Infectious diseases 2 Flashcards
Define meningitis
Inflammation of leptomeningeal (pia mater and arachnoid) coverings of the brain
Which meningeal layers are inflamed in meningitis
Pia and arachnoid
Define encephalitis
Inflammation of brain parenchyma
Bacterial causative agents in meningitis (3)
Streptococcus pneumoniae,
Neisseria meningitidis
Haemophilus influenzae type B
Most common cause of aseptic meningitis
Enterovirus
Main cause of encephalitis
Herpes virus
Main symptoms of meningitis (4)
Photophobia
Neck stiffness
Headache
Fever
Symptoms of encephalitis (7)
Altered state of consciousness, seizures, personality change, cranial nerve palsies, speech problems, motor and sensory deficit
Ix for meningitis
lumbar puncture to obtain CSF
Ix for encephalitis (3)
Blood cultures, neuroimaging (MRI), CSF analysis
What organisms commonly infect neonates (3)
Group B streptococcus
E coli
Listeria monocytogenes
Which gram -ve diplococci often infects children and teenagers
Neisseria meningitides
Which bacteria often infects unvaccinated children and teenagers
Haemophilus influenzae
Which gram +ve cocci often infects adults and the elderly
Strep pneumonia
Which bacteria often infects the elderly, alcoholics and cheese/unpasteurised milk
Listeria monocytogenes
Which organism infects neonates with an extended delivery
Group B strep
Which organism infects neonates that have had an infection in a previous pregnancy
Group B strep
Which organism causes a late neonatal infection
E coli
What buzzword guides you to Group B strep infection in a neonate (2)
Extended labour, infection in previous pregnancy
What buzzword guides you to E coli infection in a neonate
Late neonatal infection
What buzzword guides you to neisseria meningitides infection in children and teenagers
grame -ve diplococci
What buzzword guides you to haemophilia influenzae infection in children and teenagers
Unvaccinated
What buzzword guides you to strep pneumoniae infection in adults and elderly
grame +ve cocci
What buzzword guides you to Listeria monocytogenes infection in adults and elderly (4)
Elderly, unpasteurised milk, cheese, alcoholics
What is Brudsinkins sign
Flexing the neck causes the patient s hips and knees to flex (meningitis)
What is Kernigs sign
Inability to straighten the leg when the hip is flexed to 90 degrees
Signs of meningitis infection (5)
Fever Tachycardia Hypotension Skin rash – petechiae meningococcal septicaemia Altered mental state.
Ix for meningitis (3)
Blood: Two sets of blood cultures
Imaging: CT scan to exclude intracranial pressure.
Lumbar puncture: Send CSF for MC&S and Gram staining
When do you avoid LP (3)
Neurological signs suggesting raised ICP
Superficial infection over LP site
Coagulopathy
CSF normally: Appearance WCC Protein Glucose Gram stain
Clear Very low Normal Normal Normal
CSF in bacterial meningitis: Appearance WCC and which cell Protein Glucose Gram stain
Turbid Very high - neutrophils Very very very high Very very very low Positive
CSF in viral meningitis: Appearance WCC and which cell Protein Glucose Gram stain
Clear/cloudy High - lymphocytes Increased Normal Normal
CSF in fungal/TB meningitis: Appearance WCC and which cell Protein Glucose Gram stain
Clear/cloudy
High lymphocytes
Increased protein
Decreased glucose
Mx of meningococcal septicaemia
Admit
Give single dose IV benzylpenicillin
Mx of bacterial meningitis
IV Ceftriaxone (3rd generation cephalosporin)
Consider corticosteroids – Dexamethasone for bacterial meningitis BUT not if meningococcal septicaemia is suspected
(cover Listeria with ampicillin)
If consciousness affected, consider IV acyclovir to cover encephalitis
Prophylaxis to close contacts: Rifampicin or ciprofloxacin
Viral causes of encephalitis (6)
(HSV-1, HSV-2, VZV, CMV, EBV, Human herpes virus)
Bacterial causes of encephalitis (4)
Neisseria meningitides
TB
Syphilis
Listeria
What type of encephalitis does neisseria meningitides cause
Meningo-encephalitis
Fungal causes of encephalitis (2)
Cryptococcus
Candida
Parasitic causes of encephalitis (2)
Toxoplasma Gondii, malaria
Which three organisms (and subtypes) are the main causes of infective endocarditis
Group A Streptococci (viridian’s or Boris)
Staphylococci aureus or epidermis
Enterococci faecalis
What are the RF of IE
Abnormal valves Prosthetic valves IV drug use Turbulent flow Recent dental work
What are 4 causes of abnormal valves
congenital, post-rheumatic, calcification/ degeneration
What organism does a case of infective endocarditis with abnormal valves suggest
Strep viridian’s or strep bovis
What organism does a case of infective endocarditis with prosthetic heart valves suggest
Staph a or epidermis