Congenital abnormality Flashcards
Congenital abnormality definition
Any abnormality of:
- Structure
- Function
- Metabolism
Present at BIRTH, causing mental or physical disability.
Teratogen
An agent (e.g drug of virus) that causes malformation of the embryo.
Most common cause of neonatal death
Preterm birth
Trauma + birth asphyxia (2nd)
Sepsis
(3rd)
Most common cause of congenital abnormality
Chromosomal (50.2%)
Cardiovascular
Limbs
Causes of congenital abnormality
Structural
Single gene mutation
Multifactorial
Nutritional (iodine, folic acid)
Teratogens
Prevalence of congenital abnormalities
2% (205/ 10,000)
Maternal age of fetal congenital abnormality
Under 20 and over 40 had higher prevalence of congenital abnormality
20-29 had lowest rate
Percentage of all congenital abnormalities detected prenatally
69%
Malformation
Abnormality in the development of an organ
Disruption
Alteration in an organ that has already formed.
Deformation
Altered structure due to extrinsic pressure
Dysplasia
Abnormal organisation of cells
Syndrome
Multiple congenital abnormalities arising from a single etiology.
Examples:
- Down’s
- Edward’s
- Patau’s
- Turner’s
- Fragile X
Sequence
Multiple congenital abnormalities that arise from the consequence of a single abnormality.
Example
- Potter’s sequence from renal agenesis.
Down’s syndrome
Most common type of chromosomal congenital abnormality (25.6%)
- Trisomy 21
Features
- CV defects
- Mid-moderate intellectual disability
- Facial features: small chin, slanted eyes, flat nose bridge
- Duodenal atresia
Edward’s syndrome
Second most common chromosomal congenital abnormality
- Trisomy 18.
Features
- Facial abnormalities: small jaw, cleft palate, narrow eyefold
- Skeletal abnormalities: microcephaly, prominent occiput,
- Over 90%
with heart defects - GI, urogenital abnormalities
- Neurological problems
- Pulmonary hypoplasia.
Prognosis: Die within first year
Potter sequence
Sequence of congenital abnormalities arising from renal agenesis.
Includes Oligohydramnios (amniotic fluid deficiency) Skeletal deformities
Patau’s syndrome
Congenital abnormality
- Trisomy 13
Features:
- > 80% with CV defect
- Facial and skeletal disorder
- GI: omphalocele
- Holoprosencephaly
Prognosis
- Dead within days of birth
Congenital heart defects examples [3]
Patent ductus arteriosus
Atrial/ Ventricular septal defect
Coarctation of aorta (i.e T13)
Gastrointestinal abnormalities in T18 [5]
Omphalocele
Oesophageal atresia
Treacho-oesophageal fistula
Umbilical/ Ingunal hernia
Pyloric stenosis
Urogenital abnormalities in T18 [5]
Gonadal dysgenesis
Horseshoe kidney
Hydronephrosis
cystic kidneys
renal agenesis
Week 10/11 ultrasound detection
Can identify
- Anencephaly
- Major limb defect
- T21, 18 and 13
Ultrasound 20 weeks detection
Detection of anomalies
- Heart
- Brain/ spine
- Cleft lip/ palate
Examples of teratogens
Androgens
Pesticides
Radiation
Rubella
Thalidomide
Warfarin
Hyperthermia
Androgen as a teratogen
Hormone
- Causes masculisation of external genitalia
- I.e in CAH
Pesticides as a teratogen
Chemical
- Causes neural tube defects
Hyperthermia as a teratogen
Physical agent that can lead to fetal death or neural tube defects
Radiation as a teratogen
Chemical that can lead to microcephaly, spina bifida
Alcohol as a teratogen
Chemical agent that causes fetal alcohol syndrome
- Maxillary hypoplasia
- Mental retardation
Warfarin as a teratogen
Drug that can lead to
- Chondrodysplasia
- Microcephaly
Thalidomide as a teratogen
Drug that leads to limb defects and heart defects
Rubella as a teratogen
Virus that can lead to congenital deafness
Fetal alcohol syndrome
- Facial features
Epicanthal folds
Flat nasal bridge
Small palpebral fissures
Thin upper lip
Upturned nose
Diagnostic tests for genetic abnormalities
Chorionic villus
- 9-12 weeks
Amniocentesis
- 15 weeks+
