Henoch-Schönlein Purpura (HSP) nephritis is a kidney complication of Henoch-Schönlein Purpura. This condition involves inflammation of the kidney’s filtering units. It can impact kidney function and requires careful management.
Understanding Henoch-Schönlein Purpura (HSP)
Henoch-Schönlein Purpura (HSP) is a form of vasculitis, characterized by inflammation of small blood vessels throughout the body. The disease is often triggered by an infection, such as an upper respiratory tract infection. HSP is also known as IgA vasculitis, reflecting the involvement of immunoglobulin A (IgA) in the inflammation.
Common non-kidney manifestations of HSP include a distinctive reddish-purple skin rash (palpable purpura), typically on the lower legs and buttocks. Individuals also experience joint pain and swelling, particularly in the knees and ankles. Gastrointestinal symptoms like abdominal pain, nausea, vomiting, and sometimes bloody stools can occur.
The Kidney Connection: HSP Nephritis
HSP nephritis refers specifically to the inflammation of the glomeruli, the tiny filtering units within the kidneys. This inflammation develops as a complication of HSP, often appearing weeks to months after initial HSP symptoms. In HSP nephritis, immune complexes containing IgA are deposited in the mesangium, a part of the glomerulus, leading to inflammation and damage.
Individuals may experience proteinuria (leakage of protein into the urine) or hematuria (blood in the urine, sometimes making it dark or cola-colored). In more severe instances, kidney function can become impaired, and patients may develop high blood pressure or swelling in various body parts. Renal involvement occurs in approximately 30-50% of children with HSP. While other manifestations of HSP often resolve on their own, HSP nephritis can lead to chronic kidney disease.
Identifying and Diagnosing HSP Nephritis
Identifying HSP nephritis involves recognizing signs and symptoms, and conducting diagnostic tests. Changes in urine appearance, such as dark or foamy urine, can indicate kidney involvement. Swelling, particularly around the eyes, legs, and feet (edema), and elevated blood pressure are also suggestive signs.
Diagnosis typically begins with urine tests, such as urinalysis, to detect blood (hematuria) and protein (proteinuria). Blood tests also assess kidney function, measuring creatinine and urea. For severe kidney involvement or definitive diagnosis, a kidney biopsy may be recommended. This procedure involves taking a small tissue sample from the kidney to examine for specific immune deposits and cellular changes. Early detection through these methods is important for timely management.
Treatment Approaches for HSP Nephritis
Managing HSP nephritis involves both supportive care and specific medication tailored to the severity of kidney involvement. Supportive care measures include controlling blood pressure, managing fluid balance, and sometimes making dietary adjustments. These steps help alleviate symptoms and reduce the burden on the kidneys.
Corticosteroids, such as prednisone, are often used to reduce inflammation in the kidneys. For more severe cases, other immunosuppressant medications may be considered. These medications work by dampening the immune system’s activity to prevent further damage to the kidney filtering units. Combination therapies involving multiple drugs might be used in more complex situations.
Long-Term Outlook and Management
The long-term outlook for individuals with HSP nephritis varies; many cases resolve completely without lasting kidney problems. A small percentage of patients may experience persistent kidney issues, ranging from ongoing proteinuria to the development of chronic kidney disease. In rare instances, individuals may progress to end-stage renal disease, which requires dialysis or a kidney transplant.
Long-term follow-up care is important, even after initial recovery from HSP nephritis. This includes regular monitoring of kidney function through blood tests, periodic measurements of blood pressure, and repeated urine tests to check for the presence of protein or blood. Such ongoing surveillance helps detect any late complications or relapses, ensuring that appropriate interventions can be initiated promptly to preserve kidney health.