Glomerular Disease Quiz

See IgA Nephropathy. Option A is correct: Berger disease (IgA nephropathy) is caused by IgA deposition in the mesangium of the glomerulus, which triggers an inflammatory response and damages the mesangium. The mesangium is the supporting tissue lying between the glomerular capillary loops. IgA (immunoglobulin A) is the antibody that protects the mucous membranes, such as those of the airways and gut, so the disease is often triggered by a mucosal infection. In a patient with an upper respiratory tract infection, over-activation of IgA can cause it to be deposited in the glomerulus. The deposits cause mesangial cell proliferation and damage, so the classic presentation is visible or invisible haematuria (blood in the urine, either seen by eye or found only on testing) one to two days after a throat infection, with or without proteinuria. Serum IgA is often raised and complement (C3 and C4, a group of immune proteins) is normal. IgA nephropathy is the most common cause of nephritic syndrome, although it can also present as nephrotic syndrome. There is no specific effective treatment, but ACE inhibitors or angiotensin receptor blockers help control proteinuria (protein in the urine) and blood pressure. Memory aid: IgA nephropathy brings IgA to the mesangium.

• Cause: deposition of IgA in the mesangium of the glomerulus, which triggers inflammation.
• Trigger: often a mucosal infection, such as an upper respiratory tract infection.
• Presentation: visible or invisible haematuria one to two days after a throat infection, with or without proteinuria.
• Tests: serum IgA is often raised and complement (C3 and C4) is normal.