Congenital Infections and Down Syndrome Flashcards
What is a congenital infection?
Antenatal transmission of maternal infection to fetus causing postnatal effects.
What are 3 important congenital infections?
CMV, Rubella and Syphilis
How are these infections transmitted?
Transplacentally
What is the aetiology of CMV?
CMV most common, can occur intrapartum, pre and post partum. Highest morbidity if transplacental. Transmission highest in early trimesters.
What is the epidemiology of CMV?
CMV 4/100 births
What may you find in the history/ exam of CMV?
Antenatal: spontaneous abortion or stillbirth.
CMV: 10% symptomatic.
Cytomegalci inclusion disease: most severe – IUGR, hepatomegaly, haem abnormalities (low Pl), petechiae, purpura (blueberry muffin baby) CNS ventriculomegaly/microcephaly, cerebral atropy and calcification, sensorineural hearing loss.
What is the aetiology of Rubella?
high teratogenic effect in early fetus transmission. Occurs if mother is in her viraemic phase. Infection at >18/40 has low risk of teratogenicity. Associated with young maternal age.
What is the aetiology of syphilis?
transplacental spirocete transmission, around 100%. No changes in organogenesis. Most asymptomatic but picked up on screen.
What is the epidemiology of syphilis and rubella?
Rubella and Syphillis very rare.
What would you find in the history and exam of rubella?
Triad of - sensorineural hearing loss, ocular abnormalities (cataracts, glaucoma, retinitis pigmentosa) and congenital heart disease (PDA, ASD, VSD, PS). May also be IUGR, jaundice, blueberry muffin, thyroid abnormalities and diabetes.
What would you find in the history and exam of syphilis?
Syphillis (early): Mucocutaneous and bone lesions (mucous patches, rhinitis, condylamatous), maculopapular desquamative rash, vescicular rash and bullae (contagious!) hepatomegaly.
Syphillis (late) Neurosyphillis, teeth bone and CN8 involvement.
What investigations would you do to look for congenital infections?
Antenatal amniotic flid culture (18/40)
Virology: from saliva, tears, urine or CSF.
Blood: serum IgG and IgM, automated reagin test ART, Troponema specific test.
CT brain for calcification, AUSS for hepatomegaly, ECHO, CXR.
How would you treat CMV, rubella and syphilis?
MDT discussion:
· Support and medical control with Ganiciclovir (CMV) Penicillin G (Syphillis)
· Rubella must be isolated.
· Surgical intervention for caridac, ocular defects and gastrostomy insertion for enteral support.
What are the complications and prognosis of congenital infections?
Intracerebral calcification are preiventricualr and poor prognostic in CMV. First year congenital rubella mortality 20%. Syphillis ok.
What is Down’s Syndrome?
Third, non sex, extra chromosome 21. Homologous pairs.
What is the aetiology of Down’s syndrome?
· Non disjunction at meiosis 95%: Extra maternal chromosome 47XX+21 or 47XY+21. High maternal age major risk.
· Robertsonian translocation 4%: Chr21 onto Chr14.
· Mosaic 1%: Some cells normal some tri21, due to non disjunction after fertilisaiton during mitosis.
Several problems: congenital heart disease 40%, GI malfomraitons, chronic secretory otitis media, recurrent respiratory infections, cataracts, squints, hypothyroidism, early onset dementia and aging.
What is the epidemiology of Down’s syndrome?
1/700 live births. 1/200 if >35.
What may you find in the history and examination in a patient with Down’s syndrome?
Can be picked up on antenatal scan
General hypotonia, short staure.
Developmental: mild LD (IQ 25-75), good social skills
Craniofacial: microcephaly, brachycephaly, round face, epicanthic folds, upward sloping palpebral fissures, protruding tongue, flat nasal bridge, low set ears. Eyes: strabismus, nystagmus, Brushfield spots in iris, cataracts.
Limbs: fifth finger crynodactily, single palmar creae, wide gar ½ toes, hyperflex
CVS: murmurs if heart disease. GI malformaitons and constipation.
What investigations would you do for Down’s Syndrome?
Antenatal USS: for heart malformations, and characteristic features.
Amniocentesis or CVS can be offered. This is confirmatory. Postnatal chromosomal analysis.
Picked up on USS or on triple test on maternal serum for screening (19/40) -> low AFP, low unconjugated oestradiol, high BHCG.
Postnatal screening for cmx: echo, oesophageal atresia.
What is the management of Down’s Syndrome?
MDT: parental education, regular f/up, educational input, Abx for resp infections, T4 for hypothyroid, surgical tx of defects.
What are the complications and prognosis of Down’s Syndrome?
Decreased fertility, infections, 15x risk of leukemia especially AML, early dementia. 75% spontaneously abort, 20% survive <5y, 50% survive >50y.
