Excessive urinary tract dilatation and proteinuria in pregnancy: a common and overlooked association?

A ten-year, single institution experience with percutaneous nephrostomy during pregnancy

PURPOSE

To evaluate the safety and efficacy of percutaneous nephrostomy (PCN) in pregnancy.

MATERIALS AND METHODS

PCN tubes were placed during 52 pregnancies in 49 patients from 2008 to 2018. The medical records during pregnancies were retrospectively reviewed for imaging findings, procedural parameters, outcomes of delivery, and complications.

RESULTS

The mean gestational age on percutaneous nephrostomy placement was 27 weeks (range, 8-36 weeks). PCN catheters were placed for the following indications: 1) flank or lower abdominal pain (42%), 2) obstructing calculi (37%), 3) pyelonephritis (20%), and 4) obstructing endometrioma (2%). Prior to PCN, retrograde ureteric stenting was performed in 17 of 49 patients (34%) and attempted but failed in 4 patients (8%). Nephrostomy drainage relieved pain completely or significantly in all 12 patients without prior ureteral stenting, but in only 4 of 10 with retrograde ureteric stents. In one patient in whom the ureteral stent had been removed, PCN relieved her flank pain. The mean number of PCN catheter exchanges was 1.6, ranging from 0 to 9, with a mean time interval of 21.3 days between exchanges. There were 29 difficult exchanges due to encrustation in 15 patients with a mean of 20.5 days between exchanges.

CONCLUSIONS

PCN drainage is a safe and effective treatment for managing symptomatic hydronephrosis in pregnant patients but is less effective in treating pain when retrograde ureteral stents are in place. Rapid encrustation, seen more commonly in pregnancy, tends to recur in the same patients and requires more frequent exchanges than the general population.

A best practice position statement on pregnancy in chronic kidney disease: the Italian Study Group on Kidney and Pregnancy

Pregnancy is increasingly undertaken in patients with chronic kidney disease (CKD) and, conversely, CKD is increasingly diagnosed in pregnancy: up to 3 % of pregnancies are estimated to be complicated by CKD. The heterogeneity of CKD (accounting for stage, hypertension and proteinuria) and the rarity of several kidney diseases make risk assessment difficult and therapeutic strategies are often based upon scattered experiences and small series. In this setting, the aim of this position statement of the Kidney and Pregnancy Study Group of the Italian Society of Nephrology is to review the literature, and discuss the experience in the clinical management of CKD in pregnancy. CKD is associated with an increased risk for adverse pregnancy-related outcomes since its early stage, also in the absence of hypertension and proteinuria, thus supporting the need for a multidisciplinary follow-up in all CKD patients. CKD stage, hypertension and proteinuria are interrelated, but they are also independent risk factors for adverse pregnancy-related outcomes. Among the different kidney diseases, patients with glomerulonephritis and immunologic diseases are at higher risk of developing or increasing proteinuria and hypertension, a picture often difficult to differentiate from preeclampsia. The risk is higher in active immunologic diseases, and in those cases that are detected or flare up during pregnancy. Referral to tertiary care centres for multidisciplinary follow-up and tailored approaches are warranted. The risk of maternal death is, almost exclusively, reported in systemic lupus erythematosus and vasculitis, which share with diabetic nephropathy an increased risk for perinatal death of the babies. Conversely, patients with kidney malformation, autosomal-dominant polycystic kidney disease, stone disease, and previous upper urinary tract infections are at higher risk for urinary tract infections, in turn associated with prematurity. No risk for malformations other than those related to familiar urinary tract malformations is reported in CKD patients, with the possible exception of diabetic nephropathy. Risks of worsening of the renal function are differently reported, but are higher in advanced CKD. Strict follow-up is needed, also to identify the best balance between maternal and foetal risks. The need for further multicentre studies is underlined.

Preeclampsia from a renal point of view: Insides into disease models, biomarkers and therapy

Proteinuria is a frequently detected symptom, found in 20% of pregnancies. A common reason for proteinuria in pregnancy is preeclampsia. To diagnose preeclampsia clinically and to get new insights into the pathophysiology of the disease it is at first essential to be familiar with conditions in normal pregnancy. Animal models and biomarkers can help to learn more about disease conditions and to find new treatment strategies. In this article we review the changes in kidney function during normal pregnancy and the differential diagnosis of proteinuria in pregnancy. We summarize different pathophysiological theories of preeclampsia with a special focus on the renal facets of the disease. We describe the current animal models and give a broad overview of different biomarkers that were reported to predict preeclampsia or have a prognostic value in preeclampsia cases. We end with a summary of treatment options for preeclampsia related symptoms including the use of plasmapheresis as a rescue therapy for so far refractory preeclampsia. Most of these novel biomarkers for preeclampsia are not yet implemented in clinical use. Therefore, we recommend using proteinuria (measured by UPC ratio) as a screening parameter for preeclampsia. Delivery is the only curative treatment for preeclampsia. In early preeclampsia the primary therapy goal is to prolong pregnancy until a state were the child has an acceptable chance of survival after delivery.