Neurology Flashcards
What is a cluster headache?
Most disabling of primary headache disorders
How common is a cluster headache?
Distinct from migraine Much rarer than migraine 1 per 1000 More common in men Affects adults typically between 20-40 Commoner in smokers
What can increase your risk of getting cluster headaches?
Smoker
Male
Autosomal dominant gene has role
What is the pathophysiology of cluster headaches?
Unknown
May be due to superficial temporal artery smooth muscle hyper-reactivity to serotonin
Hypothalamic grey matter abnormalities
How do cluster headaches present?
Abrupt onset
Excruciating pain around one eye, temple or forehead
Ipsilateral cranial autonomic features
- Eye may become watery and bloodshot with lid swelling, lacrimation
- Facial flushing
- Rhinorrhea
- Miosis +/- ptosis (20%)
Pain unilateral and almost always affects the same side
Rises to crescendo over minutes and lasts 15-160 mins, once or twice a day - usually at same time
Often nocturnal/early morning - often wakes from sleep
+/- vomiting
Episodic - clusters last 4-12 weeks and are followed by pain free periods of months or even 1-2 years before next cluster
Can be chronic
What could be a differential for cluster headaches?
Migraine
How are cluster headaches diagnosed?
Clinical diagnosis
At least 5 headache attacks fulfilling above criteria
How are acute attacks of cluster headaches treated?
Analgesics are unhelpful
100% 15L for 15 mins via non-rebreathable mask
Triptan (selective serotonin agonist) - reduces vascular inflammation
How are cluster headaches prevented?
CCB eg verapamil is first line prophylaxis
Avoid alcohol during cluster period
Corticosteroids eg prednisolone may help during cluster
How common are headaches?
One of the most common symptoms
Symptoms are unpleasant, disabling and common worldwide and have substantial economic impact because of time lost from work
What are the different types of headache?
Primary - no underlying cause relevant to headache
Secondary - underlying cause, need to identify underlying cause eg giant cell arteritis
Other - trigeminal neuralgia (facial pain) - painful cranial neuropathy
Name an example of a primary headache
Migraine (20% population)
Cluster
Tension (affect 99% in lifetime)
What are the red flags associated with headaches?
HIV/immunosuppressed Fever Thunderclap headache (subarachnoid haemorrhage) Seizure and new headache Suspected meningitis Suspected encephalitis Red eye? acute glaucoma Headache + new focal neurology eg papilloedema
Name an example of a secondary headache cause
Meningitis, subarachnoid haemorrhage, giant cell arteritis, medication overuse headache
What is a migraine?
Recurrent throbbing headache often preceded by an aura and associated with nausea, vomiting and visual changes
Migraine aura may affect the patients eyesight with visual phenomena such as fortification spectra (zig-zag lines), shimmering or scotomas (black holes in visual field), but may also result in pins and needles, dysphasia and rarely weakness of limbs and motor function
How common are migraines?
Most common cause of episodic headache (recurrent)
More common in women
In 90% onset before 40
If onset > 50 then pathology sought
Usually severity of migraine decreases with advancing age
What can cause migraines?
No specific causes but partial triggers
CHOCOLATE - Chocolate, Hangovers, Orgasms, Cheese, Oral contraceptives, Lie-ins, Alcohol, Tumult (loud noise), Exercise
Brain chemical imbalance may be cause
May be caused by changes in brainstem and its interactions with trigeminal nerve
What can increase your risk of getting migraines?
Strong genetic component - FHx
Female
Age - can occur at any age but majority have first migraine in adolescence
What is the pathophysiology of migraine?
Genetic factors play role in neuronal hyper-excitability
Changes in brainstem blood flow lead to an unstable trigeminal nerve nucleus and nuclei in basal thalamus
Cortical spreading depression - self-propagating wave of neuronal and glial depolarisation that spreads across the cerebral cortex thought to cause aura of migraine and leads to release of inflammatory mediators which impact on trigeminal nerve nucleus
Results in release of vasoactive neuropeptides including calcitonin-gene-related peptide and substance P - results in neurogenic inflammation - vasodilation and plasma protein extravasation leading to pain that propagates all over cerebral cortex
How do migraines present?
Prodrome that precedes headache by hours/days consisting of - yawning, cravings, mood/sleep changes
Migraine without aura
- Attacks last 4-72 hours
- Two of following - unilateral, pulsing, moderate/severe head pain, aggravated by routine physical activity
- During headache at least one of - nausea and/or vomiting, photophobia, phonophobia
- Not attributed to another disorder
Migraine with aura
- At least 2 attacks
- Aura precedes attack by minutes and may persist during it
- Visual - chaotic cascading, jumbling, distorting lines, dots or zigzags, scotoma, hemianopia
- Somatosensory - paraesthesiae spreading from fingers to toes
- Unilateral, pulsatile headache
General
- At least 2 of - unilateral pain, throbbing eye pain, moderate-severe intensity, motion sensitivity
- At least one of - nausea/vomiting, photophobia/phonophobia, normal examination with no attributable cause
Give 5 possible differential diagnoses of migraine?
Tension headache, cluster headache, medication over-use headache
Sudden migraine may resemble meningitis or subarachnoid haemorrhage
Visual and hemisensory symptoms must be distinguished from thromboembolic TIAs
Brain tumour and temporal arteritis
How is migraine diagnosed?
Mainly clinical diagnosis Always examine - Eyes - for papilloedema - BP - Head and neck Exclude other causes - CRP/ESR - Red flags - indication for neuroimaging - Lumbar puncture
What are the indications for lumbar puncture?
Worst headache of life - thunderclap
Severe rapid onset headache, progressive headaches, unresponsive headaches
Neuroimaging should precede lumbar puncture to rule out mass/lesion/raised ICP
What are the indications for neuroimaging?
Worst/severe headache Change in pattern of migraine Abnormal neurological exam Onset > 50 Epilepsy Posteriorly located headache
How do you treat migraines?
Reduce triggers Acute - Triptans eg sumatriptan - NSAIDs - +/- anti-emetic
How do triptans work?
Selectively stimulate 5-hydroxytryptamine receptors in brain
Contraindicated in IHD, coronary spasm and uncontrolled high BP
S/E arrhythmias or angina +/- MI
Why do you prescribe NSAIDs for migraines?
Less likely to get medication over-use headache
Avoid paracetamol or ibuprofen
How do you prevent migraines?
If more than 2 attacks a month, or acute treatment required more than 2x a week
Beta-blocker
Tricyclic anti-depressant
Anti-convulsant
What is a tension headache?
Most chronic daily and recurrent headaches are tension headaches
How common are tension headaches?
Commonest primary headache
Can be episodic < 15 days/month or chronic > 15 days/month for at least 3 months
No organic cause
What can cause tension headaches?
Stress Sleep deprivation Bad posture Hunger Eyestrain Anxiety Noise
How do tension headaches present?
Usually one of following
- Bilateral, pressing/tight non-pulsatile, mild/moderate intensity, +/- scalp tenderness
Without vomiting or sensitivity to head movement, no aura
Not aggravated by physical acitivty
Tight band-like sensation
Pressure behind eyes, mild-moderate pain
Headaches can last from 30 mins to 7 days
Not attributed to another disorder
What could be a differential diagnosis of tension headaches?
Migraine
Cluster headache
Giant cell arteritis
Drug-induced headache
How are tension headaches diagnosed?
Clinical diagnosis from history
How are tension headaches treated?
Reassurance and lifestyle advice - regular exercise, avoid triggers
Stress relief
Symptomatic treatment of episodes occuring > 2 days a week
- Aspirin, paracetamol, NSAIDs, no opioids
Limit analgesia to no more than 6 days a month to reduce chance of medication over use headaches
Tricyclic antidepressants
How do medication overuse headaches present?
Worsens whilst on regular analgesia especially opioids
Other causes mixed analgesics eg co-codamol, ergotamine, triptans
Common reason for episodic headache becoming chronic daily headache
What is a TIA?
Brief episode of neurological dysfunction due to temporary focal cerebral ischaemia without infarction
Symptoms generally resolve within 24 hours
How common are TIAs?
15% first strokes preceded by TIA, also foreshadowing of MI
More common in men
Black ethnicity at greater risk due to hypertension and atherosclerosis predisposition
What causes TIA?
Small vessel occlusion
Atherothromboembolism from carotid chief cause
Cardioembolism resulting from microemboli from
- Mural thrombus post-MI or in AF
- Valve disease
- Prosthetic valve
Hyperviscosity
- Polycythaemia, sickle cell anaemia, extremely raised WCC or myeloma
- Can result from hypoperfusion - most important to consider in young people - cardiac dysrhythmia, postural hypotension, decreased flow through atheromatous arteries
What can increase your risk of a TIA?
Increasing age Hypertension Smoking Diabetes Heart disease - valvular, ischaemic, or AF Past TIA Raised packed cell volume Peripheral arterial disease Polycythaemia vera Combined OC Hyperlipidaemia Excess alcohol Clotting disorder Vasculitis eg SLE, giant cell arteritis, rare risk factor
What happens to the brain during a TIA?
Cerebral ischaemia resulting in lack of O2 and nutrients to brain result in cerebral dysfunction
Short lived period of ischaemia with symptoms only lasting a maximum of 5-15 minutes after onset and then resolves before irreversible cell death occurs
Symptoms gradually progressing suggest different pathology eg demyelination, tumour or migraine
How does a TIA present?
Sudden loss of function, usually only lasts for minutes
Complete recovery and no evidence of infarction on imaging
Site of TIA often suggested by symptoms
How does an anterior circulation TIA present?
90%
Weak, numb contralateral leg +/- similar if milder arm
Hemiparesis - weakness of entire side of body
Hemisensory disturbance
Dysphasia
Amaurosis fugaux- sudden transient loss of vision in one eye, temporary reduction in retinal, ophthalmic or ciliary blood flow leading to temporary retinal hypoxia, TIA causing this often first clinical evidence of ICA stenosis
How does a posterior circulation TIA present?
10% Diplopia Vertigo Chocking and dysarthria Ataxia Hemisensory loss Hemianopia vision loss Transient global amnesia Tetraparesis
What is a possible differential diagnosis of a TIA?
Cannot differentiate from stroke until full recovery
Hypoglycaemia, migraine aura, focal epilepsy
Intracranial lesion - tumour or subdural haematoma
Syncope due to arrhythmia
Todd’ paralysis - transient weakness of arm, hand or leg after seizure
Retinal or vitreous haemorrhage
Giant cell arteritis
How is a TIA diagnosed?
Often solely on Hx Bloods - FBC - polycythaemia? - ESR - raised in vasculitis - Glucose - hypoglycaemia? - Creatinine, electrolytes - Cholesterol Carotid artery doppler USS to look for stenosis/atheroma MR/CT angiography if stenosis to determine extent ECG - AF/MI ischaemia CT/diffusion weight MRI Echo/cardiac monitoring to assess for cardiac cause
What is the ABCD2 score?
To assess risk of stroke after TIA - Age > 60 = 1 - BP > 140/90mmHg > 1 - Clinical features - Unilateral weakness = 2 - Speech disturbance w/o weakness = 1 - Duration of symptoms - Lasting more than 1 hour = 2 - Lasting 10-59 minutes = 1 - Diabetes = 1 Score greater than 6 strongly predicts stroke and referred to specialise immediately Score greater than 4 assessed by specialist with 24 hours All patients with suspected TIA seen within 7 days
When are you also at an increased risk of stroke?
AF
More than 1 TIA in one week
TIA whilst on anti-coagulant
How do you treat TIAs?
Antiplatelet drugs
- Aspirin immediatley + dipyridamole for 2 weeks then lower dose
- P2Y12 inhibitor long term eg clopidogrel
Anticoagulant in AF, mitral stenosis or recent big septal MI eg warfarin
Long term statins
Control CVS risk factors - antihypertensives, improve diet, stop smoking
Don’t drive for at least 4 weeks following TIA
What is a stroke?
Syndrome of rapid onset neurological deficit caused by focal, cerebral, spinal or retinal infarction
Characterised by rapidly developing signs of focal or global disturbance of cerebral functions, lasting for more than 24 hours or leading to death
How common are strokes?
Major neurological disease of our time
3rd most common cause of death in high income countries - 11% all deaths in UK
Leading cause of adult disability worldwide
Higher rates in Asian and black African populations than Caucasian
Uncommon under 40
Incidence increases with age
More common in men
Incidence falling due to more vigorous approach to risk factors in primary care ie statin use and control of BP
Ischaemia/infarction 80%
Haemorrhagic 17%
Other causes 3%
What can cause ischaemic strokes?
Small vessel occlusion/thrombosis in situ
Cardiac emboli from AF, MI or IE
Large artery stenosis
Atherothromboembolism
Hypoperfusion, vasculitis, hyperviscosity
Hypoperfusion - watershed stroke where sudden BP drop by more than 40mmHg, then low cerebral blood flow leading to global ischaemia and watershed infarcts in vulnerable areas of cortex between boundaries of different arterial territories
What can cause haemorrhagic strokes?
CNS bleeds due to trauma, aneurysm rupture, anti-coagulation, thrombolysis, carotid artery dissection, SAH
What can cause strokes in young people?
Vasculitis
Thrombophilia
SAH
Carotid artery dissection - spontaneous/neck trauma
Venous sinus thrombosis - very rare, may occur in pregnancy, hypercoagulable states and thrombotic disorders or with dehydration or malignancy
- Leads to cortical infarction, seizures, raised ICP
What can increase your risk of a stroke?
Male Black/Asian Hypertension Past TIA Smoking DM Increasing age Heart disease (valvular/ischaemic) Alcohol Polycythaemia, thrombophilia AF Hypercholesterolaemia Combined OC Vasculitis IE
What occurs in ischaemic strokes?
Arterial disease and atherosclerosis
Thrombosis occurs at site of atheromatous plaque in carotid/vertebral/cerebral arteries
Large artery stenosis acts as embolism source rather than occluding vessel hypertension results in small infarcts known as lacunes and/or gradual accumulation of diffuse ischaemic change in deep white matter
What can cause haemorrhagic strokes?
Hypertension resulting in micro-aneurysm rupture
Cerebral amyloid angiopathy - deposition of amyloid B in walls of small and medium sized arteries in normotensive patients
Space occupying lesions
Young adults 1/5 strokes due to carotid/vertebral artery dissection
How do ACA strokes present?
Leg weakness and sensory disturbance
Gait apraxia - difficulty walking
Truncal ataxia
Incontinence
Drowsiness - consciousness controlled partly by frontal lobe
Akinetic mutism - decrease in spontaneous speech, stuporous state
How do MCA strokes present?
Contralateral arm and leg weakness and sensory loss
Hemianopia
Aphasia and dysphasia (if in dominant hemisphere)
Facial droop
How do PCA strokes present?
Contralateral homonymous hemianopia
Cortical blindness
Visual agnosia - cannot interpret visual info
Prosopagnosia - cannot detect faces
Colour naming and discriminate problems
Unilateral headache - rare in ischaemic stroke
How do posterior circulation strokes present?
More catastrophic as wide region supplied
Likely to get locked in
Motor deficits such as hemiparesis or tetraparesis and facial paralysis
Dysarthria and speech impairment
Vertigo, nausea and vomiting
Visual disturbances
Altered consciousness
What is a lacunar stroke?
Small cortical stroke in midbrain, internal capsule presenting with one of
- Unilateral weakness and/or sensory deficit of face and arm, arm and leg or all three
- Pure sensory loss
- Ataxic hemiparesis (cerebellar or motor symptoms)
How do you distinguish between a haemorrhagic/ischaemic infarct?
No reliable way of distinguishing between them
Intracerebral haemorrhage associated with severe headache/coma (signs of raised ICP)
Patients on oral anticoagulants assumed to have haemorrhagic unless proved otherwise
What is a possible differential diagnosis of stroke?
Hypoglycaemia
Migraine aura
Focal epilepsy
Syncope due to arrhythmia
How are stroke diagnosed?
Urgent CT head/MRI before treatment
- Rules out haemorrhagic stroke before beginning thrombolysis
- Infarction seen as low density lesion - subtle changes evident within 3 hours
- In MRI, hyper-intense within hours of onset
Pulse, BP, ECG
- Look for AF
- Careful treating BP as may compromise cerebral perfusion
Bloods
- FBC - looking for thrombocytopenia and polycythaemia
- Blood glucose - ruling out hypoglycaemia
How is stroke treated?
Maximise reversible ischaemic tissue
- Ensure dehydration
- Keep O2 sats > 95%
- If ischaemia stroke confirmed by CT then thrombolysis
Thrombolysis
- Can be give up to 4.5 hours post symptom onset
- Rule out haemorrhage first
- Tissue plasminogen activator IV alteplase
- Start antiplatelet therapy clopidogrel 24 hours after thrombolysis
If time of onset unknown then aspirin daily for 2 weeks then lifelong clopidogrel
Haemorrhagic
- Frequent GCS monitoring
- Antiplatelets CI
- Any anti-coagulants reversed for warfarin reversal used beriplex and vit K
- Control hypertension
- Manual decompression of raised ICP/diuretics
- Surgery may be required
When can you not give thrombolysis?
Recent surgery in last 3 months Recent arterial puncture Hx of active malignancy Evidence of brain aneurysm Patient on anti-coagulation Severe liver disease Acute pancreatitis Clotting disorder
How do you prevent a stroke?
Platelet treatment (lifelong) eg aspirin + dipyridamole/clopidogrel
Cholesterol treatment like statins
AF treatment - warfarin or NOACs eg pixiban
BP treatment
What is a subarachnoid haemorrhage?
Spontaneous bleeding into subarachnoid space - between arachnoid layer of meninges and pia mater
Can often be catastrophic
How common are subarachnoid haemorrhages?
Typical age 35-65
Account for 5% of strokes
Most common cause is rupture of Berry aneurysms
What can cause subarachnoid haemorrhages?
Rupture of berry aneurysms (80%) - Rupture of junction of posterior communicating artery with internal carotid or anterior communicating artery with anterior cerebral artery (in circle of Willis) - 15% multiple - Associated with PKD, and coarctation of aorta Arteriovenous malformation (10%) - Vascular developmental malformation often with fistula between arterial and venous systems causing high flow through AVM and high-pressure arterialisation of draining veins No cause found (15%) Rare - Bleeding disorder - Mycotic aneurysms - endocarditis - Acute bacterial meningitis - Tumours
What can increase your risk of SAH?
Hypertension Known aneurysm FHx Disease that predisposes you to aneurysm - PKD - Ehlers Danlos syndrome (hyper-mobile joints with increased skin elasticity) - Coarctation of aorta Smoking, bleeding disorders, post-menopausal decreased oestrogen
What is the pathophysiology of SAH?
Most common cause ruptured aneurysm which leads to tissue ischaemia (less blood can reach tissue) as well as rapid raised ICP as blood, acts like space-occupying lesion, puts pressure on brain, resulting in deficits if not resolved quickly
How do SAH present?
Sudden onset severe occipital headache - thunder clap
Depressed level of consciouness
Coma/drowsiness may last for days
Neck stiffness
Kernig’s sign (unable to extend patient’s leg at knee when thigh flexed)
Brudzinski’s sign
Retinal and vitreous bleeds
Papilloedema
Vision loss or diplopia
Focal neurology at presentation (fixed dilated pupils - signs of CN3 palsy)
Marked increase in BP as a reflex to following haemorrhage
Sentinel headache
- May earlier have experienced a sentinel headache due to small warning leak
- Ask about Hx
What is a differential diagnosis of SAH?
Must be differentiated from migraine 50-60% no cause of headache Meningitis Intracerebral bleeds Cortical vein thrombosis
How is SAH diagnosed?
ABG - to exclude hypoxia
Head CT - gold standard
- Detects > 90% of SAH within 1st 48 hours
- Seen as star shaped lesion due to blood filling in gyro patterns around brain and ventricles
CT angiography if aneurysm confirmed to see extent
Lumbar puncture
- If CT normal but SAH still suspected
- CSF uniformly bloody early on and becomes yellow after several hours due to Hb breakdown (xanthochromia)
- Xanthochromia confirms SAH
How is SAH treated?
Refer all proved SAH to neurosurgeon immediatrly
Maintaun cerebral perfusion keeping well hydrated (IV fluids) and aim for BP < 160mmHg
CCBs to reduce vasospasm and consequent morbidity from ischaemia IV/oral nimodipine
Endovascular coiling
- Preferred to surgical clipping since lower complication rate where possible
- Promotes thrombosis and ablation of aneurysm
- First line treatment where angiography shows aneurysm
Surgery - intracranial stents and balloon remodelling for wide-necked aneurysms
What are the potential complications of SAH?
Rebleeding
Cerebral ischaemia due to vasospasm - can result in permanent deficit
Hydrocephalus due to blockage of arachnoid granulations - requires ventricular or lumber drain
Hyponatraemia
What is a subdural haemorrhage?
Caused by accumulation of blood in subdural space - between arachnoid and dura mater following rupture of bridging vein between cortex and venous sinus (vulnerable to deceleration injury)
Considered very treatable in all those whose conscious level fluctuates and also in those having evolving stroke - especially if on anticoagulants
How common is subdural haemorrhage?
Most common where patient has small brain eg alcoholic or dementia or babies that have suffered trauma, or elderly with brain atrophy making bridging veins more vulnerable
Majority from trauma but trauma often forgotten as so minor or so long ago
Chronic, apparently spontaneous SDH common in elderly and also occurs with anticoagulants
What can cause subdural haemorrhage?
Trauma either due to deceleration due to violent injury or due to dural metastases resulting in bleeding from bridging veins between cortex and venous sinus
Bridging veins bleed and form haematoma between dura and arachnoid reducing pressure and bleeding stops
Days/weeks later haematoma starts to autolyse due to massive increase in oncotic and osmotic pressure thus water sucked into haematoma resulting in haematoma enlargement
Results in gradual rise in intra-cranial pressure over many weeks
Shifting midline strucutres away from side of clot and if untreated leads to eventual tectorial herniation and coning
What can increase your risk of subdural haemorrhages?
Traumatic head injury
Cerebral atrophy/increasing age
Alcoholism, anticoagulation and physical abuse of infant
How do subdural haemorrhages present?
Interval between injury and symptoms can be days to weeks or months
Fluctuating level of consciousness +/- insidious physical or intellectual slowing
Sleepiness
Headache
Personality change
Unsteadiness
Signs of ICP eg headache, vomiting, nausea, seizure and raised BP
Focal neurology eg hemiparesis or sensory loss (occurs later)
Seizures
Stupor, coma, coning
In elderly symptoms will develop slowly as brain has more compliance to raised ICP
What is a possible differential diagnosis of subdural haemorrhage?
Stroke, dementia, CNS masses eg tumours/abscesses
SAH
Extradural haemorrhage
How are subdural haemorrhages diagnosed?
CT head
- Diffuse spreading, hyperdense crescent shaped hemisphere
- As clot ages and protein degradation occurs becomes isodense and eventually hypodense
- Shifting of midline structures
MRI head for subacute and smaller haematomas
How are subdural haemorrhages treated?
Assess and manage ABCs, prioritise head CT
Stabilise patient
Refer to neurosurgeons - irrigation/evacuation via burr twist drill and burr hole craniotomy
Address cause of trauma
IV mannitol to reduce ICP
What is an extradural haemorrhage?
Suspect this after head injury and conscious level falls or is slow to improve or there is a lucid interval
Collection of blood between dura mater and bone usually caused by head injury
What can cause extradural haemorrhages?
Most commonly due to traumatic head injury resulting in fracture of temporal or parietal bone causing laceration of middle meningeal artery - typically after trauma to temple
What can increase your risk of extradural haemorrhage?
Usually occurs in young adults (rare < 2 and > 60)
How do extra-dural haemorrhages present?
Characteristic history - head injury, brief post-traumatic loss of consciousness or initial drowsiness, lucid interval
Severe headache, nausea, vomiting, confusion, seizures due to rising ICP +/- hemiparesis with brisk reflexes
Rapid rise in ICP as epidural space full of blood
Ipsilateral pupil dilates, coma deepens, bilateral limb weakness develops and breathing becomes deep and irregular (brainstem compression)
Decreased GCS and coning
Death due to respiratory arrest
Bradycardia and raised BP late signs
What is a possible differential diagnosis of extradural haemorrhages?
Epilepsy, carotid dissection, CO poisoning
Subdural haematoma
SAH
Meningitis
How are extradural haemorrhages diagnosed?
CT head - gold standard
- Shows hyperdense haematoma that is biconvex and adjacent to skull
- Blood forms more rounded shape compared with sickle shaped subdural haematoma
Skull x-ray - may be normal or show fracture lines crossing course of middle meningeal artery
How are extra-dural haemorrhages treated?
ABCDE emergency management - assess and stabilise patient
Give IV mannitol if increased ICP
Refer to neurosurgery - clot evacuation +/- litigation of bleeding vessel
Maintain airway via intubation and ventilation in unconscious patient
What is encephalitis?
Infection and inflammation of brain parenchyma
How common is encephalitis?
Most frequent in children and elderly - mainly viral caue
More common in immunocompromised
What can cause encephalitits?
Mainly viral - Herpes simplex viruses 1 and 2 - Varicella zoster, EBV, cytomegalovirus, HIV, mumps, measles Non-viral - Bacterial meningitis - TB - Malaria
What can increase your risk of getting encephalitis?
Extremes of age
Immunocompromised
What is the pathophysiology of encephalitis?
Disease that mostly affects frontal and temporal lobes resulting in decreased consciousness, confusion and focal signs
How does encephalitis present?
Whole brain affected - problems with consciousness
Insidious onset (days) or can be abrupt
Triad - fever, headache, altered mental state
Begins with features of viral infection - fever, headaches, myalgia, fatigue, nausea
Progresses to - personality and behavioural changes, decreased consciousness, drowsiness, confusion
Focal neurological deficit - hemiparesis, dysphasia, seizures, raised ICP, midline shift, coma
Signs of meningitis
Hx of travel and/or animal bite
What is a possible differential diagnosis of encephalitis?
Meningitis
Stroke
Brain tumour
How is encephalitis diagnosed?
MRI
- Areas of inflammation and swelling, generally in temporal lobes in HSV encephalitis
- May be midline shifting due to raised ICP
Lumbar puncture
- CSF shows elevated lymphocyte count
- Viral detection by CSF PCR highly sensitive for herpes simplex and varicella zoster
- False negative may occur within first 48 hours symptoms onset
Blood and CSF serology usually helpful
How is encephalitis treated?
If viral - immediate treatment with anti-viral IV acyclovir
Early treatment can reduce mortality and long neuro damage
Anti-seizure medication
If meningitis suspected then emergency IM benzylpenicillin
What is shingles?
Caused by reactivation of varicella zoster virus usually within dorsal root ganglia
Primary infection with VZV causes chickenpox, following which the virus remains latent in sensory ganglia
Development of shingles may indicate decline in cell-mediated immunity such as that due to age or malignancy
How common is the Varicella zoster virus?
90% children have been exposed to chicken pox before 16
Can affect all ages but seen as disease of elderly
Incidence and severity can increase with age
Shingles cannot be caught from contact with person or chickenpox
What can increase your risk of getting shingles?
Increasing age Immunocompromised HIV Hodgkin's lymphoma Bone marrow transplants
How does shingles occur?
Viral infection affecting peripheral nerves
When latent virus reactivated in dorsal root ganglia travels down affected nerve via sensory root in dermatomal distribution over period 3-4 days
Results in perineural and intramural inflammation
In immunocompromised, most frequent site is throacic nerves followed by ophthalmic division of trigeminal nerve
Can also affect cervical, lumbar and sacral nerve roots
Person with weeping shingles rash can cause chickenpox in non-immune person after close contact
How does shingles present?
Pain and paraesthesia in dermatomal distribution
Rash for days
Malaise, myalgia, headache, fever
Rash - consists of papules and vesicles restricted to same dermatome
- Neuritic pain
- Crust formation and drying occurs over next week with resolution in 2-3 weeks
- Patients infectious until lesions are dried
- Rash doesn’t extend outside dermatome
What is a possible differential for shingles?
Before rash appears pain may come from chest or abdominal pain - cholecystitis or renal stones
Cluster headaches/migraines
Atopic eczema, contact dermatitis or herpes simplex or impetigo
How is shingles diagnosed?
Clinical diagnosis
Rash diagnostic
How is shingles treated?
Oral antiviral therapy begun within 72 hours of rash onset
- Oral acylovir x5 daily
- Or oral valicilovir x2 daily
- Or oral famciclovir x2 daily
Rapid treatment to minimise risk of peripheral herpetic neuralgia
Topical antibiotics treatment for secondary bacterial infection
Analgesia eg ibuprofen for pain
What are the complications of shingles?
Ophthalmic branch of trigeminal nerve - damage will affect sight Post herpetic neuralgia - Pain lasting for more than 4 months after developing shingles - Occurs in 10% patients often elderly - Burning, intractable pain - Responds poorly to analgesics Treat with - Tricyclic antidepressants - Anti-epileptics - Anti-convulsants
What is meningits?
Inflammation of meninges
How common is meningitis?
Occurs in people of all age groups but more common in infants, young children and elderly
Meningococcal disease notifiable to PHE
What can cause meningitis in adults and children?
Neisseria meningitides - gram negative diplococci transmitted by droplet spread
Streptococcus pneumoniae/pneumoncoccus
Less common H influenzae
What can cause meningitis in pregnant women and older adults?
Listeria monocytogenes - found in cheese
What can cause meningitis in neonates?
E coli
Group B haemolytic stretpcoccus - strep agalactiae
What can cause meningitis in immunocompomised?
Cytomegalovirus Cryptococcus neoformans (fungi) TB HIV Herpes simplex virus
What can increase your risk of meningitis?
Intrathecal drug administration Immunocompromised Elderly Pregnant Bacterial endocarditis Crowding - military base, university students Diabetes Malignancy IVDU
What is the pathophysiology of meningitis?
Microorganisms reach meninges either by direct extension from ears, nasopharynx, cranial injury or congenital meningeal defect or bloodstream
Immunocompromised patients at risk of infection with unusual organisms
Acute bacterial meningitis
- Typically sudden
- Can lead to meningococcal septicaemia when bacteria invade blood
- Presence of endotoxin leads to inflammatory cascade
- Petechial rash and signs of sepsis
- Pia arachnoid congested with polymorphs
- Layer of pus which may organise to form adhesions causing cranial nerve palsies and hydrocephalus
Chronic infection eg TB
- Brain covered in viscous grey-green exudate with numerous meningeal tubercules
Viral
- Predominantly lymphcytic inflammatory CSF reaction without pus formation
- Little or no cerebral oedema unless encephalitis develops
How does meningitis present?
Triad - headache, neck stiffness, fever
In acute bacterial
- Onset sudden
- Papilloedema bilateral occuring over hours-weeks
- Intense malaise, fever, rigors, severe headache, photophobia, vomiting
- Irritable and prefers to lie still
- Neck stiffness, positive Kernig’s and Brundzinski’s sign
- Meningococcal septicaemia - non-blanching petechial and purpuric rash
- Altered mental state with high fever
- Seizures and focal CNS signs
- Progressive drowsiness, materialising signs, cranial nerve lesions indicate complication
Viral meningitis
- Benign, self-limiting condition lasting 4-10 days
- Headache may follow for some months
Chronic
- TB
- Long Hx and vague symptoms of headache, anorexia and vomiting
- Sings of meningeal tried often absent/late
What is a possible differential diagnosis of meningitis?
Aseptic meningitis due to tumour
SAH
Encephalitis
How is meningitis diagnosed?
Blood cultures before lumbar puncture
Blood tests - FBC, U&E, CRP, serum glucose
Lumbar puncture - if unable to perform within 30 mins give empirical antibiotics
- Send for microscopy and sensitivity
- Can give headache, paraesthesia, CSF leak and damage to spinal cord
CT head
- To exclude lesions
Throat swabs - bacterial and viral
Pneumococal and meningococcal serum PCR
How do you differentiate between bacterial, TB and viral meningitis on lumbar puncture results?
Bacteria - Neutrophil polymorphs - High protein - Low glucose TB - Lymphocytes - High protein - Low/normal glucose Viral - Lymphocytes - Normal protein - Normal glucose
How do you treat meningococcal septicaemia?
IV benzylpenicillin or cefotaxime immediately
Lumbar puncture not performed due to risk of coning and raised ICP
Diagnosis confirmed by blood cultures
When would you do a head CT before a lumbar puncture?
Age > 60 Immunocompromised Hx of CNS disease New onset/recent seizures Decreasing conscious levels GCS < 14 Focal neurological signs Papilloedema
How do you treat bacterial meningitis?
Start antibiotics before tests come back if suspected
IV cefotaxime or ceftriaxone
If over 50/immunocompromised add IV amoxicillin to cover listeria
Consider steroids to reduce cerebral oedema
IV vancomycin if return traveller
Prophylaxis for contacts
- Oral ciprofloxacin stat
- Oral rifampicin - cannot give when pregnant
What are the potential complications of meningitis?
Hearing loss
Seizures
Developmental problems
What does paresis mean?
Impaired ability to move a body part in response to will
Weakness
What does paralysis mean?
Ability to move a body part in response to will completely lost
What does ataxia mean?
Incoordination
Willed movements clumsy, ill-directional or uncontrolled
What are involuntary movements?
Spontaneous movement of body part, indefinitely of will
What is apraxia?
Disorder of consciously organised pattern of movement or impaired ability to recall acquired motor skills
What is a lower motor neurone?
Located in anterior horns of spinal cord and in CN nuclei in brainstem
What are the potential sites of damage along a motor pathway?
Motor nuclei of cranial nerves Motor neurones in spinal cord Spinal ventral roots Peripheral nerves Neuromuscular junction Muscle
What are the UMN damage signs?
Everything goes up
Spasticity (increased muscle tone)
Brisk reflexes
Plantars upturned on stimulation - positive Babinski’s sign
Characteristic pattern of limb muscle weakness (pyramidal pattern)
- Upper limbs extensor muscles weaker than flexors
- Lower limb flexors weaker than extensors
- Finer more skillful movement impaired
What are the LMN damage signs?
Everything goes down Muscle tone reduced - flaccid Muscle wasting Fasciculation - visible spontaneous contraction of motor units - not enough to diagnose LMN, need weakness too Reflexes depressed/absent
What is motor neurone disease?
Cluster or major degenerative diseases charaterised by selective loss of neurones in motor cortex, cranial nerve nuclei and anterior horn cells
How common is MND?
Relatively uncommon
More common in men
Median age onset 60
Often fatal in 2-4 years
What can cause MND?
Usually sporadic and of unknown cause No established factors 5-10% familial - Linked to mutation in free radical scavenging enzyme superoxide dismutase - Also linked to TDP-42, C9LRF72 and FUS
What occurs in MND?
Degenerative condition affecting motor neurones, namely anterior horn cells
Relentless and unexplained destruction of UMN and anterior horn cells in brain and spinal cord
Causes both UMN and LMN dysfunction
No sensory loss of sphincter disturbance
Never affects eye movements
Causes reactive oxygen species which damage DNA, lipids and proteins
Most patients die within 3 years from respiratory failure as a result of bulbar palsy and pneumonia
How does MND present?
What are the 4 main clinical patterns?
Amyotrophic lateral sclerosis (UMN and LMN)
- Weakness and UMN neurone signs
- Split hand sign (thenar wasting, less hypothenar wasting)
- Cramps
- Wrist and foot drop
Progressive muscular atrophy (LMN)
- Weakness, muscle wasting, fasciculations
- Affects distal before proximal
Progressive bulbar palsy (LMN)
- Lower CN 9-12 and nuclei
- Dysarthria, dysphasia, nasal regurgitation (chocking)
- LMN lesion of tongue and muscles of talking, swallowing, flaccid fasciculating tongue, jaw jerk normal/absent, speech quiet, hoarse of nasal
Primary lateral sclerosis (LMN)
- Loss of beta cells in motor cortex
- UMN signs
- No cognitive decline
When may you think of MND?
> 40, stumbling spastic gait, foot drop +/- proximal myopathy, weak grip and shoulder abduction or aspiration pneumonia
Frontotemporal dementia
Spread of symptoms
Rectal and bladder sphincters and oculomotor muscles spared
No sensory symptoms
What is a differential diagnosis of MND?
MS/polyneuropathies Myasthenia gravis Diabetic amyotrophy GBS Spinal cord tumour
How is MND diagnosed?
Based on clinical findings
- Definite - LMN and UMN signs in 3 regions
- Probable - LMN and UMN in 2 regions
- Probably with lab support - LMN and UMN signs in 1 region or UMN in more than one region + electomyography shows acute denervation in more than 2 limbs
- Possible - LMN and UMN signs in 1 region
- Suspected - LMN/UMN sign only in 1 or more
Brain/spinal cord MRI (excludes structural causes)
Lumbar puncture - excludes inflammatory causes
Nerve conduction studies + electromyography
Denervation of muscles due to degeneration of LMNs confirmed by EMG
How is MND treated?
Anti-glutametergic drugs
- Oral riluzole (Na+ channel blocker inhibiting glutamate), prolongs life by 3 months
- Raised LFTs so monitor
- S/E vomiting, raised pulse, headache, vertigo
Drooling - oral propantheline or amitriptyline
Dysphasia
- Blend food
- Nasogastric tube
- percutaneous catheter gastrostomy
Spasms - oral baclofen
Non-invasive ventilation if respiratory failure
Analgesia - NSAIDs or opioids
Specialist MDT supprot - neurologist, speech and language therapists, occupational therapist, specialist nurse, physiotherapise
What is Parkinson’s disease?
Degenerative movement disorder caused by reduction in dopamine in substantia nigra
Characterised by triad of rigidity, bradykinesia, resting tremor
How common is Parkinson’s?
Increasing prevalence with age
Peak age of onset 55-65
More common in men
What can cause Parkinson’s?
Idiopathic
Drug induced
Combination of
- Environmental factors - pesticides, methyl-phenyl tetrahydropyridine in illegal opiates
- Parkinson’s genes
- Oxidative stress and mitochondrial dysfunction
