Review Question - QID 101021

Hematuria and immunofluorescence findings of IgA deposits in the mesangium suggest Berger’s disease (IgA glomerulonephropathy). Berger’s disease can occur concurrently or within several days of an infection.

Berger's disease is the most common worldwide nephropathy. It presents following immune system activation due to upper respiratory infection or gastroenteritis. Granular IgA deposits in the glomerular mesangium are diagnostic. Importantly, Berger’s disease can occur concurrently or within a few days of infection, while poststreptococcal glomerulonephritis presents weeks after infection.

Suzuki et al. discuss the pathophysiology of IgA nephropathy. Patients with IgA nephropathy often have a genetically determined increase in a particular form of circulating IgA. Synthesis and binding of antibodies to this form of IgA prompts formation of immune complexes that accumulate within glomeruli. Immune complexes induce proliferation and secretion of extracellular matrix, cytokines, and chemokines, which cause renal injury.

Kodner reviews the diagnosis and management of nephrotic syndrome. Unlike the nephritic syndrome, patients with nephrotic syndrome present with marked edema, proteinuria, hypoalbuminemia, and hyperlipidemia. Diabetes mellitus is the most common secondary cause (seen predominantly in adults), whereas minimal change disease is the most common cause in children.

Illustration A demonstrates immunostaining of IgA in the glomerulus of a patient with nephritic syndrome.

Incorrect Answers:
Answer 1: Lipoid nephrosis, or minimal change syndrome, is the most common cause of nephrotic syndrome in young children. IgA is not present in glomeruli.
Answer 3: Post-streptococcal glomerulonephritis classically occurs in children weeks, not days, after an infection with group A hemolytic streptococci. Immunofluorescence shows C3 and IgG, but not IgA.
Answer 4: Systemic lupus erythematosus commonly causes a diffuse proliferative glomerulonephritis. IgA is not present in glomeruli.
Answer 5: HIV infection is associated with focal segmental glomerulosclerosis, a cause of nephrotic syndrome in adults with refractory hypertension. IgA is not present in glomeruli.