Twin anaemia polycythaemia sequence

Last revised by Bahman Rasuli on 16 Oct 2020

Citation, DOI, disclosures and article data

Citation:

Radswiki T, Rasuli B, Skalski M, et al. Twin anaemia polycythaemia sequence. Reference article, Radiopaedia.org (Accessed on 19 Apr 2024) https://doi.org/10.53347/rID-15453

DOI:

https://doi.org/10.53347/rID-15453

Permalink:

https://radiopaedia.org/articles/15453

rID:

15453

Article created:

18 Oct 2011, The Radswiki ◉

Disclosures:

At the time the article was created The Radswiki had no recorded disclosures.

View The Radswiki's current disclosures

Last revised:

16 Oct 2020, Bahman Rasuli ◉

Disclosures:

At the time the article was last revised Bahman Rasuli had no recorded disclosures.

View Bahman Rasuli's current disclosures

Revisions:

7 times, by 7 contributors - see full revision history and disclosures

Systems:

Obstetrics, Haematology

Tags:

cases

Synonyms:

Twin anaemia-polycythaemia sequence (TAPS)
Twin anaemia polycythaemia sequence (TAPS)
TAPS

Twin anaemia polycythaemia sequence (TAPS) is considered a variant of the twin to twin transfusion syndrome (TTTS).

As with twin-to-twin transfusion syndrome, the underlying mechanism is thought to be abnormal placental vascular anastomoses, however, in TAPS the rate of transfusion is slow and therefore results in a gradual discordance of fetal haemoglobin, without the hormonal disbalance and subsequent liquor discordance seen in TTTS. One twin develops anaemia and the other polycythaemia.

Radiographic features

Antenatal ultrasound

One of the features suggesting the diagnosis is a discordance in fetal middle cerebral artery peak systolic velocity (MCA-PSV) measurements ⁴. In contrast to the classic twin-to-twin transfusion syndrome, there is no amniotic fluid discordance (i.e. no-twin oligo-polyhydramnios sequence (TOPS)) ⁵.