Fever and headache Flashcards
viral causes of meningitis
Common, mild, spontaneous improves enteroviruses, influenza
bacterial causes of meningitis
common serious medical emergency N. meningitis, streptococcus pneumoniae. Rare: homophilius influenzae, listeria monocytosis, mycobacterium tuberculosis
Fungal causes ofmeningitis
rare, AIDs ir cancer
cryptococcus neoformans
Protozoa
Rare accidental ingestion of worm eggs of larvae angiostrongylus cantonensis - not in NZ
Other causes of meningitis
common, drugs, trauma, neurosurgery, cancer
Inflammation of the meninges causes
Headache
photophobia
neck stiffness
drowsiness
systemic inflammatory response causes
fever
drowsiness
septic shock
rash (nisseria meningitidis)
Pathogenesis of bacterial meningitidis
illness proceeded by nasopharyngeal colonisation
10-20% of young adults colonised with N. meningitidis
Bacteria enter subarachnoid space and propagate
Diagnostic techniques
CSF fluid
Blood cultures
Throat swab
Blood to detect bacterial DNA by PCR
Other early warning signs
Sore hamstrings
Kernels sign: lift legs slowly and if they say stop because their headache is getting worse. You’re stretching the cauda equina and meninges, most patients with meningitis don’t have it, but if found then worth noting
CSF measures with bacterial meningitis
glucose = decreased protein = elevated WBC = increased, mainly neutrophils Gram stain = +/- Culture = ++/-
CSF measures with viral meningitis
glucose = normal protein = increased or normal WBC = increased, lymphocytes gram stain = - Culture = -
What if no characteristic rash?
all efforts to find the etiology
especially exclude meningococcal disease
If CSF gram stain negative
- streptococcus pneumoniae antigen test CSF
CSF - PCR meningococcus pneumonococcus,common viral causes
Blood PCR - meningococcus
Throat swab - carriage of meningococcus or pneumonococcus
Seasonal?
More common in winter
Demographic?
More common in very young maori and pacific children
Ways N. meningitidis evades the immune system
- Protein on the outside that binds to factor H, Which down regulates the complement process
- produces “blebs” of lipopoly saccharide in persons blood
neutrophil polysaccharide traps
When the lipopolysaccharide load is very high, out neutrophils commit suicide an release their DNA which forms a net across a capillary to trap circulating bacteria, immune cells and immune proteins as they go past. This is why capillaries get clogged in septic shock.
What happens in shock?
Reduced BP, tachycardia,reduced perfusion of organs
Management of bacterial meningitis
Give IV antibiotics resuscitate take blood cultures when IV line sited transfer to hospital investigations pain relief, fluid, IV antibiotics
prophylaxis to contacts - meningococcus
management of viral meningitis
reassurance
analgesia
can usually recover at home
