Micro Sem 2 Flashcards by dudi spicer

2 most common causes of meningitis in neonates and premature births. give bacterial origins

E coli (gut) and Group B Strep (vagina).

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2 most common viruses that cause meningitis

Enterovirus and HSV

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in a case of suspected viral meningitis, if CSF was unavailable would the isolation of a virus from another specimen be significant?

The sample MUST be from CSF to confirm. Isolation from another specimen not necessarily associated with meningitis

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what are the 3 main causes of bacterial meningitis? which can be prevented by vaccine

strep Pneumonia, Nisserium Meningitides & H. Influenzae type B.Strep and Hib have vaccine

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how do you treat meningitis in premature birth?

give mother penicillin 4 hours before birth

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how do you treat viral meningitis?

self limiting so supportive therapy

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meningital symptoms with a petechial rash point to which causitive agent?

N. meningitidis

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hallmark of CSF in bacterial menigitis

turbid CSF, low glucose high protein

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why and in what circumstances would you want to innoculate CSF in a serum broth

to make any surviving bacteria grow in a case where anti-biotic was used before csf was taken

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how should treat patients contacts in cases of meningitis

prophylactic antibiotics or vaccinate

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why would you admit someone to hospital overnight in an allergic reaction (nut) despite improvement

due to a potential delayed inflammatory response by cytokines and eosinophils

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why should one wait to perform an allergen test after someone’s first allergic reaction?

mast cells need to regenerate

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what is impetigo? how is it transmitted and what is most likely cause?

‘school sores’ is a highly contagious bacterial skin infection usually caused by Staph. A. It is common amongst young children and people who play close contact sport

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main symptoms for rheumatic fever and what causes it?

high fever, carditis (murmur) and polyarthritis. It occurs following a Strep P infection

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describe the pathology of symptoms in rheumatic fever

auto-immune response damages the heart and joints. Type II hypersensitivity involving the M protein in heart (molecular mimicry)

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what is the gold standard for diagnosing coeliac

jejunal biopsy

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associated features with coeliac?

infertility, delayed puberty, anaemia, osteoporosis

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butterfly rash on nose is typical of what

lupus

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explain pathology of SLE

type III hypersensitivity. Immune complexes are systemic originally. Symptoms occur when they begin to deposit

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what can cause onset of SLE

sunburn and cell death

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what are some clinical manifestation of SLE

depends where the immune complexes deposit. Skin = Rash. Lungs = Pleurisy. Kidney = nephritis. CNS

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patient comes in with polyarthritis. Says has infection 2 weeks ago. Doctor did ANA and rheumatoid factor test. What are these for?

ANA (for SLE) and Rheumatoid factor (for rheumatoid arthritis)

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bacteria that can cause post infective arthritis?

salmonella, campylobacter, yersinia and STIs

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how is yersinia infection acquired?

environmental organism - associated with farmed animals and milk

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explain lifecycle of hookworm

walking barefoot >worm bites foot > enters blood > goes to respiratory tract > is swallowed then adults mature in gut

why may someone with hookworms be anaemic?

blood loss associated with the way the worms attach to the intestine

explain pathogensis and life cycle of roundworms

faecal-oral. Ingest eggs > hatch and invade intestinal mucosa > get into blood

PUO in a recently returned traveller?

malaria until prove otherwise. can be rapidly fatal

which is the dangerous form of malaria? why?

P. Falciparin. Can infect all stages of the RBC life cycle. Can have multiple parasties per RBC. RBCs get nodules so potential to clot

how does P Vivax infect?

mozzie bite > latent in liver

life cycle of strongoloides

Almost identical to hookworm.Larva enter through feet > blood > lungs > swallow > mature in gut > lay eggs > hatch rapidly so can find eggs in faeces

a patient who fought in Nam in 1970s was recently diagnosed with leukaemia. He also only now presents with parasitic symptoms. why?

immunosupressed. would have had parasite since the 70s

which bacteria causes typhoid fever? explain pathogenisis

salmonella typhi.Faecal-oral ingestion. Replicate in gut > carried by macrophages to lymphs > get into blood > sceptacaemia

itching coupled with white vaginal discharge that is clumped (cottage cheese) is a sign of what? what is responsible for infection? treatment?

candidiasis(thrush). Candida albicans. treat with candicidin or nystatin

in the context of STI's gram negative diplococci ingested by cells is a sign of what?

clamydia

what 2 STIs are commonly found together? treatmemt?

Gonorrhea + clamydia. treat with ceftriaxone and azythromycin

mild fever, malaise, anorexia and nausea. yellow eyes and tender, enlarged liver. no IV drug use. new male-male sex partner. likely diagnosis

Hep B

what is hallmark in Hep B diagnostic and WHO definition

presence of surface antigen (HBs Ag) indicates current infection.

what do positice Anti HBs, HBe Ag, Anti HBe, Anti HBc IgM and Anti HBc IgG as refer to in regard to hepatitis testing? a

Anti HBs = cleared infection and have immunity.HBe Ag = active (replicating infection).Anti HBe = not active (not replicating).Anti HBc IgM = antibodies to core. have disease, likely recent.Anti HBc IgG = Antibodies to core, chronic infection

painful blisters on and around vagina. possible diagnosis?

HSV 2

how does one acquire HSV. where does it survive latently?

From another person (kissing, sex). can be latent for years or decades in dorsal root ganglion.

what factors can exacerbate HSV (4)?

cold, stress, UV light, immunosupression

consequences of infection with HSV?

can be symptomatic or asymptomatic. Can be transmitted during pregnancy which is a problem

treatment of HSV?

acyclovir - wont remove virus but will suppress symptoms

diffuse erythematous maculopapular rash. possible infections (2)?

ruebella, parvo-virus.

if checking for a specific virus why would you measure both IgM and IgG

to distinguish b/w recent or past infection.

limitations in testing for specific antibodies of IgM?

if positive dont know how long IgM has been around for

outcomes for parvo-virus in pregancy?

will normally terminate the pregnancy

other name for parvo-virus

erythrovirus

outcomes for rubella during pregnancy?

depends on age of infection. the earlier the infection the worse the outcome.1/3 live normally, 1/3 live with parents, 1/3 institutionalised

clinical signs of ruebella?

maculopapular rash, lymphadenopathy, low grade fever, polyarthritis

Congenital rubella syndrome classic presentation

Ear (deafness), eye (cataracts or retinopathy) and cardio (patent ductus arteriosis or pulmonary artery stenosis)

FBE showed significant leucocytosis (49% lymphocytes). some atypical mononuclear cells were seen. lab thought it was virus. Give 3 potential infectious agents.

CMV, EBV, HIV

what is the normal proportion of lymphocytes witihn leukocytes?

20%

what do atypical mononuulear cells mean?

activated CD8 T cells

What does EBV do to immune system? how do we test for it?

make B cells spit out whatever antibody they are programmed to. This includes the AB for sheep's blood which is what we test for (Monodpot test).

what is possible outcomes of infections with CMV.

commonly acquired by late adulthood (60s). Most will never know they have it and will be asymptomaatic

possible outcomes of CMV when pregnant?

10% of babies that get CMV will have long term sequalae

what should be the management of a pregant person with CMV

nothing in utero. monitor baby when born and try to control it spreading the virus

apart from endocarditis where else can Staph E. commonly cause infection?

intravenous catheters and on medical prostheses

which organism associated with water?

P. Aeroginosa

what type of bacteria is P. Aeroginosa? what color does it grow on MAC?

GNR. grows green

centrimide agar is selective for what?

pseudomonas

would the presence of P. Aeroginosa on supposedly sterile endoscopes pose a threat?

depends on what doing with endoscope. If using in a sterile site (eg brain) is a problem.In a non sterile site(eg colonoscopy) not too much of a problem

what is the susceptibility of P. Aeroginosa to antibiotics?

extremely resistant

what 4 pieces of information are needed to design an appropriate sterilisation process for a particular instrument?

1. type and amount of contamination2. Death rate of organism3. Level of sterility assurance required4. will the instrument survive the process

Three days after undergoing coronary artery by-pass surgery, S.J., a 58-year-old man, developed a fever (38.5°C).Clinical examination was normal except for mild tachycardia and the finding that the operation scar showed some surrounding redness and a discharge of some blood stained fluid.The patient was treated with fiucloxacillin and his operation site was cleaned. His symptoms settled, and he was discharged after 10 days.During the next three weeks at home, however, he lost weight and developed a fever and malaise so that he was readmitted to hospital 21 days after his original discharge. On examination his surgical wound appeared normal and had healed well. A soft diastolic murmur was heard on auscultation. Diagnosis?

sub-acute endocarditis as progressed slowly over weeks.

Mrs. EW, a 67-year-old woman with rheumatic heart disease was admitted to hospital for mitral valve replacement together with a coronary artery bypass graft. Three days after her operation, she was found to have a fever (39.8°C), and her respiratory rate was 36/min. she was diagnosed with lobar pneumonia. She was commenced on cefotaxime, however, 48 hours later, when the results of the laboratory investigations suggested that the cause of her infection was Klebsiella pneumoniae, a decision was made to change to IV gentamicin. The patient’s fever dropped and her respiratory symptoms slowly improved over the next few days. 5 days after the onset of pneumonia, Mrs. EW awoke with a low grade fever. She complained of cramping abdominal pain, and passed several watery, foul-smelling stools.Diagnosis and what has caused this?

C. Difficile - it is part of normal microbiota but the antibiotics killed the many of the regular microbiota and resulting in overgrowth

in the C. Difficile case what pathogens wouldve been screened for in routine faeces sample (5)

EHEC, camplyobacter, salmonella, yersinia, shigella

what type of condition does C difficile need?

strict anaerobe

how is C difficile transmitted?

fecal-oral route. the organism forms spores that are not killed by alcohol-based hand cleansers or routine surface cleaning.

most common virus transmitted in solid organ transplant

CMV

how can CMV infection be prevent in organ transplant?

prophylactic antivirals (gangcyclovir)

how should CMV be treat if infectious? result?

anti-viral (gangcyclovir) will suppress disease but not cure

what questions should a GP ask if patient comes positive for hep C? (3)

IV drug use, blood contacts, past surgeries

consequences of not treating hep c?

70-80% likelihood of becoming chronic carrier

how can Hep C be treated (name the drug types). results?

RNA polymerase inhibitors and protease inhibitors. No side effects and will clear virus

type of bacteria is chlamydia? where (cellularly) does it reside? what is significant about staining?

gram neg with no cell wall, obligate intracelullar parasite so cant see on staining

2 forms of chlamydia? whats the dif? which can be treated?

i) elementary body (EB, 0.2 μm) - infectious, nonreplicating, hardy. ii) reticulate body (RB, 0.8 μm) – intracellular,replicating form.Can treat the RB with antibiotics.

Micro Sem 2 Flashcards

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