Neonatal and childhood infections 101121 Flashcards
TORCH infections
o T Toxoplasmosis o O Other – Syphilis, HIV, HBV, HCV o R Rubella o C CMV o H HSV
Common clinical features in congenital infections
o Mild/no apparent maternal infection Low platelets, rash
o Wide range of severity in the baby Cerebral abnormalities
o Similar clinical presentation Hepatosplenomegaly/hepatitis/jaundice
o Serological diagnosis
o Long term sequelae if untreated
Toxoplasmosis
May be asymptomatic (60%) at birth but may still go on to have long-term sequelae such as:
• Deafness Low IQ Microcephaly
40% of babies are symptomatic at birth (4 C’s)
• Choroidoretinitis Microcephaly/hydrocephalus
• Intracranial calcifications Seizures / convulsions
• Hepatosplenomegaly/jaundice
Congenital HSV symptoms
o This can spread to the neonate through the genital tract blistering rash
o It can cause disseminated infection with liver dysfunction and meningoencephalitis
o Infection control is particularly important because you don’t want this to spread
congenital Clamydia symptoms
o Infection transmitted during delivery
o Mother may be asymptomatic
o Causes neonatal conjunctivitis or pneumonia (RARE)
o Treated with erythromycin
congenital Rubella symptoms
o Effect on the foetus depends on the time of infection
o Mechanism: mitotic arrest of cells, angiopathy, growth inhibitor effect
o Classical Triad:
Cataracts Congenital heart disease (PDA; ASD/VSD) Deafness/SNHL
o Other features:
Microphthalmia Glaucoma Retinopathy ASD/VSD
Microcephaly Meningoencephalopathy Developmental delay Growth retardation
Bone disease Hepatosplenomegaly Thrombocytopaenia Rash
Why are premature babies more at risk
o Premature neonates are at INCREASED risk because:
Less maternal IgG
NICU care
Exposure to micro-organisms, colonisation and infection
Group B strep
• Features:
o Gram +ve coccus Catalase -ve
o Beta haemolytic Lancefield Group B
o 33% of women have GBS commensal
• In neonates, causes…
o Bacteraemia Meningitis
o Disseminated infection (i.e. joint infection)
E. coli
• Features: o Gram -ve rod o The K1 antigen is particularly problematic • In neonates, causes: o Bacteraemia Meningitis o UTI
risk factors for early onset sepsis
• Baby: Mother: o Birth asphyxia PROM/PPROM o Resp. distress Fever o Low BP Foetal distress o Acidosis Meconium staining o Hypoglycaemia Previous history GBS o Neutropenia o Rash o Hepatosplenomegaly o Jaundice
Listeria monocytogenes
Listeria monocytogenes: • Features: o Gram +ve rod • In neonates, causes: o Sepsis in both the mother and baby
early onset sepsis investigations
- FBC CRP Blood culture
- Deep ear swab LP Surface swabs
- CXR (full body)
Treatment for early onset sepsis
• Supportive – ventilation, circulation, nutrition
• Antibiotics (e.g. benzylpenicillin (GBS) & gentamicin (e.coli) used in combination because…
o GBS is treated by benzylpenicillin
o E. coli is treated by gentamicin
o +amoxicillin if listeria
Late onset sepsis treatment
• Treat early – low threshold for starting therapy
• Review and stop antibiotics if cultures are negative and clinically stable
• Antibiotics (guidelines do vary):
o 1st line: cefotaxime + vancomycin
o 2nd line: meropenem
o Community-acquired: cefotaxime, amoxicillin ± gentamicin
Men B/neisseria neningitis
main cause of meningitis. Men B / Neisseria meningitidis
The meningococcal disease can be fulminant to the point where limb amputation is necessary
Given: 2m, 4m and 12m
The vaccine is very immunogenic and is usually given with paracetamol because it can make the child ill
Streptococcus pneumoniae
(Pneumococcus) – leading cause of morbidity/mortality especially in <2 years
Gram-positive diplococcus, Alpha-haemolytic, Optochin-sensitive
Can lead to Meningitis, Bacteraemia, Pneumonia Given: 12w, 12m
Features:
• More than 90 capsular serotypes (difficult to generate a vaccine)
• Increasing penicillin resistance
Pneumococcal conjugate vaccine
• Previously there was a polysaccharide vaccine with 23 capsular types of pneumococcus
• Children <2 showed a poor response to this vaccine antibody response was improved by conjugating the polysaccharide with proteins such as CRM
o The conjugate vaccine is immunogenic in children from 2 months
o This conjugate vaccine was called Prevenar 7 which targeted 7 serotypes
o These serotypes were almost eradicated however, we are still seeing a lot of cases of invasive pneumococcal disease (may be due to serotype replacement)
This could lead to a change in phenotype
o More serotypes were added to create Prevenar 13
respiratory tract infections
strep pneumonia, mycoplasma pneumonia, whooping cough,
strep pneumoniae
o Streptococcus pneumoniae – the most important bacterial cause:
Sensitive to amoxicillin or penicillin
Respiratory tract infections
o Features:
1/3 of all childhood illnesses Mostly URTIs
Mostly viral Age is important
Sputum is difficult to obtain Often need to give empirical antibiotics
o Streptococcus pneumoniae – the most important bacterial cause:
Sensitive to amoxicillin or penicillin
o Mycoplasma pneumoniae – cold agglutinins:
Features:
• Tends to affect older children (> 4 years) Person-to-person droplet transmission
• Incubation period 2-3 weeks Epidemics evert 3-4 years
• Occurs in school children / young adults Mainly asymptomatic
Clinical features (if not asymptomatic):
• Fever Headache
• Myalgia Pharyngitis
• Dry cough
Extrapulmonary Manifestations
• Haemolysis
o IgM antibodies to the I antigen on erythrocytes
o Cold agglutinins in 60%
• Neurological
o Encephalitis Aseptic meningitis
o Peripheral neuropathy Transverse myelitis
o Cerebellar ataxia
• Cardiac
• Polyarthralgia, myalgia, arthritis
• Otitis media
• Bullous myringitis (vesicles on tympanic membrane – pathognomonic of mycoplasma disease)
Treated with macrolides (azithromycin)
o If a respiratory tract infection fails to respond to treatment, consider:
Whooping cough (Bordatella pertussis)
TB
Recurrent or persistent infections
- May be a feature of immunodeficiency – either congenital (e.g. SCID) or acquired (e.g. HIV)
- Warrants investigation by paediatric infectious diseases specialist
UTI
o Diagnosis
Symptoms – If child can give a history
Pure growth of >105 CFU/mL
Pyuria – pus cells on urine microscopy
o Organisms
Escherichia coli – MAIN ORGANISM
Other coliforms (Proteus, Klebsiella, Enterococcus sp.)
Coagulase-negative Staphylococcus (Staphylococcus saprophyticus)
o Early diagnosis and antibiotic treatment is important
Obtain sample before starting treatment
Renal tract imaging may be required to check for congenital anomalies
Antibiotic prophylaxis may be given after treatment of the infection