Infectious disease Flashcards

1
Q

What is Kawasaki disease

A

a systemic medium-sized vessel vasculitis
(aka mucocutaneous, lymph node syndrome)

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2
Q

Describe the epidemiology of kawasaki disease

A
  • affects young children u5, peak incidence at 1yr
  • mc in Japanese children
  • mc in boys
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3
Q

Give 6 clinical features kawasaki disease

A
  • Persistent high fever for over 5 days
  • Non-purulent conjunctivitis
  • Red (strawb) tongue and cracked lips
  • Cervical lymphadenopathy
  • widespread maculopapular rash
  • Peeling of fingers and toes (later sign)
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4
Q

What is a major complication of kawasaki disease

A

coronary artery aneurysm

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5
Q

How is kawasaki disease investigated

A
  • Clinical diagnosis
  • ECHO - rule out aneurysms
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6
Q

How is kawasaki disease managed

A
  • IV immunoglobulins - reduce risk of CA anueyrsms
  • High dose aspirin
  • ECHO at 6 weeks
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7
Q

Why is aspirin given to children with kawasaki disease

A

reduce the risk of thrombosis

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8
Q

What is the major route of HIV infection in children

A

mother-child (vertical) transmission during pregnancy (intrauterine), at delivery (intrapartum), or through breastfeeding

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9
Q

How is HIV diagnosed in children over 18 months

A

HIV antibody screen: detects antibodies against the virus

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10
Q

How is HIV diagnosed in children less than 18 months

A

HIV DNA PCR

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11
Q

Why is the presence of antibodies against HIV in children under 18 months not diagnostic of the illness

A
  • Children <18 months who are born to
    infected mothers will have transplacental maternal HIV antibodies
  • at this age a positive antibody test confirms HIV exposure but not HIV infection.
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12
Q

Presentation of children with mild and moderate immunocompromise in HIV

A
  • Mild: may have lymphadenopathy or parotid enlargement
  • Moderate: recurrent bacterial infections, chronic diarrhoea and lymphocytic interstitial pneumonitis
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13
Q

Clinical features of severe AIDS in children

A
  • Pneumocystis jirovecii pneumonia
  • severe faltering growth
  • encephalopathy
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14
Q

How is HIV managed in children

A
  • Antiretroviral therapy should be started in all infants and some older children depending on clinical status/ HIV load and CD4 count
  • Don’t delay routine immunisations (except BCG)
  • MDT and Regular follow up: weight, development and clinical signs of disease
  • Prophylactic co-trimoxazole
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15
Q

Co-trimoxazole is given as a prophylaxis to some children with HIV.
a) what infection is this against
b) what circumstances is it prescribed (2)

A

a) pneumocystis jirovecii pneumonia
b) all infants who are HIV-infected and older children with low CD4 counts

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16
Q

Give 4 ways vertical transmission is reduced in HIV

A
  • Positive mothers should be on antiretroviral drugs to reduce viral load at time of delivery
  • Post exposure prophylaxis given to infant after birth (zidovudine)
  • avoid breastfeeding
  • C-sections in all women with > 400 copies / ml
  • IV zidovudine should be given during the caesarean if the viral load is unknown or there are > 10000 copies / ml
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17
Q

What testing is done in children to HIV positive parents and at what age is each test done (2)

A
  • HIV viral load at 3m - if -ve, child has not contracted HIV during birth and will not develop HIV unless they have further exposure
  • HIV Abx test at 24m - to assess whether they have contracted HIV since their 3 month viral load, for example through breast feeding
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18
Q

What causes scalded skin syndrome

A

caused by a type of staphylococcus aureus bacteria that produces epidermolytic toxins

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19
Q

Describe the clinical presentation of scalded skin syndrome

A
  • fever and malaise
  • red rash with wrinkled tissue
  • typically starts on face and flexural regions then spreads
  • after the rash, large fluid-filled blisters form
  • widespread erythema and tenderness
  • Nikolsky sign
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20
Q

Describe Nikolsky sign

A
  • The epidermis separates and creates an erosion when the skin is gently rubbed
  • Large areas of skin blister and peel away, leaving red, wet, and painful areas
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21
Q

How is scalded skin syndrome managed

A
  • IV anti-staph Ab e.g. flucloxacillin
  • Analgesia
  • monitor hydration and fluid balance
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22
Q

What causes toxic shock syndrome

A

Toxin-producing staph aureus and group A streptococci

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23
Q

Characteristics of toxic shock syndrome

A
  • Fever over 39
  • hypotension
  • diffuse erythematous, macular rash
  • desquamation of rash, especially of the palms and soles
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24
Q

Toxic shock syndrome causes organ dysfunction. Give 5 examples of this

A
  • Mucositis - oral and genital mucosa
  • GI dysfunction - vomiting/ diarrhoea
  • Liver impairment
  • renal impairment
  • Clotting abnormalities and thrombocytopenia
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25
Q

How is toxic shock syndrome managed

A
  • IV fluids
  • areas of infection should be surgically debrided (removed)
  • IV antibiotics - flucloxacillin + clindamycin
  • IVIg to neutralise circulating toxins
26
Q

What is measles

A

Highly infectious disease caused by measles virus

27
Q

Features of measles

A
  • Prodrome: fever, conjunctivitis, irritability
  • koplik spots - typically develop before the rash, white spots on the buccal mucosa
  • discrete maculopapular rash becoming blotchy & confluent
  • rash begins behind the ears and spreads to the whole body
28
Q

How is measles diagnosed

A
  • ELISA (blood test) - measles-specific IgM and IgG serology
  • clinical
29
Q

How is measles managed

A
  • supportive treatment
  • avoid school 5 days after initial rash
  • Notify public health
  • vitamin A supplements
30
Q

How is measles prevented in the UK

A

Immunisation - 2 doses of MMR vaccine

31
Q

Give 3 complications of measles

A
  • otitis media - mc
  • febrile convulsions
  • encephalitis
  • subacute sclerosing panencephalitis (rare, years after infection)
  • pneumonia
32
Q

How long after measles infection does subacute sclerosing panencephalitis typically manifest

A

7 years

33
Q

What causes subacute sclerosing panencephalitis

A

variant of the measles virus which persists in the CNS

34
Q

What is chickenpox

A
  • common virus spread by respiratory droplets
  • Highly infectious during viral shedding
35
Q

What virus causes chickenpox

A

varicella zoster

36
Q

Describe the presentation of chickenpox

A
  • Fever initially
  • itchy, rash starting on head/trunk before spreading. Initially macular then papular then vesicular
  • itching may lead to permanent scars/ secondary infection
37
Q

How is chickenpox managed

A
  • keep cool, trim nails
  • calamine lotion
  • Immunocompromised kids - aciclovir
  • avoid school until lesions are dry and have crusted over
38
Q

Give 4 complications of chickenpox

A
  • secondary bacterial infection of the lesions
  • generalised encephalitis
  • pneumonitis
  • disseminated haemorrhagic chickenpox
39
Q

What severe complication can occur in a small number of chickenpox patients with bacterial infections?

A

Invasive group A streptococcal soft tissue infections, potentially leading to necrotizing fasciitis.

40
Q

What causes scarlet fever

A

group A, beta haemolytic streptococcus - strep.pyogenes

41
Q

Scarlet fever is most common between what ages

A

2 - 8 years old

42
Q

Describe the presentation of scarlet fever

A
  • Fever : typically lasts 24 to 48 hours
  • headache, N+V, malaise
  • sore throat
  • sandpaper like maculopapular rash initially on trunk then spreads (spares area around mouth)
  • flushed cheeks
  • strawberry tongue
  • cervical lymphadenopathy
43
Q

How is scarlet fever managed

A
  • 10 days course of phenoxymethylpenicillin (penicillin V)
  • penicillin allergy: clarithromycin (10d), azithromycin (5d)
  • pregnancy - erythromycin 10d
  • notify public health
  • can return to school 24h after starting antibiotics
44
Q

When are outbreaks of rubella more common

A

winter and spring

45
Q

What is the incubation period of rubella

A

14-21 days

46
Q

When are individuals with rubella infectious

A

individuals are infectious from 7 days before symptoms appear to 4 days after the onset of the rash

47
Q

features of rubella

A
  • prodrome, e.g. low-grade fever
  • rash: maculopapular, initially on the face before spreading to the whole body, usually fades by the 3-5 day
48
Q

Give 3 complications of rubella

A
  • arthritis
  • encephalitis
  • myocarditis
49
Q

What causes diphtheria

A

Corynebacterium diphtheriae (gram positive bacillus)

50
Q

How may diphtheria present

A
  • neuritis
  • heart block
  • sore throat with a grey, pseudomembrane on the posterior pharyngeal wall
  • bulky cervical lymphadenopathy
51
Q

What causes slapped cheek syndrome

A

parvovirus B19
(aka erythema infectiosum)

52
Q

Describe the presentation of slapped cheek syndrome

A
  • may be asymptomatic
  • fever, headache and myalgia
  • characteristic rose-red rash on face which may spread to the trunks and limbs
  • aplastic crisis in children with haemolytic anaemia
53
Q

What is impetigo

A

superficial bacterial skin infection usually caused by either Staphylcoccus aureus or Streptococcus pyogenes

54
Q

Describe the features of non-bullous impetigo

A
  • usually occurs around the nose or mouth
  • exudate from lesions dries to form a golden crust
  • no systemic symptoms, will not be unwell
55
Q

Describe the features of bullous impetigo

A
  • always caused by s. aureus
  • fluid filled vesicles form and then burst leaving golden crust
  • fever and malaise
56
Q

How is impetigo managed

A
  • Localised, non-bullous: hydrogen peroxide 1% cream or fusidic acid
  • widespread, non-bullous: 5 days topical fusidic acid or mupirocin
  • widespread or bullous: 5 days flucloxacillin or clarithromycin (if penicillin allergy)
  • children should be excluded from school until the lesions are crusted and healed or 48 hours after commencing antibiotic treatment
57
Q

Give 3 complications of impetigo

A
  • cellulitis
  • Staphylococcal scalded skin syndrome
  • scarring
58
Q

What commonly causes hand, foot and mouth disease

A

coxsackie A16 and enterovirus 71

59
Q

Describe the presentation of hand, foot and mouth disease

A
  • mild systemic upset: sore throat, fever
  • oral ulcers
  • followed later by vesicles on the palms and soles of the feet
60
Q

How is hand, foot and mouth disease managed

A
  • symptomatic treatment only: general advice about hydration and analgesia
  • children do not need to be excluded from school
  • highly contagious: advice about measures to avoid transmission