What is IGA nephropathy?

Patient's question:

Problem Description: What is IgA Nephropathy

Doctor's answer:

Also known as Berger's disease, it is a special type of glomerulonephritis that primarily affects children and young adults. It is often preceded by an upper respiratory infection. The pathological features are characterized by mesangial hyperplasia, and immunofluorescence can reveal IgA deposition in the mesangial area.
Pathological changes: The severity of the disease varies greatly. In the early stages, the lesions are mild and focal, with only a few glomeruli showing mild mesangial widening and segmental hyperplasia. Focal hyperplastic changes can progress to focal sclerosis. Some cases are more pronounced, with diffuse mesangial hyperplasia and occasional crescent formation. The most prominent feature is the presence of IgA deposition in the mesangial area, accompanied by reduced levels of C3, IgG, and IgM, as demonstrated by immunofluorescence. Electron microscopy confirms the deposition of electron-dense material in the mesangial area.
Clinical-pathological correlation: The main symptoms are recurrent microscopic or gross hematuria, which may be accompanied by mild proteinuria. A small number of patients develop nephrotic syndrome. IgA nephropathy typically follows a chronic, progressive course, with about half of the patients experiencing gradual disease progression and developing chronic renal insufficiency. IgA nephropathy is a group of chronic glomerulonephritides with similar immunopathological features caused by multiple etiologies. Clinically, approximately 40%–45% of patients present with gross or microscopic hematuria, 35%–40% present with microscopic hematuria accompanied by proteinuria, and the remaining patients develop nephrotic syndrome and renal failure.
IgA nephropathy is a common glomerulonephritis worldwide. The prevalence of IgA nephropathy varies significantly across different continents, countries, or regions within a country. For example, in Asia, the incidence of IgA nephropathy accounts for 50% of primary glomerulonephritides in Japan and Singapore, whereas in the low-prevalence areas of Native Americans in the western United States, it accounts for only 2%. Generally, the incidence is higher in whites and East Asians than in blacks. In China, the incidence of IgA nephropathy accounts for 26%–34% of primary glomerulonephritides, with a male-to-female ratio of approximately 2:1. Currently, there is no specific treatment for IgA nephropathy that primarily manifests as hematuria. Due to the wide variability in pathological types and the extent of glomerular damage in IgA nephropathy, patients should be closely monitored for the frequency of gross hematuria recurrence, the severity of proteinuria, the presence of hypertension, and the degree of renal function impairment, with appropriate preventive and therapeutic measures implemented accordingly.
From the above, it can be seen that IgA nephropathy is not malignant. Factors associated with the prognosis of IgA nephropathy:
(1) Male patients and those with a later onset age have a poorer prognosis.
(2) Persistent microscopic hematuria accompanied by proteinuria indicates a poor prognosis.
(3) Moderate to severe proteinuria often suggests progression to renal insufficiency, with a poor prognosis. However, patients with IgA nephropathy who present with nephrotic syndrome and mild renal tissue pathological changes and respond well to glucocorticoid therapy have a good prognosis.
(4) Hypertension in IgA nephropathy patients, especially uncontrolled severe hypertension, indicates a poor prognosis.
(5) The impact of pregnancy on IgA nephropathy patients: Pregnancy is generally safe for IgA nephropathy patients without hypertension or renal impairment.