Infection Flashcards
Define “brain abscess” and “subdural empyema”
Brain abscess - localised area of pus within the brain
Subdural empyema - a thin layer of pus between the dura and arachnoid membranes over the surface of the brain
What are the clinical features associated with a brain abscess?
Fever
Headache
Focal symptoms (seizures, dysphasia, hemiparesis)
Signs of raised intracranial pressure (papilloedema, depressed consciousness)
Features of an underlying source (dental/sinus/ear infection)
Meningism
What are the two main differentials for when a patient presents with symptoms of a brain abscess (apart from abscess!)
Any focal lesion, commonly a tumour
Subdural haematoma
List some possible causes of a brain abscess
Penetrating head injury
Spread from adjacent infection
Neurosurgical procedure
Blood-borne infection (e.g. bacterial endocarditis)
Which organisms can cause brain abscesses?
There is often a mixture of organisms present but depends on the predisposing condition
Common organisms include:
- Streptococci, particularly the strep milleri group
- strep anginosus
- strep intermedius
- strep constellatus
- Anaerobes e.g. bacteriodes, prevotella
Describe the management of brain abscesses
Surgical drainage if possible
Treat strep with penicillin and ceftriaxone
Treat anaerobes with metronidazole
High doses required to penetrate the brain
Which brain infections/diseases are more common in HIV patients? (patients with low CD4 counts)
Cryptococcus neoformans (fungi)
Toxoplasma gondi
Progressive multifocal leukoencephalopathy
Cytomegalovirus (CMV)
HIV-encephalopathy (HIV-associated dementia)
How do spirochaetes appear under the microscope?
Helical coils
Give three types of spirochaetes and the diseases that they cause
Borrelia burgdorferi - Lyme disease
Treponema pallidum - (neuro)syphilis
Leptospirosis
Describe the neurological signs/symptoms associated with late stage lyme disease
PNS is affected more than the CNS Mononeuropathy Mononeuritis multiplex Painful radiculopathy Cranial neuropathy Myelitis, meningio-encephalitis
Which drugs are used to treat lyme disease?
IV ceftriaxone
Oral doxycycline
How is (neuro)syphilis treated?
High dose penicillin
What neurological symptoms can present in patients with syphilis?
Headache Behavioural changes Movement problems (can look like Parkinson's or Huntingdon's disease)
How many types of poliovirus are there? How are they transmitted?
3
Transmitted by the faecal-oral route
What age group is most affected by the polio virus? What disease does this cause?
Children under 5
Poliomyelitis
Describe the initial presentation of poliomyelitis
Fever Fatigue Headache Vomiting Neck stiffness Pain in limbs
What happens when the poliovirus invades the nervous system?
Ascending, asymetric, flaccid paralysis, especially in the legs
- often permenent but can sometimes be reversed
Death occurs in 5-10% of those paralysed dues to paralysis of respiratory muscles
No sensory features
Which parts of the nervous system does poliovirus infect?
Anterior horn cells of lower motor neurones
Describe the symptoms of rabies encephalitis
Anorexia Irritability and agitation Inspiratory spasms Cough Autonomic dysfunction Altered mental status Hydrophobia Aerophobia Hypersalivation
Describe the type of paralysis that can be caused by rabies
Ascending paralysis
Which bacteria cause tetanus and botulism?
Clostridium;
- tetanus: clostridium tetani
- botulism: clostridium botulinum
How are clostridium bacterial infections treated?
Antitoxin
Penicillin
Metronidazole
What is CJD?
Creutzfeld-Jakob disease
Neural disease caused by prion
What are the main two types of CJD?
Sporadic CJD - presents as a rapidly progressing dementia, causes death within 6 months
New variant CJD - linked to bovine spongiform encephalopathy (cattle), usually has younger onset but longer course than sporadic
How might sporadic CJD show up on MRI?
increased intensity in caudate and putamen
Which type of CJD can produce an abnormal ECG?
Sporadic CJd
Describe the clostridium bacteria
gram positive, anaerobic, spore-forming bacillus
