MICRO: Neonatal and childhood infections Flashcards

1
Q

What congenital infections are screened for during pregnancy in the UK and other countries?

A

UK:

  • HepB
  • HIV
  • Syphilis

Other countries also check for:

  • Toxoplasmosis
  • Rubella
  • CMV
  • GBS
  • HepC
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2
Q

What are the TORCH infections?

A

Congenital infection screen, they can present with variable signs:

  • Toxoplasmosis
  • Other – syphilis; HIV; hepatitis B/C
  • Rubella
  • Cytomegalovirus (CMV)
  • Herpes simplex virus (HSV)
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3
Q

What are 3 common clinical features of congenital infections?

A
  • Low platelets, rash
  • Cerebral abnormalities
  • Hepatosplenomegaly/hepatitis/jaundice
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4
Q

What is the main host of toxoplasmosis? Once infected where does toxoplasmosis localise?

A

Cats - although other hosts exist

Neural and muscle tissue

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5
Q

What are the symptoms of congenital toxoplasmosis? What are the long term complications?

A

Symptoms at birth (in 40%):

  • Seizures
  • Intracranial calcifications
  • Choroidoretinitis
  • Hydrocephalus
  • Hepatosplenomegaly/jaundice

Long term sequelae (in 60%):

  • Deafness,
  • Low IQ
  • Microcephaly
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6
Q

What is the mechanism of congenital rubella syndrome?

A

Rubell causes mitotic arrest of cells; angiopathy; growth inhibitor effect

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7
Q

What are the features of congenital rubella syndrome?

A

Eyes: cataracts; microphthalmia; glaucoma; retinopathy

Cardiovascular: PDA; ASD/VSD

Ears: deafness

Brain: microcephaly; meningoencephalitis; developmental delay

Other: growth retardation; bone disease; hepatosplenomegaly; thrombocytopenia; rash

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8
Q

What are these features of?

A

Congenital rubella syndrome - cataracts and rash

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9
Q

What could be the cause of this rash?

A

Herpes simpex virus (HSV) - worst when primary infection is acquired by the mother in the third trimester

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10
Q

What are two features of congenital chalmydia infection in a neonate? What antibiotic is used?

A

Infection transmitted during delivery

Causes neonatal conjunctivitis, or rarely pneumonia

Tx: macrolide e.g. erythromycin

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11
Q

Define the neonatal period.

A

First 4-6 weeks of life (if born prematurely then this is longer and adjusted for expected birth date)

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12
Q

What are the reasons for increased incidence and severity of infections in neonates?

A

Immature host defences

Risk increases with increased prematurity because there is less maternal IgG, and more exposure to microorganissm for colonisation and infection duirng this period.

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13
Q

What is meant by ‘early onset’ neonatal infection ?

A

Within 48 hours of birth

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14
Q

What are the microbiological features of GBS?

A
  • Gram positive coccus
  • Catalase negative
  • Beta-haemolytic
  • Lancefield Group B
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15
Q

What 3 types of infections does GBS commonly cause in the neonate?

A
  • Bacteraemia
  • Meningitis
  • Disseminated infection e.g. joint
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16
Q

What 3 infections does E coli commonly cause in the neonate?

A
  • Bacteraemia
  • Meningitis
  • UTI
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17
Q

What microorganism is shown?

A

Listeria monocytogenes - rare but more commonly seen in the immunocompromised. Gram +ve rod, shows some haemolysis on blood agar.

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18
Q

What are 4 maternal risk factors for early-onset sepsis in a neonate?

A
  • PROM/prem. Labour
  • Fever
  • Foetal distress
  • Meconium staining
  • Previous history
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19
Q

What are 4 fetal/neonatal risk factors for early onset sepsis?

A
  • Birth asphyxia
  • Resp. distress
  • Low BP
  • Acidosis
  • Hypoglycaemia
  • Neutropenia
  • Rash
  • Hepatosplenomegaly
  • Jaundice
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20
Q

Give 3 causes of early onset neonatal infections.

A
  • GBS (most common)
  • E coli
  • Listeria
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21
Q

List the investigations which should be done in early onset sepsis.

A
  • FBC
  • CRP
  • Blood culture
  • Deep ear swab
  • Surface swabs
  • LP
  • CXR
22
Q

List the investigations that should be done in late-onset sepsis.

A
  • FBC
  • CRP
  • Blood culture(s)
  • Urine
  • ET secretions if ventilated
  • Swabs from any infected sites
23
Q

List the investigations that should be done for infections during childhood.

A
  • FBC
  • CRP
  • Blood cultures
  • Urine
  • +/- Sputum; throat swabs etc

LP less done in childhood

24
Q

What antibiotics should be used for early-onset neonatal sepsis?

A

Benzylpenicillin (for GBS) and gentamicin (for E coli) +/- amoxicilllin (for Listeria)

25
Q

Define late-onset sepsis.

A

After 48-72 hours

26
Q

List 3 most common causes of late-onset neonatal sepsis.

A
  • Coagulase negative Staphylococci (CoNS) e.g. Staphylococcus epidermidis (most common)
  • Group B streptococci
  • E. coli
  • Listeria monocytogenes

Other:

  • S. aureus
  • Enterococcus sp.
  • Gram -ve – Klebsiella spp. /Enterobacter spp. Pseudomonas aeruginosa/Citrobacter koseri
  • Candida
27
Q

What are the clincial features of sepsis in a neonate?

A
  • Bradycardia
  • Apnoea
  • Poor feeding/bilious aspirates/ abdominal distension
  • Irritability
  • Convulsions
  • Jaundice
  • Respiratory distress

Other:

  • Increased CRP; sudden changes in WCC/platelets
  • Focal inflammation – e.g. Umbilicus; drip sites etc.
28
Q

What antibiotics are used for late onset sepsis?

A

1st line: cefotaxime & vancomycin

2nd line: meropenem

Community acquired: cefotaxime, amoxicillin +/-gentamicin

29
Q

What condition is the most common bacterial cause of paediatric morbidity and mortality?

A

Meningitis

30
Q

What investigations should be done for meningitis?

A
  • Blood cultures
  • Throat swab
  • LP
  • Rapid antigen screen
  • EDTA blood for PCR
  • Clotted serum for serology
31
Q

Describe the CSF characteristics of bacteria, viral and fungal meningitis.

A

Rapid antigen tests can be useful; if no growth then try PCR.

32
Q

Which microorganisms are shown?

A

Neisseria meningitidis

Gram -ve

33
Q

What is the biggest cause of meningitis in children in the UK?

A

Meningitis B

34
Q

What microorganism is shown?

A

Streptococcus pneumoniae - gram +ve cocci arranged in pairs, alpha haemolytic

35
Q

What types of infections are caused by streptococcus pneumoniae?

A
  • Meningitis
  • Bacteraemia
  • Pneumonia

Especially in children <2yo

36
Q

What is shown?

A

Streptococcus pneumoniae - alpha haemolysis (green around the colonies). Autolysis in the centre (doughnut shaped)

37
Q

What type of vaccine is the pneumococcal vaccine?

A

Conjugated vaccine (immunogenic in children from 2 months, serotypes conjugated to a carrier ) - 13 different serotypes

NB: this used to be a polysaccharide vaccine but children <2yo had a poor response.

38
Q

What microorganism is shown?

A

Haemophilus influenzae

39
Q

What causes meningitis at different ages in children?

A
40
Q

What is the biggest cause of deaths in children under 5 years? (WHO 2016)

A
  1. Prematurity (16%)
  2. Pneumonia (13%)

WHO 2022 - “Globally, infectious diseases, including pneumonia, diarrhoea and malaria, along with pre-term birth complications, birth asphyxia and trauma and congenital anomalies remain the leading causes of death for children under 5 years.”

41
Q

What is the most common cause of respiratory infections in children?

A

S. pneumoniae (pneumococcus)- –most UK strains remain sensitive to penicillin or amoxicillin

42
Q

What is a common cause of respiratory infections in older children (>4yrs)? What antibiotic is used?

A

Mycoplasma pneumoniae - macrolides are the treatment of choice e.g. azithromycin

43
Q

How common do outbreaks of Mycoplasma pneumonia occur? What is the incubation period?

A

Epidemics occur every 3-4 years - in school aged children and young adults. Incubates for 2-3 weeks

44
Q

What are the classical symptoms of mycoplasma pneumoniae?

A

Many asymptomatic

Classically presents:

  • Fever
  • Headache
  • Myalgia
  • Pharyngitis
  • Dry cough
45
Q

What are the extrapulmonary symptoms of mycoplasma pneumoniae?

A

Haemolysis - IgM antibodies to the I antigen on erythrocyte; cold agglutinins.

Neurological (1% cases) - encephalitis most common; aseptic meningitis, peripheral neuropathy, transverse myelitis, cerebellar ataxia; aetiology unknown.

Cardiac

Polyarthralgia, myalgia, arthritis

Otitis media and bullous myringitis

46
Q

How much growth to diagnose UTI?

A

Pure growth >105cfu/ml

If leukocyte negative and nitrite negative then UTI unlikely.

47
Q

How common are UTIs in children?

A

3% of girls

1% of boys

48
Q

What are the most common bacterial causes of UTI in children?

A

E coli (most common)

Other coliforms:

  • Proteus species
  • Klebsiella enterococcus
  • Coagulase negative staphylococcus e.g. Staph saprophyticus
49
Q
A

GBS

50
Q
A

MenB

51
Q
A

Pneumonia (13%) but also prematurity (16%)