Syndrome
Parotid Tumour
What is Ramsey-Hunt Syndrome?
Herpes zoster (shingles) of the geniculate ganglion causing facial muscles palsy and herpetic vesicles of the external auditory meatus/soft palate
Outline the features of an upper motor neurone lesion of the facial nerve
Weakness of the lower part of the face on the side opposite to the lesion
Wrinkling of the forehead and eye closure are normal
What are the features of an eighth cranial nerve palsy?
Cochlear nerve branch - sensorineural deafness and tinnitus
Vestibular nerve branch - vertigo +/- nausea/vomiting
List some causes of eighth nerve palsy
Brainstem (tumour, mutiple sclerosis)
Cerebellopontine angle (acoustic neuroma)
Petrous temporal bone (trauma, middle ear infection)
What is nystagmus?
Rhythmic oscillation of the eyes
What are the two types of nystagmus?
Pendular - no rapid phase (due to longstanding visual impairment)
Jerk - rapid and slow phases (two subtypes: horizontal or vertical)
The lower four cranial nerves lie in the medulla (the “bulb”) are usually affected together. Outline the features of a lower motor neurone type palsy of the bulbar cranial nerves (bulbar palsy)
Dysarthria (slow speech)
Dysphagia
Nasal regurgitation
Wasting and fasciculation of the tongue
What are the most common causes of bulbar palsy?
Motor neurone disease
Syringobulbia (fluid-filled cavity in the brainstem)
Outline the features of an upper motor neurone type palsy of the bulbar cranial nerves (pseudobulbar palsy)
Weakness of the muscles of speech and swallowing with small, spastic tongue (no wasting or fasciculation)
What are the most common causes of pseudobulbar palsy?
Motor neurone disease
Multiple sclerosis
What is normal CSF pressure?
80-120 mmH2O
What is the purpose of nerve conduction studies?
Differentiates between axonal and demyelination neuropathy
What are some known complications of lumbar punctures?
Post-procedure headache, infection, herniation (coning)
What are the cardinal investigations of suspected muscle disease? (4)
Serum creatine kinase and aldose EMG Muscle biopsy (histology and immunohistochemical staining)
What area of the brain is chiefly responsible for states of arousal?
Reticular formation (extending from the brainstem to the thalamus)
What is coma?
A state of unconsciousness from which the patient cannot be roused
What is a stuporous state?
When a patient is sleepy but can be roused with vigorous stimulation
A patient unresponsive to anything except pain is broadly corresponsive to what GCS level?
8
What must coma be differentiated from?
Persistent vegetative state
Brain death
Locked-in syndrome
What is a persistent vegetative state?
A state of wakefulness in which sleep-wake cycle persists but without detectable awareness
What is the cardinal sign of brain death?
Bilaterally fixed and dilated pupils
What are dysconjugate eyes a sign of?
Brain stem lesion
Conjugate lateral deviation of the eyes indicates what two potential pathologies?
Ipselateral cerebral haemorrhage/infarction
Contralateral pontine lesion
What is brain death?
Irreversible loss of the capacity for consciousness, combined with the irreversible loss of the capacity to breathe
What are the three main criteria of the diagnosis of brain death?
- Irremediable structural brain damage
- Absent motor responses to any stimulus
- Absent brainstem function (lack of pupillary, corneal, gag, cough, doll’s head or caloric reflexes, lack of spontaneous breathing)
What is the definition of a stroke?
Rapid onset of neurological deficit lasting greater than 24-hours, which is the result of a vascular origin.
What is the definition of stroke in evolution?
When symptoms and signs are getting worse (usually within 24-hours of onset)
What is the definition of a minor stroke?
When the patient recovers without significant neurological deficit, usually within one week
What is the definition of a transient ischaemic attack?
Transient episode of neurological dysfunction caused by focal brain, spinal cord or retinal ischaemia without acute infarction.
Arterial thrombosis causing stroke can arise from what locations?
Atheromatous plaques
Cardiac mural thrombi (post-MI)
Left atrium (due to atrial fibrillation)
What is the differential diagnosis of stroke?
Intracranial venous thrombosis
Multiple sclerosis
Space-occupying lesion e.g. tumour/abscess
In young adults, 20% of are caused by carotid/vertebral artery dissection. What clinical picture might be suggestive of this pathophysiology?
Recent neck pain, trauma or neck manipulation
What are the major risk factors for thromboembolic stroke?
Hypertension, diabetes mellitus, cigarette smoking, hyperlipidaemia, obesity, excessive alcohol consumption
What are the differential diagnoses for transient ischaemic attack?
Demyelination, tumour
How is the risk of stroke measured following a confirmed TIA?
ABCD2 risk
Hemiplegia is often caused by infarction of what area of the brain during a cerebral haemorrhage stroke?
Infarction of the internal capsule
What is the internal capsule?
Narrow zone of motor and sensory fibres that converges on the brainstem from the cerebral cortex
Brainstem infarction can manifest in a number of different clinical presentations. Name a few. (4)
Lateral medullary syndrome
Coma
Locked-in syndrome
Pseudobulbar palsy
What is lateral medullary syndrome?
Most common of the brainstem vascular syndromes caused by occlusion of the posteiror inferior cerebellar artery
Presents as sudden vomiting, vertigo, facial numbness, Horner’s syndrome, diminished gag reflex
Coma as a result of stroke is caused by infarction of what site in the brain?
Reticular activating syndrome
Upper brainstem stroke causes what pathology?
Locked-in syndrome
Lower brainstem stroke causes what pathology?
Pseudobulbar palsy
What is multi-infarct dementia?
Also called vascular dementia
Multiple small cortical infarcts resulting in generalised intellectual loss with step-wise progression
Clinical picture of dementia, pseudobulbar palsy and Parkinsonian ‘shuffling’ gait
What is the indicated acute treatment of stroke?
Aspirin (300mg ASAP)
Thrombolysis (IV tPA) given within 4.5hrs in acute ischaemic stroke
What secondary interventions are put in place following acute stroke?
Hypertension management
Carotid endarterectomy (in the case of stenosed carotid artery to prevent recurrence of stroke)
Address other modifiable risk factors including smoking, obesity etc.
What are the major risk factors for intracerebral haemorrhage?
Hypertension, excess alcohol consumption, increasing age and smoking
What is the presentation of intracerebral haemorrhage?
Sudden loss of consciousness and stroke often accompanied by severe headache
What is a subarachnoid haemorrhage?
Refers to spontaneous arterial bleeding into the subarachnoid space
What is the radiological appearance of a subarachnoid haemorrhage?
Hyperdense appearance typically around the branching points of arteries of the Circle of Willis
What are the most common aetiologies of subarachnoid haemorrhage?
Rupture of saccular ‘berry aneurysms’
Congenital arteriovenous malformation
What are the symptoms of a berry aneurysm before it ruptures?
Often asymptomatic before they rupture
Any symptoms are due to mass effect, most commonly a painful third cranial nerve palsy
What are the symptoms of a berry aneurysm when it ruptures?
Sudden onset of severe headache (often occipital), accompanied by nausea and vomiting
Potential loss of consciousness and meningeal irritation (neck stiffness and positive Kernig’s sign)
Lumbar punctures must be delayed until at least 12 hours after onset of symptoms in order to confirm diagnosis. Why is this?
To allow sufficient time for haemoglobin to degrade into oxyhaemoglobin and bilirubin (detectable for up to two weeks following SAH)
How is subarachnoid haemorrhage immediately managed?
Best rest and supportive measures with control of hypertension and IV nimodipine (CCB) to reduced cerebral artery spasm.
Discussion with neurosurgeon for obliteration of aneurysm to prevent re-bleeding
What is a subdural haematoma?
Accumulation of blood in the subdural space following a venous bleed.
What is the aetiology of subdural haematoma?
Almost always trauma. Latency between trauma and onset of symptoms may be weeks or months
What are the main clinical features of a subdural haematoma?
Headache, drowsiness and fluctuant confusion
What is an extradural haematoma?
Bleeding outside of the dura mater most commonly due to temporal bone fracture and subsequent rupture of the underlying middle meningeal artery
Clinically how does extradural haematoma present?
Head injury with a brief period of unconsciousness followed by a lucid interval of recovery.
Then followed by rapid neurological deterioration if drainage is not immediately carried out.
seizure
transient occurrence of signs and symptoms due to abnormally excessive or asynchronous neuronal activity within the brain.
epilepsy
a continuing tendency to have seizures
epilepsy classification
generalised seizure type
partial seizure type
tonic seizures
intense body stiffening
tonic-clonic seizures (grand mal)
sudden onset
rigid tonic phase followed by a convulsion (clonic) phase
eyes remain open; lasts seconds to minutes
may be associated with tongue biting or urinary incontinence
what period typically follows a grand mal seizure?
post-ictal phase
post-ictal phase
flaccid unresponsiveness followed by confusion or drowsiness lasting several hours.
headache is common
absence seizures (petit mal)
disorder of childhood in which the child ceases all activity, stares and pales for a few seconds only.
tendency to develop generalised tonic-clonic seizures in adulthood
myotonic seizures
isolated muscle jerking
akinetic seizures
cessation of movement, falling and loss of consciousness
partial seizures
epileptic activity involving part of the brain only
- simple (not affecting consciousness or memory)
- complex (affecting awareness and memory)
May become generalised (secondarily generalised)
stimuli that may induce seizures in an epileptic patient?
flashing lights or a flickering television screen may provoke an attack
how is a seizure medically aborted?
rectal or IV diazepam or lorazepam
repeated seizures with minimal recovery periods between may lead to what medical emergency?
status epilepticus
status epilepticus
continuous seizures for greater than thirty minutes
risk to life in status epilepticus
death from cardiorespiratory failure
What may precipitate status epilepticus?
Sudden withdrawal of anti-epileptic drugs, intercurrent illness or alcohol abuse
How is status epilepticus managed outside of a hospital setting?
Rectal diazepam or buccal midazolam
How is status epilepticus managed in a hospital setting?
Administer oxygen and obtain IV access
IV lorazepam/rectal diazepam (first line)
If seizures continue - given phenytoin (second line) then phenobarbital (third line)
For refractory status epilepticus, what management is required?
Intubation, ventilation and anaesthesia in intensive care
What is the principle of treatment for epilepsy?
Monotherapy is the goal with dose titrated up until seizures are controlled
Describe the common syndrome of intoxication of all anti-convulsants
Ataxia, nystagmus and dysarthria
What is the pathophysiology of idiopathic Parkinson’s disease?
Progressive depletion of dopamine-secreting cells in the substantia nigra due to abnormal accumulation of cytoplasmic inclusions called Lewy bodies
Outline the clinical features of Parkinson’s disease
Combination of rest tremor, rigidity and bradykinesia (slow movements)
Poverty of movement and speech
Postural changes (stoop)
Non-motor features (depression, hallucinations, dementia, insomnia, fatigue, weight loss etc.)
How is Parkinson’s disease managed?
Levodopa (combined with peripheral decarboxylase inhibitor)
Dopamine agonists
Monoamine oxidase B inhibitors (inhibit dopamine catabolism)
Physiotherapy
What is benign essential tremor?
Familial (autosomal dominant) tremor of the arms and head. Not usually present at rest and made more obvious when adopting a posture and anxiety.
Improved by alcohol, propranolol and mirtazepine
What is chorea?
Continuous flow of jerky, quasi-purposive movements interfering with voluntary movements but absent during sleep
What is Huntington’s Disease?
Autosomal dominant (full penetrance) relentlessly progressive course with chorea, personality change preceding dementia and death
What is the pathophysiology of Huntingdon’s Disease?
CAG repeats in the Huntingdon’s disease gene on chromosome 4 leads to the production of mutant huntingtin protein leading to a depletion of GABA and acetylcholine in the basal ganglia
What is hemiballismus?
Violent swinging of one side of the body usually caused by infarction or haemorrhage in the contralateral subthalamic nucleus
What is myoclonus?
Sudden, involuntary jerking of a single muscle or group of muscles. Most commonly benign essential myoclonus which is a sudden body jerk just before falling asleep.
What is multiple sclerosis
A chronic debilitating autoimmune disorder of the CNS in which multiple plaques of demyelination occur disseminated in time and space.
Multiple sclerosis has a predilection for distinct CNS sites; name five.
- Optic nerves
- Periventricular white matter
- Brainstem
- Cerebellum
- Cervical spinal cord
The clinical features of multiple sclerosis depend on the site of demyelination. Outline the clinical presentation of optic neuropathy caused by multiple sclerosis
Blurred vision and unilateral eye pain
Inflammation at the optic head causes pallor and disc swelling (optic neuritis)
Retrobulbar (proximal to the fundus) neuritis may occur in which case fundus examination is normal
The clinical features of multiple sclerosis depend on the site of demyelination. Outline the clinical presentation of brainstem demyelination caused by multiple sclerosis
Diplopia, vertigo, dysphagia, dysarthria, facial muscle weakness
The clinical features of multiple sclerosis depend on the site of demyelination. Outline the clinical presentation of spinal cord lesions caused by multiple sclerosis
Numbness/paraesthesia are common in MS and reflect involvement of the spinothalamic tract and posterior column lesions.
There are four main clinical patterns of multiple sclerosis; what are they?
- Relapsing-remitting MS (85-90%)
- Secondary progressive MS
- Primary progressive MS (10-15%)
- Relapsing-progressive MS (<5%)
Describe the relapsing-remitting variant of multiple sclerosis
Symptoms occur in attacks with onset over days which then recover over a period of weeks. Disability is accumulated over time due to suboptimal recovery of relapses.
Describe the secondary progressive variant of multiple sclerosis
Late-stage of relapsing-remitting MS with a progressive disability over years.
Describe the primary progressive variant of multiple sclerosis
Characterised by progressive worsening disability with no evidence of relapsing or remitting.
What is the differential diagnosis of multiple sclerosis?
Early MS, without the diagnostic necessity of time, may be difficult to distinguish from other inflammatory conditions including:
- SLE
- Sarcoidosis
- Mass or vascular lesion
What investigations are indicated for the diagnosis and monitoring of multiple sclerosis?
MRI of brain and spinal cord
Electrophysiological tests
CSF examination (usually unnecessary - useful for exclusion of other pathology)
Outline some of the treatment options for multiple sclerosis
6
- Short courses of steroids - reduces severity of relapses
- Subcutaneous beta-interferon - reduces relapse rate
- Glatiramer acetate - similar effect to interferon
- Natalizumab - monoclonal antibody (second line option)
- Newer agents e.g. fingolimod - reduce relase rate significantly
- Physiotherapy nand occupational therpay
What is Kernig’s sign?
Inability to allow full extension of the knee when the hip if flexed to 90 degrees
Outline the clinical picture of infective meningitis
Headache, neck stiffness and fever develop over minutes to hours
Photophobia, vomiting and papilloedema
List three major complications of infective meningitis
Venous sinus thrombosis
Severe cerebral oedema
Cerebral abscess
How may a major complication present with ongoing meningitis?
Progressive drowsiness
Lateralising signs
Cranial nerve lesions
What is the cardinal sign of meningococcal septicaemia?
Non-blanching, petechial or purpuric rash (with shock)
Outline the course of viral meningitis
Usually benign and self-limiting condition lasting about 4-10 days with no serious sequelae
Outline the presentation of chronic meningitis
Long history of vague symptoms including headache, lassitude, anorexia, vomiting etc.
List some potential diagnosis of meningitis
Subarachnoid haemorrhage
Migraine
Viral encephaliits
Cerebral malaria (can mimic meningitis)
Give four examples of bacteria which can cause meningitis
Neisseria meningitidis
Streptococcus pneumoniae
Staphylococcus aureus
Listeria monocytogenes
Give four examples of viruses which can cause meningitis
Enterovirus (ECHO, Coxsackie)
Poliomyelitis
Mumps
HIV
Give two examples of fungi which can cause meningitis
Cryptococcus neoformans
Candida albicans
It is important to immunise close contacts of those diagnosed with meningococcal meningitis (i.e. close family). What prophylaxis is used?
Oral rifampicin/ciprofloxacin to erradicate nasal carriage of causative organism
How is tuberculous meningitis diagnosed?
Auramine stain
How is cryptococcal meningitis diagnosed?
India ink stain
What investigation should not be performed if meningococcal sepsis is suspected?
Lumbar puncture (due to risk of cerebellar coning)
How is acute suspected bacterial meningitis treated?
Immediate third-generation cephalosporin (e.g. ceftriaxone) and amoxicillin (covering Listeria) and dexamethasone
Specific antibiotics following results of Gram staining, culture and sensitivities
What is encephalitis?
Inflammation fo the brain parenchyma
How does encephalitis differ from meningitis?
Unlike meningitis, there is usually cerebral dysfunction with altered mental status, motor and sensory deficits
What are the clinical features of acute viral encephalitis?
Mild, self-limiting illness with fever, headache and drowsiness
Severe disease is rare but can cause seizures and coma
In the case of suspected HSV or VZV encephalitis, what is the treatment?
IV aciclovir (10mg/kg every 8 hrs for 14-21 days)
Cerebral abscess follows infection spread from parameningeal infective focuses or from a distal site e.g. bloodstream. Give examples of parameningeal infective focuses.
Paranasal air sinuses
Middle ear
Skull fracture
Outline the clinical features of a cerebral abscess
Headache, focal neurological signs, seizures
Potential raised intracranial pressure
What investigation is contraindicated in the case of suspected cerebral abscess?
Lumbar puncture (due to risk of cerebellar coning)
How is cerebral abscess treated?
IV antibiotics and sometimes surgical decompression
How doe spinal epidural abscess present?
Back pain and fever accompanied by paresis/root lesions
What four clinical syndromes may arise from untreated neurosyphilis?
- Asymptomatic neurosyphilis
- Meningovascular syphilis
- General paralysis of the insane
- Tabes dorsalis
How is neurosyphilis treated? What is the outcome of the treatment
Benzylpenicillin 1g IM daily for 10 day
May arrest but not reverse any neurological damage
Outline the presentation and treatment of Creutzfeldt-Jakob disease
Pathologically spongiform change in the brain due to infective prion causing progressive dementia and death (incurable)
The HIV virus is not directly neuroinvasive or neurovirulent but can cause meningitis in a variety of ways. How?
HIV seroconversion
AIDS-demnetia complex
Progressive multifocal leukoencephalopathy (PML)
What is progressive multifocal leukoencephalopathy?
A fatal demyelinating disease of the central nervous system (CNS), caused by the lytic infection of oligodendrocytes by a human polyomavirus, JC virus (JCV)
How is progressive multifocal leukoencephalopathy related to HIV?
Patients become susceptible to JCV infection at very low CD4 counts, as in HIV infection
What are the clinical features of a cerebral tumour?
3
Progressive focal neurological deficits
Raised intracranial pressure
Focal/generalised epilepsy
List three of the most common primary malignant brain tumours
Glioma
Embryonal tumours (e.g. medulloblastoma)
Lymphoma
List two of the most common primary benign brain tumours
Meningioma
Neurofibroma
What primary cancers commonly metastasise to the brain?
Bronchus, breast, prostate
What neurological defects may arise from frontal lobe tumours?
Personality change, aparthy, intellectual deterioration
Frontal speech area (Broca’s area) - expressive dysphasia
Motor cortex (pre-central gyrus) - hemiparesis
What neurological defects may arise from parietal lobe tumours?
Homonymous field defect
Cortical sensory loss
Hemiparesis
Seizures
What are the cardinal signs/symptoms of raised intracranial pressure?
Headache (changes with posture, worse on coughing, sneezing, bending or straining)
Vomiting
Papilloedema
As tumours grow, there may be compression of the brainstem causing what symptoms?
Drowsiness respiratory depression, bradycardia, coma and death
What are the potential differential diagnoses of brain tumour?
Other masses (cerebral abscess, tuberculoma, subdural/intracranial haematoma) Stroke Benign idiopathic intracranial hypertension
What is benign idiopathic intracranial hypertension?
Benign condition common in young obese women presenting with headache and papilloedema causing raised intracranial pressure
What is hydrocephalus?
Excessive amounts of CSF within the cranium
Where is CSF produced in the brain?
In the cerebral ventricles
What are the two potential mechanisms behind the cause of hydrocephalus?
- Increased production of CSF (rare)
2. Blockage to outflow
What is a congenital cause of hydrocephalus?
Arnold-Chiari malformation
What is Arnold-Chiari malformation?
Cerebellar tonsils descend into the cervical canal - blocking drainage of CSF
List some causes of adult hydrocephalus
Posterior fossa/brainstem tumours
Subarachnoid haemorrhage/head injury/trauma
Third ventricle colloid cyst (intermittent hydrocephalus)
Normal-pressure hydrocephalus
What is normal pressure hydrocephalus?
Dilation of the cerebral ventricles without signs of raised ICP.
How does normal pressure hydrocephalus present?
Common in the elderly
Dementia, urinary incontinence and ataxia
How is hydrocephalus treated?
Surgical insertion of a shunt to allow drainage of CSF (ventriculoperitoneal/ventriculoatrial)
What are the key features of a headache history?
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Location, severity and character Associated symptoms e.g. nausea, photophobia, fever Presence of autonomic symptoms e.g. ptosis or tearing Triggers - the effect of posture? Is the headache episodic or part of a pattern? Duration Analgesic use Family history Red flag symptoms Sudden onset? Features of raised ICP? Jaw claudications/scalp tenderness?
What is a tension headache? What is the cause?
Very common bilateral headache
Neurovascular irritation and referred tenderness to scalp
What does a tension headache feel like?
Feeling of pressure/tightness all around the scalp
No associated symptoms common in migraine such as aura or photophobia
How is tension headache treated?
Explanation and reassurance
Analgesic withdrawal (to avoid overuse headache)
Tricyclic antidepressants in frequently recurrent cases
Migraine is a very common, debilitating headache disorder characterised into three types. Name them
- Migraine with aura (classic migraine)
- Migraine without aura (common migraine)
- Migraine variants (unilateral motor or sensory symptoms often mistaken as a stroke)
What is the typical presentation of migraine?
Unilateral, throbbing associated with nausea, vomiting, photophobia
What cause visual auras?
Related to depression of visual cortex/retinal function and may preceed a migraine by minutes or hours
What are some of the potential symptoms of aura?
Scotoma Unilateral blindness Flashes Aphasia Numbness
Give a few differential diagnoses of migraine
3
Meningitis
Subarachnoid haemorrhage
TIAs/stroke
How are mild migraines treated in the acute setting?
Simple analgesics and high-dose soluble aspirin/NSAIDs
Antiemetic if nauseous (e.g. metoclopramide)
How are moderate/severe migraines treated in the acute setting?
Triptans (e.g. sumatriptan)
What prophylaxis may be prescribed to prevent migraines?
Anticonvulsants e.g. valproate
beta-blockers - propranolol
Amytriptyline
What are trigeminal autonomic cephalgias?
Headaches characterised by unilateral trigeminal distribution of pain with ipsilateral autonomic features e.g. tearing
Name the types of trigeminal autonomic cephalgias
Cluster headache
Paroxysmal hemicrania
Hemicrania continua
SUNCT syndrome
What are cluster headaches?
Rapid onset, short-lived unilateral headaches with clustering of multiple attacks over a period of a few months before a period of remission
Describe the clinical presentation of cluster headaches
Pain often begins around the eyes and only lasts 1-2 hours
Autonomic features include tearing, rhinorrhoea and Horner’s sydnrome
What vertebral levels does the spinal cord extend from and to?
C1 to L1
What structure continues from the spinal cord at L1?
Cauda equina
Paraplegias is almost always caused by a lesion in what anatomical location?
Spinal cord
Hemiparesis is almost always caused by a lesion in what anatomical location?
The brain
Outline the presentation of spinal cord compression
Progressive weakness of the legs with upper motor neurone pattern
What are the two patterns of onset for spinal cord compression?
Acute (hours to days)
Chronic (weeks to months)
At what level are sensory symptoms felt in spinal cord compression?
Sensation diminishing one/two spinal levels below the level of the lesion
What symptoms are felt in the later stages of spinal cord compression?
Painless urinary retention and constipation
What is the most common cause of acute spinal cord compression?
Vertebral tumour (metastasis from brain, breast, lung etc.)
What is a frequent infective cause of spinal compression in some parts of the world?
Tuberculosis
Chronic compression of the spinal cord due to cervical spondylotic myelopathy is the most common cause of what disability in the elderly?
Spastic paraparesis
What is the differential diagnosis of spinal cord compression?
Intrinsic lesions of the spinal cord:
Transverse myelitis (inflammation due to viral infection)
Anterior spinal artery occlusion
Multiple sclerosis
What is cauda equina syndrome?
Spinal damage at the L1 level or below
Cauda equina syndrome can present acutely or chronically. What are the typical symptoms?
Back pain, weakness and numbness of the legs
Reduced reflexes
Saddle paraesthesia
Loss of sphincter control
Reduced desire to void urine progressing to painless urinary retention
What is Freidrich’s ataxia?
An autosomal recessive disorder is the most common hereditary spinocerebellar degeneration causing ataxia, dysarthria and nystagmus
What is motor neurone disease?
Destruction of motor neurones and anterior horn cells
What is the prognosis of motor neurone disease?
Most patients die within three years from respiratory failure as a result of bulbar palsy and pneumonia
Motor neurone disease comprises of a mixture of four clinical patterns. What are they?
- Progressive muscular atrophy
- Amyotrophic lateral sclerosis
- Progressive bulbar and pseudobulbar palsy
- Primary lateral sclerosis
What are the features of progressive muscular atrophy?
Muscle wasting and fasciculations
What are the features of amyotrophic lateral sclerosis?
Progressive spastic tetra/paraparesis with lower motor neurone signs e.g. fasciculations
What are the features of progressive bulbar/pseudobulbar palsy?
Dysarthria, dysphagia with wasting and fasciculation of the tongue
What are the features of primary lateral sclerosis?
Progressive tetraparesis
What are the differential diagnoses of the motor neurone disease?
Cervical spine lesion (distinguished by the presence of sensory symptoms)
Idiopathic multifocal motor neuropathy
What is the medical treatment for motor neurone disease?
Riluzole (slows progression slightly)
What is dementia?
A clinical syndrome with multiple causes defined by a progressive acquired loss of higher mental function of sufficient severity to cause significant disability
What are the four different clinical entities of dementia?
Alzheimers disease (most common)
Vascular (multi-infarct) dementia
Dementia with Lewy bodies
Frontotemproal dementia
What is the presentation of Alzheimer’s disease?
Insidious onset with slow disintegration fo personality and intellect.
Decline in language and visuospatial skills are common
How is Alzheimer’s disease treated?
Acetylcholinesterase inhibitors (donezepril, rivastigmine and galantaime)
Memantine (NMDA receptor antagonist)
What is the typical pattern of progression of vascular dementia?
Stepwise deterioration
How is dementia with Lewy bodies characterised clinically?
Fluctuating cognition and Parkinsonism
What is the most prominent feature of frontotemporal dementia?
Early personality changes
What treatment must be avoided in dementia with Lewy bodies?
Neuroleptics
What is a mononeuropathy?
A process affecting a single nerve
What is mononeuritis multiplex?
A process affecting several or multiple nerves
What is carpal tunnel syndrome?
A mononeuropathy of the median nerve due to compression under the flexor retinaculum.
What are the clinical features of carpal tunnel syndrome?
Pain and paraesthesia in the affected hand, typically worse at night
How is carpal tunnel syndrome?
Nocturnal splints or local injections of steroids
Surgical decompression is definitive treatment (flexor retinaculum fasciotomy)
What is polyneuropathy?
Acute or chronic diffuse disease process involving motor, sensory and autonomic nerves.
What are the common potential sensory symptoms in polyneuropathy?
Numbness, tingling, pain in extremities, unsteadiness
What are the common potential motor symptoms in polyneuropathy?
Muscular weakness
What are the common potential autonomic symptoms in polyneuropathy?
Postural hypotension, urinary retention, erectile dysfunction, diarrhoea/constipation, diminished sweating, impaired pupillary response, arrhythmias
What are some common causes of mono neuritis multiplex?
Diabetes mellitus, malignancy, sarcoidosis
What is Guillain-Barre Syndrome?
Post-infective acute neuropathy causing inflammatory demyelination
What are the clinical features of Guillain-Barre Syndrome?
Progressive onset of distal limb weakness/numbness (usually symmetrical) that reaches its nadir in approx. 4 weeks
What are the clinical features of Guillain-Barre Syndrome?
Sensory symptoms - paraesthesia
Motor symptoms - progressive onset of distal limb weakness/numbness (usually symmetrical)
Autonomic symptoms - postural hypotension, cardiac arrhythmias, ileus and bladder atony
What is Miller Fisher Syndrome?
A rare variant of Guillain-Barre Syndrome that affects cranial nerves to the eyes causing ophthalmoplegia and ataxia
How is Guillain-Barre Syndrome?
Diagnosis is made clinically and can be confirmed after a number of weeks with nerve conduction studies
What is the differential diagnosis of Guillain-Barre Syndrome?
Other causes of neuromuscular paralysis:
Hypokalaemia, polymyositis, myasthenia gravis
Outline the management of Guillain-Barre Syndrome?
Vital capacity monitored 4-hourly to recognise deteriorating respiratory failure
Intravenous immunoglobulin (+/- plasma exchange)
Supportive treatment (heparin, physiotherapy, NG/PEG tube)
What is the most common cause of thiamin (vitamin B1) deficiency?
Chronic alcohol dependency
What pathology arises from pyridoxine (vitamin B6) deficiency?
Sensory neuropathy
What pathology arises from vitamin B12 deficiency?
Syndrome of subacute combined degeneration of the cord causing distal sensory loss
How does the presentation of muscular disease differ from the weakness caused by neuropathy?
In muscular disease reflexes and sensation are normal
What is myasthenia gravis?
An autoimmune disorder of the neuromuscular junction transmission characterised by weakness and fatiguability of ocular, bulbar and proximal limb muscle
What is the pathophysiology of myasthenia gravis?
Autoantibodies to acetylcholine receptors causing receptor loss
What is the presentation fo myasthenia gravis?
Fatigue muscle on sustained or repeated activity that improves after rest.
Ocular muscles are the first to be involved causing ptosis
Difficulty talking, swallowing and breathing follows
How is myasthenia gravis treated?
Anticholinesterases
Immunosuppression
Plasmapheresis and intravenous immunoglobulin
Thymectomy
What are the muscular dystrophies?
Inherited group of progressive myopathic disorders
What is the inheritance patterns of both Duchenne’s and Becker’s muscular dystrophies?
X-linked recessive
What is the presentation of Duchenne’s muscular dystrophy?
Present in early adulthood with weakness in proximal muscles and grossly elevated creatine kinase (100-200x normal limit)
What is the presentation of Becker’s muscular dystrophy?
Present later in life with a milder degree of clinical involvement than Duchenne’s muscular dystrophy
What is myotonia?
Delayed muscle relaxation after contraction
What are the two most common myotonia disorders?
Dystrophia myotonica and myotonia congenita
What is dystrophia myotonica?
Autosomal dominant condition causing progressive distal muscle weakness, myotonia, facial muscles weakness and ptosis
What is myotonia congenita?
Autosome dominant condition causing myotonia exacerbated by rest and cold
Becomes evident in childhood
What is delirium?
Acute or subacute condition in which impairment of consciousness accompanied by changes in personality and mood
Severity can vary and often fluctuates
How is delirium managed/treated?
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Investigation and treatment of the underlying condition
Withdrawing all possible drugs responsible (TCAs, opiates and benzodiazepines etc.)
Rehydration
Adequate pain relief/sedation
What are the most commonly prescribed hypnotics?
Benzodiazepines
What are the four most common side effects of a neuroleptic such as haloperidol?
Drowsiness, hypotension, tachycardia and convulsions