Neurology 2 Flashcards
Define encephalitis
Encephalitis is defined as inflammation of the brain parenchyma associated with neurological dysfunction such as altered state of consciousness, seizures, personality changes, cranial nerve palsies, speech problems, and motor and sensory deficits
Describe epidemiology of encephalitis
- 2500 cases occur in England a year
- Globally 7 per 100000 per year diagnosed
- Highest incidence in those under 1 and over 65
Describe aetiology of encephalitis
- Cause only found in 50% cases
- Viruses are the main cause, herpesvirus most common (or st. louis)
- Arboviruses main cause worldwide
- Most common bacteria Neisseria meningitides
- Fungal cryptococcus
- Parasitic toxoplasma gondii
List risk factors of encephalitis
- Age <1 or >65 years
- Immunodeficiency
- Post-infection
- Blood/body fluid exposure
- Organ transplantation
- Animal or insect bites
- Location
- Season
- Swimming or diving in warm freshwater or nasal/sinus irrigation
- Vaccination
- Occupation
- Hunting/trekking in woods
- Spelunking (cave-exploring)
- Death in animals
- Cancer
List symptoms of encephalitis
- Acute onset febrile illness with behavioural, cognitive and psychiatric manifestations
- Viral prodrome
- Altered mental state
- Focal neurological deficit
- Meningismus (headache, photophobia, neck stiffness)
- Optic neuritis
- Movement disorder
- Cough
- GI infection
- Seizures
- Biphasic illness
- Autonomic and hypothalamic disturbances
- Myocarditis/pericarditis
- Arthritis
- Retinitis
List signs of encephalitis
- Fever
- Rash
- Parotiditis
- Lymphadenopathy
- Optic neuritis
- Acute flaccid paralysis
- Movement disorder
- GI infection
- Biphasic illness
- Autonomic and hypothalamic disturbances
- Myocarditis/pericarditis
- Jaundice
- Parkinsonism
List investigations of encephalitis
- FBC
- Peripheral blood smear
- Serum electrolytes (hyponatraemia rickettsial infections)
- Liver function tests
- Blood cultures
- Throat swab
- Nasopharyngeal aspirate
- Sputum culture
- Chest radiography
- CT brain
- MRI brain
- Electroencephalogram (EEG - background slowing)
- Cerebrospinal fluid (CSF) analysis
- CSF culture
- CSF serology
- CSF polymerase chain reaction (PCR)
Define TIA
- An ischaemic (usually embolic) neurological event lasting less than 24 hours
- Without treatment more than 1 in 12 will have a stroke within a week
Describe epidemiology of TIA
- In england each year 2000 people have a first episode of TIA
- Age adjusted annual incidence rate 190 per 100000
Describe aetiology of TIA
- In situ thrombosis of an intracranial artery or artery to artery embolism of thrombus as a result of stenosis or unstable atherosclerotic plaque
- Cardioembolic events
- Small vessel occlusion
- Occlusion due to hypercoagulability, dissection, vasculitis, vasospasm or sickle cell occlusive disease
List risk factors for TIA
- Cardiovascular disease (eg. AF, valvular heart disease, carotid stenosis, congestive heart failure, hypertension)
- Diabetes mellitus
- Hyperlipidaemia
- Other significant illnesses such as a hypercoagulable state or vasculitis (e.g., temporal arteritis)
- Cigarette smoking
- Alcohol-use disorder.
List symptoms and signs of TIA
- Sudden onset and brief duration of symptoms
- Unilateral weakness or paralysis
- Dysphasia
- Ataxia, vertigo or loss of balance
- Sudden transient loss of vision in one eye (amaurosis fugax)
- Homonymous hemianopia
- Diplopia
List investigations for TIA
- Blood glucose
- FBC + platelet
- PT, INR, partial thromboplastin time
- Fasting lipid profile
- Serum electrolytes
- ECG
- CT
- Carotid doppler/echocardiogram
Describe management of TIA
- Control risk factors (lower BP cautiously, statin, stop smoking
- Antiplatelet drugs (aspirin 300mg for 2 wees then clopidogrel 75mg daily)
- Anticoagulant for AF
- Carotid endartorectomy within 2 weeks if 70-99% stenosis
Describe ABCD2 score
- Used in TIA
- Calculates risk of stroke after tia, determines whether emergency referral is needed
- Age over 60
- BP > 140/90
- Clinical features (unilateral weakness 2 points, speech disturbance 1 point)
- Duration of symptoms (over 1 hour 2 points, 10-59mins 1 point)
- Diabetes
If over 4 must be assessed by a specialist within 24 hours
List complications of TIA
- Stroke
- MI
Describe prognosis of TIA
- 8% admitted for TIA have a stroke during hospitalisation
- 10% presenting to A&E have a stroke within 3 months
- Due to underlying disease, 5% of patients will be dead after 6 months
List contraindications for thromolysis
- Recent intracranial haemorhage
- Neoplasm
- Significant head injury in last 3 months
- Recent cranial or spinal surgery
- Severe hypertension
- Pregnancy
- Bleeding disorder
- Recent lumbar puncture
- On warfarin or DOAC
Describe aetiology of migraine
- Inflammation of the trigeminal nerve
- Changes the way the brain rocesses stimuli
Describe aetiology of meningitis
Babies
- E coli (late neonatal)
- Group B strep (long labor)
Children
- H influenzae
- Strep pneumoniae
Teens
- Neisseria meningitidis (gram negative diplococci)
Elderly
- Strep pyogenes (gram positive cocci)
- Listeria monocytogenes (cheese/unpasturised milk/ alcoholics)
Define extradural haematoma
A collection of blood in the potential space between the dura and bone
Describe aetiology of extradural haematoma
- Traumatic skull fracture, especially at pterion damaging middle meningeal artery
- Any tear in venous sinus
- Alcohol and other intoxication increases incidence
Describe epidemiology of extradural haematoma
- Young
- Most common in 20-30 yearold males
- 1 in 1000000 people anually
List symptosm of extradural haemorrhage
- Acute headache following a lucid interval
- Usually initial LOC then lucid for hours to days
- Increasingly severe headace
- Decreasing GCS, symptoms of raised ICP (vomiting, confusion, seizures, paresis)
List signs of extradural haemorrhage
- Low GCS
- Hemiparesis
- Brisk reflexes
- Upgoing plantar
- Ipsilateral pupil dilates, coma, bilateral limb weakness, deep and impaired breathing in brainstem compression
Describe investigations for extradural haemorrhage
- Urgent non-contrast CT head (lemon/lens shape)
- MRI
Define wenickes encephalopathy
Neurological emergency resulting from thiamine deficiency with varied neurocognitive manifestations (mental status, fait, oculomotor)
Describe epidemiology of wenickes encephalopathy
- 0.8-2.8% post mortem
- Higher prevelence in pateints witha history of alcohol dependence and aids, and bone marrow transplant
- Prevalence higher in males
Describe aetiology of wenickes encephalopathy
- Thiamine defienciency leading to periaqueductal punctate haemorrhage
- Reduced intake
- Relative defieicny due to increased demand
- Malabsorption from GI
List risk factors for wernickes encephalopathy
- Alcohol dependence
- AIDS
- Cancer and treatment with chemotherapeutic agents
- Malnutrition
- History of gastrointestinal surgery
- Genetics
- Bone marrow transplantation
- Infants who have been fed formula milk deficient in thiamine
- Male sex
List signs and symptoms of wernickes encephalopathy
Classical triad
- Confusion (irritability, delerium, psychosis, coma)
- Ataxia
- Opthalmoplagia (nystagmus, lateral rectus or conjugate nerve palsies)
- Can develop to korsakoff - long term Wernickes (memory loss)
List investigations of wernickes encephalopathy
- Red cell transketolase activity is reduced
- Clinical diagnosis, attempt trial of thiamine and observe treatment response
- May consider FBC, serum electrolytes, renal LFTs, urinary drug screen, ammonia, blood alcohol, blood thiamine, magnesium, serum albumin
- ECG, CT, neuropsychology
Describe epidemiology of horners syndrome
- in 6250 population
- Any age and ethnicity
Describe aetiology of horners syndrome
- Central nerve lesions (CVAs, MS, basal scull tumours, meningitis, neck trauma)
- Preganglionic nerve lesions (apical lung tumours, lymphadenopathy, lower brachial plexus trauma, aneurysm of the aorta, neuroblastoma)
- Postganglionic lesions (cluster headache or migraine, herpes zoster infection, internal carotid artery dissection, raeders syndrome, carotid cavernous fistula, temporal arteritis)
List symptoms of horners syndrome
= Inability to open eye fully on affected side
- Loss of sweating on affected side
- Facial flushing (preganglionic)
- Orbital pain/headache (post ganglionic)
- Symptoms of underlying cause
List signs of horners syndrome
- Constricted pupil on affected side, more apparent in a darkened room
- Ipsilateral dry skin
- Ipsilateral partial ptosis
- Enopthalmos possibly
Describe investigations for horners syndrome
- CXR for apical carcinoma
- CT/MRI for cerebrovascular accident
- CT angiography carotid ultrasound to look for dissection
- FBC, urine test
- Pharmacological testing (cocaine eye drops will cause pupil to dilate if sympathetic innervation remains, apraclonidine will cause pupil dilationand lid elevation on the abnormal side, hydroxyamphetamine postganglionic neurone damage means no response)
Describe management of horners syndrome
- Depends on the underlying cause
- If mild, no treatment needed
- May require neurosurgery, radiology, surgery
List complications of horners syndrome
- Dizziness
- Vision loss
- Neck pain or severe headache
- Inability to control muscle movement
Describe prognosis of horners syndrome
Dependent on underlying cause, often goes once underlying cause is treated effectively
Define hydrocephalus
- Enlargement of cerebral ventricles and/or subarachnoid space as a result of excess CSF accumulation.
- Communicating decreased CSF absorption of increased CSF production with no onstruction
- Non-communicating obstricted passage of CNS
Describe epidemiology of hydrocephalus
- Prevalence: Communicating more common than non-communicating
- Congenital 3/1000 live births US. 60% of cases
- Acquires all ages, NPH over 60s. 40% of cases
- Moe common in females than males
Describe aetiology of hydrocephalus
Communicating - deceased absorption
- Inflammatory diseases (eg. Meningitis) causing scarring
- Subarachnoidal or intraventricular haemorrhage
- Congenital absence of villi
Communicating - increased production
- Choroid plexus papilloma
- Choroid plexus carcinoma
- Inflammation of the choroid plexus
Non-communicating
- Congenital (arnold-chiari, dandy-walker malformation where 4th ventricle does not open, intrauterine infections)
- Acquired (brain tumour, especially medullobastomas, pinealoma, ependymomas, astrocytomas)
Normal pressure
- Enlarged ventricles with normal intracranial pressure
List symptoms of hydrocephalus
- Headache, nausea and vomiting
- Impaired consciousness
- Double vision
List sings of hydrocephalus
- Papilloedema
- Abnormal gait
- Abducens nerve pulsy
- Cushing triad (irregular breathing, widening pulse pressure, bradycardia)
- Lower extremity spacticity, hyperreflexia
Infants
- Macrocephaly
- Tense fontanelle
- Setting sun sign
Define normal pressure hydrocephalus
- A form of communicating hydrocephalus primarily affecting those aged over 60
- Distinct clinical triad of urinary incontinence, dementia and ataxic gait (2W’s: wacky, wobbly, wet)
- Episodic increase in ICP
Describe investigations for normal pressure hydrocephalus
- MRI (ventriculomegaly, periventricular hypodensity)
- CSF tap test (improvement of symptoms after CSF removal)
- Cognitive assessment, B12 and TFT
Describe investigations for hydrocephalus
- Ultrasonography (infants under 7 months, shows enlarged ventricles)
- MRI or CT in older infants and adults, enlarged ventricles and obstruction, mickey mouse ventricles, sulcal enlargement, upward bowing of the corpus callosum)
Where does SAH most commonly occur?
Junction of anterior communicating and anterior cerebral artery
Define neurofibromatosis
Congenital disorders that affect organs of ectodermal origin, especially the skin, CNS and eyes
Describe epidemiology of neurofibromatosis
- Type 1: 1 in 2,500, no male-female or racial predominance
- Type 2: 1 in 35,000
Describe aetiology of neurofibromatosis
- Autosomal dominant inheritence (type 1 17q11.2 type 2 22q11)
- May be de novo mutations, especially type 2 (50% de novo)
List signs and symptoms of neurofibromatosis type 1
- Multiple neurofibromas (benign peripheral nerve sheath tumours that origionate from neural crest cells and affect the myelinated nerves, typically manifest under the skin, onset from adolescence)
- Seizures and/or focal neurological signs due to brain lesions
- Intellectual disability
- Bone involvement (scoliosis, short stature, pseudoarthritis, fractures)
- Cafe au lait spots (brown hyperpigmented flat macule or patch, onset before 2 years)
- Lisch nodules (pigmented iris hamartomas between 5-10 years)
- Auxillary and inguinal speckling
- Hypertension
- Short stature, scoliosis
- Associated with wilms tumour, phaeochromocytoma and optic pathway glioma (vision loss, proptosis, precocious puberty)
List symptoms of neurofibromatosis type 2
- Age of onset 18-24
- Bilateral vestibular schwannoma (affect vestibulococclear nerve, causing tinnitus, hearing loss, or vertigo)
- Early onset cataracts, usually bilateral
- Multiple cerebral or spinal tumours
- Other features: skin lesions, seizures and/or cafe au lait spots
Describe investigations for neurofibromatosis
- MRI of brain and spine with contrast to detect neurofibromas and meningiomas
- Opthalmogical exam for optic glioma in NF type 1
- Auditary testing for acoustic neuromas in NF type 2
- Genetic testing for the mutations
List diagnostic criteria for neurofibromatosis type 1
2 of
- More than 6 cafe au lait macules over 5mm pre puberty of 15mm post puberty
- More than 2 neurofibromas or 1 plexiform
- Freckling in the axillary or inguinal regions
- Optic glioma
- More than 2 lisch nodules
- Distinctive osseous lesion typical of NF1 eg. sphenoid dysplasia
- First degree relative with NF1
List diagnostic criteria for neurofibromatosis type 2
Either
- Bilateral vestibular schwannoma on CT or MRI
- First degree relative with NF2 and either unilateral vestibular schwannoma OR one of neurofibroma, meningioma, glioma, schwannoma, juvenile cataract
Define huntingtons disease
A slowly progressive, neurodegenerative disorder characterised by chorea, incoordination, cognitive decline, personality changes, and psychiatric symptoms, culminating in immobility, mutism, and inanition.
Describe epidemiology of huntingtons disease
- 4-8 per 100000 europe
- 20 years from time of diagnosis to time of death
- Typical onset is 35-45 years of age, affects men and women equally
- 10 times more common in north americans of european descent than pure african or asian descent or native americans
- Tasmania and Lake Maracaibo high prevalence
Describe aetiology of huntingtons disease
- Autosomal dominant
- CAG repeat in N-terminus of the gene that codes for the huntington protein
- More repeats means more severe and earlier presenting disease
List symptoms and signs of huntingtons disease
- Impaired work or school performance
- Personality change
- Irritability and impulsivity
- Chorea (rndom movements of fingers and toes)
- Twitching or restlessness
- Loss of coordination
- Deficit in fine motor coordination
- Slowed rapid eye movements
- Motor impersistence
- Impaired tandem walking
- Change in hygiene, disinhibition, depression, obsessions or compulsions
List investigations for huntingtons disease
- Clinical diagnosis
- Can perform CAG repeat testing
- MRI/CT scan (evident caudate or striatal atrophy)
Define spinal cord compression (inc. cauda equina)
- Processes that compress arterial, venous and cerebrospinal fluid spaces as well as the cord inself.
- Can occur due to extrinsic causes and lesions or intrinsic aetiologies
- Cauda equina syndrome is a severe form of disc herniation, compressing on the cauda equina
Describe epidemiology of spinal cord compression (inc.cauda equina)
- Trauma is the main cause
- More than 80% affect males
- Sports related primarily ffect those under 29
- In people over 65, falls leading cause
- Cauda equina syndrome low incidence
Describe aetiology of spinal cord compression
- Trauma (car accidents, diving, sports injuris, knife wounds)
- Vertebral compresision fractures (osteoporosis, osteomalacia, steroid therapy)
- Disc herniation
- Tumours (sarcoma, CNS, multiple myeloma, metastatic)
- Infection (TB, abscess)
List risk factors of spinal cord compression (inc cauda equina)
- Age 16-30 years and male sex
- Trauma
- Tumour
- Osteoporosis
- High risk occupation/ recreational activities
- IVDU (abscess)
- Immunosuppression (abscess)
List investigations of spinal cord compression (inc. cauda equina)
- MRI spine, inc. gadolinium enhanced
- Plain spine x ray
- CT spine
- CT myelography
- FBC, ESR, CRP, B12, U and E, syphillis serology, PSA, calcium, immunoglobulin electrophoresis
- Urine bence Jones protein
Define lumbar puncture
- A thin needle is inserted between L3 and L4, or L4 and L5
- Lateral recumbent position (patient on side with head on one pillow, knees and torseo flexed.) or sitting
- Local anaesthetic is used
List indications for lumbar puncture
- Suspected meningitis or encephalitis
- Suspected SAH with normal CT
- CNS leukaemia or lymphoma
- Evaluation of neurological conditions
- Injecting medicine, or epidural
- Removing some CSF to reduce ICP
List complications of lumbar puncture
- Headaches
- Swelling and back pain where the needle was inserted
- If raised ICP, coning/ arnold chiari malformation may occur
- Bleeding/haematoma - if on anticoagulant or clotting disorders
- Infection
- Poor sample/bloody tap
- Radiculopathy
Describe lambert eaton syndrome
- Presynaptic problem - reduced release of acetylcholine due to antibodies attacking presynaptic calcium channels
- Improves with movement, eye symptoms less likely, associated with small cell lung cancer, autonomic symptoms
List absolute contraindications to thrombolysis
- Prior intracranial hemorrhage
- Known structural cerebral vascular lesion
- Known malignant intracranial neoplasm
- Ischemic stroke within three months (excluding stroke within three hours*)
- Suspected aortic dissection
- Active bleeding or bleeding diathesis (excluding menses)
- Significant closed-head trauma or facial trauma within three months
List relative contraindications to thrombolysis
- History of chronic, severe, poorly controlled hypertension
- Severe uncontrolled hypertension on presentation (SBP >180 mmHg or DBP >110 mmHg)
- History of ischemic stroke more than three months prior
- Traumatic or prolonged (>10 minute) CPR or major surgery less than three weeks
- Recent (within two to four weeks) internal bleeding
- Noncompressible vascular punctures
- Recent invasive procedure
- For streptokinase/anistreplase - Prior exposure (more than five days ago) or prior allergic reaction to these agents
- Pregnancy
- Active peptic ulcer
- Pericarditis or pericardial fluid
- Current use of anticoagulant (eg, warfarin sodium) that has produced an elevated international normalized ratio (INR) >1.7 or prothrombin time (PT) >15 seconds
- Age >75 years
- Diabetic retinopathy
Describe presentation of a paraganglionoma
- Paraganglioma is also known as a carotid body tumour or chemodectoma
- Pulsatile mass in the neck
- A neoplasm that forms in the carotid bifurcation and starts developing in the child but normally is only diagnosed at 40-50 y/o.
- It can cause compression of nearby structures such as sympathetic nerves causing Horner’s, recurrent laryngeal causing hoarseness, dysphagia due to compression of other cranial nerves and if carotids become compressed you can have dizziness.
Describe lateral pontine syndrome
Ischaemic stroke of the anterior inferior cerebellar artery.
- Causes ipsilateral facial droop, loss of pain sensation and temp sensation on the ipsilateral face, and loss of pain and temp + hemiplegia on the contralateral body
Describe central cord syndrome
- Most common form of cervical spinal cord injury
- Loss of motion and sensation in the arms and hands, often due to trauma damaging the neck
- Affects legs less
Describe COAT RACK in wernickes/korsakoff syndrome
Wernicke’s encephalopathy (acute phase): COAT
- Confusion
- Ophthalmoplegia
- Ataxia
- Thiamine tx
Korsakoff’s syndrome (chronic phase): RACK
- Retrograde amnesia
- Anterograde amnesia
- Confabulation
- Korsakoff’s psychosis
Describe lymphoctic choriomeningitis infection
- A zoonotic virus associated with rodents which causes meningitis
- Biphasic syndrome of headache, fever, and nuchal rigidity
