Newborn dysmorphology

Question 1

What is newborn dysmorphology?

Answer 1

Dysmorphology – study of abnormalities of human form and the mechanisms that cause them
- 2.5% of all NBs

Question 2

Classification of birth defects

Answer 2

Classification of Birth Defects

Intrinsic structures affected – malformations and dysplasia

Extrinsic affected – deformation and disruption

Syndrome – pattern of multiple abnormalities that are related by
pathophysiology and result from a single, defined etiology

Sequence – multiple malformations that are caused by a single
event that can have many etiologies

Association – nonrandom collection of malformations in which
there is an unclear or unknown relationship among the
malformations such that they do not fit the criteria for a
syndrome or sequence.

Question 3

Etiology

Answer 3

Etiology
- Genetic, maternal infection, DM, maternal fever,
uterine environment, PBA, mercury, alcohol,
thalidomide, phenytoin, warfarin, ARBs, penicillin,
valproic acid, phenytoin, cytotoxic drugs

Question 4

2 major intrinsic causes of deformation

Answer 4

Deformations – 2 major intrinsic causes
2. Oligohydramnios
- Major extrinsic cause are those that result in fetal
crowding to restrict fetal movement
- Shape of the amniotic cavity has a profound effect on
the shape of the fetus. Influenced by:
o Uterine shape
o Amniotic fluid volume
o Size and shape of fetus
o >1 fetus
o Site of placental implantation
o Presence of uterine tumors
o Shape of the abdominal cavity and tightness
of abdominal musculature
- May be completely normal. Correction usually occurs
spontaneously

Question 5

What is disruption?

Answer 5

involves entanglement followed by tearing apart or
amputation of a normally developed structure distal to the insult by amniotic bands; or interruption of blood supply to a developing part, which can lead to infarction, necrosis, and/or resorption of structures distal to the insult (atresia/necrosis)

Question 6

What are the diagnostics?DDx:

Answer 6

Dx
1. Pattern-recognition approach
2. Systematic genetic-mechanism approach
3. Full skeletal survey
4. CNS imaging
5. Chromosomal analysis/ genotyping

Question 7

Management

Answer 7

Mgt
1. Refer to geneticist
2. Anticipatory guidance and counselling, medical
monitoring

Question 8

Differentials

Answer 8

DDx: TORCH Infections:
Toxoplasma gondii (p.79)

Others: Syphillis (p.74)
VZV (p.57)
Parvovirus B19 (p.56)
Rubella (p.55)
CMV (p.66)
Herpes (p.66)