Hemorrhagic vasculitis

Etiology and pathogenesis

Hemorrhagic vasculitis belongs to juvenile forms of vasculitis. Viral infections (especially cytomegalovirus and hepatitis C viruses) as well as drug intolerance most often act as triggers for onset or exacerbation.

The pathogenesis is based on two components: immune disorders and hemostatic system pathology.

• Immune conflict. Inflammation affects vessels of various calibers, but areas with turbulent blood flow (ostia, curves, bifurcations) are particularly vulnerable. Activation of cellular immunity causes a cytokine imbalance leading to endothelial dysfunction. Circulating immune complexes (CIC) and autoantibodies against endothelial cells are formed in the blood.
• Hemostatic shifts. Vascular damage triggers intravascular hypercoagulation. Along with inflammation, this disrupts local hemodynamics and leads to tissue ischemia.

Clinical presentation

The disease debuts acutely, with severe intoxication syndrome (malaise, fever ranging from subfebrile to febrile levels). The course can be isolated (simple form) or mixed. Several key syndromes are distinguished:

1. Cutaneous syndrome. The hallmark of the disease. It is characterized by a symmetrical small-spotted or maculopapular hemorrhagic rash (palpable purpura). The elements do not fade upon pressure and appear in waves. Favorite localization includes the lower extremities (shins, feet), buttocks, and areas around large joints. In severe cases, necrosis occurs in the center of the rash, accompanied by angioedema. The outcome of the rash is hyperpigmentation and desquamation (peeling).
2. Abdominal syndrome. Associated with hemorrhages into the intestinal wall, mesentery, or peritoneum. It manifests as cramping abdominal pain, dyspepsia (nausea, vomiting), and signs of gastrointestinal bleeding (blood in stool). It can manifest immediately or in a delayed manner — against the background of new waves of rash.
3. Renal syndrome. Varies from a mild course (transient microhematuria and trace proteinuria) to the development of glomerulonephritis (GN). Most often, GN presents as a hematuric type, less frequently as nephrotic or mixed (but always with a predominance of hematuria).

Diagnostics

The diagnosis is based on pediatric classification criteria:

• Major criterion (mandatory): allergic purpura or petechiae predominantly affecting the lower extremities.
• Minor criteria (at least one required): abdominal pain, joint syndrome (arthralgia or arthritis), signs of renal involvement.

Laboratory shifts:

• CBC: moderate leukocytosis, elevated ESR (inflammatory markers).
• Immunology: elevated CIC levels (especially with renal involvement) and a specific marker — IgA. Cryoglobulins are rarely detected.
• Coagulogram: signs of intravascular coagulation (high levels of fibrin/fibrinogen degradation products [FDP]).

Differential diagnosis is carried out with systemic lupus erythematosus (SLE), Crohn's disease, chronic hepatitis, and malignancies.

Principles of step-by-step therapy

All children in the active phase are prescribed strict bed rest, reduced physical activity, and a hypoallergenic diet (exclusion of obligate allergens). Antibiotics are prescribed only when an infectious trigger is proven.

Medical tactics depend on the severity of the course and the presence of nephritis:

• Mild course. The basis of therapy is antiplatelet agents (dipyridamole 5–7 mg/kg/day, pentoxifylline 5–10 mg/kg/day, or ticlopidine 250 mg). Taken 2–3 times a day.
• Moderate and severe forms. Anticoagulants (heparin) are used. The starting dose is 150–300 IU/kg/day. The course of treatment varies from 10–14 days (for isolated cutaneous purpura) to 1–1.5 months (upon development of GN).
• Glucocorticoids (GC). Prednisolone is not used routinely. Indications: persistent wave-like rash, severe abdominal syndrome, glomerulonephritis. Doses: 1.0–1.5 mg/kg/day for 6–21 days (without renal involvement) or 2 mg/kg/day for 4–6 weeks with gradual tapering (for GN).
• Cytostatics. Cyclophosphamide in combination with GC is used exclusively for high glomerulonephritis activity.

Class and exam questions

What else to study on this topic

• Mechanisms of circulating immune complex (CIC) formation
• Differential diagnosis with systemic lupus erythematosus (SLE)
• Heparin dose escalation scheme in severe cases
• Features of the development of nephrotic and mixed forms of glomerulonephritis
• Sanation of chronic infection foci as a stage of complex therapy

Other topics of «Chapter 9. Rheumatic Diseases»

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.