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Radiology
Fetal Thyroid Masses and Fetal Goiter
Built from Obstetric Imaging
What’s inside
12 sections · 100 slides
Overview
- What this topic covers
What a fetal goiter is
The gland, the definition and the scan picture
- The gland at the front of the neck
- How the fetal thyroid comes online
- What the word goiter means here
- Goiter beside a normal thyroid at the same age
- The enlarged gland on its own
- Reading the axial view of the neck
- Looking along the length of the neck
- Calling the gland too big
How common it is and why iodine matters
Numbers, endemic deficiency and first-trimester screening
- 1:35,000
- How often it happens
- Iodine is still a worldwide problem
Why a fetal goiter happens
Gland that never formed, hormone factory that jams, antibodies that cross
- Three routes to an underactive goiter
- The big cause: a gland that never formed right
- When the hormone factory jams
- When the instruction never leaves the brain
- Too little iodine, and too much
- Where an overactive goiter comes from
- Graves disease in pregnancy
- Choosing between the two antithyroid drugs
- One mother, two opposite fetal outcomes
- Antibodies that cross the placenta
The harm a fetal goiter does
Pressure from the mass, and the effects of the wrong hormone level
- Two separate kinds of trouble
- How a goiter is picked up
- From swollen gland to preterm birth
- Pressure on the food pipe
- Pressure on the windpipe and the neck
- When the fetal gland is overactive
- When the fetal gland is underactive
- Why speed matters so much
- Who to watch, and how often
Working out what the gland is doing
Why pictures alone are not enough, and how function is tested
- Pictures alone cannot answer the question
- The order of work when a goiter is seen
- Diagnostic pathway for an enlarged fetal thyroid
- What the pathway asks about the mother
- What the pathway asks about the fetus
- Sampling the fetus's own blood
- Testing the fluid instead of the blood
Reading the ultrasound for clues
Doppler pattern, bone maturation, heart rate, movements and a score
- Where the blood flows tells you a lot
- Two flow patterns, two directions
- Blood flow only around the edge
- Blood flow through the whole gland
- Bones as a clock for thyroid hormone
- Assessing bone maturation on ultrasound
- Heart rate and the way the fetus moves
- Four findings scored together
- How the score is used
- Ultrasound Score to Distinguish Between Hypothyroidism and Hyperthyroidism
- Ultrasound Score to Distinguish Between Hypothyroidism and Hyperthyroidism (continued)
- “
- Other findings that shift the odds
- Always measure the fluid around the fetus
- Watching treatment work on the screen
Magnetic resonance and three-dimensional imaging
What the other modalities add, and where they stop
- What magnetic resonance imaging adds
- Planning the airway with MRI
- Where three-dimensional ultrasound fits
Other lumps in the fetal neck
What else makes a mass here, and how each is told apart
- What else can make a mass here
- Starting point for the differential
- Teratoma of the neck
- Cervical teratoma in three dimensions
- Thyroglossal duct cyst
- Why a thyroglossal cyst is removed
- Branchial cleft cyst
- Why the branchial cyst must be found early
- Ectopic thymus
- Why the rest of the thymus must be found first
- Cystic hygroma in the first trimester
- Lymphangioma in front of the thyroid
- The remaining possibilities
Treating the goiter before birth
Shrinking the mass, the levothyroxine route, and the dose problem
- What treatment before birth is for
- Every reported case shrank the gland
- Putting the hormone where the fetus can swallow it
- The dose nobody has settled
- Two ways authors choose the dose
- Review of Treatment Options for Congenital Goitrous Hypothyroidism
- Review of Treatment Options for Congenital Goitrous Hypothyroidism (continued)
- Review of Treatment Options for Congenital Goitrous Hypothyroidism (continued)
- How to read that treatment table
- Goiter before and after levothyroxine
- Blood flow in the gland before and after treatment
- When the mother is on antithyroid drugs
- Treating an overactive fetal gland
- Draining excess amniotic fluid
Delivery and life after birth
Securing the airway, and the newborn screening safety net
- Securing the airway before the cord is cut
- Intubation while still attached to the mother
- Planning an EXIT procedure
- The newborn screening safety net
Pulling it together
What the referring physician needs to know, and the key points
- What the referring physician needs to know
- What to do once the goiter is confirmed
- Key points to carry away
- The treatment message in three lines
- Suggested reading
- References
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- Obstetric Imaging: Fetal Diagnosis and Care, 2nd Edition