ID Flashcards by Rachel Longwell

What are the two possibilities seen if a gram positive organism is looked at down the microscope
How are gram positive cocci further defined? How do they look under a microscope?

Bacilli
Cocci

Catalase test- staph- positive- clusters
Strep- negative- chains

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What are 2 gram positive bacilli and how are they defined

Anaerobic- clostridium

Aerobic- listeria

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What are the 2 ways strep are classified

Haemolysis- alpha is total, beta is partial and gamma is none

Lancfield- a,b,d and e

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What is an example of
Group A strep
Group B strep
Group E&F strep

Partial haemolysis
Total haemolysis
No haemolysis

Pyogenes
Agalactiae
Viridans and pneumonia

Groups E and F
Groups A and B
Enterococcus

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What is the most severe form of malaria

What are the most common other 2 forms called? What makes them be able to be latent?

Falciparum

Vivax and ovale- hypnosis tests unhook

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What does chickungunya cause

Febrile convulsions

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What causes Chagas’ disease

What does it cause

Trypansoma Cruzi

Myocarditis

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What is seen on uss with Zika virus other than anencephaly

Subcortical calcifications

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How does malaria normally present?

What indicates severe disease?

Fever, haemolytic anaemia, myalgia and malaise

Drowsiness headache and vomiting

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Malaria- what is the difference between thick and thin films?

Thick films- counts how many rbc infected

Thin- what species is involved

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How is malaria treated?
What is normal prophylaxis?
Why does prophylaxis differ in east Africa? What is used instead?

Chloroquine or artemisinin based therapies
Mefloquinine
Likely chloroquine resistance therefore give malarone

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What causes typhoid
What protects against it?
What are two characteristic features?

Salmonella enteritica
CF
Salmon pink rash and diarrhoea

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What type of virus causes dengue?
How does it present
How does haemorrhagic fever present?

Flavivirus
Biphasic breakback fever with rash and oedema of extremities
Shock with bleeding bruising and petechiae

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What is the most likely bug to cause septic arthritis or osteomyelitis?
What is more likely in toddlers
Which bug is more likely in sickle cell
Where is the most common site

Staph aureus
Kingella
Salmonella
Lower limbs

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Osteomyelitis

What might you see on X-ray

Fat pads, lytic lesions periosteal elevation

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Osteomyelitis- length of treatment
Septic arthritis-“
Discitis-“

OM- 3-4
SA- 2-3
6 weeks

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What are the three phases and what will be seen in each

1) exposure- no symptoms and signs, all tests negative
2) primary infection- no symptoms and signs but chest X-ray may have Hohn focus or be normal and TST positive
3) disease- symptoms signs abnormal chest X-ray and tst positive

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TB
What are the features in cxr
How does it differ from adults

Bilateral hilar lymphadenopathy
Atelectasis
Consolidation

Any lobe is involved
No calcification

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What is miliary TB

What other infection might make it more common?

Disseminated disease involving multi organs. Lymphohaematogenous spread
HIV/AIDS

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What is measured in the mantoux test?
How long after exposure does it become positive
What might give a false negative

Area of induration
3w to 3 months
Incorrect admin, reading it wrong, having a bcg previously, doing it too early

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What are two benefits of quantiferon gold to TST?

Only need one visit

Won’t pick up vaccinated people

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Mantoux test size, when is it positive
>5mm
>10mm
>15mm

Very high risk exposure or cxr changes
Young or other chronic disease, likely living in a high risk area
No other risk factors

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TB
WHO recommended treatment
Recommendations for all exposed kids

6 months RI with PE in the first 2 months

3 months treatment then test. If negative give BCG. If positive complete course

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Rifampicin
Side effects
What medications does it effect? How? Why?

Orange secretions
Hepatitis especially with isoniazid
P450 induced so reduces OCP

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Isoniazid Side effects What might help?

Hepatitis Peripheral neuropathy Vitamin b6- pyrodoxine

Pyrazinamide | Side effects

GI upset | Hepatitis

Ethambutol Side effects Will they resolve when the meds are stopped?

Neuritis and colour vision reduction | Yes!

Can you give BCG to HIV positive individuals?

No!

CMV what is the risk to baby if it is mums first infection What stage of pregnancy is it worst to contract it? What are the features What is seen in ultrasound

50% Worst in the first half of preg. IUGR, blueberry muffin rash, chorioretinitis , SN hearing loss Periventricular calcification

Zika What type of virus is it How does it present What is different on head ultrasound

Flavivirus Microcephalic, contractures, hypotonia and irritable Subcritical calcification

Congenital syphillis What is it associated with How does it present in the newborn If it is missed how might it present

Lacking antenatal care Sniffles, peeling skin, pseudopariesis, jaundice and hepatosplenomegaly Abnormal teeth and facial deformities. Blindness

Toxoplasmosis When is it most likely to affect the baby? How does it present?

3rd trimester | Asymptomatic or prolonged jaundice then blindness seizures and developmental delay

What is the most common cause of eosinophilic meningitis? What is usually ingested? What will you see on LP? How is it managed?

Angiostrongylus Snails High opening pressure, high cell count, eosinophils >10% Analgesia, therapeutic taps and steroids

What is the most common helminithic infection in humans

Ascariasis=roundworms

What is the other name for a pinworm infection How do they present How are they found

Enterobius vermicularis Itchy bums Cellotape test

Which helminithic infectionis seen in travellers | What rash do they commonly get?

Hookworm-ancylostoma | Itchy rash in the soles of the feet that moves around

Which helminithic infection is involved in sheep stations

Echinococcous

Viruses How do dna and rna viruses differ in how they replicate What enzyme do retroviruses use to replicate

DNA- use the cells nucleus | RNA- replicate within the cytoplasm

Herpes | Where to the 2 main types cause lesions

1- mouth | 2-genitals

Where does the herpes virus lie dormant | What infection indicates reactivation

Sensory ganglion neurons | Cold sores

What are 3 skin manifestations of herpes?

Herpetic whitlow Eczema herpeticum Erythema multiforme

How does intrauterine herpes present

Microcephalic, vesicles and chorioretinitis

What does HHV 6 cause | How does it present?

Rosella High fever Blanching rash

What does HHV 8 cause?

Kaposis sarcoma

Varicella What does primary infection cause What is most likely to cause a secondary bacterial infection What does involvement of the tip of the nose suggest

Chicken pox Strep pyogenes Hutchinsons sign- corneal involvement

Varicella- Where is encephalitis likely to involve What is the more likely CNS manifestation of varicella

Temporal lobes | Cerebellar ataxia

How does congenital varicella present

IUGR Scarring Limb shortening Chorioretinitis

What percentage of people seroconvert to the varicella vaccine

97%

Poliovirus What is the most common clinical manifestation? What else can it cause

``` Slapped cheek (fifth disease) Acute aplastic crises ```

Adenoviruses | How do they most likely present

Resp infections

Enteroviruses What family of viruses are they What is the most likely presentation

RNA viruses | Non specific viral illnesses

Enteroviruses What causes hand foot and mouth most commonly? What might give cns disease What causes herpangina

Coxsackie A. Enterovirus 71 | Coxsackie A

Enteroviruses Give 4 CNS manifestations What 3 types of enteroviruses might cause them

Polio, flaccid paralysis, aseptic meningitis, encephalitis | Polio, echo, coxsackie B

What type of enterovirus causes myocarditis | Who is most likely to get it?

Coxsackie B | Young adolescent males

CMV What family of viruses does it belong to? What four things is it the commonest cause of

Herpes | CP, SN hearing loss, Low IQ and congenital infections

CMV How do the majority of primary infections present? How else might they present? If you are immunocompromised how might you present? How might it affect transplants

Asymptomatic Mono like but no sore throat Unwell with fevers and joint pains. Pneumonitis and GI disease Causes rejection.

CMV How do perinatal and congenital infections differ? What is seen on head uss

Perinatal- majority are still asymptomatic Congenital- iugr, chorioretinitis, late onset hearing loss, jaundice and seizures Periventricular calcification

How do CMV and HIV link?

CMV increases rate of HIV progression | More likely to get retinitis and cns side effects

Congenital CMV | Is there firm evidence for treatment? What might be used

No! | Ganciclovir

EBV What type of virus is it? What can reactivate it? What malignancies is it associated with?

DNA virus Immunosuppression Burkitts, Hodgkin lymphoma, NP carcinoma and gastric carcinoma

Infectious mono How does it present What signs might there be? What can give a diffuse maculopapular rash

Fever sore throat and lethargy Palatal petechiae, lymphadenopathy and hepatosplenomegaly Amoxicillin

EBV | Give 4 complications of acute infection

Splenic rupture Airway obstruction Myocarditis GBS

EBV | What things can have a severe disseminated reaction?

CVID/AT/CH/WA X linked lymphoproliferative syndrome HIV

EBV | What is seen on blood film

Atypical mononuclear cells

EBV | What antibodies are positive in acute and chronic infection

VCAs early | EBNAs later

HIV What type of cells does it infect What enzyme is important

CD4 cells | Reverse transcriptase

HIV How might an acute infection present What might be seen on bloods to show progress of hiv What is most predictive of rate of progress What is most predictive of complication risks

Lymphadenopathy, flu like illness T cell depletion, increasing viral load Viral load CD 4 counts

What level of T cells causes AIDS What are examples of aids defining illnesses (6) What sign in children is unique to HIV

``` <200 Kaposis sarcoma PCP pneumonia Chronic oesophageal candidiasis Lymphocytic interstitial pneumonia CMV pneumonitis or retinitis Mycobacterium avium HIV encephalopathy ``` Chronic or recurrent parotitis

Why is combination treatment used in AIDS | What is the aim

To prevent resistance | To reduce and slow progression of disease

HIV what 3 drug classes are most commonly used? Give examples What other 2 drug classes might be used

Nucleoside reverse transcriptase inhibitors- lamudivine, zidovudine Protease inhibitor nelfinar Non nucleoside RTIs Fusion inhibitors

What 2 large groups of conditions does a group A strep cause What are the common complications How are they treated Are they resistant?

Pharyngitis and skin infections HUS, rheumatic fever, PANDAS, reactive arthritis Penicillin Usually never!

What causes group A strep to turn into scarlet fever | How does scarlet fever present

Production of strep pyogenes erythrogenic exotoxin | Sore throat then strawberry tongue and sandpaper rash

Group B strep What is it called What is the most likely cause of infection? What are the 2 different presentations and how do they present How is it treated How long is treatment- bacteraemia? Meningitis?

Agalactiae Maternal colonisation Early onset sepsis- very sick like RDS. Can be still born Late sepsis- up to 3 months. Occult bacteraemia or meningitis High dose amoxicillin or penicillin. Bacteraemia-10 d Meningitis-14 d

Strep pneumoniae How does it link to influenza How is it treated What does an intermediate mic to penicillin suggest? What is given instead?

Causes secondary bacterial pneumonias Penicillin Possible cephalosporin resistance- vanc instead

Listeria In older children what might infection suggest How does late and early disease differ What is it resistant to

``` T cell issues Late- more likely meningitis Early- vague with maculopapular rash. Might have had a sick fluey mum Prem babies with MEC stained liquor Cephalosporins ```

Coagulase negative staph Give 2 examples What do they cause Are they sensitive to penicillins?

Staph epidermidis and staph saphrophyticus Line infections! No!

Staph Aureus Give two ways it can become a MRSA How does it cause diseases like toxic shock syndromes

Altered penicillin binding proteins Beta lactamase Production of exotoxins

What antibiotic is pseudomonas intrinsically resistant to? | What colour of pus does it cause

Cefuroxime | Blue/green

What type of diarrhoea is seen in cryptosporidium

Secretory

What is seen on microscopy with giardia?

Multi flagellated organism

What is klebsiella an example of? | What is it therefore resistant to?

ESBL | Resistant to carbapenems

What is an example of a VRE

E faecum

What mnemonic helps remember resistant organisms

``` E-enterococcus (VRE) S-staph aureus (MRSA) K- klebsiella (ESBL) A- acinetobacter P-pseudomonas E- enterobacter ```

What might help differentiate strep from staph toxic shock?

Septicaemia

Measles How well does it seroconvert after a vaccine? After 2? Does infection provide life long immunity? If you are exposed and your immunity is ok how should you be treated If you’re exposed and you’re immunodeficient how should you be treated?

95% 99% Yes Give vaccine within 72 hrs Give IVIG within 1 week

What is the most common cause of bacterial tracheitis

Staph aureus

Which antibacterial agents disrupt cell membrane function

Anti fungals

Which 3 groups of antibiotics inhibit cell wall synthesis How do they do this What 3 days can resistance occur- give examples of bugs Are they bacteriostatic or bacteriocidal?

Penicillins, cephalosporins and carbapenems Insert a beta lactam ring into the cell membrane Staph aureus- makes a beta lactamase MRSA and pneumococcus- alter penicillin binding proteins Pseudomonas- reduces cell wall permeability Bacteriocidal

Which 2 antibiotics inhibit folate synthesis | What is a way to remember this

Co trimoxazole Trimethoprim Both used for UTIs- think pregnancy and folate!

Which antibiotic inhibits DNA gyrase

Ciprofloxacin (quinolones)

How does vancomycin work What pharmacokinetic parameters are most important What part of the dosing is most important

Acts directly on the cell wall AUC/MIC Peak concentration

Beta lactatams Which pharmacokinetic parameter is most important What about the dosing therefore is most important

Time above MIC | Dosing interval

Give 2 examples of antibiotics that act on the 30s subunit

Gentamicin | Doxycycline

Give 3 examples of antibiotics that act on the 50s subunit

Macrolides Clindamycin Chloramphenicol

What pharmacokinetic parameter is most important in amino glycosides What therefore in dosing is most important

Cmax/MIC | Peak concentration

What pharmacokinetic profile suggests resistance

MBC >4x MIC

``` Cephalosporins Give examples of the 5 generations What do generation 1-3 treat well What is good about generation 3 What dose generation 4 treat What does generation 5 treat ```

``` 1- cephalexin 2- cefuroxime 3- cefotaxime and cefreiaxone 4- cefepime 5- ceftaroline ``` 1-3 improving gram negative cover, gradually lose gram positive 3- blood brain barrier cover 4- pseudomonas 5- MRSA

What do cephalosporins not cover?

Listeria Atypical (mycoplasma and chlamydia) MRSA (unless 5th gen) Enterococcus

What organisms rarely can be resistant to carbapenems | What antibiotics have to be used instead

Klebsiella and E. coli (new deli metallo beta lactams) | Coloistin or fosfamycin

What does vancymicin cover well

Gram positives and MRSA

If vanc does not work well for MRSA what is another good option

Linezolid

What do aminoglycosides cover well? | What is an example of a bug it won’t cover well

Gram negatives | Enterococcus

What do macrolides cover well- give 2 examples

Atypical | Mycoplasma and gonorrhoea

Why are macrolides useful in CF

Modulate airway inflammation

How effective is the pertussis vaccine if three doses are given

95%

Can pertussis cause retinal haemorrhages?

No!! (New evidence)

Pneumococcus What type of organism is it To use penicillin what is needed. If not what is used to treat

Encapsulated | High MIC needed- <0.6. Otherwise 3rd gen cephalosporins

How are staph further characterised?

Coagulase- positive- epi negative- aureus

What are enterococcus How are they normally treated. What are they normally resistant to? How is e cloacae treated How is VRE treated? Is it bacteriocidal or bacteriostatic? What will this not be useful for? HOW IS CPE treated

``` Strep with no haemolysis Amoxicillin Cephalosporins Meropenem Linezolid. Cloacae Tigecycline ```

How long before and after the rash are the following infectious? Measles Chicken pox

Measles- 3D before 5-6 after | Chicken pox- 24-48 hrs before, 3-7days after

What is aspergillosis usually resistant to? What is It therefore treated with What are most species of candida sensitive to

Fluconazole Voriconazole Amphotericin B

What are three vaccines that can’t be frozen

Hep A and B DTAp Tetanus

How does rubella normally present When is it infectious What can happen especially in girls What is it otherwise known as

Painful lymphadenopathy with rash 5 days before and after rash Arthritis 3 day measles

``` What are 2 examples of an inactivated vaccine Attenuated Toxoid Subunit Conjugate ```

``` Influenza and polio MMR and TB Diphtheria and tetanus HPV and hep B Hib ```

What can adenovirus cause

Haemorrhaging cystitis