Congenital Infections and Down Syndrome

Question 1

What is a congenital infection?

Answer 1

Antenatal transmission of maternal infection to fetus causing postnatal effects.

Question 2

What are 3 important congenital infections?

Answer 2

CMV, Rubella and Syphilis

Question 3

How are these infections transmitted?

Answer 3

Transplacentally

Question 4

What is the aetiology of CMV?

Answer 4

CMV most common, can occur intrapartum, pre and post partum. Highest morbidity if transplacental. Transmission highest in early trimesters.

Question 5

What is the epidemiology of CMV?

Answer 5

CMV 4/100 births

Question 6

What may you find in the history/ exam of CMV?

Answer 6

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.

Question 7

What is the aetiology of Rubella?

Answer 7

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.

Question 8

What is the aetiology of syphilis?

Answer 8

transplacental spirocete transmission, around 100%. No changes in organogenesis. Most asymptomatic but picked up on screen.

Question 9

What is the epidemiology of syphilis and rubella?

Answer 9

Rubella and Syphillis very rare.

Question 10

What would you find in the history and exam of rubella?

Answer 10

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.

Question 11

What would you find in the history and exam of syphilis?

Answer 11

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.

Question 12

What investigations would you do to look for congenital infections?

Answer 12

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.

Question 13

How would you treat CMV, rubella and syphilis?

Answer 13

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.

Question 14

What are the complications and prognosis of congenital infections?

Answer 14

Intracerebral calcification are preiventricualr and poor prognostic in CMV. First year congenital rubella mortality 20%. Syphillis ok.

Question 15

What is Down’s Syndrome?

Answer 15

Third, non sex, extra chromosome 21. Homologous pairs.

Question 16

What is the aetiology of Down’s syndrome?

Answer 16

· 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.

Question 17

What is the epidemiology of Down’s syndrome?

Answer 17

1/700 live births. 1/200 if >35.

Question 18

What may you find in the history and examination in a patient with Down’s syndrome?

Answer 18

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.

Question 19

What investigations would you do for Down’s Syndrome?

Answer 19

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.

Question 20

What is the management of Down’s Syndrome?

Answer 20

MDT: parental education, regular f/up, educational input, Abx for resp infections, T4 for hypothyroid, surgical tx of defects.

Question 21

What are the complications and prognosis of Down’s Syndrome?

Answer 21

Decreased fertility, infections, 15x risk of leukemia especially AML, early dementia. 75% spontaneously abort, 20% survive <5y, 50% survive >50y.