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55 Cards in this Set
- Front
- Back
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bacterial meningitis common causes
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H influenzae, Listeria monocytogenes, Neisseria meningitidis, Strepococcus pneumoniae
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Neisseria Meningitidis specs (aka meningococcal meningitis)
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gram neg cocci in pairs or tetrads; coffee bean shape; thin capsule forming a halo may be apparent; oxidase pos; ferment glucose and maltase, but not lactose
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Neisseria Meningitidis virulence factors
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surface capsule and outer membrane bound lipooligosaccharide (LOS)-associated endotoxin
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Neisseria Meningitidis transmission
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person-to-person via respiratory droplets; leading cause of bacterial meningitis in children and young adults in USA-occurs in outbreaks (serogroup B)
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patients at risk for Neisseria Meningitidis infection
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3-12 months age; congenital deficiency to terminal complement (C5-9); close contacts of infected individuals with fxnal or anatomic asplenia
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pathogenesis of Neisseria Meningitidis
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incubation 2-10 days
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treatment of Neisseria Meningitidis
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penicillin G DOC; also cefotaxime or ceftriaxone and chloramphenicol
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vaccine for Neisseria Meningitidis
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polyvalent against capsular polysaccharide groups A, C, Y, and W135 for kids >2 yrs
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prophylaxis for ppl exposed to patients with Neisseria Meningitidis
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Rifampin, oral ciprofloxacin, or ceftriaxone IM
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meningitis in infants <1 month is likely
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E coli, S agalactiae, and S. pneumonia
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Streptococcus agalactiae specs (group B streptococcus or GBS; aka type III meningitis)
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gram-pos in chins; cell surface Lancefield group B carbohydrate antigen; encapsulated (type III of 9); B-hemolysis; catalase neg, bacitracin resistant
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major virulence factor of Streptococcus agalactiae
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type III capsular polysaccharide
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DOC for Streptococcus agalactiae infection
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penicillin G and ampicillin; alternatives=vancomycin and 3rd gen cephalosporins; gentamicin for synergy in severe infections
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Listeria monocytogenes meningitis specs
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intracellular; gram pos; small rods with rounded ends; facultative anaerobic; narrow zone B-hemolysis; grow in cold temp; motile with tumbling motility; glucose fermenters; serotypes based on flagella antigens
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what does Listeria monocytogenes typically cause
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food-borne illness in adults and meningitis in newborns
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where is Listeria monocytogenes found
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soil and animal reservoirs; processed meat and dairy products
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what allows Listeria monocytogenes to escape membrane bound vacuoles/phagosomes into cytoplasm
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listeriolysin O (B-hemolysin) and phospholipases
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treatment of Listeria monocytogenes infection
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penicillin or ampicillin usually with aminoglycoside
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Kernig sign
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flexion of neck when knee is flexed; test for meningeal irritation
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echovirus type 9 specs (enteroviral meningitis)
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picornaviridae family; small, ether-resistant, nonenveloped; cubic symmetry; ssRNA positive sense
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polioviruses
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picornaviridae family; 3 serotypes
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nonpolioviruses of picornaviridae
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61 serotypes; coxsackie A (23 serotypes) and B (6 serotypes); echoviruses (28 serotypes); new enteroviruses (4 serotypes)
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hepatovirus of picornaviridae
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hep A
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rhinoviruses of picornaviridae
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115 serotypes; 'common cold'
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epidemiology of enteroviruses
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seasonal-summer and fall; 90% aseptic meningitis cause; fecal-oral or oral-oral
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pathogenesis of echovirus type 9
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multiplies in oropharynx and small intestine; viremia for few days-may be asymptomatic
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treatment of echovirus type 9
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symptomatic; no vaccine
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St. Louis encephalitis virus specs
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arthropod-borne; enveloped, ssRNA positive sense; Flavivirus (includes yellow fever and dengue fever)
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arthropod borne viruses that cuase human encephalitis
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Bunyaviridae, Togaviridae, and Flaviviridae families
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Bunyaviridae specs
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spherical or pleomorphic enveloped; triple segemented circular ssRNA negative sense; 3 symmetrical circular, helical nucleocapsids
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what can arboviruses trigger in the brain/cerebellar tissues
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virus-antibody complexes may cause complement activation leading to DIC in brain
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treatment of St. Louis virus encephalitis
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supportive; no vaccines
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Herpes simplex virus (HSV) type 1 encephalitis specs
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icosahedral nucleocapsid, linear dsDNA, lipoprotein envelope; cause multinucleated giant cell formation; latency characteristic; necrosis to brain parenchyma-perivascular inflammation=hemorrhage in irregular fashion throughout R temporal lobe
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latency locations for HSV-1
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trigeminal ganglion or autonomic nerve roots
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treatment of Herpes simplex virus (HSV) type 1 encephalitis
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high dose acyclovir for 21 days; no vaccine
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Taenia solium specs (neurocysticercosis)
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adult pork tapeworm; suckers/grooves; proglottids (long chain of segments); male and female components
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epidemiology of Taenia solium
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rural regions where pigs have access to human feces; pigs intermediate host
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pathogenesis of Taenia solium in humans
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intestine for 2 months to mature, attaches to small intestine whre lives for many years; proglottids mature, become gravid, and detach-migrate to anus or passed in stool; ingested eggs hatch in intestine and penetrate mucosa and get into blood stream=grows into cysticercus
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treatment of Taenia solium
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praziquantel or albendazole; corticosteroids for swelling/edema
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Rabies virus specs
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Rhabdovirus family; bullet-shaped nucleocapsid surrounded by lipoprotein envelope (glycoproteins arranged in knob-like structures on envelope); ssRNA negative polarity; contains RNA dep RNA polymerase
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2 forms of rabies
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urban transmitted by dogs and sylvatic rabies via wild carnivores and bats
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incubation of rabies
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3-8 weeks; short as 9 days, long as 7 years
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pathogenesis of rabies
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viral glycoproteins bind acetylcholine receptors; move via axonal transport to CNS; no viremic stage; replicated exclusively in gray matter and travels down peripheral nerves to salivary glands and other tissues
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most characteristic pathologic finding of rabies
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intracytoplasmic inclusions called Negri bodies found in neurons
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treatment of rabies
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no antiviral care; only supportive; almost 100% fatal; pre-exposure immunization
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C. tetani specs
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gram-pos anaerobic rod; forms terminal spores which germinate in wound sites and produce potent exotoxin-tetanospasmin
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where is tetanus found
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soil; GI tract of animals
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pathogenesis of tetanus
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moves from contaminated site to peripheral motor neuron terminals within 2-14 days
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tetanospasmin
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Zn++ dependent endopeptidase which cleaves synaptobrevin, critical for docking and fusion apparatus of neutoexocytosis; blocks release of inhibitory neurotransmitters glycine and GABA by descending inhibitory neurons
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trismus
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lockjaw
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treatment of tetanus
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supportive; bezodiazepines to control spasms and rigidity; B-blockers to control sympathetic hyperactivity; passive immunization with human tetanus immune globulin and active immunization; metronidazole DOC
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why not penicillin for tetanus treatment
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may act as GABA antagonist
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West Nile virus specs
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flavivirus; enveloped, icosahedral nucleocapsid; positive sense ssRNA
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characteristic brain pathology of West Nile virus
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scattered microglial nodules and perivascular inflammatory infiltrates of lymphocytes
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Prion agent specs
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abnormal, protease-resistant conformer (PrPsc) of a normal cellular protein (PrPc); abnormal protein has high content in B-sheet polypeptide unlike normal with rich a-helix polypeptides
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