W10: Eye Pathology; NS Pathology; Neurology; Neurovasc.; Neurosurgery Flashcards
principles behind investigations such as FFA, OCT, ERG, EOG and VEP.
FFA: normal fluorescence of optic nerve; Na fluorescein;
Optical Coherence Tomography (OCT): measures input waves (neurosensory img of retina); macular disease.
ERG: electroretinogram (ERG) is a diagnostic test that measures the electrical activity of the retina in response to a light stimulus. The ERG arises from currents generated directly by retinal neurons in combination with contributions from retinal glia
electroocoulogram (EOG) is an elecrophysiologic test that measures the existing resting electrical potential between the cornea and Vitreous membrane. Normal Retinal pigment epithelium is 6 millivolts (mV)
Visual Evoked Potentials (VEPs) testing measures the signals from your visual pathway
Describe the retinal diseases that lead to sudden painless loss of vision
Central retinal arterial occlusion
Branch retinal art. occlusion
central vein occlusion
-retinal haemorr. | -swelling: macula + optic nerve
=> intravitreal anti-VEGF
Art. ischaemic optic neuropathy (AION)
-ARTERITIC: giant cell arteritis (temporal art.)
*headache, scalp tenderness, loss of appt., pain on chewing
=> systemic steroids
-NON-ARTERITIC: painless (NAION)
=> RF (aspirin e.g.)
Describe the retinal conditions that cause gradual painless loss of vision
CATARACTS: lens opcaficiation +dazzle/glare
=>sx; phacoemulsification w/ intraoc lens implant
DM RETINOPATHY: microaneurysms,retinal haemorr. etc. | fluorescein OCT
=> intravitreal antiVEGF; Laser panretinl photocoag., AIDS
GLAUCOMA: optic neuropathy w/ optic nerve dmg. peripheral vis loss. intraoc. pressure
*open/closed angle | chronic / acute
=>topical
=> Trabeculectomy
MACULAR DEGEN. (AGE-RELATED):calcification @ macula, progressive central vis. loss.
- octomography: oedema ID, fluoro ID leakage
*neovasc. @ choroid + pigment changes
*advanced: atrophy => loss of vis.
=>antiVEGF
=> low vision aids
Elaborate on the retinal appearance in central retinal artery or central retinal vein occlusion
CRAO:
It usually causes sudden loss of eyesight in one eye.
retinal whitening and a cherry red spot are due to opacification of the nerve fiber layer as it becomes edematous from ischemia. The fovea is cherry red because it has no overlying nerve fiber layer
A branch retinal vein occlusion occurs when part of this branch vein system is blocked. A blockage causes backpressure and leads to hemorrhaging, exudation, and/or decreased blood flow in the area of the retina drained by that particular branch retinal vein.
Understand how optic neuritis and ischaemic optic neuropathy develop
optic neuritis: arises from auimm attack of myelin
ischaemic neuropathy: inflamm of vasc and RF HT, hyperglycaemia, DM
Give a differential diagnosis for conditions that cause a Red Eye
ALLERGIC CONJUNCTIVITIS:itchy mucoid discharge, lid swelling, CHEMOSIS (conj. swelling)
=> topical antihistamines
INFECTIVE CONJUNCTIVITIS: gritty discharge
=> topical abx
CORNEAL ABRASION: pain/watering
=> topical abx + analgesia
SCLERITIS: systemic AuIm. pain++ tender++, deep vessels.
*nodule
=> systemic steroids
ACUTE ANTERIOR UVEITIS: iris+cilliary body inflamm
*photophobia, floaters, pain
*HYPOPYON - wbc sedimentation
=> topical steroids
=> dilating drop (prevents posterior synechei complication - attachment to lens capsule + prevent dilatation)
Hallmarks of orbital cellulitis
orbital tissue infection. often visual +systemic illness/SEPSIS
=> IV abx / urgent CT drainage
Watershed cerebral infarctions
Watershed cerebral infarctions, also known as border zone infarcts, occur at the border between cerebral vascular territories where the tissue is furthest from arterial supply and thus most vulnerable to reductions in perfusion
Causes of generalised interruption
HYPOXIA w/ intact circulation: CO2 poisoning, resp arrest
INABILITY TO USE O2: cyanide, CO
ISCHAEMIA: cardiac arrest (partial/complete cortical necrosis); brain swelling (trauma); HypoT + Shock
Encephalitis
Viral ∴ slower pres.
- HSV >CN V. (latent) =>ACICLOVIR
- Arbovirus; travel hx (animal vector)
flu prodrome > progressive headache + fever
+meningism +!temporal/memory dysf.
- lymphocytosis, normal glucose, (+) protein, mononuclear
- transitory PLEDS EEGs
Meningitis
Nisseria men. (meningococcous)
Strep. pneumon. (pneumococcus) => peniccillin sens
Enteroviruses (faecooral) > non-paralytic men.
FEVER-STIFF NECK-ALTERED MENTAL. => confusion+delirium
+ etc. (photo, petichial rash, headache)
- cultures, lumbar, CT
- ↑pressure, neutropenia, hypoglycaemia, (++) protein
=>CEFTRIAXONE
BRAIN ABSCESS + EMPYEMA
Polymicrobia, (bact. endocarditis!), trauma, infection spread (dental, sinus, ear)
IMAGING Dx +biopsy +culture
=> Penicillin / Ceftriaxone
=> Metronidazole
=> Sx drain
!HIV
- toxoplasmosis
- aseptic meningitis
- 1º cerebral lymphoma
- fungal (cryptococcal) men.
Describe the use of passive and active immunisation to prevent neurological disease
RABIES: paraesthesia, ascending paralysis, animal bite
=> select vax. | HUMAN RABIES Ig (passive)
TETANUS: soil spore toxin release. blocks motor inhibition = rigid + spasm
=> TOXOID VAX. + Ag. | Penicillin + Ig.
BOTULISM: infantile, food borne, IVDU
irreversible binding = ACh block @ autonomic nerve junction
=> anti toxin / penicillin / wound debdridement
Post infective inflamm syndromes
Think: children
Acute Disseminated Encephalomyelitis (ADEM):
Post-infective. AuIm attack of myelin sheath.
•nausea and vomiting, headache, irritability and sleepiness, unsteadiness or inability to walk, problems with vision, weakness or tingling in certain areas of the body
Guillain-Barre Syndrome: AuIm attack on peripheral nerves => pins needles, weakness, numb., balance and co-ord
Creutzfeldt–Jakob disease
prion.
sporadic, familial acquired
- rapid dementia, insidious
- MYOCLONUS (sudden twitching jerking)
- global decline
~6mos
•MRI
=> supportive tx
Discuss epidemiology and aetiology of head injury
SKULL FRACTURES •contre-coup • depressed fracture: men. risk • linear > hinge fracture •mosaic •ring fracture
INTRACRANIAL INJURIES
• EDH: outer dura-skull. d/t skull fracture MMA tear
-fast. sport. young.
• SDH: tear of bridging veins nil fracture
slow venous.
• SAH: beneath arachnoid. natural disease - berry aneurysm.
-trauma: contusion
INTRINSIC BRAIN INJURIES
CEREBRAL CONTUSION: surface bruises
cerebral laceration
DIFFUSE AXONAL INJURY: microscopic dx, blobs. vasc injury.
Coup + Contracoup
List the clinical conditions that can cause raised intracranial pressure and the body’s physiological response to such an insult
- morning headache + sickness (brainstem)
- papilloedma (optic nerve)
- pupillary dilatation (CN III)
- ↓Glasgow (cortex+brainstem)
- Brainsteam death (coning)
Understand how raised ICP can lead to subfalcine, tentorial and brainstem herniation
Increased pressure = shift of tissue
=> subfalcine herniation: herniation under falx cerebri, crushing lateral ventricles + midline shift
+ tentorial herniation + brainstem herniation
Classify brain tumours
1º Tumours & 2º Tumours (Mets)
1º: Brain cells: glial + embryonic neuronal cell tumours
1º cells surrounding CNS
Malignant gliomas:
- medulloblastoma
- meningioma: skull invasion common
- nerve sheath: acoustic neuroma (CN VIII)
2º: commonly from *BREAST LUNG KIDNEY MELANOMA *
Describe the features and histology of certain tumours
- CNS lymphoma: diffuse large B cell lymphoma, deep central
Understand the different presentations of multiple sclerosis
-OPTIC NEURITIS most common; vis loss. + pain eye moving +desaturation => optic disc swelling + relative afferent pupillary defect
- Brainstem Relapse: +CN involvement
• NYSTAGMUS (internucler opthalmoplegia @ PONS)
• vertigo; ataxia (cerebellum)
• UMN symptoms: weakness, reflexes+++, hypertonic, clonus, babinski
-Spinal Cord Lesion: partial/transverse myelitis +BLADDER/URINARY
• hyperaesthesia
• UMN signs below level of demyelination
Understand the different courses of multiple sclerosis
d/t episodic demyelination or clinically isolated syndrome, greatly relapsing-remitting in nature.
> 2ºProgressive OR 1º Progressive from start: spinal + bladder
PROGRESSIVE PHASE d/t accumulating axonal loss
=> cerebral atrophy
• fatigue, temp/sensation, dysethesia paraesthesia
• stiffness spasms, etc
• bladder+bowel, swallowing
• vis problems
Understand the criteria for diagnosis of multiple sclerosis
- Clinical or MRI (new demyelination via T2)
- Episodic evidence
- Oligocloncal CSF
- EEG (vis. or somatosens)
- bloods: systemic
Understand when treatment of multiple sclerosis is appropriate.
ACUTE RELAPSE:
=> oral pred. | => rehab.
DISEASE MOD:
=> B-interferon / Natalizumab (LT SFX! - progressive multifocal leukoencephalopathy)
SYMPTOMATIC:
=> relaxants
=> amitriptyline/gabapentin (dysaesthesia)
=> urinary: anticholnergic / catherisation
=> Laxatives
Describe the classifications of muscle and nerve diseases
AUTOIMMUNE MUSCLE DISEASE: Polymyotisis; Dermatomyotisis | ↑CK, EMG Abn. BIOPSY
PERIPHERAL NERVE DISEASE
ANTERIOR HORN DISEASE
Define the aeitilogy, clinical features, investigations, management and complications of myasthenia gravis
neuromuscular junct. AuAb blocking ACh R. = prevent muscle contraction + cholinesterase breakdown of ACh
• fatiguable weakness
• OCULAR MG: ptosis + diplopia (Anti ACh Ab found)
• GENERALISED MG: limbs, bulbar, breathing
(Anti MUSK Ab; CT chest)
> respiratory failure (myasthenic crisis)
aspiration pneumonia
=> symptomatic tx + Cholinesterase inhibitor
=> Disease mod: plasma exchange, Ig infusion, Imm suppr.
=>Thymectomy
List the causes of a peripheral neuropathy
hereditary nature, metabolic syndrome, toxic: drugs, LYME, HIV, Leprosy
> nerve root disease: moyotomal weakness
individual lesion periph. nerve: dermatome/myotome
generalised periph. neuropathy: distal disturbances. !postural hypoT.
ACUTE DEMYELINATING: GUILLAINE BARRE SYNDROME (POST-INFECTIVE)
CHRONIC DEMYELINATING: CHRONIC INFLAMM DEMYL. POLYNEUROPATHY (RELAPSE-REMISSION)
=> steroids
Lower Motor Neurone Damage
signs: fasiculations muscle wasting hypotonia weakness (-) loss of tendon reflex
Define the etiology, clinical features, investigations, management and complications of Guillain-Barre syndrome.
ACUTE DEMYELINATING: GUILLAINE BARRE SYNDROME (POST-INFECTIVE)
paresthesia, weakness, pain, numbness, balance/coord dysfunction in limbs.
> paralysis; breathing difficulty; diplopia; difficulty speaking; bladder/bowel; pain+++
*lumbar, LFT, spirometry, nerve conduction
=> IVIg
=> plasmapheresis
+ ventilator, feeding tube, analgesia, catheter, laxatives, TED stockings
Describe the clinical presentation and management of motor neurone disease
degeneration of anterior horn => spinal muscle atrophy
MND: limb > bulbar spread / > resp spread
+LMN signs: fasiculations; wasting; weakness; tongue atrophy
+UMN signs: spasticity, brisk reflex, extensor plantar
cognitive decline
=> supportive
=> TILUZOLE (glutamate antagonist
=> anticipatory planning
UMN Signs
Nil wasting, ↑Tone; reflexes; spasticity; extensor plantar
*pyramidal pattern of weakness (strong flexors, weak extensors, pronation)
=> below level of any lesion; bilateral
Spinal Cord Lesion Features
Dorsal Column Lesions = loss of proprioception + vibration only
Anterior Lesion: pain+temp loss below, intact proprio + temp
+UMN signs
Spondylosis
Neck pain,
cauda equina syndrome
spinal stenosis = nerves in the lower back compressed
d/t tumour (breast, prostate, lung); Lumbar disc herniation: most commonly L4/5, L5/S1 levels , trauma, infection
!sx emergency; incomplete/complete CES (severity of incontinence/retention)
* MRI spine
bilateral: sciatica, weakness/numbness, urinary/bowel!
+ numbness genitals/anus (saddle anesthesia)
+ pain+++
=> decompression by a lumbar laminectomy
Define myelopathy and radiculopathy
MYELOPATHY = d/t SC compression = whole SC
RADICULOPATHY = individual nerve root
Identify the sinister features associated with back pain
TUNA FISH
Trauma
Unexplained wt loss
Neuro symptoms
Age >50
Fever
IVDU
Steroids
Hx Cancer
Recognise red flags for secondary headache
- sudden onset + >50yo
- ↑frequency/severity
- new onset + underlying condition / SYSTEMIC
- focal signs
- papilledema + headache
1º Headaches
TENSION HEADACHE (most freq.) *BP, muscle tension bilateral => analgesia | => preventative: amitryptiline (antidepressants)
MIGRAINE
*naussea, photo/sonophobia, anticipatory anxiety = medication overuse
- premonitory features of migraine
- aura: transient brainstem dysfunction (occipital)
- early headache
- severe headache
- postdrome period
> CHRONIC MIGRAINE: less severe more frequent headaches | anticipatory anxiety=overuse
ACUTE MGMT => aspirin/NSAIDS; Triptans (5HT agonist)
PROPHYLAXIS => propanolol, valporate (prego!), Antidepr., Botox
1º Headaches: Trigeminal Autonomic Cephalalgias
CLUSTER HEADACHES: unilateral orbital/temporal
acute short duration
+ipsilateral autonomic symptoms
abortive => triptans (no overuse risk)
transitional => prednisolone / greater occipital block
preventative => verapamil (ECG!), Lithium, Melatonin
PAROXYSMAL HEMICRANIA: sharp throbbing
=> INDOMETACIN RESPONSIVE (NSAID non COX2)
> hemicrania continua: unilateral continuous headache +superimposed pain. +facial involvement
2º Headache
THUNDERCLAP CT, LP; ?SAH, aneurysm rupture+bleed => coiling/clipping =>Nimodipine -|Ca2+ spasms (vasospasms) => HHH Rx
GIANT CELL ARTERITIS: non-sepc +scalp tenderness; jaw claudication.
*systemic unwell
*↑ESR; CRP; Platelet
=> prednisolone + temporal artery biopsy
LOW PRESSURE: postural headache, spontaneous
d/t venous engorgement / subdural hygomas
=> rest, IV caffiene, epidural blood patch
HIGH PRESSURE: intracranial hypertension; wakening,
progressive headache + focal symptoms
+ papilloedema
TRIGEMINAL NEURALGIA
unilateral or mandibular/maxillary stabbing d/t phys. env. triggers
= vascular compression of root nerve
=> CARBAMAZEPINE (ANTI-EPILEPTIC)
pregbalin
PHENYTOIN
=> Sx: glyceron ganglion injection
State the differential diagnosis of blackouts
Reflex
Orthostatic: BP, dehydration, meds., endocrine
Cardiogenic: arrythmia, AO stenosis, exertion trigger!
Describe the techniques used in the investigation of possible epilepsy
MRI or EEG
- rule out cardiac causes too
Identify the classification of seizures: generalised and focal
GENERALISED SEIZURE: quick spread of discharges
- absence seizures(fleeting arrest)
- generalised tonic-clonic: stiff-relax (lateral tongue bite! infective PMH)
- myoclonic seizures
FOCAL SEIZURE: +aura, can progress as 2º generalised
- temporal lobe: deja vu; nil recollection
- frontal lobe: unusual, bizarre motor, quick recovery
exacerbating risks!
- missed meds, fatigue, hormonal changes, drug/alcohol. stress/anxiety
Epilepsy Treatment
1ºGeneralised
=> Na Valporate - wt gain, ataxia, nausea !prego
=> Lamotrigine - skin rash, seep difficulty
=> Levetiracetam - depression
Partial/2º Generalised
=> Lamotrigine
=> Carbamezapine (glutamate) - ataxia, drowsiness, nystagmus blurred vis.
Absence:
=> Ethoosuximide -Drowsiness, dizziness, tiredness, headache, stomach upset,
Define the causes, presentation, investigation and management of status epilepticus
d/t nonadherence, alcoholism, refractory epilepsy, toxic cause, acute injury
*generalised +/-convulsive seizure continuously w/ no intermittent recovery > permanent brain injury!
=> MIDALOZAM (buccal), LORAZEPAM (bolus)
=> Na valporate, Levetiracetam, phenytoin
=> Anaesthesia +propafol/thiopentone
Epilepsy DVLA regulation
seizure-free for 1yr | individual basis
