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Written exam > Infectious diseases > Flashcards

Infectious diseases Flashcards

1
Q

Conditions caused by GAS (strep pyogenes)

A

Pharyngitis
Retropharyngeal abscess
Scarlet fever
Impetigo, erysipelas, cellulitis (inc perianal)
Strep TSS
Rheumatic fever
APSG

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2
Q

Describe scarlet fever rash

A
  • Fine, diffuse “sandpaper” rash - appears 24-48 hrs into illness (after 1st fever) but can be first sign
  • Begins on neck and upper chest, spreads to rest of trunk and extremities, spares palms and soles
  • Prominent in flexor skin creases (Pastia lines [from capillary rupture] - pathognomonic for scarlet fever)
  • Lasts approx 1 week then fades with desquamation of trunk, hands and feet
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3
Q

Features of scarlet fever

A
  • Due to GAS pyrogenic exotoxin
  • Pharyngitis, lymphadenopathy, fever
  • Sandpaper rash, appears 1-2 days post onset of fever
  • Pastia’s lines
  • Strawberry tongue
  • Circumoral pallor
  • Desquamation of trunk, hands and feet with fading of rash (~1 week after onset)
  • Abdo pain, myalgia, malaise
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4
Q

What systemic complication is associated with impetigo? (GAS)

A

Post strep GN (from M serotypes 49, 55, 57,59)
NOT rheumatic fever

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5
Q

CMV (HHV-5) transmission

A

Urine, resp secretions, blood
Vertically - in utero by transplacental passage, passage through infected genital tract, postnatally via breast milk (or donor milk)

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6
Q

CMV cytomegalic inclusion disease signs

A

IUGR
Jaundice, hepatosplenomegaly
Thrombocytopaenia/anaemia
Blueberry muffin rash (also in rubella)
Microcephaly, cerebral atrophy
Chorioretinitis
SNHL
Lethargy, hypotonia, seizures
Periventricular intracebral calcifications (CMV CircuMVents the ventricles)

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7
Q

CMV - SNHL stats

A

10% asymptomatic children (1/3 if symptomatic) will have progressive SNHL +/- neurodisability (also seizures and CP)

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8
Q

Eye signs CMV v rubella

A

CMV - chorioretinitis
Rubella - cataracts

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9
Q

Risk period of CMV infection in pregnancy

A

Early in pregnancy - transmission rate 30-50%

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10
Q

Diagnosis CMV

A

Urine CMV culture/PCR (and other sites) - must be within 2-4 wks to be “congenital”
Infant blood for CMV PCR
Paired maternal and infant serology
+ neuroimaging, opthal, audiology

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11
Q

MRI findings of CMV

A

Ventriculomegaly (hydrocephalus)
Periventricular calcifications

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12
Q

CMV v toxoplamosis MRI

A

CMV - microcephaly, ventriculomegaly, periventricular calcifications, lenticulostriate changes
Toxoplasmosis - hyrocephalus, diffuse cerebral calcifications

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13
Q

Congenital CMV treatment

A

Oral valganciclovir if <28 days AND moderate symptomatic disease (or IV ganciclovir if poor oral absorption)
Must treat for 6 mths
Risk of neutropaenia

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14
Q

TORCH

A

Toxoplasmosis
Other - syphilis, VSV, parvovirus, enteroviruses, Zika, GBS
Rubella
CMV
HSV

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15
Q

Neonatal HSV - risk of transmission

A

High if primary infection og genital herpes near the time of delivery
Low if hx of recurrent herpes
60-80% of pregnant F with HSV + babies have no prior clinical hx of HSV sx

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16
Q

Neonatal HSV presentation

A

45% - skin, eyes, mouth (SEM) - present in 1st 1-2 wks (sx = vesicular lesions, conjunctivitis, keratitis, chorioretinitis)
30% CNS only - present in 2nd-3rd week (sx = irritability, sz, poor feeding, lethargy - haemorrhagic CSF common with HSV)
25% disseminated - present in 1st 1-2 wks (sx = liver, lung, heart, kidney, CNS). Fatal in 50% cases

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17
Q

Neonatal HSV workup

A

HSV culture of mth, nasopharynx, eyes, anus
HSV culture and PCR of skin and mucosal lesions
HSV PCR of blood and CSF
LFTs
CXR
Opthal
Neuroimaging - MRI

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18
Q

Neonatal HSV treatment

A

Skin, eyes, mouth (SEM) - IV acyclovir 14 days
CNS or disseminated - IV acyclovir min 21 days + 6 mths PO acyclovir suppressive therapy

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19
Q

Hep B - chronic infection and complications rate of perinatal infections

A

90% become chronically infected if contract perinatally
25% develop cirrhosis and/or liver cancer in adult life

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20
Q

Maternal hep B Ag status - risk of transmission

A
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21
Q

Hep B - prevention of maternal transmission

A

1) Universal screening - if high initial, test viral load
2) Infants born to HbsAg pos Mo -> Hep B vaccin and HBIG within 12 hrs of birth
3) 3 further doses of Hep B vaccine as per immunisation schedule
4) Infant testing at > 9 mths to monitor surface antibody and rule out infection (ie HBsAg neg)
5) +/- tenofovir anti-viral Rx in Mo

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22
Q

Parvovirus B19 - complication of neonatal infection

A

Fetal anaemia, cardiac failure, hydrops

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23
Q

Treatment for parvovirus B19

A

No intervention available to prevent infection
Test fetus -> if positive, intrauterine transfusion to prevent foetal anaemia/hydrops
Monitor for anaemia postnatally

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24
Q

Presentation of neonatal parechovirus

A

Sepsis features - high fever, tachycardia, irritability, mottling, poor perfusion
Other - mottled red rash (erythrodermic), abdo distension, oedema, hepatitis
Presentation more severe than appears from bloods
Test via PCR (throat/rectal swabs)
Nb HPeVs-3 outbreak 2015

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25
Q

Condition?

A

Parechovirus - septic, oedematous, mottled red rash, abdominal distension

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26
Q

Congenital rubella - antenatal risk period

A

Highest risk if maternal infection pre-conception or 1st trimester (up to 50%)

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27
Q

Congenital rubella syndrome - classic triad

A

SNHL (58%)
Eyes - cataracts, retinopathy, micropthalmia (43%)
Cardiac - PA stenosis, PDA

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28
Q

Antenatal risk of VSV

A

Highest between 8 and 20 wks gestation - more likely to have birth defects then

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29
Q

VSV - clinical signs

A

Cicatricial skin scarring (dermatomal distribution)
Limb hypoplasia
Microcephaly, cortical atrophy
Seizures
Cataracts
Chorioretinitis, micropthalmia, nystagmus
Neuro defects

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30
Q

VSV treatment for exposed pregnant women

A

If immune compromised -> give VZ IG ASAP - until 10 days post exposure
If not available - give IVIG
Do NOT give VSV vaccine if pregnant (live vaccine)

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31
Q

Treatment for neonatal exposure to maternal VSV

A

> 7 days before delivery - no treatment
<7 days before ->2 days post - give VZIG
If under 28 weeks - give VZIG (maternal antibodies would not have crossed placenta)

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32
Q

Toxoplasmosis - how caught + presentation

A

Risk factors - ats, kitty litter, gardening, eating unwashed/raw vegetables or undercooked meat
Self limited non-specific illness in immune competent hosts
Crosses placenta 4-8 wks after maternal infection

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33
Q

Toxoplasmosis - risk of maternal infection

A

1st trimester - low risk (10-15%) but complications +++
1nd trimester - 30%
3rd trimester - 60%, but low complication rate

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34
Q

Congenital toxoplasmosis - clinical features

A

85% normal at birth
Of these, 85% if untreated will have 1 or more episodes of chorio-retinitis
Hearing loss 10-30%, developmental delay 20-75%
Only 75% of congenitally infected produce detectable IgM

35
Q

Toxoplasmosis - antenatal diagnosis

A

Maternal IgM detectable within 1-2 wks, undetectable by 6-9 mths
IgG avidity (bonding of antigen and antibodies)

Fetal antibody - unlikely before 20 weeks
Amniotic fluic PCR - good after 18 weeks gestation

36
Q

Toxoplasmosis - antenatal treatment

A

If maternal infection but fetus not affected - Spiramycin
If Mo and fetus infected - Pyrimethamine plus Suphadiazine

37
Q

Neonatal diagnosis of toxoplasmosis (if sx)

A

Paired maternal and infant serology (IgM, IgG, IgG avidity)
PCR on blood +/- CSF
CSR, neuro imaging, opthal, audiology
Monitor IgG and IgM over time

38
Q

Condition?

A

Toxoplasmosis

39
Q

Toxoplasmosis - treatment in infant

A

Treat until 12 mths
- Pyrimethamine (haem toxicity - monitor)
- Sufadiazine
- Folinic acid (leucovorin)
Monitor FBC due to risk of neutropaenia
Neurodevelopmental, opthal, audiology f/u

40
Q

GBS - presentation

A

Early onset <5-7 days - sepsis, pneumonia, meningitis 10%
Late onset >5-7 days - occult bacteraemia, meningitis 30%, osteoarticular involvement
Very late onset >90 days - usually in premature or prolonged hospital stay

41
Q

Neonatal syphillis - signs

A

Osteochondritis/periostits
Snuffles, haemorrhagic rhinitis
Skin - bullous lesions, palms/soles involved (desquamating rash), mucous patches
Unexplained large placenta
Nephrotic syndrome (rare - usually 2-3 mths old)
Hepato/splenomegaly, jaundice
Non-immune hydrops fetalis

42
Q

Infant syphilis workup

A

Serology - trepenemal (TPPA aka acquired antibodies from Mo) + RPR - level of disease response
Long bone xrays - periosteal reactions
LP - SCF VDRL, protein, cell count
Skin lesions/placenta - darkfield microscopy for spirochetes
Check if Mum had full STI evaluation (HIV, hep B&C)
Treatment if confirmed/suspected - 10 days IV benpen
F/U infant serology 3&6 mths

43
Q

Condition?

A

Herpetic whitlow
May treat with acyclovir
Do NOT burst lesions

44
Q

HHV-6 - symptoms

A

Roseola (6th disease, exanthema subitum)
Fever 3-5 days, then abrupt cessation of fever
Then macular-to-maculopapular rash
Seizures can occur in febrile stage
Other: Nagayama spots, irritability, LOA, diarrhoea, URTI sx, lymphadenopathy, palpebral/periorbital oedema (Berlinger sign)

45
Q

Quantitiative HIV RNA viral load reverse transcriptase (RT) CPR

A

1st line to diagnose infectivity. In adults and older kids, ELISA and Western blotting can be used to detect HIV specific antibodies.
Can be performed within 24 hrs of infection.
A positive virologic result should be confirmed with repeat testing with a 2nd sample ASAP after result is available.

46
Q

UTI bugs

A

F: E Coli, Klebsiella, Proteus
M: E Coli, gram + organisms

47
Q

UTI treatment in infant

A

Neonate - amox + gent
Infant - ceftriaxone

48
Q

Duration IV treatment meningitis > 1mth

A

N meningitidis - 5 days
S pneumoniae - 10-14 days
H influenzae - 7 days
GBS - 14-21 days
Gram neg bacilli - 21 days
Listeria - 21 days

49
Q

Cerebellar ataxia + oculucutaneous telangectasia - ?dx

A

Ataxia telangiectasia
- Ataxia usually presents before age 5 yrs
- Telangiectasia most common in bulbar conjunctivae, but also ears, neck and ACF
- AFP is raised

50
Q

Pin worm/threadworm

A

Enterobius vermicularis
- Eggs = bean shaped
- Adult females = pin shaped.
- Presents as white threads in stool

51
Q

Whipworm

A

Trichuris
- Occurs in tropics
- Ass. with poor hygiene & poverty
- Usually asymptomatic, but can have symptoms if heavy parasite burden
- Eggs = barrel shaped
- Complications = rectal prolapse

52
Q

Hookworm

A

Necator americanus
- Chronic infection leads to anaemia and poor gth
- Often ass. with eosinophilia

53
Q

Necator americanus - regions

A

Hookworm
Africa, Americas, Indonesia, Sth Pacific

54
Q

Necator duodenale - regions

A

Hookworm
Mediterranean countries, Iran, India, Pakistan, Far East

55
Q

Hookworm varieties

A

Necator americanus
Ancylostoma duodenale
Ancylostoma braziliense (cats and dogs)
Ancylostoma caninum (dogs)

56
Q

Roundworm varieties

A

Ascaris lumbrocoides (humans)
Ascaris suum (pigs)
Trichuris (whipworm)

57
Q

Pinworm/threadworm

A

Enterobius vermicularis

58
Q

Hep C - method of transmission

A

IV blood exposure
Mucous membranes possible but less efficient

59
Q

Abx treatment CAP > 2 mths

A

High dose amoxicillin - studies have shown equivalent outcomes to parenteral therapy for moderately severe CAP

60
Q

Dengue

A

Flavivirus
- Aedes aegypti mosquito
- Sx: high temp, myalgias, retro-orbital headache
- Also: thrombocytopaenia and mild bleeding (petechiae, epistaxis) at defervescence common
- Dengue haemorrhagic fever can lead to distributive shock
- Similar to Chikungunya, but C does not have bleeding sx

61
Q

Plasmodium vivax

A
  • Malarial illness
  • Mild cf P faciparum
  • May occur despite prophylaxis
  • Dormant hepatic phase, so may present some mths/years after initial infection
  • Ix = thick and thin blood films, but PCR and antigen testing is possible
62
Q

Enterotoxigenic e coli

A
  • Most common form of traveller’s diarrhoea
  • Sx = watery diarrhoea and abdominal cramping +/- vomiting +/- fever
  • If high fever or bloody diarrhoea, think campylobacter jejuni or S typi
63
Q

CXR - myocarditis

A

Enlarged cardiac shadow
Bilateral patchy opacification (from HF/viral infection)

64
Q

Pathogenic mosquitos

A
  • Aedes aegyptes - Dengue fever and Zika
  • Anopheles - malaria
  • Tsetse flies - trypanosomiasis
  • Sandflies - leishmaniasis
  • Ixodes ticks - Lyme disease
65
Q

Endocarditis prophylaxis - when indicated

A
  • Prosthetic cardiac valve
  • Previous IE
  • CHD if unrepaired cyanotic defect (or persistent defect post repair), for 6 mths post op
  • heart transplant with valvulopathy
  • RHD if extraction, periodontal, replanting avulsed teeth, other surgery
66
Q

Commonly associated bacteraemia in malaria

A

Salmonella

67
Q

Thick and thin blood smear - used to detect what?

A

Malaria
- Thin - measures parasite density AND identification of parasite (through RBC morphology)
- Thick - parasite density. RBC lysed so does NOT identify particular parasite.

68
Q

Indications for IvIG

A
  • Dermatomyositis (reduces MAC in plasma, and C3b and MAC deposited in endomysial capillaries)
  • Guillain-Barre syndrome (hastens recovery)
  • ITP (superior to corticosteroids)
  • Kawasaki’s (used with aspirin reduces risk of CA aneurysms)
69
Q

Otitis externa - bugs

A

P aeruginosa
S epidermidis
S aureus

70
Q

Diagnosis?

A

Varicella zoster virus
Would be itchy but NOT painful (cf otitis externa)

71
Q

Enterococcus fecalis

A
  • Gram positive cocci
  • Causes UTIs in pts with indwelling catethers or underlying renal tract abnormalities
  • Cephalosporin resistant
72
Q

Bacterial tracheitis - bug

A
  • Staph aureus - most common
  • Moraxella catarrhalis - more severe disease
  • Strep pneumoniae
73
Q

Viral causes of paralysis

A

Poliovirus type 3
Enterovirus 71

74
Q

HHV-6

A
  • aka roseola infantum, exanthem subitum, 6th disease
  • 3-5 days fever, resolves abruptly following by rash
  • acute febrile illness with or without rash with fever, fussiness, rhinorrhoea
75
Q

IV agent for neonatal candiasis

A

Amphoterocin B

76
Q

Features of GAS perianal infection

A

Perianal erythema
Fever
Intensely itchy
Pain on defection
Mucopurulent anal discharge

77
Q

PFAPA (Marshal syndrome) - acronym

A

Periodic fever with aphthous stomatitis, pharyngitis and adenitis
NOT associated with amyloidosis

78
Q

Periodic fever syndrome associated with amyloidosis

A

Familial mediterranean fever

79
Q

Granulomatosis infantiseptica

A
  • Caused by listeria when severe in utero infection
  • Causes abscesses in fetal liver, lungs, kidney, spleen and brain
  • Stillborn or die shortly after birth
80
Q

Meningococcal serotypes

A

A - linked with outbreaks in Africa and Asia
B - most common
C - 2nd most common
W135 - responsible for small outbreaks internationally, increasingly common in Aust
Y - uncommon in Austraia

81
Q

HFM virus

A

Coxsackie A16

82
Q

ESKAPE organisms (multi-drug resistant organisms)

A

Enterococcus faecium
Staphylococcus aureus Klebsiella pneumoniae Acinetobacter baumannii Pseudomonas aeruginosa Enterobacter spp.

83
Q

Leishmania - method of transmission

A

Sandflies

Written exam (14 decks)

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