Neurological emergencies

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  • Created by: z
  • Created on: 14-03-16 19:58

Meningitis

  • clinical syndrome characterised by inflammation of the meninges
    • acute, severe headache, stiff neck, photophobia fever, vomiting drowsy, unresponsive, rash
  • Kernig's sign - pain on hip flexion w/ bent knee (supine)
  • Brudzinski's sign- pain on head lifting when knees lifted (supine)
  • non-blanching rash- meninfococcal septcaemia- start immediate Tx
  • causes of meningitis:
    • neisseria meningitides 'meningococcus'
    • step. pneumoniae 'pneumococcus'
    • listeria monocytogenes (>50yrs)
    • Hib, staph aureus, Gm -ves (e.coli, klebsiella etc). M. tb
  • Rfs
    • extremes of age
    • immunosuppresion (DM), splenectomy, malignancy
    • alcoholism, cirrhosis, IVDU
    • dural defect (traumatic, surgical, congenital etc)
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Meningitis: investigations

  • if suspect bacterial mei=nigitis esp meningococcus - TREAT IMMEDIATElY
    • benzopenicillin at GP before hosp transfer
  • CT if impaored GCS or focal signs (hemiparesis, ophthalmoparesis, papilloedmema)
  • Bloods- FBC, U&E, CRP, culture, clotting screen
  • LP (CT first, check ICP for coning risk)
    • insert b/w spinous processes into subarachnoid space- L3/4 or L4/5
    • N=B, early V; L=TB, late V, prot+++=B, decr gluc=B, (V)
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Meningitis treatment

  • bacterial meningitis
    • urgent benzylpenicillin at GP if suspected
    • consider dexamethasone before 1st does in adults unless meningococcal septicaemia
      • unknown cause - cefotaxime/ceftrioxone
      • meningococus - cefotaxime or benzylpenicillin
      • pneumococcus - cefotaxime
      • listeria - amoxicillin/ampicin + gentamicin
      • H. influenza - cefotaxime
      • staph. aureus - rifampicin
      • bets-lactam sllergy - chloramphenicol
  • tb meningitis
    • NB onset- gradual (1-9/12), CN signs (VI>III>IV), papilloedema, sudden deterioration
    • RIPE + steroids for 2 months
    • RI for 12 months
  • viral meningitis
    • antipyretics + reassurance
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Encephalitis

  • symptoms
    • headache, fever, focal neurolofy (esp dysphasia), sezures
  • untreated mortality 70%
  • causes:
    • typically viral: HSV, varicella (imm comp pts), CMV, EBV
    • bacterial: listeria, tb, malaria, vasculitis
    • AI: limbic encephalitis, anti-NDMA receptor encephalitis
      • sympt: psychosis, behavioural issues, mvmt disorder
  • HSV encephalitis
    • Rx w/ acyclovir
    • EEG
    • CT/MRI
    • HSV PCR
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Acute flaccid weakness differential Dx

  • nerve
    • guillain-barre syndrome
    • vasculitis
    • toxic - lead, thallium
    • metabolic - porphyria (abnormal haem synthesis resulting in porphyrin build up)
  • muscle
    • inflammatory- poliomyositis, dermatomyositis
    • metabolic - acid maltase, periodic paralysis
  • neuromuscular junction
    • myasthenia gravis (AI attack on AChR of skeletal m.)
    • toxins
      • botulin: inhibits ACh release at NMJ-
      •  symmetrical descending paralysis
    • lambert-eaton myasthenia gravis (AI against presynaptic voltage gated Ca channel)
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Guillain barre syndrome

  • most common cause of acute neuromuscular weakness
  • inflammatory radiculopathy- most common type= AIDP (AI demyelinating polyneuropathy)
  • antecedent infection in 75% (Campylobacter jejuni)
  • back pain in 50%
  • distal UL/proximal LL weakness, facial and bulbar involvement, ophthalmoparesis rare
  • investigations
    • LP - no pleocytosis (AKA incr cell count), incr protein
    • nerve conduction study
      • may be normal early
      • later: F wave latencies, conduction block, decreased conduction velocity
  • bad prognostic factors:
    • short time to nadir
    • evidence of axonal loss
    • campylobacter positivity
    • old age
  • Tx - IV immunoglobulin/plasma exchange, supportive (ventilation/O2 etc)
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Myasthenia gravis

  • Ab against acetylcholine nicotinic postsynaptic R at NMJ of skeletal muscles
    • AChR Abs or MuSK Abs
  • demographics: bimodal- young people or 60/70yro; F:M, 2:1
  • muscles affected: ocular, bulbar, neck proximal limb, distal limb, respiratory
    • risk of resp failure- best way to check resp func is FVC
  • no autonomic features
  • investigation:
    • ice test 
    • tensilon test (short acting acetylcholinesterase inhibitor- v. short sympt improvement)
    • repetitive stimulation EMG
    • serology (AChR abs +ve in 90%, MuSH abs +ve in only 5%)
  • Rx
    • symptomatic - pyridostigmine (cholinesterase inhibitor)
    • immunosuppressant - prednisolone/azathioprine/methotrexate
    • +/- thymectomy
    • acute > plasma exchange, IV Ig
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Status epilepticus

  • continuous seizures for 30mins or serial seizures over 30mins w/o regaining consciousness
  • causes: non-compliance, alcohol, OD, stroke, metabolic, hypoxia, tumours, trauma etc
  • Mx
    • ABC (+supportive measures e.g. O2, fluids)
    • treat cause/remove precipitant
    • 50mls of 20% IV glucose if BM low
    • lorazepam 1-2mg IV
    • phenytoin 15-30mg load then 100mg tds (fosphenytoin infuses faster)
    • thiopentane/propofol infusion- paralyse and ventilate (ITU)
  • collateral Hx
  • exam- general medical + neurological (?focal signs, ?papilloedema)
  • Ix
    • bloods- FBC, U&E, BM, Ca, Mg, BGs
    • AED levels (anti-epileptic drug monitoring)
    • ?MSSU, blood culture
    • ?CT brain scan, ?LP, EEG monitor
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Coma causes

  • neuro
    • infective
    • meningitis/encephalitis/brain abscess
    • vasc (SAH,infarc, intracerebral haem, subdural/sagittal sinus thrombosis)
    • neoplastic (primary/met, malignant meningitis)
    • epilespy
    • trauma
    • inflammatory - MS
    • vasculitis
  • systemic
    • metabolic- Na, Ca, gluc, )2, pH, porphyria, thiamine
    • endocrine- thyroid, Cushing's, hyperPT
    • infection - UTI, LRTI
  • extrinsic
    • drugs- anti-cholinergics, steroids, GAs, withdrawal
    • toxins- solvents, CO, heavy metals
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Coma examination and assessment

  • general medical (ABC)
    • HR- ?arrythmia
    • BP- ?septicaemia/Addison's)
    • breath- ?alcohol
    • temp (fever,hypothermia)
    • neck stiffness/kernig's sign
    • rash, cyanosis, jaundice
  • neuro
    • head, neck, ear drums
    • fundi
    • level of conc (GCS)
    • brainstem- pupils, oculocephalic reflexes
    • limbs- power and reflexes
    • respiration - Cheyne-stokes (cycling b/w apnea and heavy breathing)
  • Ix- urgent FBC, U&E, glucose, poisons screen, BGs
    • ?CT brain, ?LP. ?EEG, ?specific tests (e.g. HSV PCR)
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Assessment of comatose patient

  • oculocephalic (Doll's eye) reflex
    • normal=positive=brainstem intact
      • move head left, eyes move right
      • head in centre, eyes central
      • move head right, eyes move left
      • NB may be exaggerate if metabolic coma
  • caloric responses- ice cold water in ear
    • normal- move eyes towards stimulus
    • asymmetrical- move one eye towards stimulus
    • negative response- eyes remain fixed and central
  • pupil state
    • small, reactive- non-structural/metabolic coma
    • fixed/dilated/down&out- CNIII damage
    • mid position, fixed- midbrain lesion
    • large, fixed- tectal
    • pinpoint- pontine
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