Dr Tracy Li1,3, Dr Monica Morgan1, Dr Jun Mai1,3,4, Dr Beata Zahorowska1,3,4, A/Prof Renuka Shanmugalingam1,3,4, Dr Kasim Ismail2, Prof Stephen Timothy Spicer1,3,4
1Department of Nephrology, Bankstown Hospital, Sydney, Australia, 2Department of Anatomical Pathology, Liverpool Hospital, Sydney, Australia, 3South Western Sydney Clinical School, University of New South Wales, Sydney, Australia, 4Western Sydney Clinical School, University of Western Sydney, Sydney, Australia
Biography:
Dr Tracy Li is a Nephrology Advanced Trainee in the Central Southwest Network and has been mostly based at Liverpool and Royal Prince Alfred Hospital. Her interests include general nephrology, hypertension and glomerulonephritis.
Background:
IgA nephropathy with minimal change variant is a rare clinical entity with distinct clinicopathological features of a dual glomerulopathy. Severe hypoalbuminemia without nephrotic-range proteinuria is an atypical finding which may occur early in the disease. Proposed mechanisms include episodic protein loss from increased glomerular permeability, albumin redistribution in interstitial spaces or concurrent systemic inflammation lowering serum albumin without overt nephrotic-range proteinuria.
Case Report:
A 21-year-old male presented with two weeks of abdominal pain, bloating, nausea and vomiting following recent fasting for Ramadan. He was incidentally found to have severe hypoalbuminemia (6g/L) with disproportionate sub-nephrotic proteinuria of 2.2g/day (urine ACR 141.5mg/mmol, urine PCR 173.6mg/mmol) with minimal peripheral oedema. He was normotensive, had microscopic haematuria and preserved renal function (creatinine 72umol/L, eGFR > 90ml/min). Interestingly, he had hypercholesterolemia (total cholesterol 10.9mmol), elevated IgA (3.76g/L) with low IgG (2.87g/L). Gastroscopy demonstrated duodenitis, but biopsies were unremarkable with no evidence of coeliac disease or enteropathy.
Within 1 week, he was re-admitted for worsening abdominal bloating, 10kg weight gain, ascites and peripheral oedema. Albumin dropped further to 4g/L with 11g/day of proteinuria. Renal biopsy demonstrated mild mesangial thickening with strong mesangial IgA staining on immunofluorescence and widespread podocyte effacement on electron microscopy.
Following treatment with prednisone 70mg daily and rituximab 1g, his albumin improved to 27g/L in one week and normalized to 41 g/L by two weeks. Urine studies showed resolved microhaematuria and proteinuria (ACR 0.2 mg/mmol, PCR 4.1 mg/mmol). He remains in remission on maintenance prednisone.
Conclusions:
The overlapping features of IgA and minimal change disease can make diagnosis difficult. Recognizing this rare variant is essential, as treatment primarily involves pharmacotherapy directed towards minimal change disease.