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Amniotic fluid embolism



Amniotic fluid embolism
Classification & external resources
ICD-10 O88.1
ICD-9 673.1
DiseasesDB 574
eMedicine med/122 
MeSH D004619


Amniotic fluid embolism (AFE) is a rare and incompletely understood obstetric emergency in which amniotic fluid, fetal cells, hair or other debris enters the mother's blood stream via the placental bed of the uterus and triggers an allergic reaction. This reaction then results in cardiorespiratory (heart and lung) collapse and coagulopathy.

It was first formally characterized in 1941.[1]

On the list of causes of maternal mortality, it is #5.[2]

Additional recommended knowledge

Contents

Presentation

The condition is so rare (between 1 in 8000 and 1 in 80,000 deliveries)[3] that most doctors will never encounter it in their professional careers, and as a result the exact process is poorly understood. However, it is believed that once the fluid and fetal cells enter the maternal pulmonary circulation a two-phase process occurs:

First phase

The patient experiences acute shortness of breath and hypotension. This rapidly progresses to cardiac arrest as the chambers of the heart fail to dilate and there is a reduction of oxygen to the heart and lungs. Not long after this stage the patient will lapse into a coma. 50% die within the first hour of symptoms.

Second phase

Although many women do not survive beyond the first stage, about 40 per cent of the initial survivors will pass onto the second phase. This is known as the hemorrhagic phase and may be accompanied by severe shivering, coughing, vomiting and the sensation of a bad taste in the mouth. This is also accompanied by excessive bleeding as the blood loses its ability to clot. Collapse of the cardiovascular system leads to fetal distress and death unless the child is delivered swiftly.

Causes

It is mostly agreed that this condition results from amniotic fluid entering the uterine veins and in order for this to occur there are three prerequisites:

  • Ruptured membranes (a term used to define the rupture of the amniotic sac)
  • Ruptured uterine or cervical veins
  • A pressure gradient from uterus to vein

Although exposure to fetal tissue is common and thus finding foetal tissue within the maternal circulation is not significant, in a small percentage of women this exposure leads to a complex chain of events resulting in collapse and death.

There is some evidence that it can be associated with abdominal trauma.[3]

Treatment

One approach which has been used in an immediate caesarean section.[4]

References

  1. ^ Stafford I, Sheffield J (2007). "Amniotic fluid embolism". Obstet. Gynecol. Clin. North Am. 34 (3): 545–53, xii. doi:10.1016/j.ogc.2007.08.002. PMID 17921014.
  2. ^ Moore J, Baldisseri MR (2005). "Amniotic fluid embolism". Crit. Care Med. 33 (10 Suppl): S279–85. PMID 16215348.
  3. ^ a b Ellingsen CL, Eggebø TM, Lexow K (2007). "Amniotic fluid embolism after blunt abdominal trauma". Resuscitation 75 (1): 180–3. doi:10.1016/j.resuscitation.2007.02.010. PMID 17467876.
  4. ^ Stehr SN, Liebich I, Kamin G, Koch T, Litz RJ (2007). "Closing the gap between decision and delivery--amniotic fluid embolism with severe cardiopulmonary and haemostatic complications with a good outcome". Resuscitation 74 (2): 377–81. doi:10.1016/j.resuscitation.2007.01.007. PMID 17379383.
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Amniotic_fluid_embolism". A list of authors is available in Wikipedia.
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