Neurology Flashcards
Describe the clinical features of raised ICP? (9)
- Headache
- Altered mental state (lethargy, irritability, slow decision making, abnormal behaviour)
- Papilloedma
- Vomiting (progresses to projectile)
- Pupil changes: irregular or dilated in one eye)
- Cranial nerve palsies (esp unilateral ptosis, III or IV lesions)
- Later changes: hemiparesis, raised BP, bradycardia
- Seizures, syncope if acute rise in ICP
- Cushings reflex
- visual changes: black spots, blurring, enlarged blind spot and reduced peripheral vision (subacute) or reduced central vision and visual acuity (acute advanced)
Describe the headache of raised ICP
nocturnal, starting on waking, worse on coughing/ moving
Describe what papillodema looks like
blurring of disc margins, loss of venous pulsations, flame haemorrhages
What is the cushings reflex and why does it occur?
hypertension + bradycardia + low resp rate due to: Ischaemia at medulla causing sympathetic activation so rise in BP + tachycardia// Baroreceptors detect increase in BP causing Bradycardia// Ischemia @ pons/ medulla resp centers so low resp rate
How should raised ICP be investigated?
- CT/ MRI for underlying lesions
- blood glucose, renal function and osmolality
- check for signs of CSF leak
- ICP monitoring can be done
Give 6 causes of raised ICP
- localised mass lesions (eg traumatic haematoma)
- neoplasms (glioma, meningioma, mets)
- abscesses
- focal odema secondary to trauma, infection or infarction
- disturbance of CSF circulation
- major venous sinus thombosis/ obstruction
- diffuse brain odema/ swelling
- idiopathic intracranial hypertension
Give 5 causes of diffuse brain odema/ swelling
- meningitis
- encephalitis
- diffuse brain injury
- sub arachnoid haemorrhage
- reyes syndrome
- water intoxication
- cerebral venous thrombosis
Describe the first line steps to management of raised ICP?
- stabilise ABC
- treat seizures with lorazepam +/- phenytoin
- Head CT if meets criteria
- assess C spine, immobilise and order neck CT if not cleared
- involve neurosurgery
- head elevation to 30 degrees
When should you intubate someone with a head injury/ raised ICP?
If: - sats <92% or - hypoxic on ABG or - GCS <8
Describe the further management of someone with raised ICP
- Analgesia with morphine and sedation w/ propofol if necessary
- mannitol (risk of hypovolaemia) or hypertonic saline if cerebral odema
- barbiturate coma
- hypothermia
- decompressive craniotomy and shunts
- treat cause (anticoag if venous outflow obstuction, diuretics then shunts if increased CSF, resections/ craniotomys/ steroids for SOLs)
- hyperventilation (causes hypercapnic vasoconstriction so decreases ICP)
Describe the clinical features of a subarachnoid haemorrhage?
- Sudden onset explosive headache (often occipital) lasting a few seconds or a fraction of a second then a diffuse headache which can last a week or so
- almost always have N+V
- altered mental status
- seizures
- neck stiffness/ meningism signs sometimes present around 6 hrs after
- intraocular haemorrhages seen on fundoscopy in 15%
- other signs of raised ICP
- 10-15% die before getting to hospital
What warning symptoms may occur prior to SAH as aneurysm expands and bleeds slightly (sentinel bleeds)?
- headache
- dizziness
- orbital pain
- diplopia
- ptosis
- sensory or motor disturbance
- seizures
- dysphagia
- bruits less common
Describe the investigation findings consistent with a subarachnoid haemorrhage? (4)
- CT scan without contrast: hyperdense blood vessel in basal cisterns (98% sensitive after 2 hrs and 100% after 6, sensitivity drops after 24hrs)
- cerebral panangiography then CT or MR angiography if aneurysm found
- LP if CT scan negative but suspect SAH- spectrophotometry should be able to detect xanthochromia if SAH occured (detected from 12hrs- 2weeks after bleed)
- ECG changes inc prolonged QT, Q waves, ST elevation
Describe the urgent and supportive management of a SAH? (4)
- stabilise pt and send straight to neurosurgical unit +/- intubation, ventilation, NG tube, analgesia and antiemetics
- endovascular obliteration by platinum spirals (coiling) or direct neurosurgical clipping to prevent rebleeding
- oral nimodipine given to prevent vasospasm which leads to cerebral ischaemia/ stroke
- hydrocephalus can occur as early or late complication, many will resolve on their own but some surgeons drain immediately
Describe the further management of an SAH? (3)
- secondary prevention (stop smoking etc)
- specialist rehab if lasting impairment
- antifibrinolytics reduce rate of rebleeding but doesnt improve overall outcomes
Describe the clinical features of meningitis
- Headache
- Fever
- Photophobia
- Neckstifness
- Vomiting
- Muscle pains
- Non blanching purpuric rash
- seizures
- altered consciousness
- Fatigue, muscle pain
What signs require urgent senior review +/- critical care input when managing a meningitis pt? (9)
- rapidly progressive rash
- poor peripheral perfusion (cap refill >4/ BP >90mmhg)
- RR <8 or >30
- HR <40 or >140
- acidosis <7.3
- WBC <4
- lactate >4
- GCS <12 or drop of 2
- poor response to initial fluid resus
How should suspected meningitis (meningitis without signs of shock, severe sepsis or signs suggesting brain shift) be managed? (7)
- blood cultures
- bloods (FBC, renal function, glucose, lactate, clotting, viral PCR, blood gas)
- LP
- dexamethasone 10mg IV
- ceftriaxone IV 2g
- careful fluid resus
- throat swab for meningococal culture
- isolate until abx for 24 hrs, tell microbiology and PH
How should suspected meningitis with signs suggestive of brain shift/ raised ICP, severe sepsis or a rapidly evolving rash be managed? (9)
- critical care input
- secure airway, give O2
- take bloods, do cultures
- fluid resus (if shock/ sepsis/ rapidly evolving rash)
- ceftriaxone 2g IV
- Dexamethasone 10mg IV (omit if severe sepsis or rapdily evolving rash)
- Neuro imagine such as CT head if signs of raised ICP
- throat swab for meningococcal culture
- DELAY LP
What tests should be done on CSF when meningitis suspected? (7)
- glucose (w/ concurrent blood glucose)
- protein
- microscopy and culture
- lactate
- meningococcal and pneumococcal PCR
- enteroviral, HSV, VZV PCR
- consider investigations for TB meningitis
What are the criteria for delaying LP in meningitis?
- signs of severe sepsis
- rapidly evolving rash
- severe cario/ resp compromise
- significant bleeding rik
- signs suggestive of brain compartment shift (do CT first): focal neurosigns, presence of papillodema, continious or uncontrolled seizures, GCS <12
State 5 complications of meningitis
septic shock, DIC, septic arthiritis, haemolytic anamia, pericadial effusion, subdural effusion, SIADH, seizures, hearing loss, cranial nerve dysfunction
Describe the clinical features of encephalitis (5)
- bizarre behaviour or confusion
- decreased GCS or coma
- fever
- headache
- seizures
- focal neuro signs (weakness, visual disturbance, aphasia, cerebellar signs)
- history of travel or bite
Describe the key differenced between meningitis and encephalitis?
- Seizures uncommon in meningitis but common in encephalitis
- photophobia, rash and neck stiffness much more common in meningitis
- focal neurological signs are a hallmark feature of encephalitis, but only occur in some and later in meningitis
- mental status is almost always altered in encephalitis, however is common but less so in meningitis