MICRO: Neonatal and childhood infections Flashcards
What congenital infections are screened for during pregnancy in the UK and other countries?
UK:
- HepB
- HIV
- Syphilis
Other countries also check for:
- Toxoplasmosis
- Rubella
- CMV
- GBS
- HepC
What are the TORCH infections?
Congenital infection screen, they can present with variable signs:
- Toxoplasmosis
- Other – syphilis; HIV; hepatitis B/C
- Rubella
- Cytomegalovirus (CMV)
- Herpes simplex virus (HSV)
What are 3 common clinical features of congenital infections?
- Low platelets, rash
- Cerebral abnormalities
- Hepatosplenomegaly/hepatitis/jaundice
What is the main host of toxoplasmosis? Once infected where does toxoplasmosis localise?
Cats - although other hosts exist
Neural and muscle tissue
What are the symptoms of congenital toxoplasmosis? What are the long term complications?
Symptoms at birth (in 40%):
- Seizures
- Intracranial calcifications
- Choroidoretinitis
- Hydrocephalus
- Hepatosplenomegaly/jaundice
Long term sequelae (in 60%):
- Deafness,
- Low IQ
- Microcephaly
What is the mechanism of congenital rubella syndrome?
Rubell causes mitotic arrest of cells; angiopathy; growth inhibitor effect
What are the features of congenital rubella syndrome?
Eyes: cataracts; microphthalmia; glaucoma; retinopathy
Cardiovascular: PDA; ASD/VSD
Ears: deafness
Brain: microcephaly; meningoencephalitis; developmental delay
Other: growth retardation; bone disease; hepatosplenomegaly; thrombocytopenia; rash
What are these features of?
Congenital rubella syndrome - cataracts and rash
What could be the cause of this rash?
Herpes simpex virus (HSV) - worst when primary infection is acquired by the mother in the third trimester
What are two features of congenital chalmydia infection in a neonate? What antibiotic is used?
Infection transmitted during delivery
Causes neonatal conjunctivitis, or rarely pneumonia
Tx: macrolide e.g. erythromycin
Define the neonatal period.
First 4-6 weeks of life (if born prematurely then this is longer and adjusted for expected birth date)
What are the reasons for increased incidence and severity of infections in neonates?
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.
What is meant by ‘early onset’ neonatal infection ?
Within 48 hours of birth
What are the microbiological features of GBS?
- Gram positive coccus
- Catalase negative
- Beta-haemolytic
- Lancefield Group B
What 3 types of infections does GBS commonly cause in the neonate?
- Bacteraemia
- Meningitis
- Disseminated infection e.g. joint
What 3 infections does E coli commonly cause in the neonate?
- Bacteraemia
- Meningitis
- UTI
What microorganism is shown?
Listeria monocytogenes - rare but more commonly seen in the immunocompromised. Gram +ve rod, shows some haemolysis on blood agar.
What are 4 maternal risk factors for early-onset sepsis in a neonate?
- PROM/prem. Labour
- Fever
- Foetal distress
- Meconium staining
- Previous history
What are 4 fetal/neonatal risk factors for early onset sepsis?
- Birth asphyxia
- Resp. distress
- Low BP
- Acidosis
- Hypoglycaemia
- Neutropenia
- Rash
- Hepatosplenomegaly
- Jaundice
Give 3 causes of early onset neonatal infections.
- GBS (most common)
- E coli
- Listeria