A 4-year-old child presents to the emergence department with fever, malaise, purpura, arthritis and abdominal pain. Among the investigations performed, there is evidence of microscopic hematuria. Most likely cause for these symptoms:
**Core Concept**
The child's presentation with fever, malaise, purpura, arthritis, abdominal pain, and microscopic hematuria suggests a systemic vasculitis, specifically a condition that affects small blood vessels. This condition is characterized by inflammation of the blood vessels, leading to damage and leakage of blood into surrounding tissues, resulting in the observed symptoms.
**Why the Correct Answer is Right**
The most likely cause of these symptoms is Henoch-Schönlein Purpura (HSP), a form of IgA vasculitis. HSP is an immune complex-mediated condition, where IgA antibodies deposit in the walls of small blood vessels, triggering an inflammatory response. The deposition of IgA immune complexes in the kidneys leads to glomerulonephritis, which can cause hematuria. The involvement of small blood vessels in various organs, such as joints, skin, and gastrointestinal tract, results in the characteristic symptoms of HSP.
**Why Each Wrong Option is Incorrect**
**Option A:** While Kawasaki disease is a systemic vasculitis that can cause fever, rash, and lymphadenopathy, it is more common in children under 5 years and is characterized by coronary artery aneurysms, which are not mentioned in the scenario.
**Option B:** Systemic Lupus Erythematosus (SLE) is a systemic autoimmune disease that can cause vasculitis, but it is more common in adults and typically presents with a wide range of symptoms, including mucocutaneous manifestations, serositis, and nephritis.
**Option C:** Polyarteritis nodosa (PAN) is a form of vasculitis that affects medium-sized arteries, but it is less common in children and typically presents with hypertension, renal failure, and gastrointestinal symptoms.
**Clinical Pearl / High-Yield Fact**
HSP is often associated with preceding upper respiratory tract infections, and the diagnosis is typically made based on the presence of skin purpura, abdominal pain, and renal involvement.
**Correct Answer: C. Polyarteritis nodosa (PAN) is a form of vasculitis that affects medium-sized arteries, but it is less common in children and typically presents with hypertension, renal failure, and gastrointestinal symptoms.**