PBL 2 Flashcards
what is meningitis?
the inflammation of the leptomeninges which is caused by microbes
what are the leptomeninges?
arachnoid and pia mater
describe the main differences between bacterial and viral meningitis?
bacterial meningitis is much more serious but viral meningitis is much more common
how can menigitis be spread?
sneezing, coughing, kissing
describe the pathophysiology of meningitis?
a pathogen enters the meninges directly or through the blood through the blood brain barrier at vulnerable regions. the pathogen multiplies in the CSF causing inflammation which makes the blood brain barrier more permeable, leading to an influx of WBC and plasma constituents which increases the volume of CSF= oedema = cerebral vasculitis = inter cranial pressure increases = damaged brain tissue
what is haemotogenous spread?
when a pathogen enters the blood stream and moves into the CSF using vulnerable spots on the blood-brain barrier
how could infectious agents enter the meninges directly?
anatomical defects, up the nose or through overlying skin
what is cerebral vasculitis?
when blood vessel walls in the brain and spine are inflamed
what are the symptoms of meningitis?
fever, cold hands and feet, nausea, vomiting, headache, non-blanching rash, nuchal rigidity, photophobia, photophobia, confusion, breathing rate increased, muscle and joint pain, drowsiness, unresponsiveness, altered mental state, seizures
what would the lumbar puncture sample of someone with meningitis look like?
clear/cloudy or purulent
it would have the presence of bacteria, increased proteins, increased polymorphonuclear cells, decreased glucose concentration
raised CSF opening pressure
what are the 2 signs of meningitis you can find in examination?
kernels sign
brudzinskis sign
what is kernigs sign?
when a patient lies flat on their back and their leg is raised with the knee flexed 90 degrees and the leg is supported and slowly straightened at the knee. if this causes back pain and can’t be extended beyond 135 degrees then this sign is positive
what is brudzinskis sign?
when a person lies flat on their back and has their neck supported and flexed. if they automatically flex their knees or hips then this sign is positive
what are some causes of meningitis?
infections bu bacteria, virus, fungi, parasites
TB
autoimmune diseases
adverse reactions to intrathecal medication
who is most at risk for meningitis?
babies and young children teenagers and young adults elderly people immunosupressed those living in a community setting pregnant those skipping recommended vaccinations
which vaccinations should you have to aim to prevent meningitis?
meningitis B vaccine, 6-in-1 vaccine, pneumococcal vaccine, MMR vaccine, Hib/MenC vaccine, meningitis ACWY vaccine
how is bacterial meningitis treated?
in hospital with IV antibiotics, IV fluids, oxygen, steroid medication (to prevent swelling around brain)
how is viral meningitis treated?
it tends to get better on its own within 7-10 days and can be treated at home with rest, painkillers and antiemetics
how can you prevent the spread of meningitis?
prophylactic antibiotics to avoid outbreaks
what are some complications of bacterial meningitis?
sepsis, hearing loss, Visio loss, memory and concentration issues, epilepsy, coordination, movement and balance problems, loss of limbs, bone and joint problems, learning difficulties, behavioural problems, kidney problems
how many cases of meningitis are fatal?
1/10
is there a predictable pattern to inheritance of the penicillin allergy?
no - about 10% of patients have this allergy but most actually lose this allergy over time
describe the difference in structure between gram positive and gram negative bacteria?
gram positive has a thicker peptidoglycan layer but no outer lipopolysaccharide and protein membrane like gram negative bacteria
why are gram negative bacteria more resistant to antibodies than gram positive?
because of their impermeable lipopolysaccharide cell wall
what colour do the following go when stained with crystal violet dye?
a) gram positive bacteria
b) gram negative bacteria
a) retains purple colour
b) pink
what type of antibiotics are cephalosporins?
beta lactam antibiotics
what’s the difference between first, second and third generation cephalosporins?
first generation - coverage against gram positive and most gram negative bacteria
second generation- coverage against gram negative bacteria and slightly effective against gram positive bacteria
third generation- best coverage against gram negative bacteria
how do cephalosporins work?
they disrupt the synthesis of the peptidoglycan layer forming the bacterial cell wall
what are some side effects of cephalosporins?
stomach upset, nausea, vomiting, diarrhea, yeast infections, dizziness
why might cephalosporins be taken with clavulanic acid?
as bacteria can produce beta lactase which can cause resistance. clavulanic acid had a high affinity for beta-lactamase enzyme so it can block its activity, allowing cephalosporins to work
