| disease | Purpuric Nephritis |
Allergic purpura is an immune-mediated systemic small to medium vasculitis, and the resulting kidney damage is called purpuric nephritis. Clinical manifestations include simple urinary abnormalities (hematuria being the most common) or typical acute nephritic syndrome, nephrotic syndrome, and even renal failure.
bubble_chart Diagnosis
I. Medical History and Symptoms
Most commonly seen in children, with adult patients accounting for only 5%, mostly under the age of 40. There may be a history of upper respiratory tract infection, medication use, or exposure to heterologous proteins. Symmetrically distributed hemorrhagic purpura must be present on the distal extremities, buttocks, and lower abdomen. Approximately half of the cases involve migratory joint pain. Some patients experience abdominal pain, melena, nausea, and vomiting. The hallmark of renal involvement is hematuria, which may be accompanied by varying degrees of proteinuria, edema, and hypertension. A minority of patients present with nephrotic syndrome or rapidly progressive nephritic syndrome, with a sharp decline in renal function. Clinical manifestations of renal involvement can occur at any time but frequently appear within 4–8 weeks of extrarenal symptoms.
II. Physical Examination Findings
Most patients exhibit characteristic rashes or traces of allergic purpura. Hypertension and edema (tense or pitting) may be present. A few cases may involve joint swelling, abdominal tenderness, lymphadenopathy, and hepatosplenomegaly.
III. Auxiliary Examinations
(1) Urinalysis invariably reveals varying degrees of hematuria, proteinuria, and casts.
(2) Platelet count, bleeding time, and prothrombin time are within normal ranges; early-stage eosinophilia may be observed.
(3) Immunological tests: Serum IgA may be elevated but is nonspecific; serum C3 and CH50 are mostly normal; circulating immune complexes are often elevated during the active phase.(4) Severe cases may show decreased Ccr and elevated blood urea nitrogen and creatinine. Patients presenting with nephrotic syndrome may have reduced serum albumin and increased cholesterol.
(5) Renal biopsy can confirm the pathological type of the disease and differentiate it from IgA nephropathy.
IV. Differential Diagnosis
When the rash of purpuric nephritis has subsided, it should be differentiated from acute nephritis. If accompanied by pulmonary hemorrhage or hemoptysis, it should be distinguished from Goodpasture syndrome. Clinically, it should also be differentiated from lupus nephritis and primary systemic small vessel vasculitis.
bubble_chart Treatment Measures
1. When there is a clear infection site, antibiotic treatment should be administered; discontinue consumption and exposure to allergenic foods and medications, and desensitization therapy may be considered if necessary; supplement with a large amount of vitamin C and ensure adequate rest.
2. For most transient minor abnormalities in urine tests, glucocorticoids or cytotoxic drugs are not required, and full recovery is generally expected. For patients with persistent isolated hematuria or proteinuria, normal blood pressure, and normal renal function, Root Leaf or Flower of Common Threewingnut glycosides tablets may be tried, with a double dose (2mg/kg.d) administered orally if necessary. For clinical presentations of acute nephritis, nephrotic syndrome, or rapidly progressive nephritis, refer to the treatment of primary glomerular diseases. Plasma exchange may be effective for severe renal lesions. If standard treatment yields poor results, a renal biopsy should be actively performed to tailor the treatment plan based on pathological findings.
