Malformations And Shit Flashcards
3 Phases (and timeframe) of Human Prenatal Development
Preimplantation/implantation (ovulation-end of 2nd week postconception) Embryonic period (wk 3-8) Fetal period (wk 9-birth)
3 Important Processes in Embryonic Period
Organogenesis
Gastrulation (formation of germ layers)
Neural crest cell migration & closure
Fetal Period (action and anomalies)
Organ maturation and body growth
No more primary dysmorphisms but still have disruptions, deformities, or dysplasias
Primary vs. Secondary malformation
Primary is genetic cause, secondary is exogenous
3 Kinds of Structural Defects, Def.s, and Period of Arisal
Malformation - poor formation of tissue/embryonic
Deformation - unusual forces on normal tissue/fetal
Disruption - breakdown of normal tissue/fetal
3 Deformation Examples
Club feet
Plagiocephaly
Hip dysplasia
3 Causes of Deformation
Anomalies of uterus structure
Abnormal fetus position
Oligohydramnios
Example of Disruption
Amniotic bands
Dysplasia (3)
Ongoing disturbance in the development of particular tissue or cell type
Usually genetic etiology
May be lasting or progressive as long as affected tissue type is growing
Sequence
Combination of morphological abnormalities that do not originate from a cellular malfunction of affected organs - one sequence leads to other malfunction
2 Examples of Sequence
Potter Sequence
Pierre Robin Sequence
Syndrome
Combination of developmental abnormalities/malformations presumed to be due to single underlying etiology
Association
Combination of independent malformations for which there is no known common pathogenic mech (3+ occurring together at greater than expected freq)
VACTERL Association (letters + 3 more points)
Sporadic, male>female, diagnosis of exclusion Vertebral defects Anal atresia Cardiac defects Tracheoesophageal fistula Renal anomaly Limb defects
4 Teratogenic Factors
Intrauterine infections
Medication/drugs
Physical causes
Maternal metabolic diseases
5 (really 6) Intrauterine Infections
TORCH - Toxoplasmosis Other (varicella and parvovirus B19) Rubella Cytomegalovirus Herpes
Phenocopy
External exposure malformation looks the same as a genetic one
2 Phenocopies of Thalidomide
Roberts Syndrome
Holt Oram
Coumarins
Short stature/limb reduction/hypoplastic nose defect arising from Warfarin
Coumarins Phenocopy
Conradi-hunermann
Diabetic Embryopathy (cause and main symptom)
Untreated and severe maternal diabetes prior to getting pregnant, during embryogenesis
Causes sirenomelia - lack of development of sacru/pelvis/legs - mermaid syndrome
Diabetic Fetopathy (cause and symptoms)
Uncontrolled maternal diabetes after completion of embryogenesis, gestational diabetes
Large baby and worry about hyperinsulinism/hypoglycemia
MoM
Multiple of the Median (of the laboratory), how serum screening tests reported
5 Kinds of Serum Screening Tests
Triple Screen Quadruple Screen First Trimester Screen Integrated Screen (best) Sequential Screen
Integrated Screen vs. Sequential Screen
Integrated takes measurements at 1st and 2nd trimester and reports at end of 2nd. Sequential just does them sequentially
Prenatal Screening vs. Diagnostic Testing
Screening is noninvasive, diagnostic is invasive
5 Proteins Measured During Maternal Serum Screen
Alpha-fetal prot (AFP) Pregnancy-associated plasma prot A (PAPP-A) hCG Unconjugated estradiol (uE3) Inhibin A (DIA)
3 Things that Increase AFP
Increasing Gestational Age
Multiple fetuses
Open neural tube defect/abdominal wall defect, or any other open defect increases a LOT
Most Common Reason for High AFP Levels
Underestimation of gestational age
1st Trimester Combined Screening (4 measurements and what it gives risk for [2])
Measures nuchal translucency (NT), PAPP-A, and hCG and gives risk for fetal trisomy 21 and 18
3 Signs for DS from 1st Trimester Combined Screening
NT increase, PAPP-A decrease, hCG increase
3 Signs for Trisomy 13/18 from First Trimester Combined Screening
NT, PAPP-A, and hCG all increase
3 Things that Decrease AFP
Trisomy 21, trisomy 18, and impending fetal demise
High Risk for DS, Trisomy 13/18, and ONTD
DS: 1/270
Trisomy 13/18 - 1/100
ONTD - >2.5 MoM
3 Things Tested for in Second Trimester Triple Screen
AFP, hCG, and uE3
4 Things Tested for in 2nd Trimester Quadruple Screen
AFP, hCG, uE3, and DIA
Sign of Open-Neural Tube Defect (ONTD)
Very high AFP
4 Signs of DS from 2nd Trimester Quadruple Screen
Increased hCG
Decreased AFP
Increased DIA
Decreased uE3
3 Signs of Trisomy 13/18 from 2nd Trimester Triple Screen
Decreased AFP, hCG, and uE3
Soft Markers
US signs suggestive of abnormalities but not diagnostic
Prenatal Ultrasonography (first 2 trimesters)
1st Trimester usually finds proof of intact intrauterine pregnancy and confirms gestational age, and while it can find developmental defects, usually 2nd trimester notices these and more specific US is recommended
3 Kinds of Invasive Prenatal Diagnostic Tests
Amniocentesis
Chorionic Villi Sampling (CVS)
Percutaneous Umbilical Blood Sampling
Preimplantation Genetic Diagnosis (PGD)
IVF, then sample single cell from blastomere and diagnose w/ FISH or PCR and only implant healthy embryo
Benefit of Amniocentesis
Least risky
Benefit of CVS
Earliest and quickest results
Advanced Maternal Age vs. Advanced Paternal Age Risks
Maternal increases risk of aneuoploidy while paternal may increase risk of de novo AD muts
Cell-Free Fetal Nucleic Acid Screen
New procedure that tests fetal DNA fragments in maternal circulation, most specific and sensitive screen
