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Renal Disease in Pregnancy

It is important to remember some basic physiologic and anatomic changes that occur during pregnancy because it does affect our management. Basically, kidney weight is significantly increased in pregnancy and you will see ureteral and caliceal dilatation usually right will be greater than left. This really needs to the physiologic hydronephrosis in pregnancy, so it can be hard on a renal ultrasound to tell what is significant in terms of hydronephrosis and what isnít.

We are going to talk primarily about urinary tract infections, renal calculi, chronic renal disease and I will spend some time talking about hemodialysis and renal transplant. A very common problem is asymptomatic bacteria, and usually that is greater than 100,000 colonies on a clean catch, but if you send a cath urine, you should realize greater than 100 colonies per ml is significant, you shouldnít have anything growing out on a cath urinalysis, if it was obtained properly.

In terms of treatment, in the third trimester, itís recommended that you avoid sulfonamides and nitrofurantoin but I have used nitrofurantoin a lot, very few G6PD deficient, I donít think I have seen a G6PD deficient neonate, but if you happen to have somebody of Mediterranean descent, this could be possible. How long to treat is a little bit open to question, you certainly can do a three day treatment but if you look at the 97 medical letter, they had a very nice summary of all the studies of three day UTI treatments with a different drug and there is up to a 40% relapse rate, and if you use one day treatment with fosfomycin.

Whether or not you start with a cephalosporin or broader spectrum aminoglycoside, kind of depends on what you ID is in your hospital and how many patientís come in with ampicillin resistant UTIs, itís about 10% at ours, because most patientís will continue spiking for about 72 hours and itís hard to really tell whether your therapy is working, I usually wonít start with ampicillin. You need two weeks followup of outpatient therapy and followup urine cultures, and antimicrobial suppression if they have had more than one UTI or if you get an ultrasound and you see a renal anomaly, I certainly wouldnít wait for two.

In terms of imaging techniques, ultrasound is certainly the safest, MRI may be helpful, or sometimes you will need to do a limited IVP in somewhat who has persistent evidence of renal calculi because ultrasound in at least two studies has been shown to miss the stone 50% of the time, so if your ultrasound is normal, it does not mean they donít have a stone. Ití helpful if itís positive. Medical treatment includes hydration and analgesia, also antibiotic therapy if you think they have an infection as well.

Letís talk a little bit about chronic renal disease, and when you talk about that, you can divide things into either primary renal diseases which are either glomerular, or nonglomerular, and systemic diseases that affect renal function such as diabetic nephropathy, lupus nephropathy, and systemic sclerosis. As a general rule, the best outcome.

An interdisciplinary approach is important to a certain extent I think, although if you have the patient with new onset renal disease during the pregnancy, my impression is that nephrology is really not very helpful, usually I will get a note from them like rule out preeclampsia and they will never biopsy the patient whatsoever if they are pregnant.

You do want to frequently assess their renal function . If their serum creatinine is greater than 3 to 4, thatís the group you are going to start dialysis earlier in these patientís, and again, you want to follow the fetus carefully with ultrasound, Dopplers and NSTs.

Itís very tough to tell with deteriorating renal function or worsening hypertension, do they have deteriorating renal disease, maybe you can treat medically or is this superimposed preeclampsia and you need to deliver the patient, if it happens in a term patient itís not a problem, you will get them delivered, but if they are very preterm it can be very difficult and there is no single lab test that will provide the answer. In some cases you might opt for a trial of therapy, if they are known lupus patients

Systemic sclerosis you probably donít see too many patientís and there are a few small case series available and this has also been generally felt to have a very poor outcome resulting in a renal crisis often in pregnancy, but again there have been other series where their disease was pretty well controlled and they had fairly good outcome, so I think it follows the general guide lines for most renal disease. The same thing probably for polyarteritis, although the case series is small and most have reported poor outcomes and have recommended pregnancy interruption.

This is a patient who was referred to UIC at 20 weeks for persistent proteinuria. This was an interesting patient.

If you look at her urine dip sticks from the referring physician, all of them had been between 2 and 4+, even beginning in the first trimester. The proteinuria had been there at the beginning of pregnancy, she had never been worked up before. She didnít have a history of hypertension, she had no known history of renal disease, diabetes, or connective tissue disease. Exam was pretty remarkable primarily for edema and her blood pressures were normal 110/70.