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Radiology
Polyhydramnios
Built from Obstetric Imaging
What’s inside
9 sections · 80 slides
Overview
- What this deck covers
What “too much fluid” means
Defining and measuring amniotic fluid on ultrasound
- The water the baby lives in
- Why we never actually measure the litres
- Two rulers for the same thing
- Measuring the pockets properly
- Four-quadrant fluid index in polyhydramnios
- Reading that four-panel scan
- The single deepest pocket
- Measuring fluid when there are twins
- Which number makes the diagnosis?
- Grading how severe it is
- Why grading is worth doing
- The other way: percentiles for gestational age
How common it is
Prevalence and the pregnancies that carry the risk
- 1%
- Who tends to get it
Why it happens
The fluid balance, and everything that can tip it
- Fluid volume is a balance
- Two ways the balance tips
- When the fetus makes too much
- How diabetes floods the sac
- When the fetus takes back too little
- The full list of causes, and how to read it
- Causes of polyhydramnios: excessive production of amniotic fluid
- Causes of polyhydramnios: excessive production of amniotic fluid (continued)
- Causes of polyhydramnios: decreased uptake of amniotic fluid
- Causes of polyhydramnios: decreased uptake of amniotic fluid (continued)
- Causes of polyhydramnios: decreased uptake of amniotic fluid (continued)
- The book's own table of causes
- 6–45%
- What one large review found
- More fluid, more anomalies
- Why that gradient matters
- When no cause can be found
- Idiopathic does not mean safe
How it shows up
Chronic and creeping, or acute and dangerous
- How it is usually picked up
- Slow build-up versus sudden flood
- The signs that should ring a bell
What to look for on the scan
A head-to-toe search for the cause
- Finding too much fluid starts a search
- Where to look when fluid is high
- Start with the face and jaw
- Then the brain
- The chest: something pressing on the gullet
- Excess fluid with a diaphragmatic hernia
- The abdomen: is there a stomach bubble?
- Absent stomach bubble with excess fluid
- Blockages further down the gut
- The skeleton and the muscles
- Hydrops points to a different set of causes
- Checking for fetal anaemia
- Shunts that overload the fetal heart
- Doppler also reports fetal wellbeing
- When the anatomy looks normal
- Too much fluid in one twin
- Where MRI helps
- So what is the differential?
Treatment and monitoring
Treat the cause, relieve the symptoms, watch the fetus
- The guiding principle
- The work-up in order
- Screen every mother for diabetes
- 22%
- When to offer amniocentesis
- Looking for infection and antibodies
- If the fetus is anaemic
- Amnioreduction: draining the excess
- What the amnioreduction studies show
- Why indomethacin is no longer used
- Keeping watch on the fetus
Outcomes and handover
Delivery risks, the newborn, and the referral letter
- What excess fluid does at delivery
- After the baby is born
- What a prospective study found
- Following the children up
- What the referring doctor needs to know
- Key points to carry away
- Key points to carry away
References
The source reference list
- References
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- Suggested readings
- Obstetric Imaging: Fetal Diagnosis and Care, 2nd Edition