Teratogens ✅

Question 1

What are teratogens?

Answer 1

Substances producing disruption of embryogenesis by either deformity or malformation

Question 2

What kind of agents can be teratogens?

Answer 2

• Chemical
• Physical
• Infectious

Question 3

What does the pattern of abnormality caused by teratogens depend on?

Answer 3

• Timing and magnitude of exposure
• Maternal metabolism
• Placental transfer
• Genetic susceptibility of the embryo

Question 4

Give 4 categories of chemical teratogenic agents

Answer 4

• Drugs
• Hormones
• Alcohol
• Environment chemicals

Question 5

Give an example of a teratogenic environmental chemical

Answer 5

Organic mercury

Question 6

What is the teratogenic effect of organic mercury

Answer 6

Neurological damage resembling cerebral palsy

Question 7

Give an example of a teratogenic physical agent

Answer 7

High levels of ionising radiation

Question 8

What can high levels of ionising radiation during pregnancy cause?

Answer 8

• Microcephaly
• Spina bifida
• Cleft palate
• Limb defects

Question 9

Other than teratogenic effects, what else can high levels of ionising radiation during pregnancy cause?

Answer 9

• Carcinogenic effects

- Mutagenic effects

Question 10

What is meant by mutagenic effects?

Answer 10

Changes to DNA which can be passed to future generations

Question 11

Give 8 types of pharmacological agent that may affect a developing foetus?

Answer 11

• Hormones
• Anti-psychotics
• Anti-convulsants
• Anti-microbials
• Anti-coagulants
• Anti-thyroid
• Vitamin A analogues
• Folic acid inhibits

Question 12

Give 2 hormones that may affect the foetus?

Answer 12

• Progesterone

- Diethylstilbestrol

Question 13

What is the teratogenic effect of exogenous progesterone

Answer 13

VACTERL

Question 14

What is the teratogenic effect of diethylstilbestrol?

Answer 14

Vaginal or clear cell carcinoma

Question 15

Give 2 anti-psychotics that can be teratogenic

Answer 15

• Lithium

- Thalidomide

Question 16

What is the teratogenic effect of lithium?

Answer 16

Ebstein anomaly

Question 17

What are the teratogenic effects of thalidomide?

Answer 17

• Short limbs (phocomelia)
• Absent auricles
• Deafness

Question 18

Give 3 anti-convulsants that can have teratogenic effects

Answer 18

• Sodium valproate
• Phenytoin
• Carbamazepine

Question 19

What is the clinical presentation of the teratogenic effects of anti-psychotics known as?

Answer 19

Fetal valproate/hydantoin/carbamazpeine syndrome

Question 20

What are the clinical features of fetal valproate/hydantoin/carbamazepine syndrome?

Answer 20

• Craniofacial, cardiac, and limb defects

- Developmental delay

Question 21

Give 2 anti-microbials that can have teratogenic effects

Answer 21

• Tetracycline

- Streptomycin

Question 22

What are the teratogenic effects of tetracycline?

Answer 22

• Tooth enamel hypoplasia

- Yellow staining of teeth

Question 23

What are the teratogenic effects of streptomycin?

Answer 23

Sensorineural deafness

Question 24

What anticoagulant can have teratogenic effects?

Answer 24

Warfarin

Question 25

What is the clinical presentation of the teratogenic effects of warfarin termed?

Answer 25

Fetal warfarin syndrome

Question 26

What are the features of fetal warfarin syndrome?

Answer 26

- Nasal hypoplasia - Microcephaly - Optic atrophy - Hydrocephalus - Congenital heart defects - Stippled epiphyses - Purpuric rash

Question 27

Give 2 anti-thyroid medications that can have teratogenic effects?

Answer 27

- Iodine | - Propylthiouracil

Question 28

What are the teratogenic effects of iodine and propylthiouracil?

Answer 28

- Goitre | - Hypothyroidism

Question 29

Give a vitamin A analogue that can have teratogenic effects?

Answer 29

Isotretinoin

Question 30

What are the teratogenic effects of isotretinoin?

Answer 30

- Craniofacial anomalies | - Conotruncal cardiac defects

Question 31

Give a folic acid inhibitor that can have teratogenic effects?

Answer 31

Methotrexate

Question 32

What are the teratogenic effects of methotrexate?

Answer 32

- Microcephaly - Neural tube defects - Short limbs

Question 33

How do drugs cause teratogenicity?

Answer 33

Either by interfering directly with embryogenesis or by exerting their pharmacological actions on fetal organs

Question 34

What is the difficulty of identifying which drugs are teratogenic?

Answer 34

- Adverse effects of medicines difficult to recognise unless they produce recognisable patterns of malformation - May be considerable delay before teratogenic effects are associated with certain drug - Presentation of teratogenic effect may be delayed