Teratogenesis Flashcards
What are birth defects?
Structural or functional anomalies that occur during intrauterine life and can be identified prenatally, at birth or later in life
- Clinically significant birth defects
- Malformation
- Disruption
- Deformation
- Dysplasia
Birth defects are…
Multifactorial diseases
What is a teratogen?
Teratogen: An agent which produces a permanent structural or functional alteration in an organism exposed during embryonic or fetal life
What is teratogenesis?
Teratogenesis: The process by which birth defects are produced
Principles: ➢ Dose of teratogen ➢ Genotype ➢ Time of action of the agent: increased teratogenicity at critical period of development
What are physically and medically important teratogens?
- Physical:
- Ionizingradiation
- Maternal diseases as teratogens:
- Uncontrolled Diabetes
- Drugs/medication:
- Thalidomide
- Valproic acid
- Phenytoin
- Warfarin
- Tetracycline
- Isotretinoin
- Alcohol
What illicit substances are teratogens?
- Cocaine
* Marijuana
What chemical is a clinically important teratogen?
Methylmercurry
What infections are clinically important teratogens?
- Infections:
- Toxoplasma Gondii ( Toxoplasmosis)
- Other (Syphilis, varicella-zoster, parvovirus B19)
- Rubella virus ( German measles) • Cytomegalovirus ( CMV)
- Herpes simplex virus
What is congenital toxoplasmosis?
Caused by protozoan toxoplasma gondii an intracellular parasite
What is the prognosis of congenital toxoplasmosis ?
Severity related to gestational age and time of infection
How is congenital toxoplasmosis managed?
- Antenatal screening
- Treatment during pregnancy reduces the risk of transmission
What are the symptoms of congenital toxoplasmosis?
At birth most children are asymptomatic but may develop symptoms later.
Classic signs: Chorioretinitis, hydrocephalus, intracranial calcifications, convulsions.
What is congenital syphilis?
Syphilis is caused by the bacteria Treponema pallidum
• Transmission:
• Sexuallytransmitted
• Transplacental→ may occur at any stage of pregnancy
What are the clinical manifestations of congenital syphilis?
Clinicalmanifestations:
- Stillbirths(hydropsfetalis),
- Congenital syphilis: deafness, hydrocephalus, intellectual disability, craniofacial anomalies
- Early or late presentation of symptoms
How is congenital syphilis managed?
Management
• Prevention:antenatalserologicalscreening
• Treatment with penicillin
• Incidence increasing due to association with HIV infection
What are signs of congenital syphilis?
Saddle nose
Saber shins
Hutchinson teeth