01-30 Pregnancy Flashcards
∆ in [Cr], why?
[Cr] falls b/c:
—systemic vasodilation → GFR increases
—so a “normal/high-nl Cr in a pregnant woman is actually high
∆s in blood pH and bicarb?
—there is a mild resp alkalosis (higher RR)
—so pH is higher and bicarb falls to comp
∆ in Hb, why?
Hb conc goes down b/c:
a) increased plasma vol
b) decr sensitivity to Epo!
URine protein level ∆?
Double normal is found in pregnany
∆ in [Na+] serum, why?
Na falls 130-135 (vs. 135-140)
—b/c Increased circulating AVP, and increased water intake
∆ in BP, why?
BP falls, decreased vascular tone.
—also perhaps due to lower albumin?
—stay lower for 2-3 mo s/p
∆ in cardiac output?
CO increases
∆s in kidney anatomy and physiology in pregnancy?
—kidneys enlarge
RBF incr
—SMM fxn → relax the renal pelvis and decr motility of the ureters
—microenvironment of the lower urinary tract is less resistant to bacterial invasion
—physiological changes persist for 2-3 months after delivery.
THIS MEANS
The net result is polyuria and increased susceptibility to urinary tract infections and to reflux of urine to the kidney resulting in pyelonephritis
—Therefore tx non-sx bacturia in pregnancy
CKD and HTN cause changes are opposite, in what way?
Pregnancy —↑ endothelial vascular relaxation: vasodilation and ↓ decr BP —↑ venous and arterial compliance OPPOSITE occurs in preg —this is key slide for this lecture
CKD effect on RBC mass, GFR and blood volume
CKD blunts the normal physiological increase in blood vol, RBC mass and GFR seen in healthy pregnancy
—linear relationship with the stage of CKD and degree of blunting
% Successful outcomes of pregnancy in CKD
Even stage 3 is 90%
—Stage 4-5 is 30-50% w/ 80-90% of women having complications
—99% delivered pre-term and/or to mothers w/ pre-eclampsia
—However, many complications are manageable with good antenatal and neonatal care, so that a successful outcome may be possible even in advanced CKD.
What do we know about the effects of pregnancy on healthy kidneys?
—despite hyperfiltration and alterations in GFR, pregnancy does not appear to be deleterious to healthy kidneys
—no increase in new onset renal disease in pregnancy…
—…w/ one important exception: SLE may present for the first time or become more severe
—may unmask previously undiagnosed renal disease (failure to increase GFR, the new onset of proteinuria, or new HTN)
Take away about CKD in pregnancy
- successful preg is possible for many CKD pts
- CKD incr r/o adverse outcome in preg
- that risk is proportional to degree of renal impairment
Adverse effets of HTN on preg
—decr perfusion of the placenta —incr r/o pre-eclampsia —prematurity —intrauterine growth retardation **Proportional to degree of HTN
DDx of HTN in pregnancy
- pre-existing HTN
- pregnancy-induced HTN (newly dx’d htn in preg not assoc’d w/ pre-eclampsia)
- pre-eclampsia
Pre-existing HTN and preg
—the better the BP ctrl the better the preg outcome (goal = < 120/80)
—mild HTN often resolves in women w/ nl GFR
—mod or severe HTN, though, usually worsens (Esp w/ kidney dz)
Preg-assoc’d HTN
—HTN occuring for first time in preg usu in 1st or 2nd tri
—most remain w/ HTN post-partum or will become so later in life
—suggests underling renal dz
—as above, good ctrl incr outcomes
Pre-eclampsia —Etiology —How common? —Presentation —Dx?
"Toxemia" of pregnancy —thrombotic microangiopathy d/o similar to HUS/TTP —4-7% nl pregnancies PRESENTATION usu only presents hours-days before delivery (but often early if pre-existing CKD or HTN) —HTN + rapid edema (almost always) —proteinuria usually —AKI —Encephalopathy (h/a, hyperflexia, szs) —placentla dysfxn -> fetal distress
Can occur w/ HELLP Syndrome —Hemolysis —Elevated... —...Liver zymes —Low... —...Platelets
DX
—proteinuria?
—low platelets
—high serum uric acid (assoc’d w/ Na+ reabs, but not specific or sensitive)
Pathogenesis of Pre-Eclampsia and possibilities for better testing.
end result: procoagulant and vasoconstricting pattern
—VEGF is seemingly important to endothelial functioning
—VEGF is inactivated by a surge of sFLT1 (a soluble version of FLT1, a receptor of VEGF)
—May be able to test sFLT1 levels soon?
Treatment of pre-eclampsia
Admit! Give IV fluids and AVOID diuretics —women are actually HYPOprofusing b/c of microthrombi/constriction —IV fluids might actually lower BP IV Mag sulfate for sz mgmt Deliver (the placenta) ASAP
Managing non-preeclamptic HTN in pregnancy
Avoid diuretics
—you want volume expansion
—pt might have as-of-yet silent pre-eclampsia
—especially ACEIs/ARBs → teratogenic
Med of choice for pregnancy HTN
α-Methyl-Dopa
—Metabolite stimulates α2-adrenergic receptors →
decr symp tone
Pregnancy in kidney transplant
—actually lower risk of rejection during pregnancy (“immunologic privilege”), but will INCREASE 3-6 months post partum
—advise women to wait 1+ yr s/p transplant
—stop azathioprine
Pregnancy in women on dialysis
Is possible
—10-50% successful outcome
—keep good nutrition, Hb up, increase dialysis to 5-6X/wk
