Neuro Infections of CNS lecture notes Flashcards
What is meningitis?
Inflammation of the meninges (in to out is PAD - pia, arachnoid dura mater)
What are non-infective causes of meningitis?
Paraneoplastic (factors released by tumour affecting the brain)
Drug side effects
Autoimmune (eg SLE, vasculitis)
How does infection get into the CNS?
Bacteraemia
Infection elsewhere locally eg. sinus, ear
Iatrogenic (eg neurosurgery)
Bacteria enters CSF via e____ (intracellularly) or paracellularly
endothelial
What symptoms do you get with meningitis
Neck stiffness
Fever
Headache
Photophobia
Vomiting
On arrival to hospital what are the immediate management for bacterial meningitis?
Assess GCS
Blood cultures
Broad spec antibiotics
What is a good first line broad antibiotic for meningitis?
Ceftriaxone or cefotaxime
Amoxicillin is also given for listeria which may have occurred if the patient has…
Travelled
What is a definitive investigation to diagnose meningitis?
Lumbar puncture
Microscopy, gram stain, culture, protein, glucose, viral PCR
Consider AFB (acid-fast bacilli) if suspect TB from history
What are some lumbar puncture contraindications?
Abnormal clotting (don’t want to make patient bleed)
Infection at the lumbar puncture site
Raised intracranial pressure (risk of coning = herniation down into spinal cord)
Petechial rash (may indicate sepsis and coagulation issue from DIC)
When to do a CT head before a lumbar puncture?
Papilledema (indicates raised ICP)
GCS 12 or lower
Continuous or uncontrolled seizures
Focal neurological signs
Describe properties of Neisseria meningitidis
Gram negative diplococci
What can cause chronic CNS infections?
TB
Syphilis
Cryptococcal (fungi)
What are viral causes of meningitis?
Herpes simplex virus (HSV)
Varicella zoster virus (VZV)
Enterovirus
What age most commonly get infected by group B strep?
Neonates
How to differentiate subarachnoid haemorrhage from meningitis
Subarachnoid haemorrhage normally has “thunderclap” onset, may have had trauma
What are differentials to meningitis?
Subarachnoid haemorrhage
Migraine
Flue and other viral illness
Sinusitis
Brain abscess
Malaria
Is meningitis notifiable?
Yes
Identify “close contacts”
What is encephalitis?
Inflammation of the brain
What symptoms are different for encephalitis to meningitis?
Confusion
Behaviour change
Seizures
What are causes of encephalitis?
Herpes simplex virus
Varicella zoster
Measles
mumps
rubella
coxsackie
tick-borne
Rabies
West Nile…
Autoimmune, paraneoplastic
Tetanus
Encephalitis normally has a preceding flu-like illness followed by…
Altered GCS
Fever
Seizure
Memory loss
Tetanus bacteria can produce a toxin called tetanospasmin which can travel along axons and interfere with n______ release increasing neuron firing
neurotransmitter
What are symptoms of tetanus?
Spasms locally
Locked jaw (severe)
Back spasm
How to manage tetanus
Muscle relaxants
Paracetamol
Immunoglobulin
Antibiotic
What is rabies?
Viral infection that enters via skin with saliva of rabid animal
Travels retrogradely along nerves.
has a 100% mortality rate without vaccination
Vaccination gives time to access immunoglobulin
What are the 2 types of rabies
Furious and paralytic
Cryptococcal meningitis is mainly seen in what population?
HIV
