Treatment of unilateral obstruction reversing heavy and bilateral proteinuria

Proteinuria is a common finding in pregnancy and usually attributable to physiological changes that concurrently reduce serum albumin by 5–10 g/l. Urinary protein loss rarely exceeds 0.4 g/day, but nephrotic levels occur in up to 0.025% of all pregnancies [1], even in the absence of features of pre-eclampsia [2] or renal impairment. Many patients with pregnancy-associated proteinuria will remit spontaneously and may be managed conservatively without renal biopsy. Non-specific glomerular lesions may be seen in association with pre-eclampsia [3]. Primary glomerular disease, diabetes and renal vein thrombosis may also produce nephrotic levels of proteinuria in pregnancy. Pre-existing renal disease predisposes subjects to develop hypertension and further accelerated renal decline in pregnancy and these may be accompanied by an increase in urinary protein [4]. We present an unusual case where nephrotic syndrome was associated with unilateral ureteric obstruction. A 29-year-old nulliparous woman of Asian origin was referred to the renal service at 26 weeks of pregnancy with proteinuria (4.5 g/24 h) and ankle swelling. At presentation she was asymptomatic and her only past medical history was of beta-thalassaemia trait. She was normotensive (110/64 mmHg), intravascular volume replete and had mild bilateral pedal oedema. The remainder of the physical examination was non-contributory. Serum creatinine (42 µmol) was normal, but the serum albumin was reduced (24 g/l). Dipstick urinalysis at booking had been normal. Serological tests for antinuclear antibody, anti-neutrophil cytoplasmic antibody, double-stranded DNA, hepatitis B and C, HIV serology and urate levels were all negative or normal. A renal ultrasound revealed the presence of gross right-sided hydronephrosis with cortical thinning, suggestive of long-standing pelvi-ureteric junction (PUJ) obstruction. Protein permselectively index was 0.21 (relatively unselective) and, thus, we felt that this was unlikely to be a due to minimal change glomerulonephritis and most likely related to her obstructed kidney [5]. She was managed conservatively. At 37 weeks’ gestation the protein leak had increased to 8.5 g/24 h, serum albumin had fallen to 17 g/l and she was becoming increasingly oedematous. A healthy baby was delivered by normal vaginal delivery after induction of labour at 37 weeks.