infectious disease Flashcards
lyme disease
spread via zoonotic (vertebrate animal to human) via tick bite. erythema migrans (early sign- raised bump red) & cardiac, neuro and joint involvement. borrelia burgdorferi (gram -ve spirochete)
dx
clinical picture, skin biopsies rarely performed.serology (elisa, western blot assay) igm & igG- sensitive as early as 4 weeks in with 90% . csf changes if neurology manifestation starts, increase in csf .
pleocytosis (increase nononuclear due to virus & PMN due to bacteria)
transmission and life cycle:
48hr post bite, incoluate and kill host cells. epidemic in north america. nymph, larve, imago to fully engorged adult.
disseminates via blood and lymph. flu like sx. regional LN.
monoarthritis, chronic atrophic acrodermatitis, bells palsy, meningeal and encephalopathy. ixodes (some spp transmit babesia casing babesiosis (kills RBC- like malaria)
trx
early phase: oral antibody 14-21 days amoxicillin. penicillin, doxycycline.
disseminated; IV systemic Ab (same agents)
prophylaxis: endemic areas/ hikihin, spring szn and forest regions then single dose doxycycline - 72 hrs pre-exposure.
rabies?
definition: segmental demyelinating viral infection spread via bite of a domestric or wild animal.
humans and domestric animals r accidental host.
virus causes brain inflammation.
characterisitcs: negri body (eospinophilic inclusion in hippocampus) * paralytic rabies:
CF & trx:
N+ V, fever, myooedema, altered sensation at bite mark, personality changes, malaise. hydrophobia !!!!
4-10 days :acute neuro sx-> coma-> 18 days (patient dies)
furious sx: encephalitic - seizures, delirium, pit gl dysfunciton autonomic dysfunction-> arrythmias etc.
parlaytic : ascending paralysis: resembles gbs, symmetrical quadriparesis, menigitis
d:x:
hisotyr: animal bite,
examine bite mark.
florescent staining of nuchal biopsy : virus localise in hair follicle in 1st week. PCR of biopsied sample/ saliva.
trx
phophylaxis?
wash wound w/ 20% soap, virucidal factors (iodine).
anti-rabies vaccine post exposure -immediate start if previously vaccinated. IM deltoid 0 & 3 day/
post exposure immunoglobulin given (effective if virus isn’t in PN).
Milwaukee protocol- ketamine & midazolam coma induction.
prophylaxis- if endemic then IM injection 0, 7 and 21 day.
booster 2-3 yrs. if titre low
tetanus
NS disease caused via clostridium tentanii-spore forming gram-+ve bacteria. 2 toxins tetanloysin an dtetanospasmin- potent. spores in wound (dirt soil). anchors to end of LMN, retrograde to GBaba & glycine releasing transmittors-> hyperactivity-> rigidity and spasicity.
CF
incubation 3-21 days: generalised muscle contraction, neck face and trunk. trismus, risus sarcondicus (grinning)opisthotonus (arched back) autonomic dysfunction. ridgity un myscles near wound
cephalic tetanus- head wound,. bells palsy.
neonatal -irritable, fail to nurse and LMN sx. apnea and sepsis mortality (common in low immunized countries with umilical stump infection. if severe- developmental failure.
dx
pcr (tissue) to detect toxin gene, tetanus antibodies decrease, serum toxin increase. CF.
treatment:
decrease toxin, passive HTIG immunoglobulin, Ab (penicillin/ metronidazole) sedation, secure airway, wound clear, control spasms (methocarbamol, diazepam) , muscle relaxant (MgSo4), redce stimulus (dark room)
prophylaxis- DTaP vaccination
5 total doses at intervals 2,4, 6 ,15 and 18 then 4-6 years.boosters every 10 yrs. vaccines like rabies are pregnancy sAFE.
TRAVELS DOSE.
penetrated or contamnated wound then give HITG if booster if < 3 doses or >10 year booster.
prophylaxis
Most common causes of death: autonomic dysfunction and asphyxia (from laryngeal spasms, respiratory
muscle spasms or extreme fatigue). Most patients in developed countries recover due to availability of
supportive care. In developing countries mortality rates range from 10- 50%.
diptheria
corynebacterium diptheria gram +ve rod w/ endotoxin.
acute infection- fibrous infalmmation of URT, eyes, skikin, gentialia, NS, heart and kidney.
infection- humans & anthropods.
GI, respiratory . contagious. winter season.
poverty, education lack, immunization & < 12 children.
