"P3... Respond to 134 Main St. for the female party with SOB."
"P3 received... En route." And you're off.
The differential for SOB is SO broad - It could be anything - Let's run an experiment: Before you continue reading this, list 5 differential diagnoses for SOB. Do 10 if you can - it should be pretty easy, right?
Cool, now that you've done that, let's move on.
So we pull up to the apartment building and head up to the third floor (of course) and there we find the patient. She is sitting on the corner of her couch, tripoding, with her husband rubbing her back. She is alert but appears very anxious, is obviously tachypneic, and is rubbing her belly... She's pregnant.
Anyone picture a pregnant patient when they did that little experiment? I didn't. That was not my mental model heading into the call. Not gonna lie, I pictured Gam Gam smoking in her kitchen...
So, this lady is G1P0 at 30 weeks gestation. She is 36-years-old, and her only history is anxiety.
Now, I know what some of you may be thinking... Let's rule it out now: It's not the anxiety - I promise. She's had a few pre-natal appointments but admittedly hasn't been good with follow-up.
I do a physical exam, and honestly, it's relatively benign... She has some SOB, tachypnea, and a bit of tachycardia - all expected. Her lungs were diminished but clear. She wasn't really able to take deep breaths. She also complained of a headache x2-3 days (which is why it's important to get a complete history).
My partner got some vitals: HR 120, BP 184/112, RR 24, and SpO2 94%.
Now, one of those vitals should immediately send up some red flags for you... She is pregnant, hypertensive, and has signs/symptoms of end-organ issues. What do we call this?
Preeclampsia! More specifically, she has preeclampsia with severe features. She also has pulmonary edema... but more on that party later!
We tend to (mistakenly) think that preeclampsia is simply just a warning sign for eclampsia - this is wrong. Preeclampsia is the number one cause of maternal and perinatal morbidity. It's not just a mom issue... Preeclampsia is associated with a 20-fold increase in perinatal mortality. It's a "thing" by itself, not just a warning sign, and one could make the argument that EMS should initiate treatment in the field.
So what is preeclampsia?
Preeclampsia is a pregnancy-induced hypertensive disorder that is believed to be caused by placental dysfunction. It's a maternal syndrome characterized by hypertension and proteinuria OR hypertension and end-organ dysfunction with or without proteinuria, after 20 weeks gestation or within 4 weeks postpartum.
That was a lot... Basically, preeclampsia is pregnancy-induced hypertension that is either symptomatic or causes proteinuria - which is just a sign that the filter in the kidneys isn't working right. It's measured by a urinalysis and is obviously not something we are going to collect in the field... We are focusing more on the symptomatic hypertension bit.
Preeclampsia can cause badness for both moms, in the form of hemorrhagic stroke, pulmonary edema, renal injury, etc., and babies, in the form of fetal growth restriction, and a few other issues.
To be fair, not all that is hypertensive and pregnant is pre-eclamptic. The mom can just have chronic hypertension or gestational hypertension that is not associated with symptoms or proteinuria... That's just hypertension. It's still aggressively managed in pregnant patients but isn't preeclampsia.
So, what do we define as hypertensive?
During pregnancy, hypertension is defined as a BP ≥140/90 and severe hypertension is defined as a BP ≥160/110. Our patient's BP was 184/112... So, she would be considered severely hypertensive.
How do we treat this?
If allowed by your protocols, you can reduce their blood pressure. The first-line drug is labetalol but hydralazine and nifedipine are also relatively common. For hypertension refractory to first-line agents there is nicardipine, etc. - for now, this is beyond the scope of this quick FB post.
So what's this preeclampsia with severe features thing? Cause she has that too.
Preeclampsia with severe features is a subset of eclampsia where there is severe hypertension and/or signs and symptoms of significant end-organ dysfunction... like her pulmonary edema. Essentially, preeclampsia exists on a spectrum. On one end you have hypertension with some filter issues, on the other, you have a massive hemorrhagic stroke and pulmonary edema - with lots in between. The neuro ones tend to be the big issues here. Neuro complications occur in 50-75% of maternal deaths due to preeclampsia. A general list of severe complications includes pulmonary edema, acute kidney injury, hepatic hematoma, HELLP syndrome, placental abruption, cerebral hemorrhage, hydrocephalus, and seizures (eclampsia).
So let's talk about her pulmonary edema because that's the complication she has and ultimately, why she actually called 911.
This occurs in approximately 10% of preeclampsia with severe features. We really only learn the heart failure version of pulmonary edema in class, but it can actually happen due to several conditions. Ultimately it's all about pressures... osmotic pressures, hydrostatic pressures, and then pre/post-capillary pressures. The whole thing is called Starling Forces and we have a video on it on the website, so for the sake of brevity - look there!
The etiology of pulmonary edema in preeclampsia is multifactorial... I won't go crazy here. It's generally not left heart failure. It's probably a combination of endothelial damage, leaky capillaries, and messed up Starling forces.
Her pulmonary edema did not present as traditionally taught, either. It was caught early. Her lungs were diminished, but clear, with NO rales or anything. Edema is a progression from interstitial fluid accumulation to intraalveolar fluid accumulation. Rales is a alveolar accumulation sign. You can have edema without rales. This is one of those times when knowing complications, patho, etc. can be important. She is obviously hypertensive and has had a headache (symptomatic hypertension) - that led to the idea of preeclampsia. Preeclampsia, esp. with a BP that high puts the patient at risk of pulmonary edema. Knowing that those things can present together is important. She is SOB, anxious, tripoding, etc. - all signs of hypoxemia.
The takeaway: When a preeclamptic patient complains of SOB they have pulmonary edema until proven otherwise.
You can treat this similarly to how you would treat really any pulmonary edema patient, namely, furosemide and respiratory support as needed. Again, follow your local protocols.
Now let's talk about the risk of eclampsia because that is important to prevent.
Eclampsia is defined as tonic-clonic seizures in the presence of preeclampsia. Magnesium can help prevent this from occurring. I want to be SUPER clear here: Magnesium does not, in any way, treat eclamptic seizures. The treatment for a prolonged eclamptic seizure is the same as any other cause of status epilepticus - Benzos. Fortunately eclamptic seizures tend to last <30 seconds and are almost always self-limiting. I think this is where the confusion comes from... The protocol says "Give mag for eclampsia" - because the seizures usually stop without intervention. The treatment then focuses on prevention - hence the mag.
Magnesium prevents the next seizure from occurring, or in the setting of preeclampsia, is prophylactic. The dose should be 4 to 6 grams over 20-30 minutes followed by an infusion of 2 grams/hr for the next 24 hours. EMS (and the ED, to be fair) tends to underdose magnesium...
So here is what we did...
We initiated her on some O2 in the house and got her downstairs. In the truck, we started an IV, withheld fluid, and obtained a 12-lead to rule out ischemia as a cause of her SOB/pulmonary edema. We then initiated transport. I then called medical control en route and asked about giving Lasix (which was required where I was working at the time). We gave 30 mg of lasix, kept her on 4 lpm of O2, and then I gave her 4 grams of magnesium.
A big thing EMS does is transport, right? Transporting to the right facility is important. This patient needs to go somewhere with obstetrics. This is where knowing the capabilities of your area hospitals is important. If you have a non-obstetric community hospital 5 minutes away or a tertiary facility with 24-hour OB coverage 20 minutes away, go there. Obviously, point of entry, protocols, etc. can dictate some of this, but there are often ways around these... hiccups. Call medical control if you need.
We brought her to the tertiary OB center - which happens to be where her doctor is anyway, so it all worked out. We called ahead and went directly up to the OB unit instead of the ED which is exactly what she needed.
There, they controlled her BP (the goal is to do so within 30-60 minutes), continued the mag, and ultimately they were able to keep her under control with medical management until she hit 34 weeks when they performed a scheduled c-section.
For the record, that's a thing. The definitive treatment for preeclampsia with severe features and eclampsia is delivery of the baby. However, they will try to keep the baby in there until 34 weeks, assuming there is no fetal distress.
I hope this was a helpful refresher on preeclampsia! It's not just a warning sign for eclampsia and it's not as simple as "hypertension!" If you have any questions, let me know in the comments! If this is something you want to learn a bit more about check out the website!
Thanks for reading!
-Dean Stockley
References:
August P & Sibai BM. Preeclampsia: Clinical features and diagnosis. UpToDate. 2023. Accessed from: https://www.uptodate.com/contents/preeclampsia-clinical-features-and-diagnosis?search=preeclampsia&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1
Baldisseri MR, et al. Ch. 4: Preeclampsia/Eclampsia. Fundamental Critical Care Support: Obstetrics. Society of Critical Care Medicine, 2018.
Karumanchi SA, Lim KH, August P. Preeclampsia: Pathogenesis. UpToDate. 2023. Accessed from: https://www.uptodate.com/contents/preeclampsia-pathogenesis?search=preeclampsia&source=search_result&selectedTitle=5~150&usage_type=default&display_rank=5
Kharal R, Henn MC, & Lall MD. Ch. 16: Hypertensive Disorders in Pregnancy. Manual of Obstetric Emergencies, 1st ed. LWW, 2020.
Watchman T. Antenatal Care. Zero to Finals: Obstetrics and Gynaecology, 1st ed. Independently published, 2020.
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